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Alajroush DR, Smith CB, Anderson BF, Oyeyemi IT, Beebe SJ, Holder AA. A Comparison of In Vitro Studies between Cobalt(III) and Copper(II) Complexes with Thiosemicarbazone Ligands to Treat Triple Negative Breast Cancer. Inorganica Chim Acta 2024; 562:121898. [PMID: 38282819 PMCID: PMC10810091 DOI: 10.1016/j.ica.2023.121898] [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] [Indexed: 01/30/2024]
Abstract
Metal complexes have gained significant attention as potential anti-cancer agents. The anti-cancer activity of [Co(phen)2(MeATSC)](NO3)3•1.5H2O•C2H5OH 1 (where phen = 1,10-phenanthroline and MeATSC = 9-anthraldehyde-N(4)-methylthiosemicarbazone) and [Cu(acetylethTSC)Cl]Cl•0.25C2H5OH 2 (where acetylethTSC = (E)-N-ethyl-2-[1-(thiazol-2-yl)ethylidene]hydrazinecarbothioamide) was investigated by analyzing DNA cleavage activity. The cytotoxic effect was analyzed using CCK-8 viability assay. The activities of caspase 3/7, 9, and 1, reactive oxygen species (ROS) production, cell cycle arrest, and mitochondrial function were further analyzed to study the cell death mechanisms. Complex 2 induced a significant increase in nicked DNA. The IC50 values of complex 1 were 17.59 μM and 61.26 μM in cancer and non-cancer cells, respectively. The IC50 values of complex 2 were 5.63 and 12.19 μM for cancer and non-cancer cells, respectively. Complex 1 induced an increase in ROS levels, mitochondrial dysfunction, and activated caspases 3/7, 9, and 1, which indicated the induction of intrinsic apoptotic pathway and pyroptosis. Complex 2 induced cell cycle arrest in the S phase, ROS generation, and caspase 3/7 activation. Thus, complex 1 induced cell death in the breast cancer cell line via activation of oxidative stress which induced apoptosis and pyroptosis while complex 2 induced cell cycle arrest through the induction of DNA cleavage.
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Affiliation(s)
- Duaa R. Alajroush
- Department of Chemistry and Biochemistry, Old Dominion University 4501 Elkhorn Avenue, Norfolk, VA 23529, U.S.A
| | - Chloe B. Smith
- Department of Chemistry and Biochemistry, Old Dominion University 4501 Elkhorn Avenue, Norfolk, VA 23529, U.S.A
| | - Brittney F. Anderson
- Department of Biological Sciences, University of the Virgin Islands, 2 John Brewers Bay, St. Thomas, VI 00802, U.S.A
| | - Ifeoluwa T. Oyeyemi
- Department of Chemistry and Biochemistry, Old Dominion University 4501 Elkhorn Avenue, Norfolk, VA 23529, U.S.A
- Department of Biological Sciences, University of Medical Sciences, Ondo City, Nigeria
| | - Stephen J. Beebe
- Frank Reidy Research center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA, 23508, U.S.A
| | - Alvin A. Holder
- Department of Chemistry and Biochemistry, Old Dominion University 4501 Elkhorn Avenue, Norfolk, VA 23529, U.S.A
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2
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Qian L, Miao T, Xu L. Probing DNA-Cleavage Efficiencies of Copper(II) Complexes: A Computational Perspective. ACS OMEGA 2020; 5:19029-19033. [PMID: 32775905 PMCID: PMC7408204 DOI: 10.1021/acsomega.0c02331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 07/10/2020] [Indexed: 06/11/2023]
Abstract
Theoretical studies on DNA-cleavage efficiencies of Cu(II) complexes 1-3 were carried out using density functional theory (DFT). The optimized Cu(II) complexes were allowed to bind to glutathiones (GSH) and ascorbic acids (VC) by the docking program so that corresponding docking structures can be obtained. To predict DNA-cleavage efficiencies, the docking structures of Cu(II) complexes with GSH and VC were further optimized by DFT. The activation energies of electrons from GSH to complexes, the redox potentials of these complexes, and binding energies of these complexes with GSH and VC were calculated. The efficiencies of complexes cleaving DNA were predicted and found to be in agreement with the experimental results. Finally, three occupied molecular orbitals of docking structures (GSH-complexes) were analyzed, and the DNA-cleavage abilities of complexes were also explained by the electron distribution on the three occupied orbitals. This work has important implications understanding the DNA-cleavage mechanism of Cu(II) complexes, which might be helpful for designing novel anticancer Cu(II) complexes for the future.
