1
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ten Hove M, Smyris A, Booijink R, Wachsmuth L, Hansen U, Alic L, Faber C, Hӧltke C, Bansal R. Engineered SPIONs functionalized with endothelin a receptor antagonist ameliorate liver fibrosis by inhibiting hepatic stellate cell activation. Bioact Mater 2024; 39:406-426. [PMID: 38855059 PMCID: PMC11157122 DOI: 10.1016/j.bioactmat.2024.05.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 05/16/2024] [Accepted: 05/17/2024] [Indexed: 06/11/2024] Open
Abstract
Endothelin-1/endothelin A receptor (ET-1/ETAR) pathway plays an important role in the progression of liver fibrosis by activating hepatic stellate cells (HSCs) - a key cell type involved in the pathogenesis of liver fibrosis. Inactivating HSCs by blocking the ET-1/ETAR pathway using a selective ETAR antagonist (ERA) represents a promising therapeutic approach for liver fibrosis. Unfortunately, small-molecule ERAs possess limited clinical potential due to poor bioavailability, short half-life, and rapid renal clearance. To improve the clinical applicability, we conjugated ERA to superparamagnetic iron-oxide nanoparticles (SPIONs) and investigated the therapeutic efficacy of ERA and ERA-SPIONs in vitro and in vivo and analyzed liver uptake by in vivo and ex vivo magnetic resonance imaging (MRI), HSCs-specific localization, and ET-1/ETAR-pathway antagonism in vivo. In murine and human liver fibrosis/cirrhosis, we observed overexpression of ET-1 and ETAR that correlated with HSC activation, and HSC-specific localization of ETAR. ERA and successfully synthesized ERA-SPIONs demonstrated significant attenuation in TGFβ-induced HSC activation, ECM production, migration, and contractility. In an acute CCl4-induced liver fibrosis mouse model, ERA-SPIONs exhibited higher liver uptake, HSC-specific localization, and ET-1/ETAR pathway antagonism. This resulted in significantly reduced liver-to-body weight ratio, plasma ALT levels, and α-SMA and collagen-I expression, indicating attenuation of liver fibrosis. In conclusion, our study demonstrates that the delivery of ERA using SPIONs enhances the therapeutic efficacy of ERA in vivo. This approach holds promise as a theranostic strategy for the MRI-based diagnosis and treatment of liver fibrosis.
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Affiliation(s)
- Marit ten Hove
- Personalized Diagnostics and Therapeutics, Department of Bioengineering Technologies, Technical Medical Centre, Faculty of Science and Technology, University of Twente, Enschede, the Netherlands
| | - Andreas Smyris
- Personalized Diagnostics and Therapeutics, Department of Bioengineering Technologies, Technical Medical Centre, Faculty of Science and Technology, University of Twente, Enschede, the Netherlands
| | - Richell Booijink
- Personalized Diagnostics and Therapeutics, Department of Bioengineering Technologies, Technical Medical Centre, Faculty of Science and Technology, University of Twente, Enschede, the Netherlands
| | - Lydia Wachsmuth
- Clinic of Radiology, University Hospital Muenster, Muenster, Germany
| | - Uwe Hansen
- Institute for Musculoskeletal Medicine, University Hospital Muenster, Muenster, Germany
| | - Lejla Alic
- Department of Magnetic Detection and Imaging, Technical Medical Centre, Faculty of Science and Technology, University of Twente, Enschede, the Netherlands
| | - Cornelius Faber
- Clinic of Radiology, University Hospital Muenster, Muenster, Germany
| | - Carsten Hӧltke
- Clinic of Radiology, University Hospital Muenster, Muenster, Germany
| | - Ruchi Bansal
- Personalized Diagnostics and Therapeutics, Department of Bioengineering Technologies, Technical Medical Centre, Faculty of Science and Technology, University of Twente, Enschede, the Netherlands
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2
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Bhattacharjee P, Iyer MR. Rational Design, Synthesis, and Evaluation of Fluorescent CB 2 Receptor Ligands for Live-Cell Imaging: A Comprehensive Review. Pharmaceuticals (Basel) 2023; 16:1235. [PMID: 37765043 PMCID: PMC10534640 DOI: 10.3390/ph16091235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/21/2023] [Accepted: 08/25/2023] [Indexed: 09/29/2023] Open
Abstract
The cannabinoid receptors CB1 and CB2 are class A G protein-coupled receptors (GPCRs) that are activated via endogenous lipids called endocannabinoids. The endocannabinoid system (ECS) plays a critical role in the regulation of several physiological states and a wide range of diseases. In recent years, drug discovery approaches targeting the cannabinoid type 2 receptor (CB2R) have gained prominence. Particular attention has been given to selective agonists targeting the CB2 receptors to circumvent the neuropsychotropic side effects associated with CB1 receptors. The pharmacological modulation of CB2R holds therapeutic promise for various diseases, such as inflammatory disorders and immunological conditions, as well as pain management and cancer treatment. Recently, the utilization of fluorescent probes has emerged as a valuable technique for investigating the interactions between ligands and proteins at an exceptional level of spatial and temporal precision. In this review, we aim to examine the progress made in the development of fluorescent probes targeting CB2 receptors and highlight their significance in facilitating the successful clinical translation of CB2R-based therapies.
