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Eubank TD, Bobko AA, Hoblitzell EH, Gencheva M, Driesschaert B, Khramtsov VV. In Vivo Electron Paramagnetic Resonance Molecular Profiling of Tumor Microenvironment upon Tumor Progression to Malignancy in an Animal Model of Breast Cancer. Mol Imaging Biol 2024; 26:424-434. [PMID: 37610610 PMCID: PMC10884355 DOI: 10.1007/s11307-023-01847-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 07/27/2023] [Accepted: 08/07/2023] [Indexed: 08/24/2023]
Abstract
PURPOSE Hypoxia and acidosis are recognized tumor microenvironment (TME) biomarkers of cancer progression. Alterations in cancer redox status and metabolism are also associated with elevated levels of intracellular glutathione (GSH) and interstitial inorganic phosphate (Pi). This study aims to evaluate the capability of these biomarkers to discriminate between stages and inform on a switch to malignancy. PROCEDURES These studies were performed using MMTV-PyMT( +) female transgenic mice that spontaneously develop breast cancer and emulate human tumor staging. In vivo assessment of oxygen concentration (pO2), extracellular acidity (pHe), Pi, and GSH was performed using L-band electron paramagnetic resonance spectroscopy and multifunctional trityl and GSH-sensitive nitroxide probes. RESULTS Profiling of the TME showed significant deviation of measured biomarkers upon tumor progression from pre-malignancy (pre-S4) to the malignant stage (S4). For the combined marker, HOP: (pHe × pO2)/Pi, a value > 186 indicated that the tumors were pre-malignant in 85% of the mammary glands analyzed, and when < 186, they were malignant 42% of the time. For GSH, a value < 3 mM indicated that the tumors were pre-malignant 74% of the time, and when > 3 mM, they were malignant 80% of the time. The only marker that markedly deviated as early as stage 1 (S1) from its value in pre-S1 was elevated Pi, followed by a decrease of pHe and pO2 and increase in GSH at later stages. CONCLUSION Molecular TME profiling informs on alteration of tumor redox and metabolism during tumor staging. Early elevation of interstitial Pi at S1 may reflect tumor metabolic alterations that demand elevated phosphorus supply in accordance with the high rate growth hypothesis. These metabolic changes are supported by the following decrease of pHe due to a high tumor reliance on glycolysis and increase of intracellular GSH, a major intracellular redox buffer. The appreciable decrease in TME pO2 was observed only at malignant S4, apparently as a consequence of tumor mass growth and corresponding decrease in perfusion efficacy and increase in oxygen consumption as the tumor cells proliferate.
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Affiliation(s)
- Timothy D Eubank
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA.
- Department of Microbiology, Immunology, and Cell Biology, School of Medicine, West Virginia University, Morgantown, WV, 26506, USA.
| | - Andrey A Bobko
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, Morgantown, WV, 26506, USA
| | - E Hannah Hoblitzell
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- Department of Microbiology, Immunology, and Cell Biology, School of Medicine, West Virginia University, Morgantown, WV, 26506, USA
| | - Marieta Gencheva
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, Morgantown, WV, 26506, USA
| | - Benoit Driesschaert
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV, 26506, USA
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Valery V Khramtsov
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA.
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, Morgantown, WV, 26506, USA.