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Affiliation(s)
- Li Qian
- College
of Pharmacy, Youjiang Medical College for
Nationalities, Guangxi, Baise 533000, China
| | - Tifang Miao
- School
of Chemistry and Materials Science, Huaibei
Normal University, Huaibei 235000, China
| | - Liancai Xu
- Department
of Material and Chemical Engineering, Zhengzhou
University of Light Industry, Zhengzhou 450002, China
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3
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Li S, Miao T, Fu X, Ma F, Gao H, Zhang G. Theoretical study on the DNA interaction properties of copper(II) complexes. Comput Biol Chem 2019; 80:244-248. [PMID: 31026737 DOI: 10.1016/j.compbiolchem.2019.03.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 03/23/2019] [Accepted: 03/25/2019] [Indexed: 11/28/2022]
Abstract
Theoretical studies on DNA-cleavage and DNA-binding properties of a series of Cu(II) complexes [Cu(bimda)(diimine)] 1-5 have been carried out by density functional theory (DFT). The optimized structures of Cu(II) complexes were docked into parallel, antiparallel and mixed G-quadruplexes, with which the binding energies of complexes 1-5 were obtained. The cytotoxicities of these complexes can be predicted preliminarily by the binding energies. To explore the energy changes of Cu(II) complexes in duplex DNA, the optimized structures of these complexes were docked into the duplex DNA, and the obtained docking models were further optimized using QM/MM method. The DNA-cleavage abilities of complexes 1-5 can be predicted accurately and explained reasonably by the computed intra-molecular reorganization energies of these complexes. This work reported here has implications for the understanding of the interaction Cu(II) complexes with the DNA, which might be helpful for the future directing the design of novel anticancer Cu(II) complexes.
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Affiliation(s)
- Shuang Li
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, China
| | - Tifang Miao
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, China.
| | - Xianliang Fu
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, China
| | - Fang Ma
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, China
| | - Hui Gao
- Key Laboratory of Molecular Target and Clinical Pharmacology, School of Pharmaceutical Sciences & Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong 511436, China; School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China.
| | - Guoping Zhang
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, China
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Jana A, Brandão P, Mondal G, Bera P, Santra A, Jana AD, Mokhamatam RB, Manna SK, Bhattacharyya N, Bera P. Synthesis, characterization, cytotoxicity effect and DNA cleavage study of symmetric dinuclear chloro and azido bridged copper(II) complexes of napthyl-pyrazole based ligand. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2018.06.054] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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5
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Miao T, Deng Q, Gao H, Fu X, Li S. Theoretical Studies on DNA-Cleavage Mechanism of Copper(II) Complexes: Probing Generation of Reactive Oxygen Species. J Chem Inf Model 2018. [DOI: 10.1021/acs.jcim.8b00055] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Tifang Miao
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, P. R. China
- Anhui Key Laboratory of Energetic Materials, Huaibei Normal University, Huaibei 235000, P. R. China
| | - Qinghua Deng
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, P. R. China
| | - Hui Gao
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, P. R. China
| | - Xianliang Fu
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, P. R. China
| | - Shuang Li
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, P. R. China
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6
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Zlobin IE, Kartashov AV, Shpakovski GV. Different roles of glutathione in copper and zinc chelation in Brassica napus roots. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 118:333-341. [PMID: 28683402 DOI: 10.1016/j.plaphy.2017.06.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 06/07/2023]
Abstract
We investigated the specific features of copper and zinc excess action on the roots of canola (Brassica napus L.) plants. Copper rapidly accumulated in canola root cells and reached saturation during several hours of treatment, whereas the root zinc content increased relatively slowly. Excessive copper and zinc entry inside the cell resulted in significant cell damage, as evidenced by alterations in plasmalemma permeability and decreases in cellular enzymatic activity. Zinc excess specifically damaged root hair cells, which correlated with a pronounced elevation of their labile zinc level. In vitro, we showed that reduced glutathione (GSH) readily reacted with copper ions to form complexes with blocked sulfhydryl groups. In contrast, zinc ions were ineffective as glutathione blockers, and glutathione molecules did not lose their specific chemical activity in the presence of Zn2+ ions. The effect of copper and zinc excess on the glutathione pool in canola root cells was analysed by a combination of biochemical determination of total and oxidized glutathione contents and fluorescent staining of free reduced glutathione with monochlorobimane dye. Excess copper led to dose-dependent diminution of free reduced glutathione contents in the root cells, which could not be explained by the loss of total cellular glutathione or its oxidation. In contrast, we observed little effect of much higher intracellular zinc concentrations on the free reduced glutathione content. We concluded that GSH plays an important role in copper excess, but not zinc excess chelation, in canola root cells.
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Affiliation(s)
- Ilya E Zlobin
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya ul. 35, 127276 Moscow, Russia
| | - Alexander V Kartashov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya ul. 35, 127276 Moscow, Russia.
| | - George V Shpakovski
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
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7
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Aliaga ME, López-Alarcón C, Bridi R, Speisky H. Redox-implications associated with the formation of complexes between copper ions and reduced or oxidized glutathione. J Inorg Biochem 2015; 154:78-88. [PMID: 26277412 DOI: 10.1016/j.jinorgbio.2015.08.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 07/03/2015] [Accepted: 08/05/2015] [Indexed: 02/08/2023]
Abstract
Binding of copper by reduced glutathione (GSH) is generally seen as a mechanism to lower, if not abolish, the otherwise high electrophilicity and redox activity of its free ions. In recent years, however, this concept has been contradicted by new evidence revealing that, rather than stabilizing free copper ions, its binding to GSH leads to the formation of a Cu(I)-[GSH]2 complex capable of reducing molecular oxygen into superoxide. It is now understood that, under conditions leading to the removal of such radicals, the Cu(I)-[GSH]2 complex is readily oxidized into Cu(II)-GSSG. Interestingly, in the presence of a GSH excess, the latter complex is able to regenerate the superoxide-generating capacity of the complex it originated from, opening the possibility that a GSH-dependent interplay exists between the reduced and the oxidized glutathione forms of these copper-complexes. Furthermore, recent evidence obtained from experiments conducted in non-cellular systems and intact mitochondria indicates that the Cu(II)-GSSG complex is also able to function in a catalytic manner as an efficient superoxide dismutating- and catalase-like molecule. Here we review and discuss the most relevant chemical and biological evidence on the formation of the Cu(I)-[GSH]2 and Cu(II)-GSSG complexes and on the potential redox implications associated with their intracellular occurrence.
