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Najeeb HA, Sanusi T, Saldanha G, Brown K, Cooke MS, Jones GD. Redox modulation of oxidatively-induced DNA damage by ascorbate enhances both in vitro and ex-vivo DNA damage formation and cell death in melanoma cells. Free Radic Biol Med 2024; 213:309-321. [PMID: 38262545 DOI: 10.1016/j.freeradbiomed.2024.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/10/2024] [Accepted: 01/14/2024] [Indexed: 01/25/2024]
Abstract
Elevated genomic instability in cancer cells suggests a possible model-scenario for their selective killing via the therapeutic delivery of well-defined levels of further DNA damage. To examine this scenario, this study investigated the potential for redox modulation of oxidatively-induced DNA damage by ascorbate in malignant melanoma (MM) cancer cells, to selectively enhance both DNA damage and MM cell killing. DNA damage was assessed by Comet and ɣH2AX assays, intracellular oxidising species by dichlorofluorescein fluorescence, a key antioxidant enzymatic defence by assessment of catalase activity and cell survival was determined by clonogenic assay. Comet revealed that MM cells had higher endogenous DNA damage levels than normal keratinocytes (HaCaT cells); this correlated MM cells having higher intracellular oxidising species and lower catalase activity, and ranked with MM cell melanin pigmentation. Comet also showed MM cells more sensitive towards the DNA damaging effects of exogenous H2O2, and that ascorbate further enhanced this H2O2-induced damage in MM cells; again, with MM cell sensitivity to induced damage ranking with degree of cell pigmentation. Furthermore, cell survival data indicated that ascorbate enhanced H2O2-induced clonogenic cell death selectively in MM cells whilst protecting HaCaT cells. Finally, we show that ascorbate serves to enhance the oxidising effects of the MM therapeutic drug Elesclomol in both established MM cells in vitro and primary cell cultures ex vivo. Together, these results suggest that ascorbate selectively enhances DNA damage and cell-killing in MM cells. This raises the option of incorporating ascorbate into clinical oxidative therapies to treat MM.
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Affiliation(s)
- Hishyar A Najeeb
- Leicester Cancer Research Centre, Department of Genetics & Genome Biology, University of Leicester, UK
| | - Timi Sanusi
- Leicester Medical School, University of Leicester, UK
| | - Gerald Saldanha
- University Hospitals of Leicester NHS Trust, Leicester Royal Infirmary, UK
| | - Karen Brown
- Leicester Cancer Research Centre, Department of Genetics & Genome Biology, University of Leicester, UK
| | - Marcus S Cooke
- Oxidative Stress Group, Department of Molecular Biosciences, University of South Florida, USA.
| | - George Dd Jones
- Leicester Cancer Research Centre, Department of Genetics & Genome Biology, University of Leicester, UK.
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2
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Plays M, Müller S, Rodriguez R. Chemistry and biology of ferritin. Metallomics 2021; 13:6244244. [PMID: 33881539 PMCID: PMC8083198 DOI: 10.1093/mtomcs/mfab021] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 04/09/2021] [Indexed: 02/07/2023]
Abstract
Iron is an essential element required by cells and has been described as a key player in ferroptosis. Ferritin operates as a fundamental iron storage protein in cells forming multimeric assemblies with crystalline iron cores. We discuss the latest findings on ferritin structure and activity and its link to cell metabolism and ferroptosis. The chemistry of iron, including its oxidation states, is important for its biological functions, its reactivity, and the biology of ferritin. Ferritin can be localized in different cellular compartments and secreted by cells with a variety of functions depending on its spatial context. Here, we discuss how cellular ferritin localization is tightly linked to its function in a tissue-specific manner, and how impairment of iron homeostasis is implicated in diseases, including cancer and coronavirus disease 2019. Ferritin is a potential biomarker and we discuss latest research where it has been employed for imaging purposes and drug delivery.
