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Wang D, Yan K, Yu H, Li H, Zhou W, Hong Y, Guo S, Wang Y, Xu C, Pan C, Tang Y, Liu N, Wu W, Zhang L, Xi Q. Fimepinostat Impairs NF-κB and PI3K/AKT Signaling and Enhances Gemcitabine Efficacy in H3.3K27M-Diffuse Intrinsic Pontine Glioma. Cancer Res 2024; 84:598-615. [PMID: 38095539 DOI: 10.1158/0008-5472.can-23-0394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 06/26/2023] [Accepted: 12/07/2023] [Indexed: 02/16/2024]
Abstract
Diffuse intrinsic pontine glioma (DIPG) is the most aggressive pediatric brain tumor, and the oncohistone H3.3K27M mutation is associated with significantly worse clinical outcomes. Despite extensive research efforts, effective approaches for treating DIPG are lacking. Through drug screening, we identified the combination of gemcitabine and fimepinostat as a potent therapeutic intervention for H3.3K27M DIPG. H3.3K27M facilitated gemcitabine-induced apoptosis in DIPG, and gemcitabine stabilized and activated p53, including increasing chromatin accessibility for p53 at apoptosis-related loci. Gemcitabine simultaneously induced a prosurvival program in DIPG through activation of RELB-mediated NF-κB signaling. Specifically, gemcitabine induced the transcription of long terminal repeat elements, activated cGAS-STING signaling, and stimulated noncanonical NF-κB signaling. A drug screen in gemcitabine-treated DIPG cells revealed that fimepinostat, a dual inhibitor of HDAC and PI3K, effectively suppressed the gemcitabine-induced NF-κB signaling in addition to blocking PI3K/AKT activation. Combination therapy comprising gemcitabine and fimepinostat elicited synergistic antitumor effects in vitro and in orthotopic H3.3K27M DIPG xenograft models. Collectively, p53 activation using gemcitabine and suppression of RELB-mediated NF-κB activation and PI3K/AKT signaling using fimepinostat is a potential therapeutic strategy for treating H3.3K27M DIPG. SIGNIFICANCE Gemcitabine activates p53 and induces apoptosis to elicit antitumor effects in H3.3K27M DIPG, which can be enhanced by blocking NF-κB and PI3K/AKT signaling with fimepinostat, providing a synergistic combination therapy for DIPG.
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Affiliation(s)
- Dan Wang
- MOE Key Laboratory of Protein Sciences, State Key Laboratory of Molecular Oncology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Kun Yan
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Hongxing Yu
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Haocheng Li
- MOE Key Laboratory of Protein Sciences, State Key Laboratory of Molecular Oncology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Wei Zhou
- MOE Key Laboratory of Protein Sciences, State Key Laboratory of Molecular Oncology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yaqiang Hong
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Shuning Guo
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yi Wang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Cheng Xu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Changcun Pan
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yujie Tang
- Key Laboratory of Cell Differentiation and Apoptosis of National Ministry of Education, Shanghai Key Laboratory of Reproductive Medicine, Department of Histoembryology, Genetics and Developmental Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Nian Liu
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Wei Wu
- MOE Key Laboratory of Protein Sciences, State Key Laboratory of Molecular Oncology, School of Life Sciences, Tsinghua University, Beijing, China
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Liwei Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- China National Clinical Research Center for Neurological Diseases, Beijing, China
- Beijing Key Laboratory of Brain Tumor, Beijing, China
| | - Qiaoran Xi
- MOE Key Laboratory of Protein Sciences, State Key Laboratory of Molecular Oncology, School of Life Sciences, Tsinghua University, Beijing, China
- Joint Graduate Program of Peking-Tsinghua-NIBS, Tsinghua University, Beijing, China
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Friedman SN, Itani M, Dehdashti F. PET Imaging for Gynecologic Malignancies. Radiol Clin North Am 2021; 59:813-833. [PMID: 34392921 DOI: 10.1016/j.rcl.2021.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
This review article summarizes the clinical applications of established and emerging PET tracers in the evaluation of the 5 most common gynecologic malignancies: endometrial, ovarian, cervical, vaginal, and vulvar cancers. Emphasis is given to 2-deoxy-2-[18F]fluoro-d-glucose as the most widely used and studied tracer, with additional clinical tracers also explored. The common imaging protocols are discussed, including standard dose ranges and uptake times, established roles, as well as the challenges and future directions of these imaging techniques. The key points are emphasized with images from selected cases.
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Affiliation(s)
- Saul N Friedman
- Division of Nuclear Medicine, Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Boulevard, St Louis, MO 63110, USA
| | - Malak Itani
- Section of Abdominal Imaging, Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Boulevard, St Louis, MO 63110, USA
| | - Farrokh Dehdashti
- Division of Nuclear Medicine, Edward Mallinckrodt Institute of Radiology, Alvin J. Siteman Cancer Center, Washington University School of Medicine, 510 South Kingshighway Boulevard, St Louis, MO 63110, USA.
