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Drakopoulos A, Koszegi Z, Seier K, Hübner H, Maurel D, Sounier R, Granier S, Gmeiner P, Calebiro D, Decker M. Design, Synthesis, and Characterization of New δ Opioid Receptor-Selective Fluorescent Probes and Applications in Single-Molecule Microscopy of Wild-Type Receptors. J Med Chem 2024. [PMID: 39044606 DOI: 10.1021/acs.jmedchem.4c00627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
The delta opioid receptor (δOR or DOR) is a G protein-coupled receptor (GPCR) showing a promising profile as a drug target for nociception and analgesia. Herein, we design and synthesize new fluorescent antagonist probes with high δOR selectivity that are ideally suited for single-molecule microscopy (SMM) applications in unmodified, untagged receptors. Using our new probes, we investigated wild-type δOR localization and mobility at low physiological receptor densities for the first time. Furthermore, we investigate the potential formation of δOR homodimers, as such a receptor organization might exhibit distinct pharmacological activity, potentially paving the way for innovative pharmacological therapies. Our findings indicate that the majority of δORs labeled with these probes exist as freely diffusing monomers on the cell surface in a simple cell model. This discovery advances our understanding of OR behavior and offers potential implications for future therapeutic research.
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Affiliation(s)
- Antonios Drakopoulos
- Pharmazeutische und Medizinische Chemie, Institut für Pharmazie und Lebensmittelchemie, Julius-Maximilians-Universität (JMU) Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Zsombor Koszegi
- Institute of Metabolism and Systems Research, University of Birmingham, B15 2TT Birmingham, U.K
- Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, B15 2TT Birmingham, U.K
| | - Kerstin Seier
- Institute of Pharmacology and Toxicology, Julius-Maximilians University of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany
| | - Harald Hübner
- Chair of Pharmaceutical Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Damien Maurel
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, 34094 Cedex 5 Montpellier, France
| | - Rémy Sounier
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, 34094 Cedex 5 Montpellier, France
| | - Sébastien Granier
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, 34094 Cedex 5 Montpellier, France
| | - Peter Gmeiner
- Chair of Pharmaceutical Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Davide Calebiro
- Institute of Metabolism and Systems Research, University of Birmingham, B15 2TT Birmingham, U.K
- Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, B15 2TT Birmingham, U.K
| | - Michael Decker
- Pharmazeutische und Medizinische Chemie, Institut für Pharmazie und Lebensmittelchemie, Julius-Maximilians-Universität (JMU) Würzburg, Am Hubland, 97074 Würzburg, Germany
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2
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Leon Duque MA, Vallavoju N, Woo CM. Chemical tools for the opioids. Mol Cell Neurosci 2023; 125:103845. [PMID: 36948231 PMCID: PMC10247539 DOI: 10.1016/j.mcn.2023.103845] [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: 01/13/2023] [Revised: 03/09/2023] [Accepted: 03/15/2023] [Indexed: 03/24/2023] Open
Abstract
The opioids are potent and widely used pain management medicines despite also possessing severe liabilities that have fueled the opioid crisis. The pharmacological properties of the opioids primarily derive from agonism or antagonism of the opioid receptors, but additional effects may arise from specific compounds, opioid receptors, or independent targets. The study of the opioids, their receptors, and the development of remediation strategies has benefitted from derivatization of the opioids as chemical tools. While these studies have primarily focused on the opioids in the context of the opioid receptors, these chemical tools may also play a role in delineating mechanisms that are independent of the opioid receptors. In this review, we describe recent advances in the development and applications of opioid derivatives as chemical tools and highlight opportunities for the future.
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Affiliation(s)
- Mark Anthony Leon Duque
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford St, Cambridge, MA 02138, United States of America
| | - Nandini Vallavoju
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford St, Cambridge, MA 02138, United States of America
| | - Christina M Woo
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford St, Cambridge, MA 02138, United States of America.
