1
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Huclier-Markai S, Alliot C, Mazza M, Reiller PE. Complexation of europium(III) with exopolysaccharides from a marine bacterium envisaged as luminescent probe in a theranostic approach. Dalton Trans 2021; 50:17215-17227. [PMID: 34783812 DOI: 10.1039/d1dt03288g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Exopolysaccharide (EPS) derivatives, produced by Alteromonas infernus bacterium, showed anti-metastatic properties in osteosarcoma (bone tumor). These EPSs could be employed as new drug delivery systems for therapeutic uses. They may represent a new class of ligands to be combined in a theranostic approach with fluorescent metals, such as Eu(III), to serve as imaging probe. The goal of this work was to investigate the feasibility of such coupling by time-resolved laser-induced fluorescence spectroscopy (TRLFS). Since these EPSs are polyelectrolytes their conformation could affect the complexation properties. Thus, viscosimetric measurements were performed as a function of their concentration as well as the background electrolyte concentration. Polysaccharides conformation exhibited a lower hydrodynamic volume for the highest ionic strengths. The resulting random-coiled conformation could affect the complexation with metal for high concentration but no change was evidenced when increasing europium concentration. Two sites of complexation of Eu(III) were evidenced by TRLFS in heparin, whereas only one site was evidenced in two modified EPSs produced from Alteromonas infernus.
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Affiliation(s)
- Sandrine Huclier-Markai
- GIP ARRONAX, 1 rue Aronnax, F-44817 Nantes Cedex 3, France. .,SUBATECH, 4 rue Alfred Kastler, BP 20722, 44307 Nantes Cedex 3, France
| | - Cyrille Alliot
- GIP ARRONAX, 1 rue Aronnax, F-44817 Nantes Cedex 3, France. .,INSERM U892- 8 quai Moncousu, F-44007 Nantes Cedex 1, France
| | - Mattia Mazza
- GIP ARRONAX, 1 rue Aronnax, F-44817 Nantes Cedex 3, France. .,SUBATECH, 4 rue Alfred Kastler, BP 20722, 44307 Nantes Cedex 3, France
| | - Pascal E Reiller
- Université Paris-Saclay, CEA, Service d'Etudes Analytiques et de Réactivité des Surfaces (SEARS), F-91191, Gif sur Yvette, France
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2
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Szkop M, Brygoła K, Janczewska M, Ciach T. A simple time-resolved fluorescence assay for quantitative determination of DOTA chelator. Anal Biochem 2019; 584:113384. [PMID: 31356774 DOI: 10.1016/j.ab.2019.113384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 07/14/2019] [Accepted: 07/25/2019] [Indexed: 01/01/2023]
Abstract
DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) is one of the preeminent metal chelator applied for diagnostic and therapeutic purposes, however to date there is no versatile and reliable nonradioisotopic method for its precise determination. In this technical note, we present a novel and sensitive fluorimetric assay for quantitative determination of DOTA based on the luminescence quenching of the highly luminescent europium ions complex with trioctyl phosphine oxide and naphthoyl trifluoroacetone sensitizing activators. The assay is carried out in two simple steps and enables the determination of DOTA in the nanomolar range providing a superior tool compared to commonly applied spectrophotometric assay with Arsenazo-III reagent.
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Affiliation(s)
- Michał Szkop
- NanoThea Inc., Waryńskiego 1, 00-645, Warsaw, Poland.
| | - Kamil Brygoła
- NanoThea Inc., Waryńskiego 1, 00-645, Warsaw, Poland
| | | | - Tomasz Ciach
- NanoThea Inc., Waryńskiego 1, 00-645, Warsaw, Poland; Faculty of Chemical and Process Engineering, Warsaw University of Technology, Waryńskiego 1, 00-645, Warsaw, Poland
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3
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Tafreshi NK, Tichacek CJ, Pandya DN, Doligalski ML, Budzevich MM, Kil H, Bhatt NB, Kock ND, Messina JL, Ruiz EE, Delva NC, Weaver A, Gibbons WR, Boulware DC, Khushalani NI, El-Haddad G, Triozzi PL, Moros EG, McLaughlin ML, Wadas TJ, Morse DL. Melanocortin 1 Receptor-Targeted α-Particle Therapy for Metastatic Uveal Melanoma. J Nucl Med 2019; 60:1124-1133. [PMID: 30733316 DOI: 10.2967/jnumed.118.217240] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 12/20/2018] [Indexed: 02/03/2023] Open
Abstract
New effective therapies are greatly needed for metastatic uveal melanoma, which has a very poor prognosis with a median survival of less than 1 y. The melanocortin 1 receptor (MC1R) is expressed in 94% of uveal melanoma metastases, and a MC1R-specific ligand (MC1RL) with high affinity and selectivity for MC1R was previously developed. Methods: The 225Ac-DOTA-MC1RL conjugate was synthesized in high radiochemical yield and purity and was tested in vitro for biostability and for MC1R-specific cytotoxicity in uveal melanoma cells, and the lanthanum-DOTA-MC1RL analog was tested for binding affinity. Non-tumor-bearing BALB/c mice were tested for maximum tolerated dose and biodistribution. Severe combined immunodeficient mice bearing uveal melanoma tumors or engineered MC1R-positive and -negative tumors were studied for biodistribution and efficacy. Radiation dosimetry was calculated using mouse biodistribution data and blood clearance kinetics from Sprague-Dawley rat data. Results: High biostability, MC1R-specific cytotoxicity, and high binding affinity were observed. Limiting toxicities were not observed at even the highest administered activities. Pharmacokinetics and biodistribution studies revealed rapid blood clearance (<15 min), renal and hepatobillary excretion, MC1R-specific tumor uptake, and minimal retention in other normal tissues. Radiation dosimetry calculations determined pharmacokinetics parameters and absorbed α-emission dosages from 225Ac and its daughters. Efficacy studies demonstrated significantly prolonged survival and decreased metastasis burden after a single administration of 225Ac-DOTA-MC1RL in treated mice relative to controls. Conclusion: These results suggest significant potential for the clinical translation of 225Ac-DOTA-MC1RL as a novel therapy for metastatic uveal melanoma.