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Affiliation(s)
- Marina Plays
- Chemical Biology of Cancer Laboratory, Institut Curie, 26 rue d'Ulm, 75005 Paris, France.,Centre national de la recherche scientifique UMR 3666, Paris, France.,Institut national de la santé et de la recherche médicale U1143, Paris, France.,PSL Université Paris, Paris, France
| | - Sebastian Müller
- Chemical Biology of Cancer Laboratory, Institut Curie, 26 rue d'Ulm, 75005 Paris, France.,Centre national de la recherche scientifique UMR 3666, Paris, France.,Institut national de la santé et de la recherche médicale U1143, Paris, France.,PSL Université Paris, Paris, France
| | - Raphaël Rodriguez
- Chemical Biology of Cancer Laboratory, Institut Curie, 26 rue d'Ulm, 75005 Paris, France.,Centre national de la recherche scientifique UMR 3666, Paris, France.,Institut national de la santé et de la recherche médicale U1143, Paris, France.,PSL Université Paris, Paris, France
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3
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Bae DH, Gholam Azad M, Kalinowski DS, Lane DJR, Jansson PJ, Richardson DR. Ascorbate and Tumor Cell Iron Metabolism: The Evolving Story and Its Link to Pathology. Antioxid Redox Signal 2020; 33:816-838. [PMID: 31672021 DOI: 10.1089/ars.2019.7903] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Significance: Vitamin C or ascorbate (Asc) is a water-soluble vitamin and an antioxidant that is involved in many crucial biological functions. Asc's ability to reduce metals makes it an essential enzyme cofactor. Recent Advances: The ability of Asc to act as a reductant also plays an important part in its overall role in iron metabolism, where Asc induces both nontransferrin-bound iron and transferrin-bound iron uptake at physiological concentrations (∼50 μM). Moreover, Asc has emerged to play an important role in multiple diseases and its effects at pharmacological doses could be important for their treatment. Critical Issues: Asc's role as a regulator of cellular iron metabolism, along with its cytotoxic effects and different roles at pharmacological concentrations, makes it a candidate as an anticancer agent. Ever since the controversy regarding the studies from the Mayo Clinic was finally explained, there has been a renewed interest in using Asc as a therapeutic approach toward cancer due to its minimal side effects. Numerous studies have been able to demonstrate the anticancer activity of Asc through selective oxidative stress toward cancer cells via H2O2 generation at pharmacological concentrations. Studies have demonstrated that Asc's cytotoxic mechanism at concentrations (>1 mM) has been associated with decreased cellular iron uptake. Future Directions: Recent studies have also suggested other mechanisms, such as Asc's effects on autophagy, polyamine metabolism, and the cell cycle. Clearly, more has yet to be discovered about Asc's mechanism of action to facilitate safe and effective treatment options for cancer and other diseases.
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Affiliation(s)
- Dong-Hun Bae
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, Australia
| | - Mahan Gholam Azad
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, Australia
| | - Danuta S Kalinowski
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, Australia
| | - Darius J R Lane
- The Florey Institute of Neuroscience and Mental Health, Melbourne Dementia Research Centre, The University of Melbourne, Parkville, Australia
| | - Patric J Jansson
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, Australia
| | - Des R Richardson
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, Australia.,Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Showa-ku, Japan
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4
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Badu-Boateng C, Naftalin RJ. Ascorbate and ferritin interactions: Consequences for iron release in vitro and in vivo and implications for inflammation. Free Radic Biol Med 2019; 133:75-87. [PMID: 30268889 DOI: 10.1016/j.freeradbiomed.2018.09.041] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 01/19/2023]
Abstract
This review discusses the chemical mechanisms of ascorbate-dependent reduction and solubilization of ferritin's ferric iron core and subsequent release of ferrous iron. The process is accelerated by low concentrations of Fe(II) that increase ferritin's intrinsic ascorbate oxidase activity, hence increasing the rate of ascorbate radical formation. These increased rates of ascorbate oxidation provide reducing equivalents (electrons) to ferritin's core and speed the core reduction rates with subsequent solubilization and release of Fe(II). Ascorbate-dependent solubilization of ferritin's iron core has consequences relating to the interpretation of 59Fe uptake sourced from 59Fe-lebelled holotransferrin into ferritin. Ascorbate-dependent reduction of the ferritin core iron solubility increases the size of ferritin's iron exchangeable pool and hence the rate and amount of exchange uptake of 59Fe into ferritin, whilst simultaneously increasing net iron release rate from ferritin. This may rationalize the inconsistency that ascorbate apparently stabilizes 59Fe ferritin and retards lysosomal ferritinolysis and whole cell 59Fe release, whilst paradoxically increasing the rate of net iron release from ferritin. This capacity of ascorbate and iron to synergise ferritin iron release has pathological significance, as it lowers the concentration at which ascorbate activates ferritin's iron release to within the physiological range (50-250 μM). These effects have relevance to inflammatory pathology and to the pro-oxidant effects of ascorbate in cancer therapy and cell death by ferroptosis.