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3
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Giakomidi D, Bird MF, Guerrini R, Calo G, Lambert DG. Fluorescent opioid receptor ligands as tools to study opioid receptor function. J Pharmacol Toxicol Methods 2021; 113:107132. [PMID: 34728348 DOI: 10.1016/j.vascn.2021.107132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 10/12/2021] [Accepted: 10/25/2021] [Indexed: 11/30/2022]
Abstract
Opioid receptors are divided into the three classical types: MOP(μ:mu), DOP(δ:delta) and KOP(κ:kappa) that are naloxone-sensitive and an additional naloxone-insensitive nociceptin/orphanin FQ(N/OFQ) peptide receptor(NOP). Studies to determine opioid receptor location and turnover variably rely on; (i) measuring receptor mRNA, (ii) genetically tagging receptors, (iii) labelling receptors with radioligands, (iv) use of antibodies in immunohistochemistry/Western Blotting or (v) measuring receptor function coupled with the use of selective antagonists. All have their drawbacks with significant issues relating to mRNA not necessarily predicting protein, poor antibody selectivity and utility of radiolabels in low expression systems. In this minireview we discuss use of fluorescently labelled opioid receptor ligands. To maintain the pharmacological properties of the corresponding parent ligand fluorescently labelled ligands must take into account fluorophore (brightness and propensity to bleach), linker length and chemistry, and site to which the linker (and hence probe) will be attached. Use of donor and acceptor fluorophores with spectral overlap facilitates use in FRET type assays to determine proximity of ligand or tagged receptor pairs. There is a wide range of probes of agonist and antagonist nature for all four opioid receptor types; caution is needed with agonist probes due to the possibility for internalization. We have produced two novel ATTO based probes; DermorphinATTO488 (MOP) and N/OFQATTO594 (NOP). These probes label MOP and NOP in a range of preparations and using N/OFQATTO594 we demonstrate internalization and ligand-receptor interaction by FRET. Fluorescent opioid probes offer potential methodological advantages over more traditional use of antibodies and radiolabels.
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Affiliation(s)
- Despina Giakomidi
- Department of Cardiovascular Sciences (Anaesthesia, Critical Care and Pain Management), University of Leicester, Hodgkin Building, Leicester LE1 9HN. UK
| | - Mark F Bird
- Department of Cardiovascular Sciences (Anaesthesia, Critical Care and Pain Management), University of Leicester, Hodgkin Building, Leicester LE1 9HN. UK
| | - Remo Guerrini
- Department of Chemical, Pharmaceutical and Agricultural Sciences and LTTA, University of Ferrara, Italy
| | - Girolamo Calo
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, 35131 Padova, Italy
| | - David G Lambert
- Department of Cardiovascular Sciences (Anaesthesia, Critical Care and Pain Management), University of Leicester, Hodgkin Building, Leicester LE1 9HN. UK.
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4
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Zhang Y, Li S, Zhang H, Xu H. Design and Application of Receptor-Targeted Fluorescent Probes Based on Small Molecular Fluorescent Dyes. Bioconjug Chem 2021; 32:4-24. [PMID: 33412857 DOI: 10.1021/acs.bioconjchem.0c00606] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In recent years, a variety of receptor-targeted fluorescent probes have been developed and widely used to realize the visualization of certain receptors, which facilitates the early diagnosis and treatment of diseases. In this Review, we focus on the recent achievements in design, chemical structure, imaging characterization, and potential applications of receptor-targeted fluorescent probes from the past 10 years. The development and application of receptor-targeted fluorescent probes will expand our knowledge of the distribution and function of disease-related receptors, shed light on the drug discovery for clinical diseases where receptors are implicated, and feed into the diagnosis and treatment of a plethora of diseases, including tumors.
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Affiliation(s)
- Yujie Zhang
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co-innovation Center of Henan Province for New Drug R&D and Preclinical Safety, and School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Shufeng Li
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co-innovation Center of Henan Province for New Drug R&D and Preclinical Safety, and School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Hang Zhang
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co-innovation Center of Henan Province for New Drug R&D and Preclinical Safety, and School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Haiwei Xu
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co-innovation Center of Henan Province for New Drug R&D and Preclinical Safety, and School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, China
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5
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Drakopoulos A, Decker M. Development and Biological Applications of Fluorescent Opioid Ligands. Chempluschem 2020; 85:1354-1364. [DOI: 10.1002/cplu.202000212] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/30/2020] [Indexed: 12/24/2022]
Affiliation(s)
- Antonios Drakopoulos
- Pharmaceutical and Medicinal ChemistryInstitute of Pharmacy and Food ChemistryJulius Maximilian University of Würzburg 97074 Würzburg Germany
| | - Michael Decker
- Pharmaceutical and Medicinal ChemistryInstitute of Pharmacy and Food ChemistryJulius Maximilian University of Würzburg 97074 Würzburg Germany
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Transferrin receptor 1 targeted optical imaging for identifying glioma margin in mouse models. J Neurooncol 2020; 148:245-258. [PMID: 32405996 DOI: 10.1007/s11060-020-03527-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 05/04/2020] [Indexed: 01/12/2023]
Abstract
OBJECTIVE Optical molecular imaging technology that indiscriminately detects intracranial glioblastoma (GBM) can help neurosurgeons effectively remove tumor masses. Transferrin receptor 1 (TfR 1) is a diagnostic and therapeutic target in GBM. A TfR 1-targeted peptide, CRTIGPSVC (CRT), was shown to cross the blood brain barrier (BBB) and accumulate at high levels in GBM tissues. In this study, we synthesized a TfR 1-targeted near-infrared fluorescent (NIRF) probe, Cy5-CRT, for identifying the GBM tissue margin in mouse models. METHODS We initially confirmed the overexpression of TfR 1 in GBM and the tumor-specific homing ability of Cy5-CRT in subcutaneous and orthotopic GBM mouse models. We then examined the feasibility of Cy5-CRT for identifying the tumor margin in orthotopic GBM xenografts. Finally, we compared Cy5-CRT with the clinically used fluorescein sodium in identifying tumor margins. RESULTS Cy5-CRT specifically accumulated in GBM tissues and detected the tumor burden with exceptional contrast in mice with orthotopic GBM, enabling fluorescence-guided GBM resection under NIRF live imaging conditions. Importantly, Cy5-CRT recognized the GBM tissue margin more clearly than fluorescein sodium. CONCLUSIONS The TfR 1-targeted optical probe Cy5-CRT specifically differentiates tumor tissues from the surrounding normal brain with high sensitivity, indicating its potential application for the precise surgical removal of GBM.