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Affiliation(s)
- Narges K Tafreshi
- Department of Cancer Physiology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida
| | - Christopher J Tichacek
- Department of Cancer Physiology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida.,Department of Radiation Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida.,Department of Physics, University of South Florida, Tampa, Florida
| | - Darpan N Pandya
- Department of Cancer Biology, Wake Forest University Health Sciences, Winston-Salem, North Carolina
| | - Michael L Doligalski
- Department of Cancer Physiology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida
| | - Mikalai M Budzevich
- Small Animal Imaging Laboratory, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida
| | - HyunJoo Kil
- Department of Pharmaceutical Sciences, Health Sciences Center, West Virginia University, and Modulation Therapeutics Inc., Morgantown, West Virginia
| | - Nikunj B Bhatt
- Department of Cancer Biology, Wake Forest University Health Sciences, Winston-Salem, North Carolina
| | - Nancy D Kock
- Section on Comparative Medicine, Department of Pathology, Wake Forest University Health Sciences, Winston-Salem, North Carolina
| | - Jane L Messina
- Departments of Anatomic Pathology and Cutaneous Pathology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida.,Department of Dermatology, University of South Florida, Tampa, Florida.,Department of Oncologic Sciences, University of South Florida, Tampa, Florida
| | - Epifanio E Ruiz
- Small Animal Imaging Laboratory, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida
| | - Nella C Delva
- Department of Cancer Physiology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida
| | - Adam Weaver
- Division of Research Integrity and Compliance, University of South Florida, Tampa, Florida
| | - William R Gibbons
- Division of Research Integrity and Compliance, University of South Florida, Tampa, Florida
| | - David C Boulware
- Biostatistics Core Facility, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida
| | - Nikhil I Khushalani
- Department of Cutaneous Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida
| | - Ghassan El-Haddad
- Departments of Diagnostic Imaging and Interventional Radiology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida; and
| | - Pierre L Triozzi
- Department of Hematology and Oncology, Wake Forest University Health Sciences, Winston-Salem, North Carolina
| | - Eduardo G Moros
- Department of Cancer Physiology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida.,Department of Radiation Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida.,Department of Physics, University of South Florida, Tampa, Florida.,Department of Oncologic Sciences, University of South Florida, Tampa, Florida
| | - Mark L McLaughlin
- Department of Pharmaceutical Sciences, Health Sciences Center, West Virginia University, and Modulation Therapeutics Inc., Morgantown, West Virginia
| | - Thaddeus J Wadas
- Department of Cancer Biology, Wake Forest University Health Sciences, Winston-Salem, North Carolina
| | - David L Morse
- Department of Cancer Physiology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida .,Department of Physics, University of South Florida, Tampa, Florida.,Small Animal Imaging Laboratory, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida.,Department of Oncologic Sciences, University of South Florida, Tampa, Florida
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4
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Bugrov AN, Zavialova AY, Smyslov RY, Anan'eva TD, Vlasova EN, Mokeev MV, Kryukov AE, Kopitsa GP, Pipich V. Luminescence of Eu 3+ ions in hybrid polymer-inorganic composites based on poly(methyl methacrylate) and zirconia nanoparticles. LUMINESCENCE 2018; 33:837-849. [PMID: 29683250 DOI: 10.1002/bio.3476] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 12/14/2017] [Accepted: 02/05/2018] [Indexed: 12/28/2022]
Abstract
Spherical nanoparticles of ZrO2 with 2 and 10 mol% EuO1.5 up to 20 nm size were prepared by the method of hydrothermal synthesis for luminescent functionalization of the polymer-inorganic nanocomposites based on poly(methyl methacrylate). Surface modification of oxide nanoparticles was carried out by 3-(trimethoxysilyl)propyl methacrylate, dimethoxymethylvinyl silane and 2-hydroxyethyl methacrylate to provide uniform distribution and to prevent agglomeration of nanosized filler in the polymer matrix. Polymer-inorganic composites were synthesized by in situ free radical polymerization in bulk. Structuring of ZrO2 -EuO1.5 nanoparticles in the poly(methyl methacrylate) was studied by very-small-angle neutron scattering. According to the results, the dependence of photoluminescent properties of ZrO2 -EuO1.5 nanoparticles on the content of lanthanide, the symmetry of the crystal field, surface treatment and the polymer matrix were established. A correlation was shown between Stark splitting in luminescence spectra of ZrO2 -EuO1.5 nanoparticles and their phase composition. Using MMT-assay it was shown that composites based on poly(methyl methacrylate) and ZrO2 -EuO1.5 nanoparticles do not have cytotoxic properties, which makes it possible to use them as prosthesis materials with contrasted and luminescent imaging properties.