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Affiliation(s)
| | - Malliga R. Iyer
- Section on Medicinal Chemistry, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5625 Fishers Lane, Rockville, MD 20852, USA
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3
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Delahaye J, Stölting M, Geyer C, Vogl T, Eisenblätter M, Helfen A, Höltke C. Development, synthesis and evaluation of novel fluorescent Endothelin-B receptor probes. Eur J Med Chem 2023; 258:115568. [PMID: 37379676 DOI: 10.1016/j.ejmech.2023.115568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 05/16/2023] [Accepted: 06/12/2023] [Indexed: 06/30/2023]
Abstract
The endothelin (ET) signaling system is comprised of three endothelin peptides (ET-1, -2 and -3) and two corresponding endothelin-A and -B receptors (ETAR and ETBR), which belong to the G-protein coupled receptor (GPCR) superfamily. The endothelin axis, as this system is also referred to, contributes to the maintenance of vascular tone, functions as regulator of inflammation and proliferation and helps in balancing water homeostasis. In pathological settings, the ET axis is known to contribute to endothelial activation in cardiovascular diseases, to cell proliferation, chemoresistance and metastasis in cancer and to inflammation and fibrosis in renal disease. Antagonists of ETAR and ETBR, either subtype-specific compounds or substances with high affinity to both receptors, have been developed for more than 30 years. In the preclinical context, in vivo imaging of endothelin receptor expression has been utilized to assess ET-axis contribution to e.g. cancer or myocardial infarction. In this work, we present the development and synthesis of two novel ETBR-specific fluorescent probes, based on the available antagonists BQ788 and IRL2500 and their preliminary evaluation in a breast cancer context.
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Affiliation(s)
| | - Miriam Stölting
- Clinic for Radiology, University Hospital Münster, Münster, Germany
| | - Christiane Geyer
- Clinic for Radiology, University Hospital Münster, Münster, Germany
| | - Thomas Vogl
- Institute of Immunology, University of Münster, Münster, Germany
| | - Michel Eisenblätter
- Clinic for Radiology, University Hospital Münster, Münster, Germany; Department of Diagnostic and Interventional Radiology, Medical Faculty OWL, Bielefeld University, Bielefeld, Germany
| | - Anne Helfen
- Clinic for Radiology, University Hospital Münster, Münster, Germany
| | - Carsten Höltke
- Clinic for Radiology, University Hospital Münster, Münster, Germany.
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4
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Ferraro R, Ascione F, Dogra P, Cristini V, Guido S, Caserta S. Diffusion‐induced anisotropic cancer invasion: a novel experimental method based on tumour spheroids. AIChE J 2022. [DOI: 10.1002/aic.17678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Rosalia Ferraro
- Università degli Studi di Napoli Federico II Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale Naples Italy
- CEINGE Advanced Biotechnologies Naples Italy
| | - Flora Ascione
- Università degli Studi di Napoli Federico II Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale Naples Italy
| | - Prashant Dogra
- Mathematics in Medicine Program Houston Methodist Research Institute Houston Texas USA
- Department of Physiology and Biophysics Weill Cornell Medical College New York New York USA
| | - Vittorio Cristini
- Mathematics in Medicine Program Houston Methodist Research Institute Houston Texas USA
- Department of Imaging Physics University of Texas MD Anderson Cancer Center Houston Texas USA
- Physiology, Biophysics, and Systems Biology Program, Graduate School of Medical Sciences Weill Cornell Medicine New York New York USA
| | - Stefano Guido
- Università degli Studi di Napoli Federico II Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale Naples Italy
- CEINGE Advanced Biotechnologies Naples Italy
| | - Sergio Caserta
- Università degli Studi di Napoli Federico II Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale Naples Italy
- CEINGE Advanced Biotechnologies Naples Italy
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5
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Kimm MA, Haas H, Stölting M, Kuhlmann M, Geyer C, Glasl S, Schäfers M, Ntziachristos V, Wildgruber M, Höltke C. Targeting Endothelin Receptors in a Murine Model of Myocardial Infarction Using a Small Molecular Fluorescent Probe. Mol Pharm 2019; 17:109-117. [PMID: 31816245 DOI: 10.1021/acs.molpharmaceut.9b00810] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The endothelin (ET) axis plays a pivotal role in cardiovascular diseases. Enhanced levels of circulating ET-1 have been correlated with an inferior clinical outcome after myocardial infarction (MI) in humans. Thus, the evaluation of endothelin-A receptor (ETAR) expression over time in the course of myocardial injury and healing may offer valuable information toward the understanding of the ET axis involvement in MI. We developed an approach to track the expression of ETAR with a customized molecular imaging probe in a murine model of MI. The small molecular probe based on the ETAR-selective antagonist 3-(1,3-benzodioxol-5-yl)-5-hydroxy-5-(4-methoxyphenyl)-4-[(3,4,5-trimethoxyphenyl)methyl]-2(5H)-furanone (PD156707) was labeled with fluorescent dye, IRDye800cw. Mice undergoing permanent ligation of the left anterior descending artery (LAD) were investigated at day 1, 7, and 21 post surgery after receiving an intravenous injection of the ETAR probe. Cryosections of explanted hearts were analyzed by cryotome-based CCD, and fluorescence reflectance imaging (FRI) and fluorescence signal intensities (SI) were extracted. Fluorescence-mediated tomography (FMT) imaging was performed to visualize probe distribution in the target region in vivo. An enhanced fluorescence signal intensity in the infarct area was detected in cryoCCD images as early as day 1 after surgery and intensified up to 21 days post MI. FRI was capable of detecting significantly enhanced SI in infarcted regions of hearts 7 days after surgery. In vivo imaging by FMT localized enhanced SI in the apex region of infarcted mouse hearts. We verified the localization of the probe and ETAR within the infarct area by immunohistochemistry (IHC). In addition, neovascularized areas were found in the affected myocardium by CD31 staining. Our study demonstrates that the applied fluorescent probe is capable of delineating ETAR expression over time in affected murine myocardium after MI in vivo and ex vivo.