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7
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Drakopoulos A, Koszegi Z, Lanoiselée Y, Hübner H, Gmeiner P, Calebiro D, Decker M. Investigation of Inactive-State κ Opioid Receptor Homodimerization via Single-Molecule Microscopy Using New Antagonistic Fluorescent Probes. J Med Chem 2020; 63:3596-3609. [DOI: 10.1021/acs.jmedchem.9b02011] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Antonios Drakopoulos
- Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy and Food Chemistry, Julius Maximilian University of Würzburg, 97074 Würzburg, Germany
| | - Zsombor Koszegi
- Institute of Metabolism and Systems Research and Centre of Membrane Proteins and Receptors, College of Medical and Dental Sciences, University of Birmingham, B152TT Birmingham, U.K
| | - Yann Lanoiselée
- Institute of Metabolism and Systems Research and Centre of Membrane Proteins and Receptors, College of Medical and Dental Sciences, University of Birmingham, B152TT Birmingham, U.K
| | - Harald Hübner
- Medicinal Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Peter Gmeiner
- Medicinal Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Davide Calebiro
- Institute of Metabolism and Systems Research and Centre of Membrane Proteins and Receptors, College of Medical and Dental Sciences, University of Birmingham, B152TT Birmingham, U.K
| | - Michael Decker
- Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy and Food Chemistry, Julius Maximilian University of Würzburg, 97074 Würzburg, Germany
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8
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Cohen AS, Khalil FK, Welsh EA, Schabath MB, Enkemann SA, Davis A, Zhou JM, Boulware DC, Kim J, Haura EB, Morse DL. Cell-surface marker discovery for lung cancer. Oncotarget 2017; 8:113373-113402. [PMID: 29371917 PMCID: PMC5768334 DOI: 10.18632/oncotarget.23009] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/11/2017] [Indexed: 12/15/2022] Open
Abstract
Lung cancer is the leading cause of cancer deaths in the United States. Novel lung cancer targeted therapeutic and molecular imaging agents are needed to improve outcomes and enable personalized care. Since these agents typically cannot cross the plasma membrane while carrying cytotoxic payload or imaging contrast, discovery of cell-surface targets is a necessary initial step. Herein, we report the discovery and characterization of lung cancer cell-surface markers for use in development of targeted agents. To identify putative cell-surface markers, existing microarray gene expression data from patient specimens were analyzed to select markers with differential expression in lung cancer compared to normal lung. Greater than 200 putative cell-surface markers were identified as being overexpressed in lung cancers. Ten cell-surface markers (CA9, CA12, CXorf61, DSG3, FAT2, GPR87, KISS1R, LYPD3, SLC7A11 and TMPRSS4) were selected based on differential mRNA expression in lung tumors vs. non-neoplastic lung samples and other normal tissues, and other considerations involving known biology and targeting moieties. Protein expression was confirmed by immunohistochemistry (IHC) staining and scoring of patient tumor and normal tissue samples. As further validation, marker expression was determined in lung cancer cell lines using microarray data and Kaplan–Meier survival analyses were performed for each of the markers using patient clinical data. High expression for six of the markers (CA9, CA12, CXorf61, GPR87, LYPD3, and SLC7A11) was significantly associated with worse survival. These markers should be useful for the development of novel targeted imaging probes or therapeutics for use in personalized care of lung cancer patients.