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Affiliation(s)
- Charles Badu-Boateng
- Kings, BHF Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Richard J Naftalin
- Kings, BHF Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London SE1 9NH, UK
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Devi JSA, Aparna RS, Aswathy B, Nebu J, Aswathy AO, George S. Understanding the Citric Acid-Urea Co-Directed Microwave Assisted Synthesis and Ferric Ion Modulation of Fluorescent Nitrogen Doped Carbon Dots: A Turn On Assay for Ascorbic Acid. ChemistrySelect 2019. [DOI: 10.1002/slct.201803726] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- J. S. Anjali Devi
- Department of Chemistry; School of Physical and Mathematical sciences; University of Kerala; Kariavattom campus; Thiruvananthapuram- 695581, Kerala India
| | - R. S. Aparna
- Department of Chemistry; School of Physical and Mathematical sciences; University of Kerala; Kariavattom campus; Thiruvananthapuram- 695581, Kerala India
| | - B. Aswathy
- Department of Chemistry; School of Physical and Mathematical sciences; University of Kerala; Kariavattom campus; Thiruvananthapuram- 695581, Kerala India
| | - John Nebu
- Department of Chemistry; School of Physical and Mathematical sciences; University of Kerala; Kariavattom campus; Thiruvananthapuram- 695581, Kerala India
| | - A. O. Aswathy
- Department of Chemistry; School of Physical and Mathematical sciences; University of Kerala; Kariavattom campus; Thiruvananthapuram- 695581, Kerala India
| | - Sony George
- Department of Chemistry; School of Physical and Mathematical sciences; University of Kerala; Kariavattom campus; Thiruvananthapuram- 695581, Kerala India
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6
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Reductive Mobilization of Iron from Intact Ferritin: Mechanisms and Physiological Implication. Pharmaceuticals (Basel) 2018; 11:ph11040120. [PMID: 30400623 PMCID: PMC6315955 DOI: 10.3390/ph11040120] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 01/18/2023] Open
Abstract
Ferritins are highly conserved supramolecular protein nanostructures composed of two different subunit types, H (heavy) and L (light). The two subunits co-assemble into a 24-subunit heteropolymer, with tissue specific distributions, to form shell-like protein structures within which thousands of iron atoms are stored as a soluble inorganic ferric iron core. In-vitro (or in cell free systems), the mechanisms of iron(II) oxidation and formation of the mineral core have been extensively investigated, although it is still unclear how iron is loaded into the protein in-vivo. In contrast, there is a wide spread belief that the major pathway of iron mobilization from ferritin involves a lysosomal proteolytic degradation of ferritin, and the dissolution of the iron mineral core. However, it is still unclear whether other auxiliary iron mobilization mechanisms, involving physiological reducing agents and/or cellular reductases, contribute to the release of iron from ferritin. In vitro iron mobilization from ferritin can be achieved using different reducing agents, capable of easily reducing the ferritin iron core, to produce soluble ferrous ions that are subsequently chelated by strong iron(II)-chelating agents. Here, we review our current understanding of iron mobilization from ferritin by various reducing agents, and report on recent results from our laboratory, in support of a mechanism that involves a one-electron transfer through the protein shell to the iron mineral core. The physiological significance of the iron reductive mobilization from ferritin by the non-enzymatic FMN/NAD(P)H system is also discussed.