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Elajaili HB, Woodcock LB, Hovey TA, Rinard GA, DeGraw S, Canny A, Dee NM, Kao JPY, Nozik ES, Eaton SS, Eaton GR. Imaging Reactive Oxygen Radicals in Excised Mouse Lung Trapped by Reaction with Hydroxylamine Probes Using 1 GHz Rapid Scan Electron Paramagnetic Resonance. Mol Imaging Biol 2024; 26:503-510. [PMID: 37821714 PMCID: PMC11006821 DOI: 10.1007/s11307-023-01860-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/13/2023] [Accepted: 09/15/2023] [Indexed: 10/13/2023]
Abstract
PURPOSE Oxidative stress is proposed to be critical in acute lung disease, but methods to monitor radicals in lungs are lacking. Our goal is to develop low-frequency electron paramagnetic resonance (EPR) methods to monitor radicals that contribute to the disease. PROCEDURES Free radicals generated in a lipopolysaccharide-induced mouse model of acute respiratory distress syndrome reacted with cyclic hydroxylamines CPH (1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine hydrochloride) and DCP-AM-H (4-acetoxymethoxycarbonyl-1-hydroxy-2,2,5,5-tetramethylpyrrolidine-3-carboxylic acid), which were converted into the corresponding nitroxide radicals, CP• and DCP•. The EPR signals of the nitroxide radicals in excised lungs were imaged with a 1 GHz EPR spectrometer/imager that employs rapid scan technology. RESULTS The small numbers of nitroxides formed by reaction of the hydroxylamine with superoxide result in low signal-to-noise in the spectra and images. However, since the spectral properties of the nitroxides are known, we can use prior knowledge of the line shape and hyperfine splitting to fit the noisy data, yielding well-defined spectra and images. Two-dimensional spectral-spatial images are shown for lung samples containing (4.5 ± 0.5) ×1014 CP• and (9.9 ± 1.0) ×1014 DCP• nitroxide spins. These results suggest that a probe that accumulates in cells gives a stronger nitroxide signal than a probe that is more easily washed out of cells. CONCLUSION The nitroxide radicals in excised mouse lungs formed by reaction with hydroxylamine probes CPH and DCP-AM-H can be imaged at 1 GHz.
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Affiliation(s)
- Hanan B Elajaili
- Cardiovascular Pulmonary Research Laboratories and Pediatric Critical Care Medicine, University of Colorado Anschutz Medical Campus, 12700 E. 19th Ave., B131, Aurora, CO, 80045, USA
| | - Lukas B Woodcock
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO, 80210, USA
| | - Tanden A Hovey
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO, 80210, USA
| | - George A Rinard
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO, 80210, USA
| | - Samuel DeGraw
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO, 80210, USA
| | - Autumn Canny
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO, 80210, USA
| | - Nathan M Dee
- Cardiovascular Pulmonary Research Laboratories and Pediatric Critical Care Medicine, University of Colorado Anschutz Medical Campus, 12700 E. 19th Ave., B131, Aurora, CO, 80045, USA
| | - Joseph P Y Kao
- Center for Biomedical Engineering and Technology and Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Eva S Nozik
- Cardiovascular Pulmonary Research Laboratories and Pediatric Critical Care Medicine, University of Colorado Anschutz Medical Campus, 12700 E. 19th Ave., B131, Aurora, CO, 80045, USA
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO, 80210, USA
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO, 80210, USA.
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Woodcock LB, Legenzov EA, Dirda NDA, Kao JPY, Eaton GR, Eaton SS. Cyclic Disulfide-Bridged Dinitroxide Biradical for Measuring Thiol Redox Status by Electron Paramagnetic Resonance. J Phys Chem B 2023; 127:8762-8768. [PMID: 37811968 PMCID: PMC10990597 DOI: 10.1021/acs.jpcb.3c03387] [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] [Indexed: 10/10/2023]
Abstract
Among low-molecular-weight thiols, glutathione (GSH) is the main antioxidant in the cell, and its concentration is an indicator of the redox status. A cyclic disulfide-linked dinitroxide was designed for monitoring GSH by electron-paramagnetic resonance (EPR) spectroscopy. Reaction of the disulfide with GSH and three other thiols was measured at 9.6 GHz (X-band) and shown to be of first order in thiols. It is proposed that the reaction of the disulfide with 1 equiv of thiolate produced a short-lived intermediate that reacts with 1 equiv of thiolate to produce the cleavage product. The equilibrium ratio of the cleaved and intact disulfide is a measure of the redox state. Since the long-term goal is to use the disulfide to probe physiology in vivo, the feasibility of EPR spectroscopy and imaging of the disulfide and its cleavage product was demonstrated at 1 GHz (L-band).