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Affiliation(s)
- Alexander N Bugrov
- Institute of Macromolecular Compounds RAS, Bolshoy prospekt, 31, 199004, St Petersburg, Russia.,St Petersburg Electrotechnical University 'LETI', ul. Professora Popova, 5, 197376, St Petersburg, Russia
| | - Anastasia Yu Zavialova
- St Petersburg Electrotechnical University 'LETI', ul. Professora Popova, 5, 197376, St Petersburg, Russia.,St Petersburg State Technological Institute (Technical University), Moskovsky prospect, 26, 190013, St Petersburg, Russia
| | - Ruslan Yu Smyslov
- Institute of Macromolecular Compounds RAS, Bolshoy prospekt, 31, 199004, St Petersburg, Russia.,Petersburg Nuclear Physics Institute NRC KI, mkr. Orlova roshcha, 1, 188300, Gatchina, Leningradskaya oblast, Russia
| | - Tatyana D Anan'eva
- Institute of Macromolecular Compounds RAS, Bolshoy prospekt, 31, 199004, St Petersburg, Russia
| | - Elena N Vlasova
- Institute of Macromolecular Compounds RAS, Bolshoy prospekt, 31, 199004, St Petersburg, Russia
| | - Maxim V Mokeev
- Institute of Macromolecular Compounds RAS, Bolshoy prospekt, 31, 199004, St Petersburg, Russia
| | - Artem E Kryukov
- Institute of Macromolecular Compounds RAS, Bolshoy prospekt, 31, 199004, St Petersburg, Russia
| | - Gennady P Kopitsa
- Petersburg Nuclear Physics Institute NRC KI, mkr. Orlova roshcha, 1, 188300, Gatchina, Leningradskaya oblast, Russia.,Grebenshchikov Institute of Silicate Chemistry RAS, Adm. Makarova emb., 2, 199155, St Petersburg, Russia
| | - Vitaliy Pipich
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich, Lichtenbergstr. 1, 85748, Garching, Germany
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5
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Sinharay S, Howison CM, Baker AF, Pagel MD. Detecting in vivo urokinase plasminogen activator activity with a catalyCEST MRI contrast agent. NMR IN BIOMEDICINE 2017; 30:10.1002/nbm.3721. [PMID: 28370884 PMCID: PMC5704996 DOI: 10.1002/nbm.3721] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 02/04/2017] [Accepted: 02/06/2017] [Indexed: 05/22/2023]
Abstract
Urokinase plasminogen activator (uPA) promotes tumor invasion and metastasis. The monitoring of uPA activity using molecular imaging may have prognostic value and be predictive for response to anti-cancer therapies. However, the detection of in vivo enzyme activity with molecular imaging remains a challenge. To address this problem, we designed a nonmetallic contrast agent, GR-4Am-SA, that can be detected with chemical exchange saturation transfer (CEST) MRI. This agent has a peptide that is cleaved by uPA, which causes a CEST signal at 5.0 ppm to decrease, and also has a salicylic acid moiety that can produce a CEST signal at 9.5 ppm, which is largely unresponsive to enzyme activity. The two CEST signals were used to determine a reaction coordinate, representing the extent of enzyme-catalyzed cleavage of the GR-4Am-SA agent during an experimental study. Initial biochemical studies showed that GR-4Am-SA could detect uPA activity in reducing conditions. Subsequently, we used our catalyCEST MRI protocol with the agent to detect the uPA catalysis of GR-4Am-SA in a flank xenograft model of Capan-2 pancreatic cancer. The results showed an average reaction coordinate of 80% ± 8%, which was strongly dependent on the CEST signal at 5.0 ppm. The relative independence of the reaction coordinate on the CEST signal at 9.5 ppm showed that the detection of enzyme activity was largely independent of the concentration of GR-4Am-SA within the tumor tissue. These results demonstrated the advantages of a single CEST agent with biomarker-responsive and unresponsive signals for reliably assessing enzyme activity during in vivo cancer studies.
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Affiliation(s)
- Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ
| | | | - Amanda F. Baker
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ
| | - Mark D. Pagel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ
- University of Arizona Cancer Center, University of Arizona, Tucson, AZ
- Department of Medical Imaging, University of Arizona, Tucson, AZ
- Corresponding Author: Mark D. Pagel, University of Arizona Cancer Center, 1515 N. Campbell Avenue, Tucson, AZ 85724-5024, Tel: (520)-404-7049, Fax: (520)-626-0395,
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6
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Dantas de Araujo A, Wu C, Wu KC, Reid RC, Durek T, Lim J, Fairlie DP. Europium-Labeled Synthetic C3a Protein as a Novel Fluorescent Probe for Human Complement C3a Receptor. Bioconjug Chem 2017; 28:1669-1676. [DOI: 10.1021/acs.bioconjchem.7b00132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Aline Dantas de Araujo
- Division of Chemistry and Structural Biology, Institute for Molecular
Bioscience, ‡Australian Research Council Centre of Excellence in Advanced Molecular
Imaging, Institute for Molecular Bioscience, and §Centre for Inflammation Disease Research, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Chongyang Wu
- Division of Chemistry and Structural Biology, Institute for Molecular
Bioscience, ‡Australian Research Council Centre of Excellence in Advanced Molecular
Imaging, Institute for Molecular Bioscience, and §Centre for Inflammation Disease Research, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Kai-Chen Wu
- Division of Chemistry and Structural Biology, Institute for Molecular
Bioscience, ‡Australian Research Council Centre of Excellence in Advanced Molecular
Imaging, Institute for Molecular Bioscience, and §Centre for Inflammation Disease Research, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Robert C. Reid
- Division of Chemistry and Structural Biology, Institute for Molecular
Bioscience, ‡Australian Research Council Centre of Excellence in Advanced Molecular
Imaging, Institute for Molecular Bioscience, and §Centre for Inflammation Disease Research, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Thomas Durek
- Division of Chemistry and Structural Biology, Institute for Molecular
Bioscience, ‡Australian Research Council Centre of Excellence in Advanced Molecular
Imaging, Institute for Molecular Bioscience, and §Centre for Inflammation Disease Research, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Junxian Lim
- Division of Chemistry and Structural Biology, Institute for Molecular
Bioscience, ‡Australian Research Council Centre of Excellence in Advanced Molecular
Imaging, Institute for Molecular Bioscience, and §Centre for Inflammation Disease Research, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - David P. Fairlie
- Division of Chemistry and Structural Biology, Institute for Molecular
Bioscience, ‡Australian Research Council Centre of Excellence in Advanced Molecular
Imaging, Institute for Molecular Bioscience, and §Centre for Inflammation Disease Research, The University of Queensland, Brisbane, Queensland 4072, Australia
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7
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Leygue N, Boulay A, Galaup C, Benoist E, Laurent S, Vander Elst L, Mestre-Voegtlé B, Picard C. Optical and relaxometric properties of monometallic (EuIII, TbIII, GdIII) and heterobimetallic (ReI/GdIII) systems based on a functionalized bipyridine-containing acyclic ligand. Dalton Trans 2016; 45:8379-93. [DOI: 10.1039/c6dt00405a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photophysical and relaxometric properties, in aqueous solution, of Ln-BPMNTA complexes and a derived ReI/GdIII dinuclear complex are reported in this paper.