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Affiliation(s)
- Margarita E Aliaga
- Facultad de Química, Pontificia Universidad Católica de Chile, Santiago 6094411, Chile.
| | - Camilo López-Alarcón
- Facultad de Química, Pontificia Universidad Católica de Chile, Santiago 6094411, Chile
| | - Raquel Bridi
- Facultad de Química, Pontificia Universidad Católica de Chile, Santiago 6094411, Chile
| | - Hernán Speisky
- Nutrition and Food Technology Institute, University of Chile, Santiago, Chile; Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Santiago, Chile.
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8
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NABI GUL, LIU ZAIQUN. FERULIC AND COUMARIC ACIDS: APPLICATION TO RELEASE OXIDATIVE STRESS OF DNA AND METHYL LINOLEATE. J Food Biochem 2011. [DOI: 10.1111/j.1745-4514.2010.00501.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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9
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Li YF, Liu ZQ. Ferrocenyl Schiff base as novel antioxidant to protect DNA against the oxidation damage. Eur J Pharm Sci 2011; 44:158-63. [DOI: 10.1016/j.ejps.2011.07.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 06/23/2011] [Accepted: 07/06/2011] [Indexed: 11/16/2022]
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10
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Zhao F, Zhao C, Liu ZQ. Synthesis of hydroxyferrocifen and its abilities to protect DNA and to scavenge radicals. J Biol Inorg Chem 2011; 16:1169-76. [DOI: 10.1007/s00775-011-0805-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 06/11/2011] [Indexed: 11/30/2022]
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11
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Feng JY, Liu ZQ. Feruloylacetone as the model compound of half-curcumin: Synthesis and antioxidant properties. Eur J Med Chem 2011; 46:1198-206. [DOI: 10.1016/j.ejmech.2011.01.039] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2010] [Revised: 01/20/2011] [Accepted: 01/25/2011] [Indexed: 10/18/2022]
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12
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Xiao C, Song ZG, Liu ZQ. Synthesis of methyl-substituted xanthotoxol to clarify prooxidant effect of methyl on radical-induced oxidation of DNA. Eur J Med Chem 2010; 45:2559-66. [DOI: 10.1016/j.ejmech.2010.02.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 02/08/2010] [Accepted: 02/18/2010] [Indexed: 11/17/2022]
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13
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Dichloro-4-quinolinol-3-carboxylic acid: Synthesis and antioxidant abilities to scavenge radicals and to protect methyl linoleate and DNA. Eur J Med Chem 2010; 45:1821-7. [DOI: 10.1016/j.ejmech.2010.01.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 01/07/2010] [Accepted: 01/08/2010] [Indexed: 02/08/2023]
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14
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Li YF, Liu ZQ, Luo XY. Properties of synthetic homoisoflavonoids to reduce oxidants and to protect linoleic acid and dna against oxidation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:4126-4131. [PMID: 20199083 DOI: 10.1021/jf904089q] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
3-(2'-, 3'-, and 4'-Hydroxybenzylidene)-7-methoxychroman-4-one (o-, m-, and p-HBMC) was synthesized for the clarification of the influence of the hydroxyl group at the B ring on the antioxidant activity of homoisoflavonoid. The three homoisoflavonoids used herein can reduce peroxynitrite. p-HBMC exhibited high activity to reduce singlet oxygen. Furthermore, o-, m-, and p-HBMC can scavenge the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(*+)) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and galvinoxyl radicals. The rates of o-HBMC trapping of DPPH and galvinoxyl radicals were higher than those of m- and p-HBMC, whereas m-HBMC can trap ABTS(*+) rapidly. o-HBMC was found to possess high activity in the beta-carotene-linoleic acid bleaching test and to protect methyl linoleate against 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH)-induced oxidation efficiently. Finally, o-HBMC served as a prooxidant in Cu(2+)/glutathione (GSH)- and hydroxyl radical-mediated oxidations of DNA. m- and p-HBMC protected DNA against hydroxyl radical-mediated oxidation of DNA effectively, and o- and p-HBMC behaved as antioxidants to protect DNA against AAPH-induced oxidation. Thus, the hydroxyl group attaching to the ortho- and para-positions in the B ring was of importance for the homoisoflavonoid's enhancement of antioxidant activity.
