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Silva L, Coelho P, Teixeira D, Monteiro A, Pinto G, Soares R, Prudêncio C, Vieira M. Oxidative Stress Modulation and Radiosensitizing Effect of Quinoxaline-1,4-Dioxides Derivatives. Anticancer Agents Med Chem 2020; 20:111-120. [DOI: 10.2174/1871520619666191028091547] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 09/24/2019] [Accepted: 09/25/2019] [Indexed: 12/12/2022]
Abstract
Background:
Quinoxaline-1,4-dioxide (QNX) derivatives are synthetic heterocyclic compounds with
multiple biological and pharmacological effects.
Objective:
In this study, we investigated the oxidative status of quinoxaline-1,4-dioxides derivatives in modulating
melanoma and glioma cell lines, based on previous results from the research group and their capability to
promote cell damage by the production of Reactive Oxygen Species (ROS).
Methods:
Using in vitro cell cultures, the influence of 2-amino-3-cyanoquinoxaline-1,4-dioxide (2A3CQNX), 3-
methyl-2-quinoxalinecarboxamide-1,4-dioxide (3M2QNXC) and 2-hydroxyphenazine-1,4-dioxide (2HF) was
evaluated in metabolic activity, catalase activity, glutathione and 3-nitrotyrosine (3-NT) quantitation by HPLC
in malignant melanocytes (B16-F10, MeWo) and brain tumor cells (GL-261 and BC3H1) submitted to radiotherapy
treatments (total dose of 6 Gy).
Results:
2HF increased the levels of 3-NT in non-irradiated MeWo and glioma cell lines and decreased cell
viability in these cell lines with and without irradiation.
Conclusions:
Quinoxaline-1,4-dioxides derivatives modulate the oxidative status in malignant melanocytes and
brain tumor cell lines and exhibited a potential radiosensitizer in vitro action on the tested radioresistant cell
lines.
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Affiliation(s)
- Liliana Silva
- Centro de Investigacao em Saude Ambiental (CISA), Escola Superior de Saude do Porto, Politecnico do Porto, Porto, Portugal
| | - Pedro Coelho
- Centro de Investigacao em Saude Ambiental (CISA), Escola Superior de Saude do Porto, Politecnico do Porto, Porto, Portugal
| | - Dulce Teixeira
- Centro de Investigacao em Saude Ambiental (CISA), Escola Superior de Saude do Porto, Politecnico do Porto, Porto, Portugal
| | - Armanda Monteiro
- Servico de Radioterapia, Centro Hospitalar de Sao Joao, Porto, Portugal
| | - Gabriela Pinto
- Servico de Radioterapia, Centro Hospitalar de Sao Joao, Porto, Portugal
| | - Raquel Soares
- Departamento de Biomedicina, Unidade de Bioquimica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - Cristina Prudêncio
- Centro de Investigacao em Saude Ambiental (CISA), Escola Superior de Saude do Porto, Politecnico do Porto, Porto, Portugal
| | - Mónica Vieira
- Centro de Investigacao em Saude Ambiental (CISA), Escola Superior de Saude do Porto, Politecnico do Porto, Porto, Portugal
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Baumstark D, Kremer W, Boettcher A, Schreier C, Sander P, Schmitz G, Kirchhoefer R, Huber F, Kalbitzer HR. 1H NMR spectroscopy quantifies visibility of lipoproteins, subclasses, and lipids at varied temperatures and pressures. J Lipid Res 2019; 60:1516-1534. [PMID: 31239285 PMCID: PMC6718440 DOI: 10.1194/jlr.m092643] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 06/18/2019] [Indexed: 01/27/2023] Open
Abstract
NMR-based quantification of human lipoprotein (sub)classes is a powerful high-throughput method for medical diagnostics. We evaluated select proton NMR signals of serum lipoproteins for elucidating the physicochemical features and the absolute NMR visibility of their lipids. We separated human lipoproteins of different subclasses by ultracentrifugation and analyzed them by 1H NMR spectroscopy at different temperatures (283-323 K) and pressures (0.1-200 MPa). In parallel, we determined the total lipid content by extraction with chloroform/methanol. The visibility of different lipids in the 1H NMR spectra strongly depends on temperature and pressure: it increases with increasing temperatures but decreases with increasing pressures. Even at 313 K, only part of the lipoprotein is detected quantitatively. In LDL and in HDL subclasses HDL2 and HDL3, only 39%, 62%, and 90% of the total cholesterol and only 73%, 70%, and 87% of the FAs are detected, respectively. The choline head groups show visibilities of 43%, 75%, and 87% for LDL, HDL2, and HDL3, respectively. The description of the NMR visibility of lipid signals requires a minimum model of three different compartments, A, B, and C. The thermodynamic analysis of compartment B leads to melting temperatures between 282 K and 308 K and to enthalpy differences that vary for the different lipoproteins as well as for the reporter groups selected. In summary, we describe differences in NMR visibility of lipoproteins and variations in biophysical responses of functional groups that are crucial for the accuracy of absolute NMR quantification.
