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Sumi D, Shinkai Y, Kumagai Y. Signal transduction pathways and transcription factors triggered by arsenic trioxide in leukemia cells. Toxicol Appl Pharmacol 2010; 244:385-92. [PMID: 20193703 DOI: 10.1016/j.taap.2010.02.012] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 02/09/2010] [Accepted: 02/21/2010] [Indexed: 12/23/2022]
Abstract
Arsenic trioxide (As(2)O(3)) is widely used to treat acute promyelocytic leukemia (APL). Several lines of evidence have indicated that As(2)O(3) affects signal transduction and transactivation of transcription factors, resulting in the stimulation of apoptosis in leukemia cells, because some transcription factors are reported to associate with the redox condition of the cells, and arsenicals cause oxidative stress. Thus, the disturbance and activation of the cellular signaling pathway and transcription factors due to reactive oxygen species (ROS) generation during arsenic exposure may explain the ability of As(2)O(3) to induce a complete remission in relapsed APL patients. In this report, we review recent findings on ROS generation and alterations in signal transduction and in transactivation of transcription factors during As(2)O(3) exposure in leukemia cells.
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Affiliation(s)
- Daigo Sumi
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, 180, Yamashiro-cho, Tokushima-city, Tokushima 770-8514, Japan.
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52
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Curtis CD, Thorngren DL, Nardulli AM. Immunohistochemical analysis of oxidative stress and DNA repair proteins in normal mammary and breast cancer tissues. BMC Cancer 2010; 10:9. [PMID: 20064251 PMCID: PMC2830938 DOI: 10.1186/1471-2407-10-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 01/11/2010] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND During the course of normal cellular metabolism, oxygen is consumed and reactive oxygen species (ROS) are produced. If not effectively dissipated, ROS can accumulate and damage resident proteins, lipids, and DNA. Enzymes involved in redox regulation and DNA repair dissipate ROS and repair the resulting damage in order to preserve a functional cellular environment. Because increased ROS accumulation and/or unrepaired DNA damage can lead to initiation and progression of cancer and we had identified a number of oxidative stress and DNA repair proteins that influence estrogen responsiveness of MCF-7 breast cancer cells, it seemed possible that these proteins might be differentially expressed in normal mammary tissue, benign hyperplasia (BH), ductal carcinoma in situ (DCIS) and invasive breast cancer (IBC). METHODS Immunohistochemistry was used to examine the expression of a number of oxidative stress proteins, DNA repair proteins, and damage markers in 60 human mammary tissues which were classified as BH, DCIS or IBC. The relative mean intensity was determined for each tissue section and ANOVA was used to detect statistical differences in the relative expression of BH, DCIS and IBC compared to normal mammary tissue. RESULTS We found that a number of these proteins were overexpressed and that the cellular localization was altered in human breast cancer tissue. CONCLUSIONS Our studies suggest that oxidative stress and DNA repair proteins not only protect normal cells from the damaging effects of ROS, but may also promote survival of mammary tumor cells.
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Affiliation(s)
- Carol D Curtis
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana IL 61801, USA
| | - Daniel L Thorngren
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana IL 61801, USA
| | - Ann M Nardulli
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana IL 61801, USA
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53
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Lee SJ, Michel SLJ. Cysteine Oxidation Enhanced by Iron in Tristetraprolin, A Zinc Finger Peptide. Inorg Chem 2010; 49:1211-9. [DOI: 10.1021/ic9024298] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Seung Jae Lee
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201-1180
| | - Sarah L. J. Michel
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201-1180
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Abstract
Redox dysregulation originating from metabolic alterations and dependence on mitogenic and survival signaling through reactive oxygen species represents a specific vulnerability of malignant cells that can be selectively targeted by redox chemotherapeutics. This review will present an update on drug discovery, target identification, and mechanisms of action of experimental redox chemotherapeutics with a focus on pro- and antioxidant redox modulators now in advanced phases of preclinal and clinical development. Recent research indicates that numerous oncogenes and tumor suppressor genes exert their functions in part through redox mechanisms amenable to pharmacological intervention by redox chemotherapeutics. The pleiotropic action of many redox chemotherapeutics that involves simultaneous modulation of multiple redox sensitive targets can overcome cancer cell drug resistance originating from redundancy of oncogenic signaling and rapid mutation.Moreover, some redox chemotherapeutics may function according to the concept of synthetic lethality (i.e., drug cytotoxicity is confined to cancer cells that display loss of function mutations in tumor suppressor genes or upregulation of oncogene expression). The impressive number of ongoing clinical trials that examine therapeutic performance of novel redox drugs in cancer patients demonstrates that redox chemotherapy has made the crucial transition from bench to bedside.