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Affiliation(s)
- Allison S Cohen
- Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - Farah K Khalil
- Department of Anatomic Pathology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - Eric A Welsh
- Biomedical Informatics Shared Resource, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - Matthew B Schabath
- Department of Cancer Epidemiology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - Steven A Enkemann
- Molecular Genomics Shared Resource, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - Andrea Davis
- Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - Jun-Min Zhou
- Biostatistics Shared Resource, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - David C Boulware
- Biostatistics Shared Resource, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - Jongphil Kim
- Department of Biostatistics, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA.,Department of Oncologic Sciences, College of Medicine, University of South Florida, Tampa, FL, USA
| | - Eric B Haura
- Department of Thoracic Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - David L Morse
- Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA.,Department of Oncologic Sciences, College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Physics, College of Arts and Sciences, University of South Florida, Tampa, FL, USA
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9
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Sewda K, Coppola D, Enkemann S, Yue B, Kim J, Lopez AS, Wojtkowiak JW, Stark VE, Morse B, Shibata D, Vignesh S, Morse DL. Cell-surface markers for colon adenoma and adenocarcinoma. Oncotarget 2017; 7:17773-89. [PMID: 26894861 PMCID: PMC4951249 DOI: 10.18632/oncotarget.7402] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 01/24/2016] [Indexed: 12/26/2022] Open
Abstract
Early detection of colorectal cancer (CRC) is crucial for effective treatment. Among CRC screening techniques, optical colonoscopy is widely considered the gold standard. However, it is a costly and invasive procedure with a low rate of compliance. Our long-term goal is to develop molecular imaging agents for the non-invasive detection of CRC by molecular imaging-based colonoscopy using CT, MRI or fluorescence. To achieve this, cell surface targets must be identified and validated. Here, we report the discovery of cell-surface markers that distinguish CRC from surrounding tissues that could be used as molecular imaging targets. Profiling of mRNA expression microarray data from patient tissues including adenoma, adenocarcinoma, and normal gastrointestinal tissues was used to identify potential CRC specific cell-surface markers. Of the identified markers, six were selected for further validation (CLDN1, GPR56, GRM8, LY6G6D/F, SLCO1B3 and TLR4). Protein expression was confirmed by immunohistochemistry of patient tissues. Except for SLCO1B3, diffuse and low expression was observed for each marker in normal colon tissues. The three markers with the greatest protein overexpression were CLDN1, LY6G6D/F and TLR4, where at least one of these markers was overexpressed in 97% of the CRC samples. GPR56, LY6G6D/F and SLCO1B3 protein expression was significantly correlated with the proximal tumor location and with expression of mismatch repair genes. Marker expression was further validated in CRC cell lines. Hence, three cell-surface markers were discovered that distinguish CRC from surrounding normal tissues. These markers can be used to develop imaging or therapeutic agents targeted to the luminal surface of CRC.
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Affiliation(s)
- Kamini Sewda
- Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Domenico Coppola
- Department of Anatomic Pathology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Steven Enkemann
- Department of Molecular Genomics, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Binglin Yue
- Department of Biostatistics and Bioinformatics, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Jongphil Kim
- Department of Biostatistics and Bioinformatics, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Alexis S Lopez
- Department of Tissue Core, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Jonathan W Wojtkowiak
- Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Valerie E Stark
- Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Brian Morse
- Department of Diagnostic Imaging, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - David Shibata
- Department of Surgery, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Shivakumar Vignesh
- Division of Gastroenterology and Hepatology, SUNY Health Sciences Center at Brooklyn, Brooklyn, NY 11203, USA
| | - David L Morse
- Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
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10
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Huynh AS, Estrella V, Stark VE, Cohen AS, Chen T, Casagni TJ, Josan JS, Lloyd MC, Johnson J, Hruby VJ, Vagner J, Morse DL. Tumor Targeting and Pharmacokinetics of a Near-Infrared Fluorescent-Labeled δ-Opioid Receptor Antagonist Agent, Dmt-Tic-Cy5. Mol Pharm 2016; 13:534-44. [PMID: 26713599 PMCID: PMC4936951 DOI: 10.1021/acs.molpharmaceut.5b00760] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Fluorescence molecular imaging can be employed for the development of novel cancer targeting agents. Herein, we investigated the pharmacokinetics (PK) and cellular uptake of Dmt-Tic-Cy5, a delta-opioid receptor (δOR) antagonist-fluorescent dye conjugate, as a tumor-targeting molecular imaging agent. δOR expression is observed normally in the CNS, and pathologically in some tumors, including lung liver and breast cancers. In vitro, in vivo, and ex vivo experiments were conducted to image and quantify the fluorescence signal associated with Dmt-Tic-Cy5 over time using in vitro and intravital fluorescence microscopy and small animal fluorescence imaging of tumor-bearing mice. We observed specific retention of Dmt-Tic-Cy5 in tumors with maximum uptake in δOR-expressing positive tumors at 3 h and observable persistence for >96 h; clearance from δOR nonexpressing negative tumors by 6 h; and systemic clearance from normal organs by 24 h. Live-cell and intravital fluorescence microscopy demonstrated that Dmt-Tic-Cy5 had sustained cell-surface binding lasting at least 24 h with gradual internalization over the initial 6 h following administration. Dmt-Tic-Cy5 is a δOR-targeted agent that exhibits long-lasting and specific signal in δOR-expressing tumors, is rapidly cleared from systemic circulation, and is not retained in non-δOR-expressing tissues. Hence, Dmt-Tic-Cy5 has potential as a fluorescent tumor imaging agent.