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Affiliation(s)
- Daniela Baumstark
- Institute of Biophysics and Physical BiochemistryUniversity of Regensburg, 93040 Regensburg, Germany; Centre of Magnetic Resonance in Chemistry and Biomedicine University of Regensburg, 93040 Regensburg, Germany
| | - Werner Kremer
- Institute of Biophysics and Physical BiochemistryUniversity of Regensburg, 93040 Regensburg, Germany; Centre of Magnetic Resonance in Chemistry and Biomedicine University of Regensburg, 93040 Regensburg, Germany
| | - Alfred Boettcher
- Institute of Clinical Chemistry and Laboratory Medicine University Hospital Regensburg, 93053 Regensburg, Germany
| | - Christina Schreier
- Institute of Biophysics and Physical BiochemistryUniversity of Regensburg, 93040 Regensburg, Germany; Centre of Magnetic Resonance in Chemistry and Biomedicine University of Regensburg, 93040 Regensburg, Germany; numares AG, 93053 Regensburg, Germany
| | - Paul Sander
- Institute of Biophysics and Physical BiochemistryUniversity of Regensburg, 93040 Regensburg, Germany; Centre of Magnetic Resonance in Chemistry and Biomedicine University of Regensburg, 93040 Regensburg, Germany
| | - Gerd Schmitz
- Institute of Clinical Chemistry and Laboratory Medicine University Hospital Regensburg, 93053 Regensburg, Germany
| | | | | | - Hans Robert Kalbitzer
- Institute of Biophysics and Physical BiochemistryUniversity of Regensburg, 93040 Regensburg, Germany; Centre of Magnetic Resonance in Chemistry and Biomedicine University of Regensburg, 93040 Regensburg, Germany.
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Pandharipande PP, Makhatadze GI. Applications of pressure perturbation calorimetry to study factors contributing to the volume changes upon protein unfolding. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1860:1036-1042. [PMID: 26341789 DOI: 10.1016/j.bbagen.2015.08.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 08/28/2015] [Accepted: 08/30/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND Pressure perturbation calorimetry (PPC) is a biophysical method that allows direct determination of the volume changes upon conformational transitions in macromolecules. SCOPE OF THIS REVIEW This review provides novel details of the use of PPC to analyze unfolding transitions in proteins. The emphasis is made on the data analysis as well as on the validation of different structural factors that define the volume changes upon unfolding. Four case studies are presented that show the application of these concepts to various protein systems. MAJOR CONCLUSIONS The major conclusions are: 1. Knowledge of the thermodynamic parameters for heat induced unfolding facilitates the analysis of the PPC profiles. 2. The changes in the thermal expansion coefficient upon unfolding appear to be temperature dependent.3.Substitutions on the protein surface have negligible effects on the volume changes upon protein unfolding. 4. Structural plasticity of proteins defines the position dependent effect of amino acid substitutions of the residues buried in the native state. 5. Small proteins have positive volume changes upon unfolding which suggests difference in balance between the cavity/void volume in the native state and the hydration volume changes upon unfolding as compared to the large proteins that have negative volume changes. GENERAL SIGNIFICANCE The information provided here gives a better understanding and deeper insight into the role played by various factors in defining the volume changes upon protein unfolding.