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Affiliation(s)
- Melanie A Kimm
- Department of Diagnostic and Interventional Radiology, School of Medicine and Klinikum rechts der Isar , Technical University of Munich , Munich 81675 , Germany
| | - Helena Haas
- Department of Diagnostic and Interventional Radiology, School of Medicine and Klinikum rechts der Isar , Technical University of Munich , Munich 81675 , Germany
| | - Miriam Stölting
- Translational Research Imaging Center, Department of Clinical Radiology , University Hospital Münster , Münster 48149 , Germany
| | - Michael Kuhlmann
- European Institute for Molecular Imaging , University Hospital Münster , Münster 48149 , Germany
| | - Christiane Geyer
- Translational Research Imaging Center, Department of Clinical Radiology , University Hospital Münster , Münster 48149 , Germany
| | - Sarah Glasl
- Institute of Biological and Medical Imaging , Helmholtz Zentrum München , Munich 85764 , Germany
| | - Michael Schäfers
- European Institute for Molecular Imaging , University Hospital Münster , Münster 48149 , Germany
| | - Vasilis Ntziachristos
- Institute of Biological and Medical Imaging , Helmholtz Zentrum München , Munich 85764 , Germany
| | - Moritz Wildgruber
- Department of Diagnostic and Interventional Radiology, School of Medicine and Klinikum rechts der Isar , Technical University of Munich , Munich 81675 , Germany.,Translational Research Imaging Center, Department of Clinical Radiology , University Hospital Münster , Münster 48149 , Germany
| | - Carsten Höltke
- Translational Research Imaging Center, Department of Clinical Radiology , University Hospital Münster , Münster 48149 , Germany
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6
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Mücke MM, Bettenworth D, Geyer C, Schwegmann K, Poremba C, Schäfers M, Domagk D, Höltke C, Lenz P. Targeting Mucosal Endothelin-A-Receptor Expression by Fluorescence Endoscopy is Feasible to Detect and Characterize Colitis-Associated Cancer in Mice. Inflamm Bowel Dis 2017; 24:111-122. [PMID: 29272493 DOI: 10.1093/ibd/izx032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND To facilitate onsite decision-making during endoscopy, both accurate detection and in vivo characterization of preneoplasia are prerequisites. However, no endoscopy technique is available that meets both demands satisfactorily. We evaluated endothelin-receptor A (ETAR)-guided fluorescence endoscopy (FE) in vivo and fluorescence reflectance imaging (FRI) ex vivo for detection and characterization of early dysplastic colitis-associated colonic lesions. METHODS Colorectal cancerogenesis was investigated in the inflammatory driven AOM-DSS model and spontaneous adenoma development in ApcMin mice. A Cy5.5-labeled nonpeptidic ETAR-specific imaging probe was injected intravenously to assess tumor development in vivo by white light endoscopy (WLE) and FE. Ex vivo tumors were evaluated by FRI, histological examination, and western blot analysis. In addition, tissue samples from patients with colitis-associated malignant and nonmalignant mucosal alterations were analyzed. Specificity experiments were performed using an unspecific Cy3.5-glycine tracer. RESULTS Overall, 62 adenomas were observed. FE was able to detect and quantify ETAR expression targeting the ETAR-specific photoprobe. A significantly higher fluorescent contrast was detected in colonic adenomas compared to adjacent nonmalignant mucosa by FE (64.3 ± 7.9 vs. 56.6. ± 7.0; P < 0.001). These results were confirmed by FRI examination, immunochemistry, and western blot analysis. Additionally, ETAR expression in samples from human patients with colitis-associated cancer was highly elevated compared to nonmalignant alterations. Specificity experiments indicated a high binding-specificity of the applied ETAR photoprobe (1.4 ± 0.3 vs. 2.5 ± 0.7; P < 0.001). CONCLUSIONS We introduced ETAR guided FE in mice for successful in vivo detection and characterization of colorectal neoplasia on a molecular level.