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7
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Johnson LE, Wilkinson T, Arosio P, Melman A, Bou-Abdallah F. Effect of chaotropes on the kinetics of iron release from ferritin by flavin nucleotides. Biochim Biophys Acta Gen Subj 2017; 1861:3257-3262. [PMID: 28943300 DOI: 10.1016/j.bbagen.2017.09.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/26/2017] [Accepted: 09/19/2017] [Indexed: 12/30/2022]
Abstract
BACKGROUND Ferritins are ubiquitous multi-subunit iron storage and detoxification proteins that play a critical role in iron homeostasis. Ferrous ions that enter the protein's shell through hydrophilic channels are rapidly oxidized at dinuclear centers on the H-subunit before transfer to the protein's cavity for storage. The mechanisms of iron loading have been extensively studied, but little is known about iron mobilization. Fe(III) reduction can occur via rapid reduction by suitable reducing agents followed by chelation of Fe(II) ions or via direct and slow Fe(III) chelation. Here, the iron release kinetics from ferritin by FMNH2 in the presence of various chaotropic agents are studied and their in-vivo physiological significance discussed. METHODS The iron release kinetics from horse and human ferritins by FMNH2 were monitored at 522nm where the Fe(II)-bipyridine complex absorbs. The experiments were performed in the presence of different concentrations of three chaotropic agents, urea, guanidine HCl, and triton. RESULTS AND CONCLUSIONS Under our experimental conditions, iron reductive mobilization by the non-enzymatic FMN/NAD(P)H system is limited by the concentration of FMNH2 and is independent on the type or amount of chaotropes present. Diffusion of FMNH2 through the ferritin pores is an unlikely mechanism for ferritin iron reduction. An iron mobilization mechanism involving rapid electron transfer through the protein shell is discussed. GENERAL SIGNIFICANCE Caution must be exercised when interpreting the kinetics of iron mobilization from ferritin using the FMN/NAD(P)H system. The kinetics are highly dependent on the amount of dissolved oxygen and the concentration of reagents used.
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Affiliation(s)
- Lindsay E Johnson
- State University of New York at Potsdam, Department of Chemistry, Potsdam, NY, USA
| | - Tyler Wilkinson
- Clarkson University, Department of Chemistry & Biomolecular Science, Potsdam, NY, USA
| | - Paolo Arosio
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
| | - Artem Melman
- Clarkson University, Department of Chemistry & Biomolecular Science, Potsdam, NY, USA.
| | - Fadi Bou-Abdallah
- State University of New York at Potsdam, Department of Chemistry, Potsdam, NY, USA.
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8
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Badu-Boateng C, Pardalaki S, Wolf C, Lajnef S, Peyrot F, Naftalin RJ. Labile iron potentiates ascorbate-dependent reduction and mobilization of ferritin iron. Free Radic Biol Med 2017; 108:94-109. [PMID: 28336129 DOI: 10.1016/j.freeradbiomed.2017.03.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 01/29/2017] [Accepted: 03/15/2017] [Indexed: 12/18/2022]
Abstract
Ascorbate mobilizes iron from equine spleen ferritin by two separate processes. Ascorbate alone mobilizes ferritin iron with an apparent Km (ascorbate) ≈1.5mM. Labile iron >2μM, complexed with citrate (10mM), synergises ascorbate-dependent iron mobilization by decreasing the apparent Km (ascorbate) to ≈270μM and raising maximal mobilization rate by ≈5-fold. Catalase reduces the apparent Km(ascorbate) for both ascorbate and ascorbate+iron dependent mobilization by ≈80%. Iron mobilization by ascorbate alone has a higher activation energy (Ea=45.0±5.5kJ/mole) than when mediated by ascorbate with labile iron (10μM) (Ea=13.7±2.2kJ/mole); also mobilization by iron-ascorbate has a three-fold higher pH sensitivity (pH range 6.0-8.0) than with ascorbate alone. Hydrogen peroxide inhibits ascorbate's iron mobilizing action. EPR and autochemiluminescence studies show that ascorbate and labile iron within ferritin enhances radical formation, whereas ascorbate alone produces negligible radicals. These findings suggest that iron catalysed single electron transfer reactions from ascorbate, involving ascorbate or superoxide and possibly ferroxidase tyrosine radicals, accelerate iron mobilization from the ferroxidase centre more than EPR silent, bi-dentate two-electron transfers. These differing modes of electron transference from ascorbate mirror the known mono and bidentate oxidation reactions of dioxygen and hydrogen peroxide with di-ferrous iron at the ferroxidase centre. This study implies that labile iron, at physiological pH, complexed with citrate, synergises iron mobilization from ferritin by ascorbate (50-4000μM). This autocatalytic process can exacerbate oxidative stress in ferritin-containing inflamed tissue.