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Affiliation(s)
- Pranav P Pandharipande
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA; Howard P. Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - George I Makhatadze
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA; Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
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Gogonea V. Structural Insights into High Density Lipoprotein: Old Models and New Facts. Front Pharmacol 2016; 6:318. [PMID: 26793109 PMCID: PMC4709926 DOI: 10.3389/fphar.2015.00318] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 12/22/2015] [Indexed: 11/13/2022] Open
Abstract
The physiological link between circulating high density lipoprotein (HDL) levels and cardiovascular disease is well-documented, albeit its intricacies are not well-understood. An improved appreciation of HDL function and overall role in vascular health and disease requires at its foundation a better understanding of the lipoprotein's molecular structure, its formation, and its process of maturation through interactions with various plasma enzymes and cell receptors that intervene along the pathway of reverse cholesterol transport. This review focuses on summarizing recent developments in the field of lipid free apoA-I and HDL structure, with emphasis on new insights revealed by newly published nascent and spherical HDL models constructed by combining low resolution structures obtained from small angle neutron scattering (SANS) with contrast variation and geometrical constraints derived from hydrogen-deuterium exchange (HDX), crosslinking mass spectrometry, electron microscopy, Förster resonance energy transfer, and electron spin resonance. Recently published low resolution structures of nascent and spherical HDL obtained from SANS with contrast variation and isotopic labeling of apolipoprotein A-I (apoA-I) will be critically reviewed and discussed in terms of how they accommodate existing biophysical structural data from alternative approaches. The new low resolution structures revealed and also provided some answers to long standing questions concerning lipid organization and particle maturation of lipoproteins. The review will discuss the merits of newly proposed SANS based all atom models for nascent and spherical HDL, and compare them with accepted models. Finally, naturally occurring and bioengineered mutations in apoA-I, and their impact on HDL phenotype, are reviewed and discuss together with new therapeutics employed for restoring HDL function.
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Affiliation(s)
- Valentin Gogonea
- Department of Chemistry, Cleveland State UniversityCleveland, OH, USA; Departments of Cellular and Molecular Medicine and the Center for Cardiovascular Diagnostics and Prevention, Cleveland ClinicCleveland, OH, USA
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Jayaraman S, Haupt C, Gursky O. Thermal transitions in serum amyloid A in solution and on the lipid: implications for structure and stability of acute-phase HDL. J Lipid Res 2015; 56:1531-42. [PMID: 26022803 DOI: 10.1194/jlr.m059162] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Indexed: 12/20/2022] Open
Abstract
Serum amyloid A (SAA) is an acute-phase protein that circulates mainly on plasma HDL. SAA interactions with its functional ligands and its pathogenic deposition in reactive amyloidosis depend, in part, on the structural disorder of this protein and its propensity to oligomerize. In vivo, SAA can displace a substantial fraction of the major HDL protein, apoA-I, and thereby influence the structural remodeling and functions of acute-phase HDL in ways that are incompletely understood. We use murine SAA1.1 to report the first structural stability study of human plasma HDL that has been enriched with SAA. Calorimetric and spectroscopic analyses of these and other SAA-lipid systems reveal two surprising findings. First, progressive displacement of the exchangeable fraction of apoA-I by SAA has little effect on the structural stability of HDL and its fusion and release of core lipids. Consequently, the major determinant for HDL stability is the nonexchangeable apoA-I. A structural model explaining this observation is proposed, which is consistent with functional studies in acute-phase HDL. Second, we report an α-helix folding/unfolding transition in SAA in the presence of lipid at near-physiological temperatures. This new transition may have potentially important implications for normal functions of SAA and its pathogenic misfolding.