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Affiliation(s)
- Amanda Shanks Huynh
- Department of Cancer Imaging & Metabolism, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Veronica Estrella
- Department of Cancer Imaging & Metabolism, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Valerie E. Stark
- Department of Cancer Imaging & Metabolism, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Allison S. Cohen
- Department of Cancer Imaging & Metabolism, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Tingan Chen
- Analytic Microscopy Core, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Todd J. Casagni
- Department of Comparative Medicine, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive Tampa, FL 33612
| | - Jatinder S. Josan
- Department of Chemistry, The University of Arizona, 1306 E University Blvd., Tucson, AZ 85719
| | - Mark C. Lloyd
- Analytic Microscopy Core, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Joseph Johnson
- Analytic Microscopy Core, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Victor J. Hruby
- Department of Chemistry, The University of Arizona, 1306 E University Blvd., Tucson, AZ 85719
| | - Josef Vagner
- The BIO5 Research Institute, University of Arizona, 1657 E Helen Street, Tucson, Arizona 85721
| | - David L. Morse
- Department of Cancer Imaging & Metabolism, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
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11
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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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12
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Vernall AJ, Hill SJ, Kellam B. The evolving small-molecule fluorescent-conjugate toolbox for Class A GPCRs. Br J Pharmacol 2014; 171:1073-84. [PMID: 23734587 DOI: 10.1111/bph.12265] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 05/09/2013] [Accepted: 05/17/2013] [Indexed: 01/15/2023] Open
Abstract
The past decade has witnessed fluorescently tagged drug molecules gaining significant attraction in their use as pharmacological tools with which to visualize and interrogate receptor targets at the single-cell level. Additionally, one can generate detailed pharmacological information, such as affinity measurements, down to almost single-molecule detection limits. The now accepted utilization of fluorescence-based readouts in high-throughput/high-content screening provides further evidence that fluorescent molecules offer a safer and more adaptable substitute to radioligands in molecular pharmacology and drug discovery. One such drug-target family that has received considerable attention are the GPCRs; this review therefore summarizes the most recent developments in the area of fluorescent ligand design for this important drug target. We assess recently reported fluorescent conjugates by adopting a receptor-family-based approach, highlighting some of the strengths and weaknesses of the individual molecules and their subsequent use. This review adds further strength to the arguments that fluorescent ligand design and synthesis requires careful planning and execution; providing examples illustrating that selection of the correct fluorescent dye, linker length/composition and geographic attachment point to the drug scaffold can all influence the ultimate selectivity and potency of the final conjugate when compared with its unlabelled precursor. When optimized appropriately, the resultant fluorescent conjugates have been successfully employed in an array of assay formats, including flow cytometry, fluorescence microscopy, FRET and scanning confocal microscopy. It is clear that fluorescently labelled GPCR ligands remain a developing and dynamic research arena.
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Affiliation(s)
- Andrea J Vernall
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, UK
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13
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Ptaszek M. Rational design of fluorophores for in vivo applications. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 113:59-108. [PMID: 23244789 DOI: 10.1016/b978-0-12-386932-6.00003-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Several classes of small organic molecules exhibit properties that make them suitable for fluorescence in vivo imaging. The most promising candidates are cyanines, squaraines, boron dipyrromethenes, porphyrin derivatives, hydroporphyrins, and phthalocyanines. The recent designing and synthetic efforts have been dedicated to improving their optical properties (shift the absorption and emission maxima toward longer wavelengths and increase the brightness) as well as increasing their stability and water solubility. The most notable advances include development of encapsulated cyanine dyes with increased stability and water solubility, squaraine rotaxanes with increased stability, long-wavelength-absorbing boron dipyrromethenes, long-wavelength-absorbing porphyrin and hydroporphyrin derivatives, and water-soluble phthalocyanines. Recent advances in luminescence and bioluminescence have made self-illuminating fluorophores available for in vivo applications. Development of new types of hydroporphyrin energy-transfer dyads gives the promise for further advances in in vivo multicolor imaging.