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Affiliation(s)
- Yan-Feng Li
- Department of Organic Chemistry, College of Chemistry, Jilin University, Changchun, China
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15
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Double edge redox-implications for the interaction between endogenous thiols and copper ions: In vitro studies. Bioorg Med Chem 2008; 16:9795-803. [PMID: 18926709 DOI: 10.1016/j.bmc.2008.09.068] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Revised: 09/24/2008] [Accepted: 09/26/2008] [Indexed: 11/22/2022]
Abstract
The present study investigated the redox-consequences of the interaction between various endogenous thiols (RSH)-glutathione, cysteine, homocysteine, gamma-glutamyl-cysteine, and cysteinyl-glycine- and Cu(2+) ions, in terms of their free radical-scavenging, ascorbate-oxidizing and O2(*-)-generating properties of the resulting mixtures. Upon a brief incubation (3-30 min) with Cu(2+), the free radical-scavenging properties (towards ABTS(*)(+) and DPPH(*)) and thiol-titratable groups of the RSH added to the mixtures decreased significantly. Remarkably, both effects were only partial, even in the presence of a large molar Cu(2+)-excess, and were unaffected despite increasing the incubation time. At equimolar concentrations, the RSH/Cu(2+) mixtures led to the formation of (EPR paramagnetic) Cu(II)-complexes that were time-stable and ascorbate-reducible, but redox-inactive towards oxygen. In turn, at a slight molar thiol-excess (3:1), the mixtures resulted in the formation of time-stable Cu(I)-complexes (EPR silent) that were unreactive towards ascorbate and oxygen. The only exception was seen for the thiol, glutathione, whose mixture with Cu(2+) mixture displayed a O2(*-)-generating capacity (cytochrome c- and lucigenin-reduction). The data indicate that, depending on their molar ratio, the interaction between Cu(2+) and the tested thiols would give place to mixtures containing either: (i) time-stable and ascorbate-reducible Cu(II)-complexes which display free radical-scavenging properties, or (ii) time-stable but redox-inactive towards oxygen Cu(I)-complexes. Among the latter, the only exception was that of glutathione.
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16
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Biophysical, spectroscopic and biochemical investigation of DNA–Cu(II)-GSH interactions. TRANSIT METAL CHEM 2007. [DOI: 10.1007/s11243-007-9034-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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17
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Chandrasekhar V, Athimoolam A, Krishnan V, Azhakar R, Madhavaiah C, Verma S. A Copper-Metalated, Hybrid Inorganic-Organic Polymer as an Oxidative Nuclease. Eur J Inorg Chem 2005. [DOI: 10.1002/ejic.200400727] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18
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Nair J, Strand S, Frank N, Knauft J, Wesch H, Galle PR, Bartsch H. Apoptosis and age-dependant induction of nuclear and mitochondrial etheno-DNA adducts in Long-Evans Cinnamon (LEC) rats: enhanced DNA damage by dietary curcumin upon copper accumulation. Carcinogenesis 2005; 26:1307-15. [PMID: 15790590 DOI: 10.1093/carcin/bgi073] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Long-Evans Cinnamon (LEC) rats, a model for human Wilson's disease, develop chronic hepatitis and liver tumors owing to accumulation of copper and induced oxidative stress. Lipid peroxidation (LPO)-induced etheno-DNA adducts in nuclear- and mitochondrial-DNA along with apoptosis was measured in LEC rat liver. Levels of etheno-DNA adducts (1,N6-ethenodeoxyadenosine and 3,N4-ethenodeoxycytidine) increased with age reaching a peak at 8 and 12 weeks in nuclear and mitochondrial DNA, respectively. This is the first demonstration that etheno-DNA adducts are also formed in mitochondrial DNA. Apoptosis was assessed by TUNEL+ cells in liver sections. CD95L RNA expression was also measured by in situ hybridization in the same sections. The highest nuclear DNA adduct levels coincided with a reduced apoptotic rate at 8 weeks. Mitochondrial-DNA adducts peaked at 12 weeks that coincided with the highest apoptotic rate, suggesting a link of etheno-DNA adducts in mitochondrial DNA to apoptosis. The DNA damage in liver was further enhanced and sustained by 0.5% curcumin in the diet. Treatment for 2 weeks elevated etheno-DNA adducts 9- to 25-fold in nuclear DNA and 3- to 4-fold in mitochondrial-DNA, providing a plausible explanation as to why in our earlier study [Frank et al. (2003) Mutat. Res., 523-524, 127-135], curcumin failed to prevent liver tumors in LEC rats. Our results also confirm the reported in vitro DNA damaging potential of curcumin in the presence of copper ions by reactive oxygen species. LPO-induced adduct formation in nuclear and mitochondrial DNA appear as early lesions in LEC rat liver carcinogenesis and are discussed in relation to apoptotic events in the progression of malignant disease.
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Affiliation(s)
- Jagadeesan Nair
- Division of Toxicology and Cancer Risk Factors, German Cancer Research Center (DKFZ), Heidelberg, Germany.
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19
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Srivatsan SG, Parvez M, Verma S. Adenine-copper coordination polymer as an oxidative nucleozyme: implications for simple prebiotic catalytic units. J Inorg Biochem 2004; 97:340-4. [PMID: 14568238 DOI: 10.1016/s0162-0134(03)00285-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Plasmid modification activity of a modified adenine-copper coordination polymer, in the presence of peracids and thiols, and ensuing preliminary mechanistic investigations are reported. These observations, when coupled with unique coordination pattern of the metal complex, have led us to propose that a synergistic interaction between nucleobases and metal ions may be responsible for primordial catalysis of certain key reactions of biochemical significance and could serve the function of a prototypical, prebiotic nucleozyme.