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Affiliation(s)
- Marcus M Mücke
- University Hospital Frankfurt, Department of Internal Medicine 1, Frankfurt a. M., Germany
| | | | - Christiane Geyer
- University of Münster, Department of Clinical Radiology, Münster, Germany
| | - Katrin Schwegmann
- University of Münster, European Institute for Molecular Imaging, Münster, Germany
| | | | - Michael Schäfers
- University of Münster, European Institute for Molecular Imaging, Münster, Germany
| | - Dirk Domagk
- Josephs-Hospital Warendorf, Warendorf, Germany
| | - Carsten Höltke
- University of Münster, Department of Clinical Radiology, Münster, Germany
| | - Philipp Lenz
- University of Münster, Department of Medicine B, Münster, Germany.,University of Münster, European Institute for Molecular Imaging, Münster, Germany.,Institute of Palliative Care, University Hospital of Münster, Münster, Germany
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7
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Wang L, Meng D, Hao Y, Hu Y, Niu M, Zheng C, Yanyan Y, Li D, Zhang P, Chang J, Zhang Z, Zhang Y. A gold nanostar based multi-functional tumor-targeting nanoplatform for tumor theranostic applications. J Mater Chem B 2016; 4:5895-5906. [DOI: 10.1039/c6tb01304j] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A gold nanostar based multi-functional tumor-targeting nanoplatform (DOX/GNSTs–PEG/PEI–FA) for tumor theranostic applications.
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8
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Pal A, Ganguly A, Chowdhuri S, Yousuf M, Ghosh A, Barui AK, Kotcherlakota R, Adhikari S, Banerjee R. Bis-arylidene oxindole-betulinic Acid conjugate: a fluorescent cancer cell detector with potent anticancer activity. ACS Med Chem Lett 2015; 6:612-6. [PMID: 26005543 DOI: 10.1021/acsmedchemlett.5b00095] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Accepted: 04/13/2015] [Indexed: 01/19/2023] Open
Abstract
Molecules offering simultaneous detection and killing of cancer cells are advantageous. Hybrid of cancer cell-selective, ROS generator betulinic acid and bis-arylidene oxindole with amino propyl-linker is developed. With intrinsic fluorescence, the molecule exhibited cancer cell-specific residence. Further, it generated ROS, triggered apoptosis, and exhibited potent cytotoxicity in cancer cells selectively. We demonstrate the first example and use of isatins as betulinic acid conjugate for selective detection of cancer and subsequent killing of cancer cells via apoptosis.
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Affiliation(s)
- Abhishek Pal
- Department
of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata 700 009, India
- Department
of Organic Chemistry, Indian Association for Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Anirban Ganguly
- Biomaterials
Group, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Sumit Chowdhuri
- Department
of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata 700 009, India
| | - Md Yousuf
- Department
of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata 700 009, India
| | - Avijit Ghosh
- Department
of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata 700 009, India
| | - Ayan Kumar Barui
- Biomaterials
Group, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Rajesh Kotcherlakota
- Biomaterials
Group, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Susanta Adhikari
- Department
of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata 700 009, India
| | - Rajkumar Banerjee
- Biomaterials
Group, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
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9
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Ma Z, Du L, Li M. Toward fluorescent probes for G-protein-coupled receptors (GPCRs). J Med Chem 2014; 57:8187-203. [PMID: 24983484 DOI: 10.1021/jm401823z] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
G-protein-coupled receptors (GPCRs), a superfamily of cell-surface receptors that are the targets of about 40% of prescription drugs on the market, can sense numerous critical extracellular signals. Recent breakthroughs in structural biology, especially in holo-form X-ray crystal structures, have contributed to our understanding of GPCR signaling. However, actions of GPCRs at the cellular and molecular level, interactions between GPCRs, and the role of protein dynamics in receptor activities still remain controversial. To overcome these dilemmas, fluorescent probes of GPCRs have been employed, which have advantages of in vivo safety and real-time monitoring. Various probes that depend on specific mechanisms and/or technologies have been used to study GPCRs. The present review focuses on surveying the design and applications of fluorescent probes for GPCRs that are derived from small molecules or using protein-labeling techniques, as well as discussing some design strategies for new probes.