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Alwadani B, Dall'Angelo S, Fleming IN. Clinical value of 3'-deoxy-3'-[ 18F]fluorothymidine-positron emission tomography for diagnosis, staging and assessing therapy response in lung cancer. Insights Imaging 2021; 12:90. [PMID: 34213667 PMCID: PMC8253862 DOI: 10.1186/s13244-021-01026-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 06/02/2021] [Indexed: 12/09/2022] Open
Abstract
Lung cancer has the highest mortality rate of any tumour type. The main driver of lung tumour growth and development is uncontrolled cellular proliferation. Poor patient outcomes are partly the result of the limited range of effective anti-cancer therapies available and partly due to the limited accuracy of biomarkers to report on cell proliferation rates in patients. Accordingly, accurate methods of diagnosing, staging and assessing response to therapy are crucial to improve patient outcomes. One effective way of assessing cell proliferation is to employ non-invasive evaluation using 3'-deoxy-3'-[18F]fluorothymidine ([18F]FLT) positron emission tomography [18F]FLT-PET. [18F]FLT, unlike the most commonly used PET tracer [18F]fluorodeoxyglucose ([18F]FDG), can specifically report on cell proliferation and does not accumulate in inflammatory cells. Therefore, this radiotracer could exhibit higher specificity in diagnosis and staging, along with more accurate monitoring of therapy response at early stages in the treatment cycle. This review summarises and evaluates published studies on the clinical use of [18F]FLT to diagnose, stage and assess response to therapy in lung cancer.
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Affiliation(s)
- Bandar Alwadani
- Diagnostic Radiology Department, College of Applied Medical Sciences, Jazan University, Al Maarefah Rd, POB 114, Jazan, 45142, Saudi Arabia.,Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD, UK
| | - Sergio Dall'Angelo
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD, UK
| | - Ian N Fleming
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD, UK.
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Hotta M, Minamimoto R, Toyohara J, Nohara K, Nakajima K, Takase K, Yamada K. Efficacy of cell proliferation imaging with 4DST PET/CT for predicting the prognosis of patients with esophageal cancer: a comparison study with FDG PET/CT. Eur J Nucl Med Mol Imaging 2021; 48:2615-2623. [PMID: 33438100 DOI: 10.1007/s00259-020-05179-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 12/26/2020] [Indexed: 12/24/2022]
Abstract
PURPOSE 4'-[Methyl-11C] thiothymidine (4DST) incorporates into DNA directly and is a PET tracer used for cell proliferation imaging. The aim of this study was to evaluate the prediction of prognosis with pretreatment 4DST PET/CT compared to fluorodeoxyglucose (FDG) PET/CT in patients with esophageal cancer. METHODS In this prospective study, we analyzed 46 patients (68.2 ± 10.0 years old) with pathologically proven esophageal squamous cell cancer who underwent pretreatment 4DST and FDG PET/CT. The maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and total lesion proliferation (TLP) were measured for FDG and 4DST PET. The study endpoints were progression-free survival (PFS) and overall survival (OS). Patients' clinical backgrounds, including age, histological type, clinical stage, and surgical treatment, were adjusted using the Cox proportional-hazards model. RESULTS In the follow-up period (median 18.8 (interquartile range: 10.1-29.0) months), 26 and 19 patients showed disease progression and cancer-related death, respectively. After adjusting for clinical variables, only the 4DST parameters (SUVmax (p = 0.001) and TLP (p = 0.022)) were statistically significant for predicting PFS. FDG MTV (p = 0.031), 4DST SUVmax (p = 0.022), and TLP (p = 0.023) were statistically significant for predicting OS. Of the PET parameters, 4DST SUVmax yielded the highest adjusted hazard ratio for both PFS (4.88, 95% confidence intervals (CI): 1.83-12.97) and OS (4.19, 95% CI: 1.23-14.20). CONCLUSION Higher accumulation of 4DST in the primary tumor may lead to shorter OS and PFS. 4DST PET/CT is useful for predicting prognosis and may outperform FDG PET/CT.
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Affiliation(s)
- Masatoshi Hotta
- Department of Nuclear Medicine, National Center for Global Health and Medicine, 1-21-1, Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan.
- Department of Diagnostic Radiology, Tohoku University Hospital, 1-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8574, Japan.
| | - Ryogo Minamimoto
- Department of Nuclear Medicine, National Center for Global Health and Medicine, 1-21-1, Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan
| | - Jun Toyohara
- Functional Brain Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2, Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Kyoko Nohara
- Department of Surgery, National Center for Global Health and Medicine, 1-21-1, Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan
| | - Kazuhiko Nakajima
- Department of Nuclear Medicine, National Center for Global Health and Medicine, 1-21-1, Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan
| | - Kei Takase
- Department of Diagnostic Radiology, Tohoku University Hospital, 1-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8574, Japan
| | - Kazuhiko Yamada
- Department of Surgery, National Center for Global Health and Medicine, 1-21-1, Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan
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Wong AAWL, Lozada J, Lepage ML, Zhang C, Merkens H, Zeisler J, Lin KS, Bénard F, Perrin DM. Synthesis and 18F-radiolabeling of thymidine AMBF 3 conjugates. RSC Med Chem 2020; 11:569-576. [PMID: 33479658 PMCID: PMC7578706 DOI: 10.1039/d0md00054j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 04/09/2020] [Indexed: 01/08/2023] Open
Abstract
In pursuit of 18F-labeled nucleosides for positron emission tomography (PET) imaging, we report on the chemical and radiochemical synthesis of two thymidine (dT) analogs, dT-C5-AMBF3 and dT-N3-AMBF3, that are radiofluorinated by isotope exchange (IEX) and studied as PET imaging agents in mice with tumor xenografts. dT-C5-AMBF3 shows preferential, and tumor-specific, uptake over dT-N3-AMBF3. This work provides a new synthetic method in order to access new nucleoside tracers for PET imaging.