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Affiliation(s)
- Lukas B. Woodcock
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Eric A. Legenzov
- Center for Biomedical Engineering & Technology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| | - Nathaniel D. A. Dirda
- Center for Biomedical Engineering & Technology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| | - Joseph P. Y. Kao
- Center for Biomedical Engineering & Technology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| | - Gareth R. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Sandra S. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
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Elajaili HB, Hernandez-Lagunas L, Ranguelova K, Dikalov S, Nozik-Grayck E. Use of Electron Paramagnetic Resonance in Biological Samples at Ambient Temperature and 77 K. J Vis Exp 2019. [PMID: 30688300 DOI: 10.3791/58461] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The accurate and specific detection of reactive oxygen species (ROS) in different cellular and tissue compartments is essential to the study of redox-regulated signaling in biological settings. Electron paramagnetic resonance spectroscopy (EPR) is the only direct method to assess free radicals unambiguously. Its advantage is that it detects physiologic levels of specific species with a high specificity, but it does require specialized technology, careful sample preparation, and appropriate controls to ensure accurate interpretation of the data. Cyclic hydroxylamine spin probes react selectively with superoxide or other radicals to generate a nitroxide signal that can be quantified by EPR spectroscopy. Cell-permeable spin probes and spin probes designed to accumulate rapidly in the mitochondria allow for the determination of superoxide concentration in different cellular compartments. In cultured cells, the use of cell permeable 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine (CMH) along with and without cell-impermeable superoxide dismutase (SOD) pretreatment, or use of cell-permeable PEG-SOD, allows for the differentiation of extracellular from cytosolic superoxide. The mitochondrial 1-hydroxy-4-[2-triphenylphosphonio)-acetamido]-2,2,6,6-tetramethyl-piperidine,1-hydroxy-2,2,6,6-tetramethyl-4-[2-(triphenylphosphonio)acetamido] piperidinium dichloride (mito-TEMPO-H) allows for measurement of mitochondrial ROS (predominantly superoxide). Spin probes and EPR spectroscopy can also be applied to in vivo models. Superoxide can be detected in extracellular fluids such as blood and alveolar fluid, as well as tissues such as lung tissue. Several methods are presented to process and store tissue for EPR measurements and deliver intravenous 1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine (CPH) spin probe in vivo. While measurements can be performed at room temperature, samples obtained from in vitro and in vivo models can also be stored at -80 °C and analyzed by EPR at 77 K. The samples can be stored in specialized tubing stable at -80 °C and run at 77 K to enable a practical, efficient, and reproducible method that facilitates storing and transferring samples.
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Affiliation(s)
- Hanan B Elajaili
- Cardiovascular Pulmonary Research Laboratories and Pediatric Critical Care Medicine, Department of Pediatrics, University of Colorado Anschutz Medical Campus
| | - Laura Hernandez-Lagunas
- Cardiovascular Pulmonary Research Laboratories and Pediatric Critical Care Medicine, Department of Pediatrics, University of Colorado Anschutz Medical Campus
| | | | - Sergey Dikalov
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center
| | - Eva Nozik-Grayck
- Cardiovascular Pulmonary Research Laboratories and Pediatric Critical Care Medicine, Department of Pediatrics, University of Colorado Anschutz Medical Campus;
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Khramtsov VV. In Vivo Molecular Electron Paramagnetic Resonance-Based Spectroscopy and Imaging of Tumor Microenvironment and Redox Using Functional Paramagnetic Probes. Antioxid Redox Signal 2018; 28:1365-1377. [PMID: 29132215 PMCID: PMC5910053 DOI: 10.1089/ars.2017.7329] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