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Affiliation(s)
- Nadine Leygue
- CNRS
- Laboratoire de Synthèse et Physico-Chimie de Molécules d'Intérêt Biologique
- SPCMIB
- UMR-5068
- F-31062 Toulouse cedex 9
| | - Alexandre Boulay
- CNRS
- Laboratoire de Synthèse et Physico-Chimie de Molécules d'Intérêt Biologique
- SPCMIB
- UMR-5068
- F-31062 Toulouse cedex 9
| | - Chantal Galaup
- CNRS
- Laboratoire de Synthèse et Physico-Chimie de Molécules d'Intérêt Biologique
- SPCMIB
- UMR-5068
- F-31062 Toulouse cedex 9
| | - Eric Benoist
- CNRS
- Laboratoire de Synthèse et Physico-Chimie de Molécules d'Intérêt Biologique
- SPCMIB
- UMR-5068
- F-31062 Toulouse cedex 9
| | - Sophie Laurent
- NMR and Molecular Imaging Laboratory
- Department of General
- Organic and Biomedical Chemistry
- University of Mons
- B-7000 Mons
| | - Luce Vander Elst
- NMR and Molecular Imaging Laboratory
- Department of General
- Organic and Biomedical Chemistry
- University of Mons
- B-7000 Mons
| | - Béatrice Mestre-Voegtlé
- CNRS
- Laboratoire de Synthèse et Physico-Chimie de Molécules d'Intérêt Biologique
- SPCMIB
- UMR-5068
- F-31062 Toulouse cedex 9
| | - Claude Picard
- CNRS
- Laboratoire de Synthèse et Physico-Chimie de Molécules d'Intérêt Biologique
- SPCMIB
- UMR-5068
- F-31062 Toulouse cedex 9
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8
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Cohen AS, Patek R, Enkemann SA, Johnson JO, Chen T, Toloza E, Vagner J, Morse DL. Delta-Opioid Receptor (δOR) Targeted Near-Infrared Fluorescent Agent for Imaging of Lung Cancer: Synthesis and Evaluation In Vitro and In Vivo. Bioconjug Chem 2015; 27:427-38. [PMID: 26488422 DOI: 10.1021/acs.bioconjchem.5b00516] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In the United States, lung cancer is the leading cause of cancer death and ranks second in the number of new cases annually among all types of cancers. Better methods or tools for diagnosing and treating this disease are needed to improve patient outcomes. The delta-opioid receptor (δOR) is reported to be overexpressed in lung cancers and not expressed in normal lung. Thus, we decided to develop a lung cancer-specific imaging agent targeting this receptor. We have previously developed a δOR-targeted fluorescent imaging agent based on a synthetic peptide antagonist (Dmt-Tic) conjugated to a Cy5 fluorescent dye. In this work, we describe the synthesis of Dmt-Tic conjugated to a longer wavelength near-infrared fluorescent (NIRF) dye, Li-cor IR800CW. Binding affinity of Dmt-Tic-IR800 for the δOR was studied using lanthanide time-resolved fluorescence (LTRF) competitive binding assays in cells engineered to overexpress the δOR. In addition, we identified lung cancer cell lines with high and low endogenous expression of the δOR. We confirmed protein expression in these cell lines using confocal fluorescence microscopy imaging and used this technique to estimate the cell-surface receptor number in the endogenously expressing lung cancer cell lines. The selectivity of Dmt-Tic-IR800 for imaging of the δOR in vivo was shown using both engineered cell lines and endogenously expressing lung cancer cells in subcutaneous xenograft models in mice. In conclusion, the δOR-specific fluorescent probe developed in this study displays excellent potential for imaging of lung cancer.
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Affiliation(s)
| | - Renata Patek
- BIO5 Institute, University of Arizona , Tucson, Arizona 85721, United States
| | | | | | | | - Eric Toloza
- Departments of Surgery and of Oncologic Sciences, University of South Florida Morsani College of Medicine , Tampa, Florida 33612, United States
| | - Josef Vagner
- BIO5 Institute, University of Arizona , Tucson, Arizona 85721, United States
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9
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Elshan NGRD, Jayasundera T, Anglin BL, Weber CS, Lynch RM, Mash EA. Trigonal scaffolds for multivalent targeting of melanocortin receptors. Org Biomol Chem 2015; 13:1778-91. [PMID: 25502141 DOI: 10.1039/c4ob02094d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Melanocortin receptors can be used as biomarkers to detect and possibly treat melanoma. To these ends, molecules bearing one, two, or three copies of the weakly binding ligand MSH(4) were attached to scaffolds based on phloroglucinol, tripropargylamine, and 1,4,7-triazacyclononane by means of the copper-assisted azide-alkyne cyclization. This synthetic design allows rapid assembly of multivalent molecules. The bioactivities of these compounds were evaluated using a competitive binding assay that employed human embryonic kidney cells engineered to overexpress the melanocortin 4 receptor. The divalent molecules exhibited 10- to 30-fold higher levels of inhibition when compared to the corresponding monovalent molecules, consistent with divalent binding. The trivalent molecules were only statistically (∼2-fold) better than the divalent molecules, still consistent with divalent binding but inconsistent with trivalent binding. Possible reasons for these behaviors and planned refinements of the multivalent constructs targeting melanocortin receptors based on these scaffolds are discussed.