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Affiliation(s)
- Antonio A W L Wong
- Department of Chemistry , University of British Columbia (UBC) , 2036 Main Mall , Vancouver , BC , V6T 1Z1 Canada .
| | - Jerome Lozada
- Department of Chemistry , University of British Columbia (UBC) , 2036 Main Mall , Vancouver , BC , V6T 1Z1 Canada .
| | - Mathieu L Lepage
- Department of Chemistry , University of British Columbia (UBC) , 2036 Main Mall , Vancouver , BC , V6T 1Z1 Canada .
| | - Chengcheng Zhang
- Department of Molecular Oncology , B.C. Cancer Research Centre (BCCRC) , 675 West 10th Avenue , Vancouver , BC , V5Z 1L3 Canada
| | - Helen Merkens
- Department of Molecular Oncology , B.C. Cancer Research Centre (BCCRC) , 675 West 10th Avenue , Vancouver , BC , V5Z 1L3 Canada
| | - Jutta Zeisler
- Department of Molecular Oncology , B.C. Cancer Research Centre (BCCRC) , 675 West 10th Avenue , Vancouver , BC , V5Z 1L3 Canada
| | - Kuo-Shyan Lin
- Department of Molecular Oncology , B.C. Cancer Research Centre (BCCRC) , 675 West 10th Avenue , Vancouver , BC , V5Z 1L3 Canada
| | - François Bénard
- Department of Molecular Oncology , B.C. Cancer Research Centre (BCCRC) , 675 West 10th Avenue , Vancouver , BC , V5Z 1L3 Canada
| | - David M Perrin
- Department of Chemistry , University of British Columbia (UBC) , 2036 Main Mall , Vancouver , BC , V6T 1Z1 Canada .
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7
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Sigal IR, Sebro R. Preclinical PET tracers for the evaluation of sarcomas: understanding tumor biology. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2018; 8:428-440. [PMID: 30697463 PMCID: PMC6334210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 12/05/2018] [Indexed: 06/09/2023]
Abstract
Sarcomas are rare tumors of mesenchymal origin. Sarcomas display significant histological heterogeneity, resulting in significant imaging heterogeneity. 18F-FDG PET has is increasingly used for the evaluation, staging and surveillance of patients with sarcomas. 18F-FDG PET maximum SUV has been shown to be correlated with sarcoma grade and overall survival. This has led to interest in alternative PET tracers to assess the biological characteristics of tumors and guide treatment decisions. Here we investigate novel PET/CT tracers used for the evaluation of sarcomas over the past 20 years and summarize what we have learned about sarcoma tumor biology from these studies.
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Affiliation(s)
- Ian R Sigal
- Department of Radiology, University of Pennsylvania3400 Spruce Street, Philadelphia, PA 19104, USA
| | - Ronnie Sebro
- Department of Radiology, University of Pennsylvania3400 Spruce Street, Philadelphia, PA 19104, USA
- Department of Orthopedic Surgery, University of Pennsylvania3400 Spruce Street, Philadelphia, PA 19104, USA
- Department of Genetics, University of Pennsylvania3400 Spruce Street, Philadelphia, PA 19104, USA
- Department of Epidemiology and Biostatistics, University of Pennsylvania3400 Spruce Street, Philadelphia, PA 19104, USA
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8
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Elmi A, McDonald ES, Mankoff D. Imaging Tumor Proliferation in Breast Cancer: Current Update on Predictive Imaging Biomarkers. PET Clin 2018; 13:445-457. [PMID: 30100082 DOI: 10.1016/j.cpet.2018.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Uncontrolled growth is a hallmark of cancer; imaging cell proliferation can provides an early indicator of therapeutic response. This capability is especially well-matched to the emerging cell cycle-specific chemotherapeutics with the goal of identifying patients that benefit from these treatments early in the course of treatment to guide personalized therapy. This article focuses on investigational cell proliferation imaging PET radiotracers to evaluate tumor proliferation in the setting of cell cycle-targeted chemotherapy and endocrine therapy for metastatic breast cancer.
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Affiliation(s)
- Azadeh Elmi
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA
| | - Elizabeth S McDonald
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA
| | - David Mankoff
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA.
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9
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Dexamethasone pretreatment impairs the thymidylate synthase inhibition mediated flare in thymidine salvage pathway activity in non-small cell lung cancer. PLoS One 2018; 13:e0202384. [PMID: 30142195 PMCID: PMC6108460 DOI: 10.1371/journal.pone.0202384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 08/02/2018] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Successful inhibition of thymidylate synthase (TS) by pemetrexed, a TS inhibitor, results in a reproducible transient burst or "flare" in thymidine salvage pathway activity at 2 hrs. of therapy which can be measurable with FLT-PET ([18F]fluorothymidine-positron emission tomography) in non-small cell lung cancer (NSCLC). Routine administration of dexamethasone with pemetrexed-based therapy could potentially confound this imaging approach since dexamethasone is known to inhibit expression of thymidine kinase 1, a key enzyme in the thymidine salvage pathway. Here we examine the potential impact of dexamethasone on the TS inhibition-mediated thymidine salvage pathway "flare" in NSCLC. MATERIALS AND METHODS In order to determine NSCLC cell line sensitivity to dexamethasone and pemetrexed, IC50 studies were performed on NSCLC cell lines H23, H1975, H460, H1299. TS inhibition-mediated "flare" in thymidine salvage pathway activity was then measured at 2hrs. of exposure to pemetrexed and cisplatin in NSCLC cells lines following using 3H-thymidine incorporation assays under the following conditions: control (no chemotherapy or dexamethasone), or treated with pemetrexed and cisplatin without dexamethasone, with 24 hrs. pre-treatment of dexamethasone or with dexamethasone administered together with chemotherapy. These conditions were chosen to model the delivery of pemetrexed-based therapy in the clinic. RESULTS The IC50 of H23, H1975, H460, H1299 for dexamethasone and pemetrexed were 40, 5.9, 718, 362 μM and 0.22, 0.73, 0.14 and 0.66 μM respectively. Significant blunting of the thymidine salvage pathway "flare" is observed at 2hrs. of pemetrexed-based therapy when dexamethasone sensitive cell lines H23 and H1975 were pretreated with dexamethasone but not when dexamethasone was given together with pemetrexed therapy or in the setting of dexamethasone resistance (H460 and H1299). CONCLUSION 24 hr. pretreatment with dexamethasone, but not same day co-administration of dexamethasone with therapy, impairs the TS inhibition-mediated "flare" in thymidine salvage pathway activity in NSCLC.