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Affiliation(s)
- Charles Badu-Boateng
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence and Physiology Department, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Sofia Pardalaki
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence and Physiology Department, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | | | - Sonia Lajnef
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques (UMR CNRS 8601), Université Paris Descartes, 75006 Paris, France
| | - Fabienne Peyrot
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques (UMR CNRS 8601), Université Paris Descartes, 75006 Paris, France; ESPE de l'académie de Paris, Université Paris Sorbonne, 75016 Paris, France
| | - Richard J Naftalin
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence and Physiology Department, King's College London, 150 Stamford Street, London SE1 9NH, UK.
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9
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Jutz G, van Rijn P, Santos Miranda B, Böker A. Ferritin: a versatile building block for bionanotechnology. Chem Rev 2015; 115:1653-701. [PMID: 25683244 DOI: 10.1021/cr400011b] [Citation(s) in RCA: 272] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Günther Jutz
- DWI - Leibniz-Institut für Interaktive Materialien e.V., Lehrstuhl für Makromolekulare Materialien und Oberflächen, RWTH Aachen University , Forckenbeckstrasse 50, D-52056 Aachen, Germany
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10
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Lane DJR, Richardson DR. The active role of vitamin C in mammalian iron metabolism: much more than just enhanced iron absorption! Free Radic Biol Med 2014; 75:69-83. [PMID: 25048971 DOI: 10.1016/j.freeradbiomed.2014.07.007] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/04/2014] [Accepted: 07/08/2014] [Indexed: 01/18/2023]
Abstract
Ascorbate is a cofactor in numerous metabolic reactions. Humans cannot synthesize ascorbate owing to inactivation of the gene encoding the enzyme l-gulono-γ-lactone oxidase, which is essential for ascorbate synthesis. Accumulating evidence strongly suggests that in addition to the known ability of dietary ascorbate to enhance nonheme iron absorption in the gut, ascorbate within mammalian systems can regulate cellular iron uptake and metabolism. Ascorbate modulates iron metabolism by stimulating ferritin synthesis, inhibiting lysosomal ferritin degradation, and decreasing cellular iron efflux. Furthermore, ascorbate cycling across the plasma membrane is responsible for ascorbate-stimulated iron uptake from low-molecular-weight iron-citrate complexes, which are prominent in the plasma of individuals with iron-overload disorders. Importantly, this iron-uptake pathway is of particular relevance to astrocyte brain iron metabolism and tissue iron loading in disorders such as hereditary hemochromatosis and β-thalassemia. Recent evidence also indicates that ascorbate is a novel modulator of the classical transferrin-iron uptake pathway, which provides almost all iron for cellular demands and erythropoiesis under physiological conditions. Ascorbate acts to stimulate transferrin-dependent iron uptake by an intracellular reductive mechanism, strongly suggesting that it may act to stimulate iron mobilization from the endosome. The ability of ascorbate to regulate transferrin iron uptake could help explain the metabolic defect that contributes to ascorbate-deficiency-induced anemia.
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Affiliation(s)
- Darius J R Lane
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, University of Sydney, Sydney, NSW 2006, Australia.
| | - Des R Richardson
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, University of Sydney, Sydney, NSW 2006, Australia.
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11
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Melman G, Bou-Abdallah F, Vane E, Maura P, Arosio P, Melman A. Iron release from ferritin by flavin nucleotides. Biochim Biophys Acta Gen Subj 2013; 1830:4669-74. [PMID: 23726988 DOI: 10.1016/j.bbagen.2013.05.031] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 04/17/2013] [Accepted: 05/21/2013] [Indexed: 01/01/2023]
Abstract
BACKGROUND Extensive in-vitro studies have focused on elucidating the mechanism of iron uptake and mineral core formation in ferritin. However, despite a plethora of studies attempting to characterize iron release under different experimental conditions, the in-vivo mobilization of iron from ferritin remains poorly understood. Several iron-reductive mobilization pathways have been proposed including, among others, flavin mononucleotides, ascorbate, glutathione, dithionite, and polyphenols. Here, we investigate the kinetics of iron release from ferritin by reduced flavin nucleotide, FMNH2, and discuss the physiological significance of this process in-vivo. METHODS Iron release from horse spleen ferritin and recombinant human heteropolymer ferritin was followed by the change in optical density of the Fe(II)-bipyridine complex using a Cary 50 Bio UV-Vis spectrophotometer. Oxygen consumption curves were followed on a MI 730 Clark oxygen microelectrode. RESULTS The reductive mobilization of iron from ferritin by the nonenzymatic FMN/NAD(P)H system is extremely slow in the presence of oxygen and might involve superoxide radicals, but not FMNH2. Under anaerobic conditions, a very rapid phase of iron mobilization by FMNH2 was observed. CONCLUSIONS Under normoxic conditions, FMNH2 alone might not be a physiologically significant contributor to iron release from ferritin. GENERAL SIGNIFICANCE There is no consensus on which iron release pathway is predominantly responsible for iron mobilization from ferritin under cellular conditions. While reduced flavin mononucleotide (FMNH2) is one likely candidate for in-vivo ferritin iron removal, its significance is confounded by the rapid oxidation of the latter by molecular oxygen.