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Affiliation(s)
- N G R Dayan Elshan
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721-0041, USA.
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10
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Kuhn PS, Cremer L, Gavriluta A, Jovanović KK, Filipović L, Hummer AA, Büchel GE, Dojčinović BP, Meier SM, Rompel A, Radulović S, Tommasino JB, Luneau D, Arion VB. Heteropentanuclear Oxalato-Bridged nd-4f (n=4, 5) Metal Complexes with NO Ligand: Synthesis, Crystal Structures, Aqueous Stability and Antiproliferative Activity. Chemistry 2015; 21:13703-13. [PMID: 26260662 PMCID: PMC4583781 DOI: 10.1002/chem.201502026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Indexed: 11/29/2022]
Abstract
A series of heteropentanuclear oxalate-bridged Ru(NO)-Ln (4d-4f) metal complexes of the general formula (nBu4N)5[Ln{RuCl3(μ-ox)(NO)}4], where Ln=Y (2), Gd (3), Tb (4), Dy (5) and ox=oxalate anion, were obtained by treatment of (nBu4N)2[RuCl3(ox)(NO)] (1) with the respective lanthanide salt in 4:1 molar ratio. The compounds were characterized by elemental analysis, IR spectroscopy, electrospray ionization (ESI) mass spectrometry, while 1, 2, and 5 were in addition analyzed by X-ray crystallography, 1 by Ru K-edge XAS and 1 and 2 by (13)C NMR spectroscopy. X-ray diffraction showed that in 2 and 5 four complex anions [RuCl3(ox)(NO)](2-) are coordinated to Y(III) and Dy(III), respectively, with formation of [Ln{RuCl3(μ-ox)(NO)}4](5-) (Ln=Y, Dy). While Y(III) is eight-coordinate in 2, Dy(III) is nine-coordinate in 5, with an additional coordination of an EtOH molecule. The negative charge is counterbalanced by five nBu4N(+) ions present in the crystal structure. The stability of complexes 2 and 5 in aqueous medium was monitored by UV/Vis spectroscopy. The antiproliferative activity of ruthenium-lanthanide complexes 2-5 were assayed in two human cancer cell lines (HeLa and A549) and in a noncancerous cell line (MRC-5) and compared with those obtained for the previously reported Os(NO)-Ln (5d-4f) analogues (nBu4N)5[Ln{OsCl3(ox)(NO)}4] (Ln=Y (6), Gd (7), Tb (8), Dy (9)). Complexes 2-5 were found to be slightly more active than 1 in inhibiting the proliferation of HeLa and A549 cells, and significantly more cytotoxic than 5d-4f metal complexes 6-9 in terms of IC50 values. The highest antiproliferative activity with IC50 values of 20.0 and 22.4 μM was found for 4 in HeLa and A549 cell lines, respectively. These cytotoxicity results are in accord with the presented ICP-MS data, indicating five- to eightfold greater accumulation of ruthenium versus osmium in human A549 cancer cells.
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Affiliation(s)
- Paul-Steffen Kuhn
- University of Vienna, Faculty of Chemistry, Institute of Inorganic Chemistry, Währinger Strasse 42, 1090 Vienna (Austria)
| | - Laura Cremer
- University of Vienna, Faculty of Chemistry, Institute of Inorganic Chemistry, Währinger Strasse 42, 1090 Vienna (Austria)
| | - Anatolie Gavriluta
- Université Claude Bernard Lyon 1, Laboratoire des Multimatériaux et Interfaces (UMR 5615), Campus de la Doua, 69622 Villeurbanne cedex (France)
| | - Katarina K Jovanović
- Institute for Oncology and Radiology of Serbia, Pasterova 14, 11000 Belgrade (Serbia)
| | - Lana Filipović
- Institute for Oncology and Radiology of Serbia, Pasterova 14, 11000 Belgrade (Serbia)
| | - Alfred A Hummer
- Universität Wien, Fakultät für Chemie, Institut für Biophysikalische Chemie, Althanstraße 14, 1090 Wien (Austria)
| | - Gabriel E Büchel
- University of Vienna, Faculty of Chemistry, Institute of Inorganic Chemistry, Währinger Strasse 42, 1090 Vienna (Austria)
- Present address: Division for Physical Sciences and Engineering and KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)
| | - Biljana P Dojčinović
- University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Center of Chemistry, Studentski trg 12-16, Belgrade (Serbia)
| | - Samuel M Meier
- Faculty of Chemistry, Institute of Analytical Chemistry, University of Vienna, Währinger Strasse 38, 1090 Vienna (Austria)
| | - Annette Rompel
- Universität Wien, Fakultät für Chemie, Institut für Biophysikalische Chemie, Althanstraße 14, 1090 Wien (Austria)
| | - Siniša Radulović
- Institute for Oncology and Radiology of Serbia, Pasterova 14, 11000 Belgrade (Serbia)
| | - Jean Bernard Tommasino
- Université Claude Bernard Lyon 1, Laboratoire des Multimatériaux et Interfaces (UMR 5615), Campus de la Doua, 69622 Villeurbanne cedex (France)
| | - Dominique Luneau
- Université Claude Bernard Lyon 1, Laboratoire des Multimatériaux et Interfaces (UMR 5615), Campus de la Doua, 69622 Villeurbanne cedex (France).
| | - Vladimir B Arion
- University of Vienna, Faculty of Chemistry, Institute of Inorganic Chemistry, Währinger Strasse 42, 1090 Vienna (Austria).