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Takami Y, Yamamoto Y, Ueno M, Chiba Y, Norikane T, Hatakeyama T, Miyake K, Toyohara J, Nishiyama Y. Correlation of 4'-[methyl- 11C]-thiothymidine uptake with human equilibrative nucleoside transporter-1 and thymidine kinase-1 expressions in patients with newly diagnosed gliomas. Ann Nucl Med 2018; 32:634-641. [PMID: 30039191 DOI: 10.1007/s12149-018-1285-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 07/19/2018] [Indexed: 10/28/2022]
Abstract
OBJECTIVE We examined expressions of human equilibrative nucleoside transporter-1 (hENT1) and thymidine kinase-1 (TK1), the key enzyme in 4'-[methyl-11C]-thiothymidine (4DST) phosphorylation, to elucidate the mechanism of 4DST uptake in patients with newly diagnosed gliomas. METHODS A total of 19 patients with newly diagnosed gliomas were examined with 4DST PET. Tumor lesions were identified as areas of focally increased uptake, exceeding that of normal brain background. For semi-quantitative analysis, tumor-to-contralateral normal brain tissue (T/N) ratio was determined by dividing the maximal standardized uptake value (SUV) for tumor by that of the mean SUV for reference tissue. The expressions of hENT1, TK1 and Ki-67 in tumor specimens were examined by immunohistochemistry and compared with 4DST T/N ratio. RESULTS All but two gliomas showed focally increased 4DST uptake. All gliomas showed hENT1 staining, except one grade II glioma, which was also not visualized on 4DST PET. A significant correlation was observed between T/N ratio and hENT1 score (ρ = 0.90, p < 0.001). All gliomas showed TK1 staining, except two gliomas which were also not visualized on 4DST PET. There was a significant correlation between T/N ratio and TK1 score (ρ = 0.92, p < 0.001). There was a significant correlation between T/N ratio and Ki-67 index (ρ = 0.50, p < 0.03). CONCLUSION Results of this preliminary study indicate that expressions of hENT1 and TK1 appear to be important determinants of 4DST uptake in newly diagnosed gliomas.
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Affiliation(s)
- Yasukage Takami
- Department of Radiology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan
| | - Yuka Yamamoto
- Department of Radiology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan.
| | - Masaki Ueno
- Department of Pathology and Host Defense, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Yoichi Chiba
- Department of Pathology and Host Defense, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Takashi Norikane
- Department of Radiology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan
| | - Tetsuhiro Hatakeyama
- Department of Neurosurgery, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Keisuke Miyake
- Department of Neurosurgery, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Jun Toyohara
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Yoshihiro Nishiyama
- Department of Radiology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan
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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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12
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Ponto LLB, Walsh S, Huang J, Mundt C, Thede-Reynolds K, Leonard Watkins G, Sunderland J, Acevedo M, Donovan M. Pharmacoimaging of Blood-Brain Barrier Permeable (FDG) and Impermeable (FLT) Substrates After Intranasal (IN) Administration. AAPS JOURNAL 2017; 20:15. [PMID: 29218424 DOI: 10.1208/s12248-017-0157-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 10/21/2017] [Indexed: 01/07/2023]
Abstract
To illustrate the use of imaging to quantify the transfer of materials from the nasal cavity to other anatomical compartments, specifically, transfer to the brain using the thymidine analogue, [18F]fluorothymidine (FLT), and the glucose analogue, [18F]fluorodeoxyglucose (FDG). Anesthetized rats were administered FLT or FDG by intranasal instillation (IN) or tail-vein injection (IV). PET/CT imaging was performed for up to 60 min. Volumes-of-interest (VOIs) for the olfactory bulb (OB) and the remaining brain were created on the CT and transferred to the co-registered dynamic PET. Time-activity curves (TACs) were generated and compared. The disposition patterns were successfully visualized and quantified and differences in brain distribution patterns were observed. For FDG, the concentration was substantially higher in the OB than the brain only after IN administration. For FLT, the concentration was higher in the OB than the brain after both IN and IV and higher after IN than after IV administration at all times, whereas the concentration in the brain was higher after IN than after IV administration at early times only. Approximately 50 and 9% of the IN FDG and FLT doses, respectively, remained in the nasal cavity at 20 min post-administration. The initial phase of clearance was similar for both agents (t1/2 = 2.53 and 3.36 min) but the slow clearance phase was more rapid for FLT than FDG (t1/2 = 32.1 and 85.2 min, respectively). Pharmacoimaging techniques employing PET/CT can be successfully implemented to quantitatively investigate and compare the disposition of radiolabeled agents administered by a variety of routes.
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Affiliation(s)
- Laura L Boles Ponto
- Department of Radiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA. .,PET Imaging Center, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA.
| | - Susan Walsh
- Department of Radiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Jiangeng Huang
- College of Pharmacy, Division of Pharmaceutics and Translational Therapeutics, Iowa City, Iowa, USA.,Department of Pharmaceutics, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Christine Mundt
- Department of Radiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,PET Imaging Center, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA
| | - Katherine Thede-Reynolds
- Department of Radiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,PET Imaging Center, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA
| | - G Leonard Watkins
- Department of Radiology, Roy J. and Lucille A. Carver College of Medicine, 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
- Department of Radiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,PET Imaging Center, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, Iowa, 52242, USA
| | - Michael Acevedo
- Department of Radiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Maureen Donovan
- College of Pharmacy, Division of Pharmaceutics and Translational Therapeutics, Iowa City, Iowa, USA
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13
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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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14
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Abstract
This article provides an overview of the key considerations for the development and application of molecular imaging agents for brain tumors and the major classes of PET tracers that have been used for imaging brain tumors in humans. The mechanisms of uptake, biological implications, primary applications, and limitations of PET tracers in neuro-oncology are reviewed. The available data indicate that several of these classes of tracers, including radiolabeled amino acids, have imaging properties superior to those of (18)F-fluorodeoxyglucose, and can complement contrast-enhanced magnetic resonance imaging in the evaluation of brain tumors.