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Affiliation(s)
- Zhao Ma
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (MOE), School of Pharmacy, Shandong University , Jinan, Shandong 250012, China
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10
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Optimizing the bioavailability of small molecular optical imaging probes by conjugation to an albumin affinity tag. J Control Release 2014; 186:32-40. [DOI: 10.1016/j.jconrel.2014.04.053] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 04/24/2014] [Accepted: 04/29/2014] [Indexed: 12/31/2022]
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11
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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: 7.8] [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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12
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Hahnenkamp A, Schäfers M, Bremer C, Höltke C. Design and synthesis of small-molecule fluorescent photoprobes targeted to aminopeptdase N (APN/CD13) for optical imaging of angiogenesis. Bioconjug Chem 2013; 24:1027-38. [PMID: 23642127 DOI: 10.1021/bc400074w] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We report here the synthesis of a nonpeptide, small-molecule fluorescent imaging agent with high affinity to aminopeptidase N (APN/CD13), a key player in a variety of pathophysiological angiogenic processes. On the basis of a recently described lead structure, we synthesized three putative precursor compounds by introducing polyethylene glycol (PEG) spacers comprising amino groups for dye labeling. Different attachment sites resulted in substantial differences in target affinity, cell toxicity, and target imaging performance. In comparison to bestatin, a natural inhibitor of many aminopeptidases, two of our compounds (22, 23) exhibit comparable inhibition potency, while a third (21) does not show any inhibiting effect. Cell binding assays with APN-positive BT-549 and APN-negative BT-20 cells and the final fluorescent probes Cy 5.5-21 and Cy 5.5-23 confirm these findings. The favorable characteristics of Cy 5.5-23 will now be proven in in vivo experiments with murine models of high APN expression and may serve as a tool to better understand APN pathophysiology.
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Affiliation(s)
- Anke Hahnenkamp
- Department of Clinical Radiology, Albert-Schweitzer-Campus 1/A16, University Hospital Muenster, D-48149 Muenster, Germany
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13
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Li Y, Wang X, Zhang J, Deuther-Conrad W, Xie F, Zhang X, Liu J, Qiao J, Cui M, Steinbach J, Brust P, Liu B, Jia H. Synthesis and Evaluation of Novel 18F-Labeled Spirocyclic Piperidine Derivatives as σ1 Receptor Ligands for Positron Emission Tomography Imaging. J Med Chem 2013; 56:3478-91. [DOI: 10.1021/jm301734g] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yan Li
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Xia Wang
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Jinming Zhang
- Nuclear
Medicine Department, Chinese PLA General Hospital, Beijing 100853, People’s
Republic of China
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum
Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research
Site Leipzig, Department of Neuroradiopharmaceuticals, 04318 Leipzig,
Germany
| | - Fang Xie
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Xiaojun Zhang
- Nuclear
Medicine Department, Chinese PLA General Hospital, Beijing 100853, People’s
Republic of China
| | - Jian Liu
- Nuclear
Medicine Department, Chinese PLA General Hospital, Beijing 100853, People’s
Republic of China
| | - Jinping Qiao
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Mengchao Cui
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Jörg Steinbach
- Helmholtz-Zentrum
Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research
Site Leipzig, Department of Neuroradiopharmaceuticals, 04318 Leipzig,
Germany
| | - Peter Brust
- Helmholtz-Zentrum
Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research
Site Leipzig, Department of Neuroradiopharmaceuticals, 04318 Leipzig,
Germany
| | - Boli Liu
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Hongmei Jia
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
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Compeer MG, Meens MJPMT, Hackeng TM, Neugebauer WA, Höltke C, De Mey JGR. Agonist-dependent modulation of arterial endothelinA receptor function. Br J Pharmacol 2012; 166:1833-45. [PMID: 22324472 DOI: 10.1111/j.1476-5381.2012.01896.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE Endothelin-1 (ET-1) causes long-lasting vasoconstrictions. These can be prevented by ET(A) receptor antagonists but are only poorly reversed by these drugs. We tested the hypothesis that endothelin ET(A) receptors are susceptible to allosteric modulation by endogenous agonists and exogenous ligands. EXPERIMENTAL APPROACH Rat isolated mesenteric resistance arteries were pretreated with capsaicin and studied in wire myographs, in the presence of L-NAME and indomethacin to concentrate on arterial smooth muscle responses. KEY RESULTS Endothelins caused contractions with equal maximum but differing potency (ET-1 = ET-2 > ET-3). ET-1(1-15) neither mimicked nor antagonized these effects in the absence and presence of ET(16-21). 4(Ala) ET-1 (ET(B) agonist) and BQ788 (ET(B) antagonist) were without effects. BQ123 (peptide ET(A) antagonist) reduced the sensitivity and relaxed the contractile responses to endothelins. Both effects depended on the agonist (pK(B): ET-3 = ET-1 > ET-2; % relaxation: ET-3 = ET-2 > ET-1). Also, with PD156707 (non-peptide ET(A) antagonist) agonist-dependence and a discrepancy between preventive and inhibitory effects were observed. The latter was even more marked with bulky analogues of BQ123 and PD156707. CONCLUSIONS AND IMPLICATIONS These findings indicate allosteric modulation of arterial smooth muscle ET(A) receptor function by endogenous agonists and by exogenous endothelin receptor antagonists. This may have consequences for the diagnosis and pharmacotherapy of diseases involving endothelins.