SIGNIFICANCE A key role of the tumor microenvironment (TME) in cancer progression, treatment resistance, and as a target for therapeutic intervention is increasingly appreciated. Among important physiological components of the TME are tissue hypoxia, acidosis, high reducing capacity, elevated concentrations of intracellular glutathione (GSH), and interstitial inorganic phosphate (Pi). Noninvasive in vivo pO2, pH, GSH, Pi, and redox assessment provide unique insights into biological processes in the TME, and may serve as a tool for preclinical screening of anticancer drugs and optimizing TME-targeted therapeutic strategies. Recent Advances: A reasonable radiofrequency penetration depth in living tissues and progress in development of functional paramagnetic probes make low-field electron paramagnetic resonance (EPR)-based spectroscopy and imaging the most appropriate approaches for noninvasive assessment of the TME parameters. CRITICAL ISSUES Here we overview the current status of EPR approaches used in combination with functional paramagnetic probes that provide quantitative information on chemical TME and redox (pO2, pH, redox status, Pi, and GSH). In particular, an application of a recently developed dual-function pH and redox nitroxide probe and multifunctional trityl probe provides unsurpassed opportunity for in vivo concurrent measurements of several TME parameters in preclinical studies. The measurements of several parameters using a single probe allow for their correlation analyses independent of probe distribution and time of measurements. FUTURE DIRECTIONS The recent progress in clinical EPR instrumentation and development of biocompatible paramagnetic probes for in vivo multifunctional TME profiling eventually will make possible translation of these EPR techniques into clinical settings to improve prediction power of early diagnostics for the malignant transition and for future rational design of TME-targeted anticancer therapeutics. Antioxid. Redox Signal. 28, 1365-1377.
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Affiliation(s)
- Valery V Khramtsov
- 1 In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University , Morgantown, West Virginia.,2 Department of Biochemistry, West Virginia University School of Medicine , Morgantown, West Virginia
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Zhai W, Feng Y, Liu H, Rockenbauer A, Mance D, Li S, Song Y, Baldus M, Liu Y. Diastereoisomers of l-proline-linked trityl-nitroxide biradicals: synthesis and effect of chiral configurations on exchange interactions. Chem Sci 2018; 9:4381-4391. [PMID: 29896379 PMCID: PMC5958346 DOI: 10.1039/c8sc00969d] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 04/05/2018] [Indexed: 01/08/2023] Open
Abstract
The chiral configuration of the two radical parts is a crucial factor controlling the exchange interactions and DNP properties of trityl-nitroxide biradicals.
The exchange (J) interaction of organic biradicals is a crucial factor controlling their physiochemical properties and potential applications and can be modulated by changing the nature of the linker. In the present work, we for the first time demonstrate the effect of chiral configurations of radical parts on the J values of trityl-nitroxide (TN) biradicals. Four diastereoisomers (TNT1, TNT2, TNL1 and TNL2) of TN biradicals were synthesized and purified by the conjugation of a racemic (R/S) nitroxide with the racemic (M/P) trityl radical vial-proline. The absolute configurations of these diastereoisomers were assigned by comparing experimental and calculated electronic circular dichroism (ECD) spectra as (M, S, S) for TNT1, (P, S, S) for TNT2, (M, S, R) for TNL1 and (P, S, R) for TNL2. Electron paramagnetic resonance (EPR) results showed that the configuration of the nitroxide part instead of the trityl part is dominant in controlling the exchange interactions and the order of the J values at room temperature is TNT1 (252 G) > TNT2 (127 G) ≫ TNL2 (33 G) > TNL1 (14 G). Moreover, the J values of TNL1/TNL2 with the S configuration in the nitroxide part vary with temperature and the polarity of solvents due to their flexible linker, whereas the J values of TNT1/TNT2 are almost insensitive to these two factors due to the rigidity of their linkers. The distinct exchange interactions between TNT1,2 and TNL1,2 in the frozen state led to strongly different high-field dynamic nuclear polarization (DNP) enhancements with ε = 7 for TNT1,2 and 40 for TNL1,2 under 800 MHz DNP conditions.