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15
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[18F]CFA as a clinically translatable probe for PET imaging of deoxycytidine kinase activity. Proc Natl Acad Sci U S A 2016; 113:4027-32. [PMID: 27035974 DOI: 10.1073/pnas.1524212113] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Deoxycytidine kinase (dCK), a rate-limiting enzyme in the cytosolic deoxyribonucleoside (dN) salvage pathway, is an important therapeutic and positron emission tomography (PET) imaging target in cancer. PET probes for dCK have been developed and are effective in mice but have suboptimal specificity and sensitivity in humans. To identify a more suitable probe for clinical dCK PET imaging, we compared the selectivity of two candidate compounds-[(18)F]Clofarabine; 2-chloro-2'-deoxy-2'-[(18)F]fluoro-9-β-d-arabinofuranosyl-adenine ([(18)F]CFA) and 2'-deoxy-2'-[(18)F]fluoro-9-β-d-arabinofuranosyl-guanine ([(18)F]F-AraG)-for dCK and deoxyguanosine kinase (dGK), a dCK-related mitochondrial enzyme. We demonstrate that, in the tracer concentration range used for PET imaging, [(18)F]CFA is primarily a substrate for dCK, with minimal cross-reactivity. In contrast, [(18)F]F-AraG is a better substrate for dGK than for dCK. [(18)F]CFA accumulation in leukemia cells correlated with dCK expression and was abrogated by treatment with a dCK inhibitor. Although [(18)F]CFA uptake was reduced by deoxycytidine (dC) competition, this inhibition required high dC concentrations present in murine, but not human, plasma. Expression of cytidine deaminase, a dC-catabolizing enzyme, in leukemia cells both in cell culture and in mice reduced the competition between dC and [(18)F]CFA, leading to increased dCK-dependent probe accumulation. First-in-human, to our knowledge, [(18)F]CFA PET/CT studies showed probe accumulation in tissues with high dCK expression: e.g., hematopoietic bone marrow and secondary lymphoid organs. The selectivity of [(18)F]CFA for dCK and its favorable biodistribution in humans justify further studies to validate [(18)F]CFA PET as a new cancer biomarker for treatment stratification and monitoring.
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16
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Peck M, Pollack HA, Friesen A, Muzi M, Shoner SC, Shankland EG, Fink JR, Armstrong JO, Link JM, Krohn KA. Applications of PET imaging with the proliferation marker [18F]-FLT. THE QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING : OFFICIAL PUBLICATION OF THE ITALIAN ASSOCIATION OF NUCLEAR MEDICINE (AIMN) [AND] THE INTERNATIONAL ASSOCIATION OF RADIOPHARMACOLOGY (IAR), [AND] SECTION OF THE SOCIETY OF... 2015; 59:95-104. [PMID: 25737423 PMCID: PMC4415691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
[18F]-3'-fluoro-3'-deoxythymidine (FLT) is a nucleoside-analog imaging agent for quantifying cellular proliferation that was first reported in 1998. It accumulates during the S-phase of the cell cycle through the action of cytosolic thymidine kinase, TK1. Since TK1 is primarily expressed in dividing cells, FLT uptake is essentially limited to dividing cells. Thus FLT is an effective measure of cell proliferation. FLT uptake has been shown to correlate with the more classic proliferation marker, the monoclonal antibody to Ki-67. Increased cellular proliferation is known to correlate with worse outcome in many cancers. However, the Ki-67 binding assay is performed on a sampled preparation, ex vivo, whereas FLT can be quantitatively measured in vivo using positron emission tomography (PET). FLT is an effective and quantitative marker of cell proliferation, and therefore a useful prognostic predictor in the setting of neoplastic disease. This review summarizes clinical studies from 2011 forward that used FLT-PET to assess tumor response to therapy. The paper focuses on our recommendations for a standardized clinical trial protocol and components of a report so multi center studies can be effectively conducted, and different studies can be compared. For example, since FLT is glucuronidated by the liver, and the metabolite is not transported into the cell, the plasma fraction of FLT can be significantly changed by treatment with particular drugs that deplete this enzyme, including some chemotherapy agents and pain medications. Therefore, the plasma level of metabolites should be measured to assure FLT uptake kinetics can be accurately calculated. This is important because the flux constant (KFLT) is a more accurate measure of proliferation and, by inference, a better discriminator of tumor recurrence than standardized uptake value (SUVFLT). This will allow FLT imaging to be a specific and clinically relevant prognostic predictor in the treatment of neoplastic disease.