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11
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Dehigaspitiya DC, Navath S, Weber CS, Lynch RM, Mash EA. Synthesis and bioactivity of MSH4 oligomers prepared by an A 2 + B 2 strategy. Tetrahedron Lett 2015; 56:3060-3065. [PMID: 26120211 PMCID: PMC4480789 DOI: 10.1016/j.tetlet.2014.12.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Oligomers incorporating the tetrapeptide MSH4, the minimum active sequence of melanocyte stimulating hormone, were synthesized by an A2 + B2 strategy involving microwave-assisted copper-catalyzed azide-alkyne cycloaddition. A2 contained an MSH4 core while B2 contained a (Pro-Gly)3 spacer. Soluble mixtures containing compounds with up to eight MSH4 units were obtained from oligomerizations at high monomer concentrations. The avidities of several oligomeric mixtures were evaluated by means of a competitive binding assay using HEK293 cells engineered to overexpress the melanocortin 4 receptor. When based on total MSH4 concentrations, avidities were only minimally enhanced compared with a monovalent control. The lack of variation in the effect of ligands on probe binding is consistent with high off rates for MSH4 in both monovalent and oligomeric constructs relative to that of the competing probe.
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Affiliation(s)
| | - Suryakiran Navath
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721-0041, USA
| | - Craig S. Weber
- Department of Physiology, University of Arizona, Tucson, AZ 85724-5051, USA
| | - Ronald M. Lynch
- Department of Physiology, University of Arizona, Tucson, AZ 85724-5051, USA
- The Bio5 Institute, University of Arizona, Tucson, AZ 85721-0240, USA
| | - Eugene A. Mash
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721-0041, USA
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12
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Haugaard-Kedström LM, Wong LLL, Bathgate RAD, Rosengren KJ. Synthesis and pharmacological characterization of a europium-labelled single-chain antagonist for binding studies of the relaxin-3 receptor RXFP3. Amino Acids 2015; 47:1267-71. [DOI: 10.1007/s00726-015-1961-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 03/07/2015] [Indexed: 10/23/2022]
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13
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Steyn LV, Ananthakrishnan K, Anderson MJ, Patek R, Kelly A, Vagner J, Lynch RM, Limesand SW. A Synthetic Heterobivalent Ligand Composed of Glucagon-Like Peptide 1 and Yohimbine Specifically Targets β Cells Within the Pancreas. Mol Imaging Biol 2015; 17:461-70. [PMID: 25604385 DOI: 10.1007/s11307-014-0817-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 12/11/2014] [Accepted: 12/18/2014] [Indexed: 12/15/2022]
Abstract
PURPOSE β Cell specificity for a heterobivalent ligand composed of glucagon-like peptide-1 (GLP-1) linked to yohimbine (GLP-1/Yhb) was evaluated to determine its utility as a noninvasive imaging agent. PROCEDURES Competition binding assays were performed on βTC3 cells and isolated rat islets. Immunostaining for insulin was used to co-localized intravenously injected Cy5-labeled GLP-1/Yhb in β cells of Sprague-Dawley rats. Rats were intravenously injected with In-111-labeled GLP-1/Yhb to determine clearance rates and tissue biodistribution. Tissue-specific binding was confirmed by competition with pre-administration of unlabeled GLP-1/Yhb and in Streptozotocin-induced diabetic rats. RESULTS In βTC3 cells, high affinity binding of GLP-1/Yhb required interactions with both receptors because monovalent competition or receptor knockdown with RNAi lowered specificity and avidity of the heterobivalent ligand. Binding specificity for isolated islets was 2.6-fold greater than that of acinar tissue or islets pre-incubated with excess unlabeled GLP-1/Yhb. Immunofluorescent localization of Cy5-labeled GLP-1/Yhb was restricted to pancreatic islets. Within 30 min, ~90% of the In-111-labeled GLP-1/Yhb was cleared from blood. Tissue-specific accumulation of radiolabeled ligand was apparent in the pancreas, but not in other tissues within the abdominal imaging field. Pancreas specificity was lost in Streptozotocin-induced diabetic rats. CONCLUSIONS The GLP-1/Yhb exhibits high specificity for β cells, rapid blood clearance rates, and low non-specific uptake by other tissues within the abdominal imaging field. These characteristics of GLP-1/Yhb are desirable for application to β cell imaging in vivo and provide a basis for developing additional multivalent β cell-specific targeting agents to aid in the management of type 1 diabetes.
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Affiliation(s)
- Leah V Steyn
- School of Animal and Comparative Biomedical Sciences, William J. Parker Agricultural Research Center, The University of Arizona, 4101 N Campbell Ave, Tucson, AZ, 85719, USA
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14
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Boulay A, Deraeve C, Vander Elst L, Leygue N, Maury O, Laurent S, Muller RN, Mestre-Voegtlé B, Picard C. Terpyridine-Based Heteroditopic Ligand for RuIILn3III Metallostar Architectures (Ln = Gd, Eu, Nd, Yb) with MRI/Optical or Dual-Optical Responses. Inorg Chem 2015; 54:1414-25. [DOI: 10.1021/ic502342x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Alexandre Boulay
- CNRS, Laboratoire de Synthèse et Physico-Chimie de Molécules d’Intérêt Biologique, SPCMIB, UMR-5068, 118 Route de Narbonne, F-31062 Toulouse cedex 9, France
- Université de Toulouse, UPS, Laboratoire de Synthèse et Physico-Chimie de Molécules d’Intérêt Biologique, SPCMIB, 118 route de Narbonne, F-31062 Toulouse cedex 9, France
| | - Céline Deraeve