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Affiliation(s)
- Shobini Jayaraman
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston MA 02118
| | - Christian Haupt
- Institute for Pharmaceutical Biotechnology, University of Ulm, 89081, Ulm, Germany
| | - Olga Gursky
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston MA 02118
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Structural stability and functional remodeling of high-density lipoproteins. FEBS Lett 2015; 589:2627-39. [PMID: 25749369 DOI: 10.1016/j.febslet.2015.02.028] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Revised: 02/16/2015] [Accepted: 02/23/2015] [Indexed: 12/28/2022]
Abstract
Lipoproteins are protein-lipid nanoparticles that transport lipids in circulation and are central in atherosclerosis and other disorders of lipid metabolism. Apolipoproteins form flexible structural scaffolds and important functional ligands on the particle surface and direct lipoprotein metabolism. Lipoproteins undergo multiple rounds of metabolic remodeling that is crucial to lipid transport. Important aspects of this remodeling, including apolipoprotein dissociation and particle fusion, are mimicked in thermal or chemical denaturation and are modulated by free energy barriers. Here we review the biophysical studies that revealed the kinetic mechanism of lipoprotein stabilization and unraveled its structural basis. The main focus is on high-density lipoprotein (HDL). An inverse correlation between stability and functions of various HDLs in cholesterol transport suggests the functional role of structural disorder. A mechanism for the conformational adaptation of the major HDL proteins, apoA-I and apoA-II, to the increasing lipid load is proposed. Together, these studies help understand why HDL forms discrete subclasses separated by kinetic barriers, which have distinct composition, conformation and functional properties. Understanding these properties may help improve HDL quality and develop novel therapies for cardiovascular disease.
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Folded functional lipid-poor apolipoprotein A-I obtained by heating of high-density lipoproteins: relevance to high-density lipoprotein biogenesis. Biochem J 2012; 442:703-12. [PMID: 22150513 DOI: 10.1042/bj20111831] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
HDL (high-density lipoproteins) remove cell cholesterol and protect from atherosclerosis. The major HDL protein is apoA-I (apolipoprotein A-I). Most plasma apoA-I circulates in lipoproteins, yet ~5% forms monomeric lipid-poor/free species. This metabolically active species is a primary cholesterol acceptor and is central to HDL biogenesis. Structural properties of lipid-poor apoA-I are unclear due to difficulties in isolating this transient species. We used thermal denaturation of human HDL to produce lipid-poor apoA-I. Analysis of the isolated lipid-poor fraction showed a protein/lipid weight ratio of 3:1, with apoA-I, PC (phosphatidylcholine) and CE (cholesterol ester) at approximate molar ratios of 1:8:1. Compared with lipid-free apoA-I, lipid-poor apoA-I showed slightly altered secondary structure and aromatic packing, reduced thermodynamic stability, lower self-associating propensity, increased adsorption to phospholipid surface and comparable ability to remodel phospholipids and form reconstituted HDL. Lipid-poor apoA-I can be formed by heating of either plasma or reconstituted HDL. We propose the first structural model of lipid-poor apoA-I which corroborates its distinct biophysical properties and postulates the lipid-induced ordering of the labile C-terminal region. In summary, HDL heating produces folded functional monomolecular lipid-poor apoA-I that is distinct from lipid-free apoA-I. Increased adsorption to phospholipid surface and reduced C-terminal disorder may help direct lipid-poor apoA-I towards HDL biogenesis.
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Current world literature. Curr Opin Lipidol 2012; 23:156-63. [PMID: 22418573 DOI: 10.1097/mol.0b013e3283521229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Nakamura S, Kidokoro SI. Volumetric Properties of the Molten Globule State of Cytochrome c in the Thermal Three-State Transition Evaluated by Pressure Perturbation Calorimetry. J Phys Chem B 2012; 116:1927-32. [DOI: 10.1021/jp209686e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shigeyoshi Nakamura
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Japan
| | - Shun-ichi Kidokoro
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Japan
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