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Affiliation(s)
- M G Compeer
- Department of Pharmacology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands
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Büther K, Compeer MG, De Mey JGR, Schober O, Schäfers M, Bremer C, Riemann B, Höltke C. Assessment of endothelin-A receptor expression in subcutaneous and orthotopic thyroid carcinoma xenografts in vivo employing optical imaging methods. Endocrinology 2012; 153:2907-18. [PMID: 22510270 DOI: 10.1210/en.2011-2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Endothelin (ET) receptor dysregulation has been described in a number of pathophysiological processes, including cardiovascular disorders, renal failure, and cancer. The aim of this study was to evaluate the expression of the ET-A receptor (ET(A)R) in murine models of thyroid carcinoma using optical imaging methods. A recently developed near-infrared fluorescent tracer was first assessed in isolated artery preparations for its functional performance in comparison with known ET(A)R antagonists BQ123 and PD156707. Before evaluation of the tracer in vivo, different thyroid carcinoma cell lines were characterized with respect to their ET receptor expression by RT-PCR and autoradiography. In vivo, sc and orthotopic papillary thyroid tumor xenografts were clearly visualized by fluorescence reflectance imaging and fluorescence-mediated tomography up to 48 h after injection of the tracer. Binding specificity of the probe was demonstrated by predosing with PD156707 as a competing inhibitor. In conclusion, optical imaging with a fluorescent ET(A)R tracer allows the noninvasive imaging of tumor-associated ET(A)R expression in vivo. In the future, this technique may help surgeons to evaluate lesion dimensions in intraoperative settings (e.g. thyroidectomy).
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Affiliation(s)
- Katrin Büther
- European Institute for Molecular Imaging, University Hospital Münster, and Interdisciplinary Centre of Clinical Research, D-48149 Münster, Germany
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Michel K, Büther K, Law MP, Wagner S, Schober O, Hermann S, Schäfers M, Riemann B, Höltke C, Kopka K. Development and Evaluation of Endothelin-A Receptor (Radio)Ligands for Positron Emission Tomography. J Med Chem 2011; 54:939-48. [DOI: 10.1021/jm101110w] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kristin Michel
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany
| | - Katrin Büther
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany
| | - Marilyn P. Law
- European Institute for Molecular Imaging, University of Münster, Mendelstrasse 11, D-48149 Münster, Germany
- Interdisciplinary Centre of Clinical Research (IZKF), Münster, Germany
| | - Stefan Wagner
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany
| | - Otmar Schober
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany
| | - Sven Hermann
- European Institute for Molecular Imaging, University of Münster, Mendelstrasse 11, D-48149 Münster, Germany
| | - Michael Schäfers
- European Institute for Molecular Imaging, University of Münster, Mendelstrasse 11, D-48149 Münster, Germany
- Interdisciplinary Centre of Clinical Research (IZKF), Münster, Germany
| | - Burkhard Riemann
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany
| | - Carsten Höltke
- Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany
| | - Klaus Kopka
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany
- Interdisciplinary Centre of Clinical Research (IZKF), Münster, Germany
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Coppola C, Paciello A, Mangiapia G, Licen S, Boccalon M, De Napoli L, Paduano L, Tecilla P, Montesarchio D. Design, Synthesis and Characterisation of a Fluorescently Labelled CyPLOS Ionophore. Chemistry 2010; 16:13757-72. [DOI: 10.1002/chem.201000611] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Joshi BP, Wang TD. Exogenous Molecular Probes for Targeted Imaging in Cancer: Focus on Multi-modal Imaging. Cancers (Basel) 2010; 2:1251-87. [PMID: 22180839 PMCID: PMC3237638 DOI: 10.3390/cancers2021251] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 05/31/2010] [Accepted: 06/02/2010] [Indexed: 01/09/2023] Open
Abstract
Cancer is one of the major causes of mortality and morbidity in our health care system. Molecular imaging is an emerging methodology for the early detection of cancer, and the development of exogenous molecular probes that can be labeled for multi-modality imaging is critical to this process. Today, molecular imaging is at crossroad, and new targeted imaging agents are expected to broadly expand our ability to detect pre-malignant lesions. This integrated imaging strategy will permit clinicians to not only localize lesions within the body, but also to visualize the expression and activity of specific molecules. This information is expected to have a major impact on diagnosis, therapy, drug development and understanding of basic cancer biology. At this time, a number of molecular probes have been developed by conjugating various labels to affinity ligands for targeting in different imaging modalities. This review will describe the current status of exogenous molecular probes for optical, nuclear and MRI imaging platforms. Furthermore, we will also shed light on how these techniques can be used synergistically in multi-modal platforms and how these techniques are being employed in current research.