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Affiliation(s)
- S G Srivatsan
- Department of Chemistry, Indian Institute of Technology-Kanpur, Kanpur, 208016 (UP), India
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20
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Teixeira PC, Onuki J, Medeiros MH, Dörnemann D, Di Mascio P. DNA damage by 3,6-dihydropyrazine-2,5-dipropanoic acid, the cyclic dimerization product of 5-aminolevulinic acid. Biol Chem 2001; 382:913-8. [PMID: 11501755 DOI: 10.1515/bc.2001.113] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
5-Aminolevulinic acid (ALA) is a heme precursor that accumulates in lead poisoning and inborn porphyrias. It has been shown to produce reactive oxygen species upon metal-catalyzed aerobic oxidation and to cause oxidative damage to proteins, liposomes, DNA, and subcellular structures. Studies have also shown that ALA may condense to yield the cyclic product 3,6-dihydropyrazine-2,5-dipropanoic acid (DHPY). Here we propose that DHPY could be involved in DNA damage in the presence of high concentrations of ALA. Exposure of plasmid pUC19 DNA to low concentrations of DHPY (2-10 microM) in the presence of 0.1 mM Cu2+ ions causes DNA strand breaks, as demonstrated by agarose gel electrophoresis. It was also shown that in the presence of Cu2+ ions DHPY is able to increase the oxidation of monomeric 2'-deoxyguanosine to form 8-oxo-7,8-dihydro-2'-deoxyguanosine as inferred from high performance liquid chromatography measurements using electrochemical detection. Addition of a metal chelator (bathocuproine, 0.5 mM), the DNA compacting polyamines spermidine (1 mM) and spermine (1 mM) or antioxidant enzymes such as superoxide dismutase (10 microg/ml) and catalase (20 pg/ml) protect the DNA against these damages. The data presented here are discussed with respect to the increased frequency of liver cancer in patients with acute intermittent porphyria.
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Affiliation(s)
- P C Teixeira
- Departamento de Bioquímica, Instituto de Quimica, Universidade de Sao Paulo, SP, Brazil
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21
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Prütz WA, Kissner R, Nauser T, Koppenol WH. On the Oxidation of Cytochrome c by Hypohalous Acids. Arch Biochem Biophys 2001; 389:110-22. [PMID: 11370661 DOI: 10.1006/abbi.2001.2321] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Oxidation of cytochrome c, a key protein in mitochondrial electron transport and a mediator of apoptotic cell death, by reactive halogen species (HOX, X2), i.e., metabolites of activated neutrophils, was investigated by stopped-flow. The fast initial reactions between FeIIIcytc and HOX species, with rate constants (at pH 7.6) of k > 3 x 10(6) M(-1) s(-1) for HOBr, k > 3 x 10(5) M(-1) s(-1) for HOCl, and k = (6.1+/-0.3) x 10(2) M(-1) s(-1) for HOI, are followed by slower intramolecular processes. All HOX species lead to a blue shift of the Soret absorption band and loss of the 695-nm absorption band, which is an indicator for the intact iron to Met-80 bond, and of the reducibility of FeIIIcytc. All HOX species do, in fact, persistently impair the ability of FeIIIcytc to act as electron acceptor, e.g., in reaction with ascorbate or O2*-. I2 selectively oxidizes the iron center of FeIIcytc, with a stoichiometry of 2 per I2, and with k(FeIIcytc + I2) approximately 4.6 x 10(4) M(-1) s(-1) and k(FeIIcytc + I2*-) = (2.9+/-0.4) x 10(8) M(-1) s(-1). Oxidation of FeIIcytc by HOX species is not selectively directed toward the iron center; HOBr and HOCl are considered to react primarily by N-halogenation of side chain amino groups, and HOI mainly by sulfoxidation. There is some evidence for the generation of HO* radicals upon reaction of HOCl with FeIIcytc. Chloramines (e.g., NH2Cl), bromamine (NH2Br), and cyclo-Gly2 chloramide oxidize FeIIcytc slowly and unselectively, but iodide efficiently catalyzes reactions of these N-halogens to yield fast selective oxidation of the iron center; this is due to generation of I2 by reaction of I- with the N-halogen and recycling of I- by reaction of I2 with FeIIcytc. Iodide also catalyzes methionine sulfoxidation and thiol oxidation by NH2Cl. The possible biological relevance of these findings is discussed.
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Affiliation(s)
- W A Prütz
- Institut für Molekulare Medizin und Zellforschung, Universität Freiburg, Germany.
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22
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Muñiz P, Sáez P, Iradi A, Viña J, Oliva MR, Sáez GT. Differences between cysteine and homocysteine in the induction of deoxyribose degradation and DNA damage. Free Radic Biol Med 2001; 30:354-62. [PMID: 11182290 DOI: 10.1016/s0891-5849(00)00480-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The effect of two naturally occurring thiols, such as cysteine and homocysteine, has been examined for their ability to induce deoxyribose degradation and DNA damage. Copper(II) ions have been added to incubation mixtures and oxygen consumption measurements have been performed in order to correlate the observed damaging effects with the rate of metal catalyzed thiol oxidation. Ascorbic acid plus copper has been used as a positive control of deoxyribose and DNA oxidation due to reactive oxygen species. Cysteine or homocysteine in the presence of copper ions induce the degradation of deoxyribose and the yield of 8-hydroxy-2'-deoxyguanosine (8-OHdG), although important differences are observed between the two thiols tested, homocysteine being less reactive than cysteine. DNA cleavage is induced by cysteine in the presence of copper(II) ions but not by homocysteine. Catalase and thiourea, but not superoxide dismutase (SOD), were shown to inhibit the damaging effects of cysteine on deoxyribose or DNA suggesting that H(2)O(2) and *OH radicals are responsible for the observed induced damage. The results indicate that there are differences between the damaging effects of the two thiols tested towards deoxyribose and DNA damage. The pathophysiological importance will be discussed.