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Affiliation(s)
- Marcin Ptaszek
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, Maryland, USA
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14
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Sridharan R, Zuber J, Connelly SM, Mathew E, Dumont ME. Fluorescent approaches for understanding interactions of ligands with G protein coupled receptors. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1838:15-33. [PMID: 24055822 PMCID: PMC3926105 DOI: 10.1016/j.bbamem.2013.09.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 09/03/2013] [Accepted: 09/08/2013] [Indexed: 11/18/2022]
Abstract
G protein coupled receptors are responsible for a wide variety of signaling responses in diverse cell types. Despite major advances in the determination of structures of this class of receptors, the underlying mechanisms by which binding of different types of ligands specifically elicits particular signaling responses remain unclear. The use of fluorescence spectroscopy can provide important information about the process of ligand binding and ligand dependent conformational changes in receptors, especially kinetic aspects of these processes that can be difficult to extract from X-ray structures. We present an overview of the extensive array of fluorescent ligands that have been used in studies of G protein coupled receptors and describe spectroscopic approaches for assaying binding and probing the environment of receptor-bound ligands with particular attention to examples involving yeast pheromone receptors. In addition, we discuss the use of fluorescence spectroscopy for detecting and characterizing conformational changes in receptors induced by the binding of ligands. Such studies have provided strong evidence for diversity of receptor conformations elicited by different ligands, consistent with the idea that GPCRs are not simple on and off switches. This diversity of states constitutes an underlying mechanistic basis for biased agonism, the observation that different stimuli can produce different responses from a single receptor. It is likely that continued technical advances will allow fluorescence spectroscopy to play an important role in continued probing of structural transitions in G protein coupled receptors. This article is part of a Special Issue entitled: Structural and biophysical characterisation of membrane protein-ligand binding.
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Affiliation(s)
- Rajashri Sridharan
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
| | - Jeffrey Zuber
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
| | - Sara M. Connelly
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
| | - Elizabeth Mathew
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
| | - Mark E. Dumont
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
- Department of Pediatrics, P.O. Box 777, University of Rochester Medical Center, Rochester, NY 14642
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15
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Hruby VJ, Cai M. Design of peptide and peptidomimetic ligands with novel pharmacological activity profiles. Annu Rev Pharmacol Toxicol 2013; 53:557-80. [PMID: 23294313 DOI: 10.1146/annurev-pharmtox-010510-100456] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Peptide hormones and neurotransmitters are of central importance in most aspects of intercellular communication and are involved in virtually all degenerative diseases. In this review, we discuss physicochemical approaches to the design of novel peptide and peptidomimetic agonists, antagonists, inverse agonists, and related compounds that have unique biological activity profiles, reduced toxic side effects, and, if desired, the ability to cross the blood-brain barrier. Designing ligands for specific biological and medical needs is emphasized, as is the close collaboration of chemists and biologists to maximize the chances for success. Special emphasis is placed on the use of conformational (ϕ-ψ space) and topographical (χ space) considerations in design.
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Affiliation(s)
- Victor J Hruby
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, USA.
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16
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Rejniak KA, Estrella V, Chen T, Cohen AS, Lloyd MC, Morse DL. The role of tumor tissue architecture in treatment penetration and efficacy: an integrative study. Front Oncol 2013; 3:111. [PMID: 23717812 PMCID: PMC3650652 DOI: 10.3389/fonc.2013.00111] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 04/22/2013] [Indexed: 12/02/2022] Open
Abstract
Despite the great progress that has been made in understanding cancer biology and the potential molecular targets for its treatment, the majority of drugs fail in the clinical trials. This may be attributed (at least in part) to the complexity of interstitial drug transport in the patient’s body, which is hard to test experimentally. Similarly, recent advances in molecular imaging have led to the development of targeted biomarkers that can predict pharmacological responses to therapeutic interventions. However, both the drug and biomarker molecules need to access the tumor tissue and be taken up into individual cells in concentrations sufficient to exert the desired effect. To investigate the process of drug penetration at the mesoscopic level we developed a computational model of interstitial transport that incorporates the biophysical properties of the tumor tissue, including its architecture and interstitial fluid flow, as well as the properties of the agents. This model is based on the method of regularized Stokeslets to describe the fluid flow coupled with discrete diffusion-advection-reaction equations to model the dynamics of the drugs. Our results show that the tissue cellular porosity and density influence the depth of penetration in a non-linear way, with sparsely packed tissues being traveled through more slowly than the denser tissues. We demonstrate that irregularities in the cell spatial configurations result in the formation of interstitial corridors that are followed by agents leading to the emergence of tissue zones with less exposure to the drugs. We describe how the model can be integrated with in vivo experiments to test the extravasation and penetration of the targeted biomarkers through the tumor tissue. A better understanding of tissue- or compound-specific factors that limit the penetration through the tumors is important for non-invasive diagnoses, chemotherapy, the monitoring of treatment responses, and the detection of tumor recurrence.