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Affiliation(s)
- M Peck
- Stanford University, Stanford, CA, USA -
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17
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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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18
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Carroll V, Michel BW, Blecha J, VanBrocklin H, Keshari K, Wilson D, Chang CJ. A boronate-caged [¹⁸F]FLT probe for hydrogen peroxide detection using positron emission tomography. J Am Chem Soc 2014; 136:14742-5. [PMID: 25310369 PMCID: PMC4210116 DOI: 10.1021/ja509198w] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
![]()
Reactive oxygen species (ROS) play
important roles in the development
and progression of cancer and other diseases, motivating the development
of translatable technologies for biological ROS imaging. Here we report
Peroxy-Caged-[18F]Fluorodeoxy thymidine-1 (PC-FLT-1), an
oxidatively immolative positron emission tomography (PET) probe for
H2O2 detection. PC-FLT-1 reacts with H2O2 to generate [18F]FLT, allowing its peroxide-dependent
uptake and retention in proliferating cells. The relative uptake of
PC-FLT-1 was evaluated using H2O2-treated UOK262
renal carcinoma cells and a paraquat-induced oxidative stress cell
model, demonstrating ROS-dependent tracer accumulation. The data suggest
that PC-FLT-1 possesses promising characteristics for translatable
ROS detection and provide a general approach to PET imaging that can
be expanded to the in vivo study of other biologically
relevant analytes.
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Affiliation(s)
- Valerie Carroll
- Department of Radiology and Biomedical Imaging, University of California , San Francisco, California 94158, United States
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19
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Liu D, Chalkidou A, Landau DB, Marsden PK, Fenwick JD. Interstitial diffusion and the relationship between compartment modelling and multi-scale spatial-temporal modelling of (18)F-FLT tumour uptake dynamics. Phys Med Biol 2014; 59:5175-202. [PMID: 25138724 DOI: 10.1088/0031-9155/59/17/5175] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Tumour cell proliferation can be imaged via positron emission tomography of the radiotracer 3'-deoxy-3'-18F-fluorothymidine (18F-FLT). Conceptually, the number of proliferating cells might be expected to correlate more closely with the kinetics of 18F-FLT uptake than with uptake at a fixed time. Radiotracer uptake kinetics are standardly visualized using parametric maps of compartment model fits to time-activity-curves (TACs) of individual voxels. However the relationship between the underlying spatiotemporal accumulation of FLT and the kinetics described by compartment models has not yet been explored. In this work tumour tracer uptake is simulated using a mechanistic spatial-temporal model based on a convection-diffusion-reaction equation solved via the finite difference method. The model describes a chain of processes: the flow of FLT between the spatially heterogeneous tumour vasculature and interstitium; diffusion and convection of FLT within the interstitium; transport of FLT into cells; and intracellular phosphorylation. Using values of model parameters estimated from the biological literature, simulated FLT TACs are generated with shapes and magnitudes similar to those seen clinically. Results show that the kinetics of the spatial-temporal model can be recovered accurately by fitting a 3-tissue compartment model to FLT TACs simulated for those tumours or tumour sub-volumes that can be viewed as approximately closed, for which tracer diffusion throughout the interstitium makes only a small fractional change to the quantity of FLT they contain. For a single PET voxel of width 2.5-5 mm we show that this condition is roughly equivalent to requiring that the relative difference in tracer uptake between the voxel and its neighbours is much less than one.
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Affiliation(s)
- Dan Liu
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
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20
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Sanghera B, Wong WL, Sonoda LI, Beynon G, Makris A, Woolf D, Ardeshna K. FLT PET-CT in evaluation of treatment response. Indian J Nucl Med 2014; 29:65-73. [PMID: 24761056 PMCID: PMC3996774 DOI: 10.4103/0972-3919.130274] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
PURPOSE Review published studies to investigate the value of clinical 3-deoxy-3-(18)F-fluorothymidine (FLT) positron emission tomography (PET) in predicting response to treatment. MATERIALS AND METHODS Interrogate databases to identify suitable publications between 2007 and 2013 with a minimum of five patients. Articles within the inclusion criteria were reviewed with major findings reported leading to a descriptive analysis of FLT PET in therapy response. RESULTS Lesions investigated included glioma, head and neck, esophageal, lung, breast, gastric, renal, rectal, sarcomas, germ cell, lymphomas, leukemia, and melanoma resulting in a total of 34 studies analyzed. A variety of therapies were applied and dissimilar PET protocols were widespread making direct comparison between studies challenging. Though baseline, early and late therapy scans were popular particularly in chemotherapy regimes. Most studies investigated showed significantly reduced FLT uptake during or after therapy compared with pretreatment scans. CONCLUSION Current evidence suggests FLT PET has a positive role to play in predicting therapy response especially in brain, lung, and breast cancers where good correlation with Ki-67 is observed. However, careful attention must be placed in undertaking larger clinical trials where harmonization of scanning and analysis protocols are strictly adhered to fully assess the true potential of FLT PET in predicting response to treatment.