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Affiliation(s)
- Georg T Wondrak
- Department of Pharmacology and Toxicology, College of Pharmacy, Arizona Cancer Center, University of Arizona, Tucson, Arizona, USA
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55
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Rao AK, Ziegler YS, McLeod IX, Yates JR, Nardulli AM. Thioredoxin and thioredoxin reductase influence estrogen receptor alpha-mediated gene expression in human breast cancer cells. J Mol Endocrinol 2009; 43:251-61. [PMID: 19620238 PMCID: PMC2994277 DOI: 10.1677/jme-09-0053] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Accumulation of reactive oxygen species (ROS) in cells damages resident proteins, lipids, and DNA. In order to overcome the oxidative stress that occurs with ROS accumulation, cells must balance free radical production with an increase in the level of antioxidant enzymes that convert free radicals to less harmful species. We identified two antioxidant enzymes, thioredoxin (Trx) and Trx reductase (TrxR), in a complex associated with the DNA-bound estrogen receptor alpha (ERalpha). Western analysis and immunocytochemistry were used to demonstrate that Trx and TrxR are expressed in the cytoplasm and in the nuclei of MCF-7 human breast cancer cells. More importantly, endogenously expressed ERalpha, Trx, and TrxR interact and ERalpha and TrxR associate with the native, estrogen-responsive pS2 and progesterone receptor genes in MCF-7 cells. RNA interference assays demonstrated that Trx and TrxR differentially influence estrogen-responsive gene expression and that together, 17beta-estradiol, Trx, and TrxR alter hydrogen peroxide (H(2)O(2)) levels in MCF-7 cells. Our findings suggest that Trx and TrxR are multifunctional proteins that, in addition to modulating H(2)O(2) levels and transcription factor activity, aid ERalpha in regulating the expression of estrogen-responsive genes in target cells.
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Affiliation(s)
- Abhi K Rao
- Department of Cellular and Developmental Biology, University of Illinois at Urbana-Champaign, 524 Burrill Hall, 407 South Goodwin Avenue, Urbana, Illinois 61801, USA
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Kang X, Zhong W, Liu J, Song Z, McClain CJ, Kang YJ, Zhou Z. Zinc supplementation reverses alcohol-induced steatosis in mice through reactivating hepatocyte nuclear factor-4alpha and peroxisome proliferator-activated receptor-alpha. Hepatology 2009; 50:1241-50. [PMID: 19637192 PMCID: PMC2757527 DOI: 10.1002/hep.23090] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
UNLABELLED Alcoholic steatosis is a fundamental metabolic disorder in the progression of alcoholic liver disease. Zinc deficiency is one of the most consistently observed biochemical/nutritional manifestations of alcoholic liver disease. The purpose of this study is to determine whether dietary zinc supplementation to mice previously exposed to alcohol could reverse alcoholic steatosis. Male 129S mice were pair-fed an alcohol or isocaloric maltose dextrin liquid diet for 16 weeks with or without dietary zinc supplementation for the last 4 weeks. Zinc supplementation significantly attenuated alcohol-mediated increases in hepatic triglyceride, cholesterol, and free fatty acids in association with accelerated hepatic fatty acid oxidation and very low density lipoproteins (VLDL) secretion. Hepatic genes related to fatty acid oxidation and VLDL secretion were up-regulated by zinc supplementation, which was accompanied by restoring activity of hepatocyte nuclear factor-4alpha (HNF-4alpha) and peroxisome proliferators activated receptor-alpha (PPAR-alpha). Zinc supplementation enhanced alcohol metabolism and attenuated oxidative stress and liver injury. Zinc supplementation also normalized alcohol-mediated increases in plasma triglycerides and partially reversed decrease in gonadal adipose depot mass. Studies in HepG2 cells showed that zinc deprivation significantly suppressed the DNA-binding activities of HNF-4alpha and PPAR-alpha, and reduced HNF-4alpha and PPAR-alpha target proteins. Consequently, zinc deprivation caused cellular accumulation of lipid droplets, triglycerides and free fatty acids in the HepG2 cells. CONCLUSION Zinc supplementation reverses alcoholic steatosis, and reactivation of HNF-4alpha and PPAR-alpha by increasing zinc availability and inhibiting oxidative stress are potential mechanisms underlying these beneficial effects of zinc on hepatic lipid homeostasis.