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Affiliation(s)
- Galina Melman
- Department of Chemistry & Biomolecular Science, Clarkson University, Potsdam, NY, USA.
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12
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Różanowska M, Bakker L, Boulton ME, Różanowski B. Concentration dependence of vitamin C in combinations with vitamin E and zeaxanthin on light-induced toxicity to retinal pigment epithelial cells. Photochem Photobiol 2012; 88:1408-17. [PMID: 22924673 PMCID: PMC3484246 DOI: 10.1111/j.1751-1097.2012.01228.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 08/20/2012] [Indexed: 01/08/2023]
Abstract
The purpose of this study was to determine the effects of increasing concentration of ascorbate alone and in combinations with α-tocopherol and zeaxanthin on phototoxicity to the retinal pigment epithelium. ARPE-19 cells were exposed to rose bengal and visible light in the presence and absence of antioxidants. Toxicity was quantified by an assay of cell-reductive activity. A 20 min exposure to visible light and photosensitizer decreased cell viability to ca 42%. Lipophilic antioxidants increased viabilities to ca 70%, 61% and 75% for α-tocopherol, zeaxanthin and their combination, respectively. Cell viabilities were ca 70%, 56% and 5% after exposures in the presence of 0.35, 0.7 and 1.4 mm ascorbate, respectively. A 45 min exposure increased cell death to ca 74% and >95% in the absence and presence of ascorbate, respectively. In the presence of ascorbate, zeaxanthin did not significantly affect phototoxicity. α-Tocopherol and its combination with zeaxanthin enhanced protective effects of ascorbate, but did not prevent from ascorbate-mediated deleterious effects. In conclusion, there is a narrow range of concentrations and exposure times where ascorbate exerts photoprotective effects, exceeding which leads to ascorbate-mediated increase in photocytotoxicity. Vitamin E and its combination with zeaxanthin can enhance protective effects of ascorbate, but do not ameliorate its deleterious effects.
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13
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Wei Y, Song J, Chen Q, Xing D. Enhancement of photodynamic antitumor effect with pro-oxidant ascorbate. Lasers Surg Med 2012; 44:69-75. [DOI: 10.1002/lsm.21157] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2011] [Indexed: 12/11/2022]
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14
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Li Y, Hamasaki T, Nakamichi N, Kashiwagi T, Komatsu T, Ye J, Teruya K, Abe M, Yan H, Kinjo T, Kabayama S, Kawamura M, Shirahata S. Suppressive effects of electrolyzed reduced water on alloxan-induced apoptosis and type 1 diabetes mellitus. Cytotechnology 2011; 63:119-31. [PMID: 21063772 PMCID: PMC3080478 DOI: 10.1007/s10616-010-9317-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Accepted: 10/18/2010] [Indexed: 12/13/2022] Open
Abstract
Electrolyzed reduced water, which is capable of scavenging reactive oxygen species, is attracting recent attention because it has shown improved efficacy against several types of diseases including diabetes mellitus. Alloxan produces reactive oxygen species and causes type 1 diabetes mellitus in experimental animals by irreversible oxidative damage to insulin-producing β-cells. Here, we showed that electrolyzed reduced water prevented alloxan-induced DNA fragmentation and the production of cells in sub-G1 phase in HIT-T15 pancreatic β-cells. Blood glucose levels in alloxan-induced type 1 diabetes model mice were also significantly suppressed by feeding the mice with electrolyzed reduced water. These results suggest that electrolyzed reduced water can prevent apoptosis of pancreatic β-cells and the development of symptoms in type 1 diabetes model mice by alleviating the alloxan-derived generation of reactive oxygen species.