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Affiliation(s)
- Weixiang Zhai
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics , School of Pharmacy , Tianjin Medical University , Tianjin 300070 , P. R. China . ;
| | - Yalan Feng
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics , School of Pharmacy , Tianjin Medical University , Tianjin 300070 , P. R. China . ;
| | - Huiqiang Liu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics , School of Pharmacy , Tianjin Medical University , Tianjin 300070 , P. R. China . ;
| | - Antal Rockenbauer
- Institute of Materials and Environmental Chemistry , Hungarian Academy of Sciences , Department of Physics , Budapest University of Technology and Economics , Budafoki ut 8 , 1111 Budapest , Hungary .
| | - Deni Mance
- NMR Spectroscopy , Bijvoet Center for Biomolecular Research , Utrecht University , 3584 CH Utrecht , The Netherlands
| | - Shaoyong Li
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics , School of Pharmacy , Tianjin Medical University , Tianjin 300070 , P. R. China . ;
| | - Yuguang Song
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics , School of Pharmacy , Tianjin Medical University , Tianjin 300070 , P. R. China . ;
| | - Marc Baldus
- NMR Spectroscopy , Bijvoet Center for Biomolecular Research , Utrecht University , 3584 CH Utrecht , The Netherlands
| | - Yangping Liu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics , School of Pharmacy , Tianjin Medical University , Tianjin 300070 , P. R. China . ;
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Khramtsov VV, Bobko AA, Tseytlin M, Driesschaert B. Exchange Phenomena in the Electron Paramagnetic Resonance Spectra of the Nitroxyl and Trityl Radicals: Multifunctional Spectroscopy and Imaging of Local Chemical Microenvironment. Anal Chem 2017; 89:4758-4771. [PMID: 28363027 PMCID: PMC5513151 DOI: 10.1021/acs.analchem.6b03796] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This Feature overviews the basic principles of using stable organic radicals involved in reversible exchange processes as functional paramagnetic probes. We demonstrate that these probes in combination with electron paramagnetic resonance (EPR)-based spectroscopy and imaging techniques provide analytical tools for quantitative mapping of critical parameters of local chemical microenvironment. The Feature is written to be understandable to people who are laymen to the EPR field in anticipation of future progress and broad application of these tools in biological systems, especially in vivo, over the next years.
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Affiliation(s)
- Valery V. Khramtsov
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia 26506, United States
| | - Andrey A. Bobko
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia 26506, United States
| | - Mark Tseytlin
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia 26506, United States
| | - Benoit Driesschaert
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia 26506, United States
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8
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Epel B, Sundramoorthy SV, Krzykawska-Serda M, Maggio MC, Tseytlin M, Eaton GR, Eaton SS, Rosen GM, Kao JPY, Halpern HJ. Imaging thiol redox status in murine tumors in vivo with rapid-scan electron paramagnetic resonance. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 276:31-36. [PMID: 28092786 PMCID: PMC5336491 DOI: 10.1016/j.jmr.2016.12.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 12/05/2016] [Accepted: 12/29/2016] [Indexed: 05/12/2023]
Abstract
Thiol redox status is an important physiologic parameter that affects the success or failure of cancer treatment. Rapid scan electron paramagnetic resonance (RS EPR) is a novel technique that has shown higher signal-to-noise ratio than conventional continuous-wave EPR in in vitro studies. Here we used RS EPR to acquire rapid three-dimensional images of the thiol redox status of tumors in living mice. This work presents, for the first time, in vivo RS EPR images of the kinetics of the reaction of 2H,15N-substituted disulfide-linked dinitroxide (PxSSPx) spin probe with intracellular glutathione. The cleavage rate is proportional to the intracellular glutathione concentration. Feasibility was demonstrated in a FSa fibrosarcoma tumor model in C3H mice. Similar to other in vivo and cell model studies, decreasing intracellular glutathione concentration by treating mice with l-buthionine sulfoximine (BSO) markedly altered the kinetic images.