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Affiliation(s)
- Xinqin Kang
- Department of Medicine, University of Louisville School of Medicine Louisville, KY40202
| | - Wei Zhong
- Department of Medicine, University of Louisville School of Medicine Louisville, KY40202,College of Veterinary Medicine, China Agricultural University, Beijing 100094, China
| | - Jie Liu
- Zunyi Medical College, Key Laboratory of Pharmacology, Zunyi 56300, China
| | - Zhenyuan Song
- Department of Medicine, University of Louisville School of Medicine Louisville, KY40202
| | - Craig J. McClain
- Department of Medicine, University of Louisville School of Medicine Louisville, KY40202,Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, KY40202,Louisville VAMC, Louisville, KY40202
| | - Y. James Kang
- Department of Medicine, University of Louisville School of Medicine Louisville, KY40202,Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, KY40202
| | - Zhanxiang Zhou
- Department of Medicine, University of Louisville School of Medicine Louisville, KY40202
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Curtis CD, Thorngren DL, Ziegler YS, Sarkeshik A, Yates JR, Nardulli AM. Apurinic/apyrimidinic endonuclease 1 alters estrogen receptor activity and estrogen-responsive gene expression. Mol Endocrinol 2009; 23:1346-59. [PMID: 19460860 PMCID: PMC2737565 DOI: 10.1210/me.2009-0093] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Accepted: 05/14/2009] [Indexed: 12/31/2022] Open
Abstract
Apurinic/apyrimidinic endonuclease 1 or redox factor-1 (Ape1/Ref-1) is a pleiotropic cellular protein involved in DNA repair and, through its redox activity, enhances the binding of a select group of transcription factors to their cognate recognition sequences in DNA. Thus, we were intrigued when we identified Ape1/Ref-1 and a number of DNA repair and oxidative stress proteins in a complex associated with the DNA-bound estrogen receptor alpha (ERalpha). Because Ape1/Ref-1 interacts with a number of transcription factors and influences their activity, we determined whether it might also influence ERalpha activity. We found that endogenously expressed Ape1/Ref-1 and ERalpha from MCF-7 human breast cancer cells interact and that Ape1/Ref-1 enhances the interaction of ERalpha with estrogen-response elements (EREs) in DNA. More importantly, Ape1/Ref-1 alters expression of the endogenous, estrogen-responsive progesterone receptor and pS2 genes in MCF-7 cells and associates with ERE-containing regions of these genes in native chromatin. Interestingly, knocking down Ape1/Ref-1 expression or inhibiting its redox activity with the small molecule inhibitor E3330 enhances estrogen responsiveness of the progesterone receptor and pS2 genes but does not alter the expression of the constitutively active 36B4 gene. Additionally, the reduced form of Ape1/Ref-1 increases and E3330 limits ERalpha-ERE complex formation in vitro and in native chromatin. Our studies demonstrate that Ape1/Ref-1 mediates its gene-specific effects, in part, by associating with endogenous, estrogen-responsive genes and that the redox activity of Ape1/Ref-1 is instrumental in altering estrogen-responsive gene expression.
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Affiliation(s)
- Carol D Curtis
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, 524 Burrill Hall, 407 South Goodwin Avenue, Urbana, Illinois 61801, USA
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Zinc coordination is required for and regulates transcription activation by Epstein-Barr nuclear antigen 1. PLoS Pathog 2009; 5:e1000469. [PMID: 19521517 PMCID: PMC2690687 DOI: 10.1371/journal.ppat.1000469] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Accepted: 05/12/2009] [Indexed: 12/17/2022] Open
Abstract
Epstein-Barr Nuclear Antigen 1 (EBNA1) is essential for Epstein-Barr virus to immortalize naïve B-cells. Upon binding a cluster of 20 cognate binding-sites termed the family of repeats, EBNA1 transactivates promoters for EBV genes that are required for immortalization. A small domain, termed UR1, that is 25 amino-acids in length, has been identified previously as essential for EBNA1 to activate transcription. In this study, we have elucidated how UR1 contributes to EBNA1's ability to transactivate. We show that zinc is necessary for EBNA1 to activate transcription, and that UR1 coordinates zinc through a pair of essential cysteines contained within it. UR1 dimerizes upon coordinating zinc, indicating that EBNA1 contains a second dimerization interface in its amino-terminus. There is a strong correlation between UR1-mediated dimerization and EBNA1's ability to transactivate cooperatively. Point mutants of EBNA1 that disrupt zinc coordination also prevent self-association, and do not activate transcription cooperatively. Further, we demonstrate that UR1 acts as a molecular sensor that regulates the ability of EBNA1 to activate transcription in response to changes in redox and oxygen partial pressure (pO2). Mild oxidative stress mimicking such environmental changes decreases EBNA1-dependent transcription in a lymphoblastoid cell-line. Coincident with a reduction in EBNA1-dependent transcription, reductions are observed in EBNA2 and LMP1 protein levels. Although these changes do not affect LCL survival, treated cells accumulate in G0/G1. These findings are discussed in the context of EBV latency in body compartments that differ strikingly in their pO2 and redox potential. Epstein-Barr virus (EBV) infects human B-cells and immortalizes them. Immortalization results in diseases that range from infectious mononucleosis to malignancies such as lymphomas. During immortalization, EBV expresses a small number of viral genes that modulate cellular proliferation and differentiation. One of the genes expressed by EBV, Epstein-Barr nuclear antigen 1 (EBNA1), activates the expression of the other viral genes required for immortalization. In this report, we have explored the mechanism by which EBNA1 activates gene expression. We have determined that EBNA1 uses the micronutrient zinc to self-associate, and that self-association is necessary for it to activate gene expression. Further, we have determined that environmental conditions such as oxygen tension and oxidative stress modulate EBNA1's capacity to self-associate, and therefore to activate gene expression. The gene expression profile and proliferative phenotype of EBV-infected cells is known to vary in differing environmental niches in the human body, such as lymph nodes and in peripheral circulation. We interpret our results to postulate that these differences arise as a consequence of varying oxygen tension in these microenvironments on EBNA1's capacity to activate viral gene expression. Our findings can be exploited to devise novel therapeutics against EBV-associated diseases that target EBNA1 through oxidative stress.