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Affiliation(s)
- P Muñiz
- Department of Biochemistry and Molecular Biology, University of Valencia, Valencia, Spain
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23
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Murata M, Yamashita N, Inoue S, Kawanishi S. Mechanism of oxidative DNA damage induced by carcinogenic allyl isothiocyanate. Free Radic Biol Med 2000; 28:797-805. [PMID: 10754276 DOI: 10.1016/s0891-5849(00)00168-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Several isothiocyanates have been proposed as promising chemopreventive agents for human cancers. However, it has been reported that allyl isothiocyanate exhibit carcinogenic potential, and benzyl isothiocyanate and phenethyl isothiocyanate have tumor-promoting activities. We investigated whether these isothiocyanates could cause DNA damage, using (32)P-labeled DNA fragments obtained from the human p53 tumor suppressor gene and the c-Ha-ras-1 protooncogene. Allyl isothiocyanate caused Cu(II)-mediated DNA damage and formation of 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxodG) more strongly than benzyl and phenethyl isothiocyanates. Catalase and bathocuproine, a Cu(I)-specific chelator, inhibited Cu(II)-mediated DNA damage by these isothiocyanates, suggesting involvement of H(2)O(2) and Cu(I). Isothiocyanates induced DNA damage frequently at thymine and cytosine residues in the presence of Cu(II). A UV-visible spectroscopic study revealed an association between the generation of superoxide and the yield of SH group from isothiocyanates. Furthermore, the yield of 8-oxodG formation was correlated with their superoxide-generating ability. Allyl isothiocyanate significantly induced 8-oxodG formation in HL-60 cells, but not in H(2)O(2)-resistant HP100 cells, suggesting the involvement of H(2)O(2) in cellular DNA damage. We conclude that oxidative DNA damage may play important roles in carcinogenic processes induced by allyl isothiocyanate.
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Affiliation(s)
- M Murata
- Department of Hygiene, Mie University School of Medicine, Tsu, Japan
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24
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Almeida CE, Felício DL, Galhardo RS, Cabral-Neto JB, Leitão AC. Synergistic lethal effect between hydrogen peroxide and neocuproine (2,9-dimethyl 1,10-phenanthroline) in Escherichia coli. Mutat Res 1999; 433:59-66. [PMID: 10047780 DOI: 10.1016/s0921-8777(98)00064-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Despite 2,9-dimethyl 1,10-phenanthroline (NC) has been extensively used as a potential inhibitor of damage due to oxidative stress in biological systems, the incubation of E. coli cultures with the copper ion chelator NC prior to the challenge with hydrogen peroxide caused a lethal synergistic effect. The SOS response seems to be involved in the repair of the synergistic lesions through the recombination pathway. Furthermore, there is evidence for the UvrABC excinuclease participation in the repair of the synergistic lesions, and the base excision repair may also be required for bacterial survival to the synergistic effect mainly at high concentrations of H2O2, being the action of Fpg protein an important event. Incubation of lexA (Ind-) cultures with iron (II) ion chelator 2,2'-dipyridyl simultaneously with NC prevented the lethal synergistic effect. This result suggests an important role of the Fenton reaction on the phenomenon. NC treatment was able to increase the number of DNA strand breaks (DNAsb) induced by 10 mM of H2O2 in lexA (Ind-) strain and the simultaneous treatment with 2,2'-dipyridyl was able to block this effect.
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Affiliation(s)
- C E Almeida
- Laboratório de Radiobiologia Molecular, Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Bloco G, Universidade Federal do Rio de Janeiro, Brazil
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25
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Yang JL, Wang LC, Chang CY, Liu TY. Singlet oxygen is the major species participating in the induction of DNA strand breakage and 8-hydroxydeoxyguanosine adduct by lead acetate. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 1999; 33:194-201. [PMID: 10334621 DOI: 10.1002/(sici)1098-2280(1999)33:3<194::aid-em3>3.0.co;2-o] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
To investigate DNA damage induced by Pb2+ and its prevention by scavengers, we determined DNA strand breakage and the formation of 8-hydroxydeoxyguanosine (8-OHdG) in DNA using plasmid relaxation assay and HPLC with electrochemical detection, respectively. Lead acetate induced DNA strand breakage in 10 mM of Hepes buffer, pH 6.8, in a time- and dose-dependent manner. Compared with lead, zinc acetate did not significantly induce DNA breakage. The singlet oxygen scavengers NaN3 and 2,2,6,6-tetramethyl-4-piperidone (TEMP) inhibited lead-induced DNA breakage more efficiently than the hydroxyl radical scavengers mannitol and DMPO. Deuterium oxide (D2O), a singlet oxygen enhancer, potentiated lead-induced DNA breakage. At low ratios to Pb2+, NADPH, glutathione, and 2-mercaptoethanol enhanced lead-induced DNA breakage, whereas high ratios of these agents protected it. Catalase and superoxide dismutase (SOD) did not protect DNA breaks induced by Pb2+. Lead-induced DNA breakage was markedly enhanced by H2O2, and this induction was inhibited by NaN3, TEMP, EDTA, catalase, BSA, and glutathione. In contrast, mannitol and SOD potentiated Pb2+/H2O2-induced DNA breaks. The results indicate that singlet oxygen, lead, and H2O2 are all involved in the reaction system, whereas hydroxyl radical and superoxide did not. Lead could cause a small amount of 8-OHdG formation in calf thymus DNA and dose-dependently induced the formation of this adduct in the presence of H2O2. Singlet oxygen scavengers were more effective than hydroxyl radical scavengers in protection from lead/H2O2-induced 8-OHdG adducts. Taken together, these results suggest that lead may induce DNA damage through a Fenton-like reaction and that singlet oxygen is the principal species involved.