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Affiliation(s)
- Bishnu P. Joshi
- Division of Gastroenterology, Department of Medicine, University of Michigan, School of Medicine, 109 Zina Pitcher Place, BSRB 1722, Ann Arbor, MI 48109, USA
| | - Thomas D. Wang
- Division of Gastroenterology, Department of Medicine, University of Michigan, School of Medicine, 109 Zina Pitcher Place, BSRB 1722, Ann Arbor, MI 48109, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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Pauli J, Brehm R, Spieles M, Kaiser WA, Hilger I, Resch-Genger U. Novel fluorophores as building blocks for optical probes for in vivo near infrared fluorescence (NIRF) imaging. J Fluoresc 2010; 20:681-93. [PMID: 20213244 DOI: 10.1007/s10895-010-0603-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 01/29/2010] [Indexed: 11/30/2022]
Abstract
Aiming at the identification of new fluorescent reporters for targeted optical probes, we assessed the application-relevant features of a novel asymmetric cyanine, DY-681, in comparison to the only clinically approved dye indocyanine green (ICG), the golden imaging standard Cy5.5, and the asymmetric cyanine DY-676 successfully exploited by us for the design of different contrast agents. This comparison included the analysis of the spectroscopic properties of the free fluorophores and their thermal stability in aqueous solution as well as their cytotoxic potential. In addition, the absorption and emission features of IgG-conjugated DY-681 were examined. The trimethine DY-681 exhibited spectral features closely resembling that of the pentamethine Cy5.5. Its high thermal stability in phosphate buffer saline (PBS) solution in conjunction with its low cytotoxicity, reaching similar values as determined for Cy5.5 and DY-676, renders this dye more attractive as ICG and, due to its improved fluorescence quantum yield in PBS, also superior to DY-676. Although in PBS, Cy5.5 was still more fluorescent, the fluorescence quantum yields (Phi(f)) of DY-681 and Cy5.5 in PBS containing 5 mass-% bovine serum albumin (BSA) were comparable. Labeling experiments with DY-681 and the model antibody IgG revealed promisingly high Phi(f) values of the bioconjugated dye.
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Affiliation(s)
- Jutta Pauli
- BAM Federal Institute for Materials Research and Testing, Division I.5, Richard-Willstaetter-Str. 11, 12489 Berlin, Germany
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Developments in fluorescent probes for receptor research. Drug Discov Today 2009; 14:706-12. [PMID: 19573791 DOI: 10.1016/j.drudis.2009.03.015] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 03/27/2009] [Accepted: 03/30/2009] [Indexed: 11/21/2022]
Abstract
Early reports on the identification of fluorescent probes for receptors date back to mid-1970s. Fluorescent probes were initially used to visualize molecular targets in an analogous way to the use of fluorescent antibodies but with the same resolution as isotopically labelled ligands. In parallel to the rapid development of techniques, such as fluorescence correlation spectroscopy, multi-photon excitation fluorescence microscopy, fluorescence polarization and in vivo fluorescence imaging, fluorescent probes are becoming multifaceted tools in life science. The present review will focus on how the design of fluorescent ligands for receptors has evolved to meet the needs of most recent fluorescence applications.
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Höltke C, Waldeck J, Kopka K, Heindel W, Schober O, Schäfers M, Bremer C. Biodistribution of a Nonpeptidic Fluorescent Endothelin a Receptor Imaging Probe. Mol Imaging 2009. [DOI: 10.2310/7290.2009.00003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Carsten Höltke
- From the Departments of Clinical Radiology and Nuclear Medicine, University Hospital Muenster; and Interdisciplinary Center for Clinical Research and European Institute of Molecular Imaging, University of Muenster, Muenster, Germany
| | - Jens Waldeck
- From the Departments of Clinical Radiology and Nuclear Medicine, University Hospital Muenster; and Interdisciplinary Center for Clinical Research and European Institute of Molecular Imaging, University of Muenster, Muenster, Germany
| | - Klaus Kopka
- From the Departments of Clinical Radiology and Nuclear Medicine, University Hospital Muenster; and Interdisciplinary Center for Clinical Research and European Institute of Molecular Imaging, University of Muenster, Muenster, Germany
| | - Walter Heindel
- From the Departments of Clinical Radiology and Nuclear Medicine, University Hospital Muenster; and Interdisciplinary Center for Clinical Research and European Institute of Molecular Imaging, University of Muenster, Muenster, Germany
| | - Otmar Schober
- From the Departments of Clinical Radiology and Nuclear Medicine, University Hospital Muenster; and Interdisciplinary Center for Clinical Research and European Institute of Molecular Imaging, University of Muenster, Muenster, Germany
| | - Michael Schäfers
- From the Departments of Clinical Radiology and Nuclear Medicine, University Hospital Muenster; and Interdisciplinary Center for Clinical Research and European Institute of Molecular Imaging, University of Muenster, Muenster, Germany
| | - Christoph Bremer
- From the Departments of Clinical Radiology and Nuclear Medicine, University Hospital Muenster; and Interdisciplinary Center for Clinical Research and European Institute of Molecular Imaging, University of Muenster, Muenster, Germany
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Heurtault B, Gentine P, Thomann JS, Baehr C, Frisch B, Pons F. Design of a liposomal candidate vaccine against Pseudomonas aeruginosa and its evaluation in triggering systemic and lung mucosal immunity. Pharm Res 2008; 26:276-85. [PMID: 18781377 DOI: 10.1007/s11095-008-9724-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Accepted: 08/29/2008] [Indexed: 11/29/2022]
Abstract
PURPOSE To design and evaluate liposomal constructs capable of inducing a potent systemic and airway humoral response to Pseudomonas aeruginosa METHODS Liposomes contained a peptide derived from P. aeruginosa pilin protein as B epitope, a peptide derived from Influenza hemagglutinin protein as Th epitope, the TLR agonist Pam3CAG or Pam2CAG as adjuvant, and a mannosylated lipid as dendritic cell targeting agent. These constructions were administered to mice intraperitoneally (i.p.) or intranasally (i.n.). Their immunogenicity was evaluated by measuring B epitope-specific immunoglobulins in the serum and the airways by ELISA. RESULTS The B epitope, in its native form or after substitution of a cysteine by a serine, induced high systemic IgG titers when formulated in the presence of Pam3CAG or Pam2CAG and administered i.p.. No IgA response was observed in the airways upon injection of candidate vaccines by i.p. route, whatever the B epitope or the adjuvant. However, i.n. vaccination resulted in a significant local production of IgA. Finally, the production of IgG was more rapid when mannose was incorporated. CONCLUSIONS All liposomal candidate vaccines tested induced the production of IgG and/or IgA directed against an immunogenic peptide from P. aeruginosa. Liposomal constructs could be attractive in the vaccination against P. aeruginosa.