- CNRS, Laboratoire de Synthèse et Physico-Chimie de Molécules d’Intérêt Biologique, SPCMIB, UMR-5068, 118 Route de Narbonne, F-31062 Toulouse cedex 9, France
- Université de Toulouse, UPS, Laboratoire de Synthèse et Physico-Chimie de Molécules d’Intérêt Biologique, SPCMIB, 118 route de Narbonne, F-31062 Toulouse cedex 9, France
| | - Luce Vander Elst
- NMR
and Molecular Imaging Laboratory, Department of General, Organic and
Biomedical Chemistry, University of Mons, 23 Place du Parc, B-7000 Mons, Belgium
- Center for Microscopy and Molecular Imaging (CMMI), Rue Adrienne Bolland, 8, B-6041 Gosselies, Belgium
| | - Nadine Leygue
- CNRS, Laboratoire de Synthèse et Physico-Chimie de Molécules d’Intérêt Biologique, SPCMIB, UMR-5068, 118 Route de Narbonne, F-31062 Toulouse cedex 9, France
- Université de Toulouse, UPS, Laboratoire de Synthèse et Physico-Chimie de Molécules d’Intérêt Biologique, SPCMIB, 118 route de Narbonne, F-31062 Toulouse cedex 9, France
| | - Olivier Maury
- Université de Lyon 1, Laboratoire de Chimie de l’ENS Lyon, CNRS UMR 5182, 46 allée d’Italie, 69364 Lyon, France
| | - Sophie Laurent
- NMR
and Molecular Imaging Laboratory, Department of General, Organic and
Biomedical Chemistry, University of Mons, 23 Place du Parc, B-7000 Mons, Belgium
- Center for Microscopy and Molecular Imaging (CMMI), Rue Adrienne Bolland, 8, B-6041 Gosselies, Belgium
| | - Robert N. Muller
- NMR
and Molecular Imaging Laboratory, Department of General, Organic and
Biomedical Chemistry, University of Mons, 23 Place du Parc, B-7000 Mons, Belgium
- Center for Microscopy and Molecular Imaging (CMMI), Rue Adrienne Bolland, 8, B-6041 Gosselies, Belgium
| | - Béatrice Mestre-Voegtlé
- CNRS, Laboratoire de Synthèse et Physico-Chimie de Molécules d’Intérêt Biologique, SPCMIB, UMR-5068, 118 Route de Narbonne, F-31062 Toulouse cedex 9, France
- Université de Toulouse, UPS, Laboratoire de Synthèse et Physico-Chimie de Molécules d’Intérêt Biologique, SPCMIB, 118 route de Narbonne, F-31062 Toulouse cedex 9, France
| | - Claude Picard
- CNRS, Laboratoire de Synthèse et Physico-Chimie de Molécules d’Intérêt Biologique, SPCMIB, UMR-5068, 118 Route de Narbonne, F-31062 Toulouse cedex 9, France
- Université de Toulouse, UPS, Laboratoire de Synthèse et Physico-Chimie de Molécules d’Intérêt Biologique, SPCMIB, 118 route de Narbonne, F-31062 Toulouse cedex 9, France
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15
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Synthesis and Characterisation of First Generation Luminescent Lanthanide Complexes Suitable for Being Adapted for Uptake via the Mannose Receptor. ACTA ACUST UNITED AC 2013. [DOI: 10.1155/2013/498598] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
With the aim of directing lanthanide complex uptake via the mannose receptor, a first generation of luminescent lanthanide complexes has been developed with an α-D-mannose targeting motif. Four complexes were produced to investigate photophysical properties and determine the effect of the coordinated mannose residue on emission intensity. The free hydroxyls of the α-D-mannose residue quenched lanthanide phosphorescence due to their close proximity, though they did not bind the lanthanide centre as observed by q-values ≈1.0 for all complexes between pH 3 and 10. Fluorescent emission was found to vary significantly with pH, though phosphorescent emission was relatively insensitive to pH. This lack of pH sensitivity has the potential to provide stable emission for the visualisation of the endosome-lysosome system where acidic pH is often encountered.
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Hart NJ, Chung WJ, Weber C, Ananthakrishnan K, Anderson M, Patek R, Zhang Z, Limesand SW, Vagner J, Lynch RM. Hetero-bivalent GLP-1/glibenclamide for targeting pancreatic β-cells. Chembiochem 2013; 15:135-45. [PMID: 24259278 DOI: 10.1002/cbic.201300375] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Indexed: 01/15/2023]
Abstract
G protein-coupled receptor (GPCR) cell signalling cascades are initiated upon binding of a specific agonist ligand to its cell surface receptor. Linking multiple heterologous ligands that simultaneously bind and potentially link different receptors on the cell surface is a unique approach to modulate cell responses. Moreover, if the target receptors are selected based on analysis of cell-specific expression of a receptor combination, then the linked binding elements might provide enhanced specificity of targeting the cell type of interest, that is, only to cells that express the complementary receptors. Two receptors whose expression is relatively specific (in combination) to insulin-secreting pancreatic β-cells are the sulfonylurea-1 (SUR1) and the glucagon-like peptide-1 (GLP-1) receptors. A heterobivalent ligand was assembled from the active fragment of GLP-1 (7-36 GLP-1) and glibenclamide, a small organic ligand for SUR1. The synthetic construct was labelled with Cy5 or europium chelated in DTPA to evaluate binding to β-cells, by using fluorescence microscopy or time-resolved saturation and competition binding assays, respectively. Once the ligand binds to β-cells, it is rapidly capped and presumably removed from the cell surface by endocytosis. The bivalent ligand had an affinity approximately fivefold higher than monomeric europium-labelled GLP-1, likely a result of cooperative binding to the complementary receptors on the βTC3 cells. The high-affinity binding was lost in the presence of either unlabelled monomer, thus demonstrating that interaction with both receptors is required for the enhanced binding at low concentrations. Importantly, bivalent enhancement was accomplished in a cell system with physiological levels of expression of the complementary receptors, thus indicating that this approach might be applicable for β-cell targeting in vivo.