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Affiliation(s)
- Katarzyna A Rejniak
- Integrated Mathematical Oncology, H. Lee Moffitt Cancer Center and Research Institute Tampa, FL, USA ; Department of Oncologic Sciences, College of Medicine, University of South Florida Tampa, FL, USA
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17
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Heterobivalent ligands target cell-surface receptor combinations in vivo. Proc Natl Acad Sci U S A 2012; 109:21295-300. [PMID: 23236171 DOI: 10.1073/pnas.1211762109] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A challenge in tumor targeting is to deliver payloads to cancers while sparing normal tissues. A limited number of antibodies appear to meet this challenge as therapeutics themselves or as drug-antibody conjugates. However, antibodies suffer from their large size, which can lead to unfavorable pharmacokinetics for some therapeutic payloads, and that they are targeted against only a single epitope, which can reduce their selectivity and specificity. Here, we propose an alternative targeting approach based on patterns of cell surface proteins to rationally develop small, synthetic heteromultivalent ligands (htMVLs) that target multiple receptors simultaneously. To gain insight into the multivalent ligand strategy in vivo, we have generated synthetic htMVLs that contain melanocortin (MSH) and cholecystokinin (CCK) pharmacophores that are connected via a fluorescent labeled, rationally designed synthetic linker. These ligands were tested in an experimental animal model containing tumors that expressed only one (control) or both (target) MSH and CCK receptors. After systemic injection of the htMVL in tumor-bearing mice, label was highly retained in tumors that expressed both, compared with one, target receptors. Selectivity was quantified by using ex vivo measurement of Europium-labeled htMVL, which had up to 12-fold higher specificity for dual compared with single receptor expressing cells. This proof-of-principle study provides in vivo evidence that small, rationally designed bivalent htMVLs can be used to selectively target cells that express both, compared with single complimentary cell surface targets. These data open the possibility that specific combinations of targets on tumors can be identified and selectively targeted using htMVLs.
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18
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Huynh AS, Chung WJ, Cho HI, Moberg VE, Celis E, Morse DL, Vagner J. Novel toll-like receptor 2 ligands for targeted pancreatic cancer imaging and immunotherapy. J Med Chem 2012; 55:9751-62. [PMID: 23098072 DOI: 10.1021/jm301002f] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Toll-like receptor 2 (TLR2) is a target for immune system stimulation during cancer immunotherapy and a cell-surface marker for pancreatic cancer. To develop targeted agents for cancer imaging and therapy, we designed, synthesized, and characterized 13 novel, fully synthetic high affinity TLR2 agonists. Analogue 10 had the highest agonist activity (NF-κB functional assay, EC(50) = 20 nM) and binding affinity (competitive binding assay, K(i) = 25 nM). As an immune adjuvant, compound 10 stimulated the immune system in vivo by generation and persistence of antigen-specific CD8+ T cells indicating its potential use in cancer immunotherapy. After conjugation of near-infrared dye to 10, agonist activity (EC(50) = 34 nM) and binding affinity (K(i) = 11 nM) were retained in 13. Fluorescence signal was present in TLR2 expressing pancreatic tumor xenografts 24 h after injection of 13, while an excess of unlabeled ligand blocked 13 from binding to the tumor, resulting in significantly decreased signal (p < 0.001) demonstrating in vivo selectivity.
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Affiliation(s)
- Amanda Shanks Huynh
- Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center and Research Institute, 12902 Magnolia Drive, Tampa, Florida 33612, USA
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19
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Ai H. Layer-by-layer capsules for magnetic resonance imaging and drug delivery. Adv Drug Deliv Rev 2011; 63:772-88. [PMID: 21554908 DOI: 10.1016/j.addr.2011.03.013] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 01/20/2011] [Accepted: 03/30/2011] [Indexed: 12/30/2022]
Abstract
Layer-by-layer (LbL) self-assembled polyelectrolyte capsules have demonstrated their unique advantages and capability in drug delivery applications. These ordered micro/nano-structures are also promising candidates as imaging contrast agents for diagnostic and theranostic applications. Magnetic resonance imaging (MRI), one of the most powerful clinical imaging modalities, is moving forward to the molecular imaging field and requires the availability of advanced imaging probes. In this review, we are focusing on the design of MRI visible LbL capsules, which incorporate either paramagnetic metal-ligand complexes or superparamagnetic iron oxide (SPIO) nanoparticles. The design criteria cover the topics of probe sensitivity, biosafety, long-circulation property, targeting ligand decoration, and drug loading strategies. Examples of MRI visible LbL capsules with paramagnetic or superparamagnetic moieties were given and discussed. This carrier platform can also be chosen for other imaging modalities.