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Affiliation(s)
- Béatrice Heurtault
- Laboratoire de Chimie Enzymatique et Vectorisation, Université Louis Pasteur, Institut Gilbert Laustriat, CNRS-UMR 7175, Faculté de Pharmacie, 74 route du Rhin, BP 60024, 67401, Illkirch Cedex, France.
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von Brandenstein MG, Ngum Abety A, Depping R, Roth T, Koehler M, Dienes HP, Fries JWU. A p38-p65 transcription complex induced by endothelin-1 mediates signal transduction in cancer cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1613-22. [PMID: 18457675 DOI: 10.1016/j.bbamcr.2008.04.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 03/31/2008] [Accepted: 04/01/2008] [Indexed: 11/29/2022]
Abstract
Endothelin-1 is a powerful mitogen for various tumor and non-tumor cells. Its signaling cascade induces the inflammatory NF-kappaB complex, leading to expression of a number of target genes. In this context, MAPK p38 has been regarded as a potential phosphate donor for the p65 subunit of NF-kappaB. In the present study in HeLa cells, we have found that ET-1 induced signalling activates the NF-kappaB transcription complex (TC) in the nucleus at 6 h specifically via ET-A - but not ET-B receptor. The TC contains p65, p38 (alpha and beta) - binding to the NLS of p65 in the cytoplasm - as well as p50, but no IkappaBalpha. Specific p38 inhibition by SB203580 or by siRNA interferes markedly with gene expression of several target genes. Complex formation occurs in the cytoplasm, and both transcription factors transmigrate as a complex in the nucleus. Overexpression of p38, treatment with Chrysin, MG132, or dimethylformamide shows dependence of TC on p38 as partner. In other tumor cells lines studied, ET-1 activates TC, with p38 as an important complex partner of p65. TC-induction by ET-1 contains about twice the amount of p38 than by TNFalpha. Thus, p38 may be an additional therapeutic target to control inflammatory gene expression in tumor cells.
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Prediction of antiangiogenic treatment efficacy by iron oxide enhanced parametric magnetic resonance imaging. Invest Radiol 2008; 42:791-6. [PMID: 18007150 DOI: 10.1097/rli.0b013e3180d5cbd9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
RATIONALE AND OBJECTIVES Tools for monitoring modern target-specific antiangiogenic and antivascular therapies are highly desirable because treatment strategies are time consuming, expensive, and yet sometimes ineffective. Therefore, the aim of this experimental study was to evaluate the predictive value of steady-state ultrasmall particles of iron oxide (USPIO; SH U 555 C)-enhanced magnetic resonance imaging (MRI) for early assessment of antivascular tumor-treatment effectiveness. METHODS Mice were inoculated with an HT-1080 fibrosarcoma xenograft and subjected to target-specific antivascular therapy using a selective thrombogenic vascular-targeting agent (truncated tissue factor fused to RGD peptide) or saline as control. Four to 8 hours after treatment, the USPIO-induced change in the transverse relaxation rate DeltaR2* was measured by MRI, and the vascular volume fraction (VVF) was calculated by calibrating DeltaR2* of the tumor by DeltaR2* of muscle tissue. Treatment response was defined by histologic grading of vascular thrombosis and tumor necrosis. RESULTS After thrombogenic treatment, half of the HT-1080 xenograft-bearing animals showed only minor (=nonresponder) whereas the other half showed extensive tumor thrombosis (=responders). For responders, a significant decrease of DeltaR2* and VVF was observed compared with the control group (DeltaR2*: controls: 16 +/- 1 s-1 vs. responder: 4 +/- 2 s-1; P < 0.001) whereas DeltaR2* and VVF remained nearly unchanged for nonresponders (DeltaR2*: nonresponder 14 +/- 2 s-1). VVF and DeltaR2* values correlated inversely with the histologic grading of vascular thrombosis and tumor necrosis (VVF: r = -0.8; DeltaR2*: r = -0.71; P < 0.01). CONCLUSION USPIO-enhanced MRI allows a noninvasive, early assessment of treatment efficacy of thrombogenic vascular-targeting agents.
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