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Affiliation(s)
- Yupin Li
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
- School of Life Sciences, Nanchang University of Science and Technology, Nanchang, 330013 People’s Republic of China
| | - Takeki Hamasaki
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
| | - Noboru Nakamichi
- Nihon Trim Co Ltd, 1-8-34 Oyodonaka, Kita-ku, Osaka, 531-0076 Japan
| | - Taichi Kashiwagi
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
| | - Takaaki Komatsu
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
| | - Jun Ye
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
- School of Life Science, Xiamen University, Fujian, 361005 People’s Republic of China
| | - Kiichiro Teruya
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
- Graduate School of Systems Life Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
| | - Masumi Abe
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
| | - Hanxu Yan
- Graduate School of Systems Life Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
| | - Tomoya Kinjo
- Graduate School of Systems Life Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
| | - Shigeru Kabayama
- Nihon Trim Co Ltd, 1-8-34 Oyodonaka, Kita-ku, Osaka, 531-0076 Japan
| | - Munenori Kawamura
- Kyowa Hospital, 191-1 Sakae, Osibetanimachi, Nishi-ku, Kobe, 851-2211 Japan
| | - Sanetaka Shirahata
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
- Graduate School of Systems Life Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
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15
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Superoxide-dependent reduction of free Fe(3+) and release of Fe(2+) from ferritin by the physiologically-occurring Cu(I)-glutathione complex. Bioorg Med Chem 2010; 19:534-41. [PMID: 21115254 DOI: 10.1016/j.bmc.2010.10.064] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 10/22/2010] [Accepted: 10/30/2010] [Indexed: 11/22/2022]
Abstract
The intracellularly-occurring Cu(I)-glutathione complex (Cu(I)-[GSH](2)) has the ability to reduce molecular oxygen into superoxide radicals (O2·-). Based on such ability, we addressed the potential of this complex to generate the redox-active Fe(2+) species, during its interaction with free Fe(3+) and with ferritin-bound iron. Results show that: (i) the complex reduces free Fe(3+) through a reaction that totally depends on its O2·--generating capacity; (ii) during its interaction with ferritin, the complex reduces and subsequently releases iron through a largely (77%) SOD-inhibitable reaction; the remaining fraction is accounted for by a direct effect of GSH molecules contained within the complex. The O2·--dependent iron-releasing efficiency of the complex was half that of its iron-reducing efficiency; (iii) the ability of the complex to release ferritin-bound iron was increased, concentration-dependently, by the addition of GSH and totally prevented by SOD; (iv) in the presence of added H(2)O(2), the Fe(2+) ions generated through (i) or (ii) were able to catalyze the generation of hydroxyl radicals. Thus, the present study demonstrates the ability of the Cu(I)-[GSH](2) complex to generate the redox-active Fe(2+) species and suggest that by favouring the occurrence of superoxide-driven Fenton reactions, its pro-oxidant potential could be increased beyond its initial O2·--generating capacity.
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16
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Jackson CS, Kodanko JJ. Iron-binding and mobilization from ferritin by polypyridyl ligands. Metallomics 2010; 2:407-11. [DOI: 10.1039/c003414b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Li W, Xu LH, Forssell C, Sullivan JL, Yuan XM. Overexpression of transferrin receptor and ferritin related to clinical symptoms and destabilization of human carotid plaques. Exp Biol Med (Maywood) 2008; 233:818-26. [PMID: 18445768 DOI: 10.3181/0711-rm-320] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Accumulation of tissue iron has been implicated in development of atherosclerotic lesions mainly because of increased iron-catalyzed oxidative injury. However, it remains unknown whether cellular iron import and storage in human atheroma are related to human atheroma development. We found that transferrin receptor 1 (TfR1), a major iron importer, is highly expressed in foamy macrophages and some smooth muscle cells in intimal lesions of human carotid atheroma, mainly in cytoplasmic accumulation patterns. In 52 human carotid atherosclerotic lesions, TfR1 expression was positively correlated with macrophage infiltration, ectopic lysosomal cathepsin L, and ferritin expression. Highly expressed TfR1 and ferritin in CD68-positive macrophages were significantly associated with development and severity of human carotid plaques, smoking, and patient's symptoms. The findings suggest that pathologic macrophage iron metabolism may contribute to vulnerability of human atheroma, established risk factors, and their clinical symptoms. The cytoplasmic overexpression of TfR1 may be the result of lysosomal dysfunction and ectopic accumulation of lysosomal cathepsin L caused by atheroma-relevant lipids in atherogenesis.