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Affiliation(s)
- Bal Sanghera
- Paul Strickland Scanner Centre, Mount Vernon Hospital, Northwood, England
| | - Wai Lup Wong
- Paul Strickland Scanner Centre, Mount Vernon Hospital, Northwood, England
| | - Luke I Sonoda
- Paul Strickland Scanner Centre, Mount Vernon Hospital, Northwood, England
| | - Gwen Beynon
- Paul Strickland Scanner Centre, Mount Vernon Hospital, Northwood, England
| | - Andreas Makris
- Cancer Centre, Mount Vernon Hospital, Northwood, England
| | - David Woolf
- Cancer Centre, Mount Vernon Hospital, Northwood, England
| | - Kirit Ardeshna
- Cancer Centre, Mount Vernon Hospital, Northwood, England ; Department of Haematology, University College London Cancer Institute and University College Hospital, London, England
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21
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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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22
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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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23
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Chan PC, Wu CY, Chang WT, Lin CY, Tseng YL, Liu RS, Alauddin MM, Lin WJ, Wang HE. Monitoring tumor response with [18F]FMAU in a sarcoma-bearing mouse model after liposomal vinorelbine treatment. Nucl Med Biol 2013; 40:1035-42. [PMID: 23969084 DOI: 10.1016/j.nucmedbio.2013.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/14/2013] [Accepted: 07/03/2013] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Previous studies have shown that the accumulation level of FMAU in tumor is proportional to its proliferation rate. This study demonstrated that 2'-deoxy-2'-[(18)F]fluoro-β-d-arabinofuranosyluracil ([(18)F]FMAU) is a promising PET probe for noninvasively monitoring the therapeutic efficacy of 6% PEGylated liposomal vinorelbine (lipo-VNB) in a subcutaneous murine NG4TL4 sarcoma mouse model. METHODS Female syngenic FVB/N mice were inoculated with NG4TL4 cells in the right flank. After tumor size reached 150 ± 50 mm(3) (day 0), lipo-VNB (5mg/kg) was intravenously administered on days 0, 3 and 6. To monitor the therapeutic efficacy of lipo-VNB, [(18)F]FMAU PET was employed to evaluate the proliferation rate of tumor, and it was compared with that observed from [(18)F]FDG/[(18)F]fluoroacetate PET. The expression of proliferating cell nuclear antigen (PCNA) in tumor during treatment was determined by semiquantitative analysis of immunohistochemical staining. RESULTS A significant inhibition (p<0.001) in tumor growth was observed on day 3 after a single dose treatment. The tumor-to-muscle ratio (T/M) derived from [(18)F]FMAU-PET images of lipo-VNB-treated group declined from 2.33 ± 0.16 to 1.26 ± 0.03 after three doses of treatment, while that of the control remained steady. The retarded proliferation rate of lipo-VNB-treated sarcoma was confirmed by PCNA immunohistochemistry staining. However, both [(18)F]FDG and [(18)F]fluoroacetate microPET imaging did not show significant difference in T/M between the therapeutic and the control groups throughout the entire experimental period. CONCLUSION Lipo-VNB can effectively impede the growth of NG4TL4 sarcoma. [(18)F]FMAU PET is an appropriate modality for early monitoring of the tumor response during the treatment course of lipo-VNB.
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Affiliation(s)
- Pei-Chia Chan
- Institute of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan
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24
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Abstract
Several new tracers are being developed for use with PET to assess pathways that are altered in cancers, including energy use, cellular signaling, transport, and proliferation. Because increased proliferation is a hallmark of many cancers, several tracers have been tested to track the DNA synthesis pathway. Thymidine, which is incorporated into DNA but not RNA, has been used in laboratory studies to measure tumor growth. Because thymidine labeled with (11)C undergoes rapid biologic degradation and has a short physical half-life, tracers labeled with (18)F have been preferred in PET imaging. One such tracer is (18)F-labeled 3'-deoxy-3'-fluorothymidine ((18)F-FLT). (18)F-FLT is trapped after phosphorylation by thymidine kinase 1, whose expression is increased in replicating cells. Several studies on breast, lung, and brain tumors have demonstrated that retention of (18)F-FLT correlated with tumor proliferation. Although (18)F-FLT has been used to image and stage several tumor types, the standardized uptake value is generally lower than that obtained with (18)F-FDG. (18)F-FLT can be used to image many areas of the body, but background uptake is high in the liver, marrow, and renal system, limiting use in these organs. (18)F-FLT PET imaging has primarily been studied in the assessment of treatment response. Rapid declines in (18)F-FLT retention within days to weeks have been demonstrated in several tumor types treated with cytotoxic drugs, targeted agents, and radiotherapy. Further work is ongoing to validate this approach and determine its utility in the development of new drugs and in the clinical evaluation of standard treatment approaches.
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Affiliation(s)
- Omid S Tehrani
- Department of Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, USA
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25
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O'Brien PJ, Lee M, Spilker ME, Zhang CC, Yan Z, Nichols TC, Li W, Johnson CH, Patti GJ, Siuzdak G. Monitoring metabolic responses to chemotherapy in single cells and tumors using nanostructure-initiator mass spectrometry (NIMS) imaging. Cancer Metab 2013; 1:4. [PMID: 24280026 PMCID: PMC3834492 DOI: 10.1186/2049-3002-1-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 10/15/2012] [Indexed: 02/03/2023] Open
Abstract
Background Tissue imaging of treatment-induced metabolic changes is useful for optimizing cancer therapies, but commonly used methods require trade-offs between assay sensitivity and spatial resolution. Nanostructure-Initiator Mass Spectrometry imaging (NIMS) permits quantitative co-localization of drugs and treatment response biomarkers in cells and tissues with relatively high resolution. The present feasibility studies use NIMS to monitor phosphorylation of 3′-deoxy-3′-fluorothymidine (FLT) to FLT-MP in lymphoma cells and solid tumors as an indicator of drug exposure and pharmacodynamic responses. Methods NIMS analytical sensitivity and spatial resolution were examined in cultured Burkitt’s lymphoma cells treated briefly with Rapamycin or FLT. Sample aliquots were dispersed on NIMS surfaces for single cell imaging and metabolic profiling, or extracted in parallel for LC-MS/MS analysis. Docetaxel-induced changes in FLT metabolism were also monitored in tissues and tissue extracts from mice bearing drug-sensitive tumor xenografts. To correct for variations in FLT disposition, the ratio of FLT-MP to FLT was used as a measure of TK1 thymidine kinase activity in NIMS images. TK1 and tumor-specific luciferase were measured in adjacent tissue sections using immuno-fluorescence microscopy. Results NIMS and LC-MS/MS yielded consistent results. FLT, FLT-MP, and Rapamycin were readily detected at the single cell level using NIMS. Rapid changes in endogenous metabolism were detected in drug-treated cells, and rapid accumulation of FLT-MP was seen in most, but not all imaged cells. FLT-MP accumulation in xenograft tumors was shown to be sensitive to Docetaxel treatment, and TK1 immunoreactivity co-localized with tumor-specific antigens in xenograft tumors, supporting a role for xenograft-derived TK1 activity in tumor FLT metabolism. Conclusions NIMS is suitable for monitoring drug exposure and metabolite biotransformation with essentially single cell resolution, and provides new spatial and functional dimensions to studies of cancer metabolism without the need for radiotracers or tissue extraction. These findings should prove useful for in vitro and pre-clinical studies of cancer metabolism, and aid the optimization of metabolism-based cancer therapies and diagnostics.