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Affiliation(s)
- Nathaniel J Hart
- Department of Physiological Sciences, University of Arizona, 1656 E. Mabel St., Tucson, AZ 85721 (USA)
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17
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Hingorani DV, Gonzalez SI, Li JF, Pagel MD. Sensing lanthanide metal content in biological tissues with magnetic resonance spectroscopy. SENSORS (BASEL, SWITZERLAND) 2013; 13:13732-43. [PMID: 24152931 PMCID: PMC3859089 DOI: 10.3390/s131013732] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 09/22/2013] [Accepted: 09/27/2013] [Indexed: 11/17/2022]
Abstract
The development and validation of MRI contrast agents consisting of a lanthanide chelate often requires a determination of the concentration of the agent in ex vivo tissue. We have developed a protocol that uses 70% nitric acid to completely digest tissue samples that contain Gd(III), Dy(III), Tm(III), Eu(III), or Yb(III) ions, or the MRI contrast agent gadodiamide. NMR spectroscopy of coaxial tubes containing a digested sample and a separate control solution of nitric acid was used to rapidly and easily measure the bulk magnetic susceptibility (BMS) shift caused by each lanthanide ion and gadodiamide. Each BMS shift was shown to be linearly correlated with the concentration of each lanthanide ion and gadodiamide in the 70% nitric acid solution and in digested rat kidney and liver tissues. These concentration measurements had outstanding precision, and also had good accuracy for concentrations ≥10 mM for Tm(III) Eu(III), and Yb(III), and ≥3 mM for Gd(III), gadodiamide, and Dy(III). Improved sample handling methods are needed to improve measurement accuracy for samples with lower concentrations.
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Affiliation(s)
- Dina V. Hingorani
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA; E-Mail:
- University of Arizona Cancer Center, Tucson, AZ 85724-5013, USA; E-Mail:
| | - Sandra I. Gonzalez
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ 85721, USA; E-Mail:
| | - Jessica F. Li
- University of Arizona Cancer Center, Tucson, AZ 85724-5013, USA; E-Mail:
| | - Mark D. Pagel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA; E-Mail:
- University of Arizona Cancer Center, Tucson, AZ 85724-5013, USA; E-Mail:
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ 85721, USA; E-Mail:
- Department of Medical Imaging, University of Arizona, Tucson, AZ 85721, USA
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18
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Hoffman J, Flynn AN, Tillu DV, Zhang Z, Patek R, Price TJ, Vagner J, Boitano S. Lanthanide labeling of a potent protease activated receptor-2 agonist for time-resolved fluorescence analysis. Bioconjug Chem 2012; 23:2098-104. [PMID: 22994402 DOI: 10.1021/bc300300q] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protease activated receptor-2 (PAR(2)) is one of four G-protein coupled receptors (GPCRs) that can be activated by exogenous or endogenous proteases, which cleave the extracellular amino-terminus to expose a tethered ligand and subsequent G-protein signaling. Alternatively, PAR(2) can be activated by peptide or peptidomimetic ligands derived from the sequence of the natural tethered ligand. Screening of novel ligands that directly bind to PAR(2) to agonize or antagonize the receptor has been hindered by the lack of a sensitive, high-throughput, affinity binding assay. In this report, we describe the synthesis and use of a modified PAR(2) peptidomimetic agonist, 2-furoyl-LIGRLO-(diethylenetriaminepentaacetic acid)-NH(2) (2-f-LIGRLO-dtpa), designed for lanthanide-based time-resolved fluorescence screening. We first demonstrate that 2-f-LIGRLO-dtpa is a potent and specific PAR(2) agonist across a full spectrum of in vitro assays. We then show that 2-f-LIGRLO-dtpa can be utilized in an affinity binding assay to evaluate the ligand-receptor interactions between known high potency peptidomimetic agonists (2-furoyl-LIGRLO-NH(2), 2-f-LIGRLO; 2-aminothiazol-4-yl-LIGRL-NH(2), 2-at-LIGRL; 6-aminonicotinyl-LIGRL-NH(2), 6-an-LIGRL) and PAR(2). A separate N-terminal peptidomimetic modification (3-indoleacetyl-LIGRL-NH(2), 3-ia-LIGRL) that does not activate PAR(2) signaling was used as a negative control. All three peptidomimetic agonists demonstrated sigmoidal competitive binding curves, with the more potent agonists (2-f-LIGRLO and 2-at-LIGRL) displaying increased competition. In contrast, the control peptide (3-ia-LIGRL) displayed limited competition for PAR(2) binding. In summary, we have developed a europium-containing PAR(2) agonist that can be used in a highly sensitive affinity binding assay to screen novel PAR(2) ligands in a high-throughput format. This ligand can serve as a critical tool in the screening and development of PAR(2) ligands.
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Affiliation(s)
- Justin Hoffman
- Department of Physiology, Arizona Health Sciences Center, 1501 North Campbell Avenue, Tucson, AZ 85724-5030, USA
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Ali MM, Bhuiyan MP, Janic B, Varma NR, Mikkelsen T, Ewing JR, Knight RA, Pagel MD, Arbab AS. A nano-sized PARACEST-fluorescence imaging contrast agent facilitates and validates in vivo CEST MRI detection of glioma. Nanomedicine (Lond) 2012; 7:1827-37. [PMID: 22891866 DOI: 10.2217/nnm.12.92] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIM The authors have investigated the usefulness of in vivo chemical exchange saturation transfer MRI for detecting gliomas using a dual-modality imaging contrast agent. MATERIALS & METHODS A paramagnetic chemical exchange saturation transfer MRI contrast agent, Eu-1,4,7,10-tetraazacclododecane-1,4,7,10-tetraacetic acid-Gly(4) and a fluorescent agent, DyLight 680, were conjugated to a generation 5 polyamidoamine dendrimer to create the dual-modality, nano-sized imaging contrast agent. RESULTS The agent was detected with in vivo chemical exchange saturation transfer MRI in an U87 glioma model. These results were validated using in vivo and ex vivo fluorescence imaging. CONCLUSION This study demonstrated the merits of using a nano-sized imaging contrast agent for detecting gliomas and using a dual-modality agent for detecting gliomas at different spatial scales.
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Affiliation(s)
- Meser M Ali
- Henry Ford Hospital, Detroit, MI 48202, USA.
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