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Affiliation(s)
- Boris Epel
- Center for EPR Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, IL, USA
| | - Subramanian V Sundramoorthy
- Center for EPR Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, IL, USA
| | - Martyna Krzykawska-Serda
- Center for EPR Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, IL, USA
| | - Matthew C Maggio
- Center for EPR Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, IL, USA
| | - Mark Tseytlin
- Department of Biochemistry, School of Medicine, University of West Virginia, Morgantown, WV 26506, USA
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA
| | - Gerald M Rosen
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA
| | - Joseph P Y Kao
- Center for Biomedical Engineering & Technology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Howard J Halpern
- Center for EPR Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, IL, USA.
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Legenzov EA, Muralidharan S, Woodcock LB, Eaton GR, Eaton SS, Rosen GM, Kao JPY. Designing Molecular Probes To Prolong Intracellular Retention: Application to Nitroxide Spin Probes. Bioconjug Chem 2016; 27:2923-2930. [PMID: 27998079 DOI: 10.1021/acs.bioconjchem.6b00595] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Targeted delivery of molecular probes into cells enables cellular imaging through optical and magnetic modalities. Probe molecules that are well retained by cells can accumulate to higher intracellular concentrations, and thus increase the signal-to-noise ratio of, and widen the temporal window for, imaging. Here we synthesize a paramagnetic spin probe bearing six ionic functional groups and show that it has long intracellular half-life (>12 h) and exceptional biostability in living cells. We demonstrate that judicious incorporation of ionic substituents on probe molecules systematically increases intracellular retention time, and should therefore be beneficial to imaging experiments.
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Affiliation(s)
- Eric A Legenzov
- Center for Biomedical Engineering & Technology, and Department of Physiology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States
| | - Sukumaran Muralidharan
- Center for Biomedical Engineering & Technology, and Department of Physiology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States
| | - Lukas B Woodcock
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208, United States
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208, United States
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208, United States
| | - Gerald M Rosen
- Department of Pharmaceutical Sciences, School of Pharmacy, and Center for Biomedical Engineering & Technology, School of Medicine, University of Maryland , Baltimore, Maryland 21201, United States
| | - Joseph P Y Kao
- Center for Biomedical Engineering & Technology, and Department of Physiology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States
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Elajaili H, Biller JR, Rosen GM, Kao JPY, Tseytlin M, Buchanan LA, Rinard GA, Quine RW, McPeak J, Shi Y, Eaton SS, Eaton GR. Imaging disulfide dinitroxides at 250 MHz to monitor thiol redox status. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 260:77-82. [PMID: 26415686 PMCID: PMC4731354 DOI: 10.1016/j.jmr.2015.08.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 08/15/2015] [Accepted: 08/25/2015] [Indexed: 05/12/2023]
Abstract
Measurement of thiol-disulfide redox status is crucial for characterization of tumor physiology. The electron paramagnetic resonance (EPR) spectra of disulfide-linked dinitroxides are readily distinguished from those of the corresponding monoradicals that are formed by cleavage of the disulfide linkage by free thiols. EPR spectra can thus be used to monitor the rate of cleavage and the thiol redox status. EPR spectra of (1)H,(14)N- and (2)H,(15)N-disulfide dinitroxides and the corresponding monoradicals resulting from cleavage by glutathione have been characterized at 250 MHz, 1.04 GHz, and 9 GHz and imaged by rapid-scan EPR at 250 MHz.
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Affiliation(s)
- Hanan Elajaili
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States
| | - Joshua R Biller
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States
| | - Gerald M Rosen
- Department of Pharmaceutical Sciences and Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | - Joseph P Y Kao
- Center for Biomedical Engineering and Technology, and Department of Physiology, University of Maryland, Baltimore, MD 21201, United States
| | - Mark Tseytlin
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States
| | - Laura A Buchanan
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States
| | - George A Rinard
- School of Engineering and Computer Science, University of Denver, Denver, CO 80208, United States
| | - Richard W Quine
- School of Engineering and Computer Science, University of Denver, Denver, CO 80208, United States
| | - Joseph McPeak
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States
| | - Yilin Shi
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, United States.
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