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Affiliation(s)
- Peter J O'Brien
- Pfizer Worldwide Research and Development, La Jolla Laboratories, La Jolla, CA, USA.
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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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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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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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Benz MR, Czernin J, Allen-Auerbach MS, Dry SM, Sutthiruangwong P, Spick C, Radu C, Weber WA, Tap WD, Eilber FC. 3'-deoxy-3'-[18F]fluorothymidine positron emission tomography for response assessment in soft tissue sarcoma: a pilot study to correlate imaging findings with tissue thymidine kinase 1 and Ki-67 activity and histopathologic response. Cancer 2011; 118:3135-44. [PMID: 22020872 DOI: 10.1002/cncr.26630] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 07/15/2011] [Accepted: 07/28/2011] [Indexed: 11/11/2022]
Abstract
BACKGROUND This study sought to determine whether [(18)F]fluorothymidine (FLT) positron emission tomography (PET)/computed tomography (CT) imaging allows assessment of tumor viability and proliferation in patients with soft tissue sarcomas who are treated with neoadjuvant therapy. METHODS Twenty patients with biopsy-proven, resectable, high-grade soft tissue sarcoma underwent [(18)F]FLT PET/CT imaging before and after neoadjuvant therapy. Histologic subtypes included sarcomas not otherwise specified (n = 5), malignant peripheral nerve sheath tumors (n = 3), gastrointestinal stromal tumors (n = 3), leiomyosarcomas (n = 3), angiosarcomas (n = 2), and others (n = 4). Changes in [(18)F]FLT peak standardized uptake value (SUVpeak) were correlated with percent necrosis in excised tissue, whereas posttreatment [(18)F]FLT tumor uptake was correlated with thymidine kinase 1 (TK1) expression and Ki-67 staining indices in excised tumor tissue. RESULTS Tumor FLT SUVpeak averaged 7.1 ± 3.7 g/mL (range, 1.9-16.1 g/mL) at baseline and decreased significantly to 2.7 ± 1.6 g/mL (range, 0.8-6.0 g/mL) at follow-up (P < .001); however, marked reductions in SUV were not specific for histopathological response. The posttreatment SUVpeak did not correlate with TK1 (P = .27) or Ki-67 expression (P = .21). CONCLUSIONS Marked reductions in [(18)F]FLT tumor uptake in response to neoadjuvant treatment were observed in most patients with sarcoma. However, these reductions were not specific for histopathologic response to neoadjuvant therapy. Furthermore, posttreatment [(18)F]FLT tumor uptake was unrelated to tumor proliferation by Ki-67 and TK1 staining. These results question the value of [(18)F]FLT PET imaging for treatment response assessments in patients with soft tissue sarcoma.
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Affiliation(s)
- Matthias R Benz
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California 90095-1782, USA
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Cavanagh BL, Walker T, Norazit A, Meedeniya AC. Thymidine analogues for tracking DNA synthesis. Molecules 2011; 16:7980-93. [PMID: 21921870 PMCID: PMC6264245 DOI: 10.3390/molecules16097980] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 09/08/2011] [Indexed: 01/24/2023] Open
Abstract
Replicating cells undergo DNA synthesis in the highly regulated, S-phase of the cell cycle. Analogues of the pyrimidine deoxynucleoside thymidine may be inserted into replicating DNA, effectively tagging dividing cells allowing their characterisation. Tritiated thymidine, targeted using autoradiography was technically demanding and superseded by 5-bromo-2-deoxyuridine (BrdU) and related halogenated analogues, detected using antibodies. Their detection required the denaturation of DNA, often constraining the outcome of investigations. Despite these limitations BrdU alone has been used to target newly synthesised DNA in over 20,000 reviewed biomedical studies. A recent breakthrough in “tagging DNA synthesis” is the thymidine analogue 5-ethynyl-2′-deoxyuridine (EdU). The alkyne group in EdU is readily detected using a fluorescent azide probe and copper catalysis using ‘Huisgen’s reaction’ (1,3-dipolar cycloaddition or ‘click chemistry’). This rapid, two-step biolabelling approach allows the tagging and imaging of DNA within cells whilst preserving the structural and molecular integrity of the cells. The bio-orthogonal detection of EdU allows its application in more experimental assays than previously possible with other “unnatural bases”. These include physiological, anatomical and molecular biological experimentation in multiple fields including, stem cell research, cancer biology, and parasitology. The full potential of EdU and related molecules in biomedical research remains to be explored.
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Affiliation(s)
- Brenton L. Cavanagh
- Health Institute and Eskitis Institute, Griffith University, Queensland 4107, Australia
| | - Tom Walker
- Health Institute and Eskitis Institute, Griffith University, Queensland 4107, Australia
| | - Anwar Norazit
- Health Institute and Eskitis Institute, Griffith University, Queensland 4107, Australia
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Adrian C.B. Meedeniya
- Health Institute and Eskitis Institute, Griffith University, Queensland 4107, Australia
- Author to whom correspondence should be addressed; ; Tel.: +61-7-3735-4417, Fax: +61-7-3735-4255
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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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