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MESH Headings
- Aged
- Aged, 80 and over
- Antigens, CD/metabolism
- Antigens, Differentiation, Myelomonocytic/metabolism
- Atherosclerosis/metabolism
- Atherosclerosis/pathology
- Carotid Stenosis/metabolism
- Carotid Stenosis/pathology
- Cathepsin L
- Cathepsins/metabolism
- Cysteine Endopeptidases/metabolism
- Female
- Ferritins/genetics
- Ferritins/metabolism
- Gene Expression Regulation
- Humans
- Iron/metabolism
- Lysosomes/metabolism
- Macrophages/metabolism
- Macrophages/pathology
- Male
- Middle Aged
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Receptors, Transferrin/genetics
- Receptors, Transferrin/metabolism
- Severity of Illness Index
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Affiliation(s)
- Wei Li
- Division of Experimental Pathology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
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18
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Investigation of ascorbate-mediated iron release from ferric phytosiderophores in the presence of nicotianamine. Biometals 2008; 21:503-13. [DOI: 10.1007/s10534-008-9137-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Accepted: 02/14/2008] [Indexed: 12/22/2022]
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19
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Haynes RK, Chan WC, Lung CM, Uhlemann AC, Eckstein U, Taramelli D, Parapini S, Monti D, Krishna S. The Fe2+-Mediated Decomposition, PfATP6 Binding, and Antimalarial Activities of Artemisone and Other Artemisinins: The Unlikelihood of C-Centered Radicals as Bioactive Intermediates. ChemMedChem 2007; 2:1480-97. [PMID: 17768732 DOI: 10.1002/cmdc.200700108] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The results of Fe(2+)-induced decomposition of the clinically used artemisinins, artemisone, other aminoartemisinins, 10-deoxoartemisinin, and the 4-fluorophenyl derivative have been compared with their antimalarial activities and their ability to inhibit the parasite SERCA PfATP6. The clinical artemisinins and artemisone decompose under aqueous conditions to give mixtures of C radical marker products, carbonyl compounds, and reduction products. The 4-fluorophenyl derivative and aminoartemisinins tend to be inert to aqueous iron(II) sulfate and anhydrous iron(II) acetate. Anhydrous iron(II) bromide enhances formation of the carbonyl compounds and provides a deoxyglycal from DHA and enamines from the aminoartemisinins. Ascorbic acid (AA) accelerates the aqueous Fe(2+)-mediated decompositions, but does not alter product distribution. 4-Oxo-TEMPO intercepts C radicals from a mixture of an antimalaria-active trioxolane, 10-deoxoartemisinin, and anhydrous iron(II) acetate to give trapped products in 73 % yield from the trioxolane, and 3 % from the artemisinin. Artemisone provides a trapped product in 10 % yield. Thus, in line with its structural rigidity, only the trioxolane provides a C radical eminently suited for intermolecular trapping. In contrast, the structural flexibility of the C radicals from the artemisinins allows facile extrusion of Fe(2+) and collapse to benign isomerization products. The propensity towards the formation of radical marker products and intermolecular radical trapping have no relationship with the in vitro antimalarial activities of the artemisinins and trioxolane. Desferrioxamine (DFO) attenuates inhibition of PfATP6 by, and antagonizes antimalarial activity of, the aqueous Fe(2+)-susceptible artemisinins, but has no overt effect on the aqueous Fe(2+)-inert artemisinins. It is concluded that the C radicals cannot be responsible for antimalarial activity and that the Fe(2+)-susceptible artemisinins may be competitively decomposed in aqueous extra- and intracellular compartments by labile Fe(2+), resulting in some attenuation of their antimalarial activities. Interpretations of the roles of DFO and AA in modulating antimalarial activities of the artemisinins, and a comparison with antimalarial properties of simple hydroperoxides and their behavior towards thapsigargin-sensitive SERCA ATPases are presented. The general basis for the exceptional antimalarial activities of artemisinins in relation to the intrinsic activity of the peroxide within the uniquely stressed environment of the malaria parasite is thereby adumbrated.
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Affiliation(s)
- Richard K Haynes
- Department of Chemistry, Open Laboratory of Chemical Biology, Institute of Molecular Technology for Drug Discovery and Synthesis, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, PR China.
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