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Affiliation(s)
- J L Yang
- Molecular Carcinogenesis Laboratory, Department of Life Sciences, National Tsing Hua University, Hsinchu, Taiwan, Republic of China.
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26
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Yamashita N, Murata M, Inoue S, Burkitt MJ, Milne L, Kawanishi S. Alpha-tocopherol induces oxidative damage to DNA in the presence of copper(II) ions. Chem Res Toxicol 1998; 11:855-62. [PMID: 9705746 DOI: 10.1021/tx970129v] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
There is currently much interest in the possibility that dietary antioxidants may confer protection from certain diseases, such as atherosclerosis and cancer. The importance of alpha-tocopherol (vitamin E) as a biological antioxidant is widely recognized. However, pro-oxidant properties of alpha-tocopherol have been observed in chemical systems, and it has been reported that the vitamin can induce tumor formation and act as a complete tumor promotor in laboratory animals. In the present communication, we find that alpha-tocopherol can act as a potent DNA-damaging agent in the presence of copper(II) ions, using a simplified, in vitro model. alpha-Tocopherol was found to promote copper-dependent reactive oxygen species formation from molecular oxygen, resulting in DNA base oxidation and backbone cleavage. Neither alpha-tocopherol nor Cu(II) alone induced DNA damage. Bathocuproine, a Cu(I)-specific chelator, and catalase inhibited the DNA damage, whereas free hydroxyl radical scavengers did not. The order of DNA cleavage sites was thymine, cytosine > guanine residues. Examinations using an oxygen electrode and cytochrome c indicate that molecular oxygen was consumed in the reaction of alpha-tocopherol and Cu(II) and that superoxide was formed. Stoichiometry studies showed that two Cu(II) ions could be reduced by each alpha-tocopherol molecule. Electron spin resonance spin-trapping investigations were then used to demonstrate that hydrogen peroxide interacts with Cu(I) to generate the reactive species responsible for DNA damage, which is either the hydroxyl radical or a species of similar reactivity. These findings may be of relevance to the tumorigenic properties of the vitamin reported in the literature. However, further studies are required to establish the significance of these reactions under in vivo conditions.
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Affiliation(s)
- N Yamashita
- Department of Hygiene, Mie University School of Medicine, Tsu, Mie 514, Japan
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27
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Prütz WA. Interactions of hypochlorous acid with pyrimidine nucleotides, and secondary reactions of chlorinated pyrimidines with GSH, NADH, and other substrates. Arch Biochem Biophys 1998; 349:183-91. [PMID: 9439597 DOI: 10.1006/abbi.1997.0440] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
HOCl-induced chlorination of pyrimidine nucleotides, PyNH, strikingly depends on the nature of the available chlorine acceptor group. For CMP, with an -NH2 group as acceptor, the reaction is slow and involves predominantly the acid [k(CMP + HOCl) approximately 100 M-1 s-1 at pH 6]; apparent rate constants of the reaction decrease around the pK alpha (HOCl), to 0 in alkaline solution. For TMP and UMP, with a heterocyclic > NH group (at 3N) as acceptor, the reaction is faster and involves mainly the conjugated CIO- anion [e.g., k(UMP + ClO-) approximately 3 x 10(4) M-1 s-1 and k(UMP + HOCl) approximately 200 M-1 s-1]. The 3-N-methylthymidine derivative is inert toward HOCl. Reactions of ClO- with TMP, UMP, and poly(U) are shown to be reversible, PyNH + ClO- = PyNCl + OH-; an increase in pH due to this reaction was confirmed, and equilibrium constants have been estimated. The chlorinated derivatives of TMP and UMP are very reactive toward GSH, disulfide, aliphatic amines, and NADH. In contrast, the PyNCl derivative of CMP is unreactive, except with GSH. Rate constants of reactions of PyNCl species with various substrates are presented. Oxidation of NADH, by both HOCl and PyNCl derivatives, leads to a stable product (not NAD+) which is irreversibly degraded by reaction with excess HOCl, but inert toward acsorbate, GSH, and H2O2. Thiols (GSH) and disulfides (DTPA) were previously found capable of scavenging up to four HOCl molecules (Prütz, W. A., Arch. Biochem. Biophys. 332, 110-120, 1996). In the present study it was established that reactions of GSH or DTPA with excess HOCl give rise to a rapid drop in the pH by release of up to four HCl molecules per GSH or DTPA, as expected for a sequence of consecutive sulfoxidations. Reactions of GSH and DTPA with PyNCl efficiently regenerate PyNH, namely up to four molecules per GSH or DTPA in the case of TMP and UMP, but only one molecule per GSH in the case of CMP. The PyNCl derivatives of TMP and UMP transfer chlorine slowly but completely to CMP or AMP. Such chlorine transfer between nucleic acid bases is likely to occur also in DNA; it is shown that HOCl in fact induces a complex series of reactions on interaction with native DNA.