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Affiliation(s)
- Hua Ai
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, China.
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20
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Huynh AS, Abrahams DF, Torres MS, Baldwin MK, Gillies RJ, Morse DL. Development of an orthotopic human pancreatic cancer xenograft model using ultrasound guided injection of cells. PLoS One 2011; 6:e20330. [PMID: 21647423 PMCID: PMC3103544 DOI: 10.1371/journal.pone.0020330] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 04/20/2011] [Indexed: 12/17/2022] Open
Abstract
Mice have been employed as models of cancer for over a century, providing significant advances in our understanding of this multifaceted family of diseases. In particular, orthotopic tumor xenograft mouse models are emerging as the preference for cancer research due to increased clinical relevance over subcutaneous mouse models. In the current study, we developed orthotopic pancreatic cancer xenograft models in mice by a minimally invasive method, ultrasound guided injection (USGI) comparable to highly invasive surgical orthotopic injection (SOI) methods. This optimized method prevented injection complications such as recoil of cells through the injection canal or leakage of cells out of the pancreas into the peritoneal cavity. Tumor growth was monitored in vivo and quantified by ultrasound imaging weekly, tumors were also detected by in vivo fluorescence imaging using a tumor targeted molecular probe. The mean tumor volumes for the USGI and SOI models after 2 weeks of tumor growth were 205 mm(3) and 178 mm(3) respectively. By USGI of human pancreatic cancer cell lines, human orthotopic pancreatic cancer xenografts were established. Based on ultrasound imaging, the orthotopic human pancreatic cancer xenograft take rate was 100% for both human pancreatic cancer cell lines used, MiaPaCa-2 and Su86.86, with mean tumor volumes of 28 mm(3)and 30 mm(3). We demonstrated that this USGI method is feasible, reproducible, facile, minimally invasive and improved compared to the highly-invasive SOI method for establishing orthotopic pancreatic tumor xenograft models suitable for molecular imaging.
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Affiliation(s)
- Amanda Shanks Huynh
- Department of Functional and Molecular Imaging, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, United States of America
| | - Dominique F. Abrahams
- Division of Comparative Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Monica S. Torres
- Division of Comparative Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Margaret K. Baldwin
- Division of Comparative Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Robert J. Gillies
- Department of Functional and Molecular Imaging, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, United States of America
| | - David L. Morse
- Department of Functional and Molecular Imaging, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, United States of America
- * E-mail:
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21
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Josan JS, De Silva CR, Yoo B, Lynch RM, Pagel MD, Vagner J, Hruby VJ. Fluorescent and lanthanide labeling for ligand screens, assays, and imaging. Methods Mol Biol 2011; 716:89-126. [PMID: 21318902 PMCID: PMC3365840 DOI: 10.1007/978-1-61779-012-6_6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
Abstract
The use of fluorescent (or luminescent) and metal contrast agents in high-throughput screens, in vitro assays, and molecular imaging procedures has rapidly expanded in recent years. Here we describe the development and utility of high-affinity ligands for cancer theranostics and other in vitro screening -studies. In this context, we also illustrate the syntheses and use of heteromultivalent ligands as targeted imaging agents.
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22
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Kamioka S, Sugiyama S, Takahashi T, Doi T. Synthesis of chiral polyazamacrocycles of variable ring size. Org Biomol Chem 2010; 8:2529-36. [PMID: 20358124 DOI: 10.1039/c001228a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Synthesis and structure elucidation of optically active tri-, tetra-, and penta-azamacrocycles having 4-methoxyphenyl pendants are described. Regioselective ring opening of a nosylaziridine with secondary benzyl amines was repeatedly performed to afford the cyclization precursors. Intramolecular N-alkylation of N-(omega-haloalkyl) nosylamide provided tri-, tetra-, and penta-azamacrocycles. On the basis of our study of the tetra-azamacrocycle previously elucidated by X-ray single-crystal analysis and in solution by NMR analysis, we conclude that the tri-azamacrocycle does not mainly have a vase-type conformation because of the steric hindrance of the 4-methoxyphenyl groups but the penta-azamacrocycle has a vase-type conformation in CDCl(3) and in CD(2)Cl(2). The vase-type conformation of the penta-azamacrocycle is, however, not as much stable as that observed in the tetra-azamacrocycle because conformational flexibility of the penta-azamacrocycle was observed in deuterated benzene.
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Affiliation(s)
- Seiji Kamioka
- Department of Applied chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8552, Japan
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