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Affiliation(s)
- W A Prütz
- Institut für Biophysik und Strahlenbiologie, Universität Freiburg, Germany
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28
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Abstract
Captopril ([2S]-1-[3-mercapto-2-methyl-propionyl]-L-proline) was found to protect erythrocytes from hemolysis caused by 2,2'-azobis (2-amidinopropane) (AAPH) and hypochlorite, erythrocyte membranes from lipid peroxidation caused by tert-butyl hydroperoxide (tBOOH) and hypochlorite, erythrocyte membrane ATPases from inactivation caused by tBOOH and hemoglobin from oxidation caused by AAPH and tBOOH. In all these systems enalapril ([S]-1-[N-(1-[ethoxycarbonyl]-3-phenylpropyl)-L-alanyl]-L-proline) was not protective or even increased the damage, especially with hypochlorite, probably due to chloramine formation. Captopril but not enalapril inhibited ascorbate autoxidation caused by Cu2+, which indicates that captopril binds Cu2+. On the other hand, deoxyribose degradation caused by iron and copper ions and DNA damage by o-phenanthroline/Cu2+/H2O2/beta-mercaptoethanol was enhanced by both captopril and enalapril. The effect of captopril was usually higher, apparently due to the reducing properties of captopril, which could reduce metal ions enabling their participation in the Fenton reaction. These results indicate that only -SH-group-containing inhibitors of angiotensin-converting enzyme (ACE) may exhibit antioxidant properties, and that the antioxidant/prooxidant action of ACE inhibitors depends on the system studied in vitro.
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Affiliation(s)
- M Bartosz
- Department of Physiology, Institute of Fundamental Sciences, Military Medical University, Lódź, Poland
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29
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Prütz WA. Measurement of copper-dependent oxidative DNA damage by HOCl and H2O2 with the ethidium-binding assay. JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS 1996; 32:125-35. [PMID: 8796484 DOI: 10.1016/0165-022x(96)00006-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The ETB-binding assay provides a rapid means to investigate time profiles for oxidative degradation of double-stranded DNA, by detecting the loss of ability of DNA to form a fluorescent intercalation complex with ETB. The assay was applied to demonstrate copper-dependent damage to DNA by HOCl using ascorbate as reductant. DNA degradation in this system proceeds with a rate comparable to that of reaction of HOCl with the DNA-Cu(I) complex, as monitored by the loss of DNA-Cu(I) absorption. The reaction of HOCl with DNA-Cu(I) is more than two orders of magnitude faster than the reaction of H2O2 with DNA-Cu(I). HOCl presumably reacts like H2O2 with DNA-Cu(I) to generate strongly oxidizing OH radicals immediately at the Cu(I) binding site. Quenching of the DNA/ETB fluorescence by DNA-bound copper was investigated because this may interfere with detection of copper-dependent damage to DNA with the ETB-binding assay, if not appropriate chelators are applied to remove the copper from the DNA.
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Affiliation(s)
- W A Prütz
- Universität Freiburg, Institut für Biophysik und Strahlenbiologie, Germany
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Oikawa S, Kawanishi S. Site-specific DNA damage induced by NADH in the presence of copper(II): role of active oxygen species. Biochemistry 1996; 35:4584-90. [PMID: 8605209 DOI: 10.1021/bi9527000] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Oxidative DNA damage by NAD(P)H in the presence of metal ions has been characterized by using 32P 5' end-labeled DNA fragments obtained from human p53 tumor suppressor gene and c-Ha-ras-1 protooncogene. NADH, as well as other endogenous reductants, induced DNA damage in the presence of Cu(II). The order of inducing effect on Cu(II)-dependent DNA damage was ascorbate > reduced glutathione (GSH) > NADH > NADPH. Although NADH caused no or little DNA damage in the presence of Fe(III)-EDTA, the addition of H2O2 induced the DNA damage. The Cu(II)-mediated DNA damage induced by NADH was inhibited by catalase and bathocuproine, a Cu(I)-specific chelator; but not by scavengers of hydroxyl free radical (.OH), suggesting the involvement of active species derived from hydrogen peroxide (H2O2) and Cu(I) rather than .OH. The predominant cleavage sites were thymine residues located 5' and/or 3' to guanine. The cleavage pattern was similar to that induced by Cu(II) plus GSH, Cu(II) plus ascorbate, or Cu(I) plus H2O2. Formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine by NADH increased with its concentration in the presence of Cu(II). UV-visible spectroscopy indicated the facilitation of reduction of Cu(II) by NADH under some conditions. ESR spin-trapping experiments and mass spectrometry showed that the carbon-centered radical was formed during the reaction of NADH with Cu(II). These results suggest that optimal molar ratios of DNA/metal ion yield copper with a high redox potential which catalyzes NADH autoxidation to NAD. being further oxidized to NAD+ with generation of superoxide radical and that H2O2 reacts with Cu(I) to form active oxygen species such as copper(I)-peroxide complex causing DNA damage.
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Affiliation(s)
- S Oikawa
- Department of Public Health, Graduate School of Medicine, Kyoto University, Japan
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31
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Lin PS, Ho KC. New cytotoxic mechanism of the bioreductive agent Tirapazamine (SR 4233) mediated by forming complex with copper. ACTA ACUST UNITED AC 1996. [DOI: 10.1002/(sici)1520-6823(1996)4:5<211::aid-roi3>3.0.co;2-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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