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59
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Cui J, Meng X, Gao X, Tan G. Curcumin decreases the expression of Pokemon by suppressing the binding activity of the Sp1 protein in human lung cancer cells. Mol Biol Rep 2009; 37:1627-32. [PMID: 19444642 DOI: 10.1007/s11033-009-9575-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Accepted: 05/01/2009] [Indexed: 02/06/2023]
Abstract
Pokemon, which stands for POK erythroid myeloid ontogenic factor, can regulate expression of many genes and plays an important role in tumorigenesis. Curcumin, a natural and non-toxic yellow compound, has capacity for antioxidant, free radical scavenger, anti-inflammatory properties. Recent studies shows it is a potential inhibitor of cell proliferation in a variety of tumour cells. To investigate whether curcumin can regulate the expression of Pokemon, a series of experiments were carried out. Transient transfection experiments demonstrated that curcumin could decrease the activity of the Pokemon promoter. Western blot analysis suggested that curcumin could significantly decrease the expression of the Pokemon. Overexpression of Sp1 could enhance the activity of the Pokemon promoter, whereas knockdown of Sp1 could decrease its activity. More important, we also found that curcumin could decrease the expression of the Pokemon by suppressing the stimulation of the Sp1 protein. Therefore, curcumin is a potential reagent for tumour therapy which may target Pokemon.
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Affiliation(s)
- Jiajun Cui
- Zhoukou Normal University, Henan, People's Republic of China
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60
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Abstract
Despite zinc ions being redox inert in biologic systems, zinc-finger structures act as redox-sensitive molecular switches controlling several crucial cellular processes. Oxidative or nitrosative stress, via modification of zinc finger cysteine thiols, leads to a release of Zn(2+) from these structures, causing not only a loss of zinc-finger function but also an increase of cytoplasmic or nuclear free Zn(2+) that may, in turn, stimulate and interfere with cellular signaling cascades. A signaling cascade stimulated by exposure of cells to zinc ions or to stressful stimuli that are reported to cause an intracellular release of zinc ions involves phosphoinositide 3'-kinases and the Ser/Thr protein kinase Akt, resulting in an inactivation of transcriptional regulators of the FoxO family. Possible modes of action of zinc ions to stimulate this signaling cascade and consequences of stimulation are discussed. Moreover, we present an overview on human diseases or disorders characterized by an intracellular Zn(2+) dyshomeostasis.
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Affiliation(s)
- Klaus-D Kröncke
- Institute of Biochemistry and Molecular Biology I, Heinrich-Heine University of Düsseldorf, Düsseldorf, Germany.
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61
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Sela D, Shlomai J. Regulation of UMSBP activities through redox-sensitive protein domains. Nucleic Acids Res 2008; 37:279-88. [PMID: 19039000 PMCID: PMC2615610 DOI: 10.1093/nar/gkn927] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
UMSBP is a CCHC-type zinc finger protein, which functions during replication initiation of kinetoplast DNA minicircles and the segregation of kinetoplast DNA networks. Interactions of UMSBP with origin sequences, as well as the protein oligomerization, are affected by its redox state. Reduction yields UMSBP monomers and activates its binding to DNA, while oxidation drives UMSBP oligomerization and impairs its DNA-binding activity. Kinetics analyses of UMSBP-DNA interactions revealed that redox affects the association of free UMSBP with the DNA, but has little effect on its dissociation from the nucleoprotein complex. A previously proposed model, suggesting that binding of DNA is regulated via the reversible interconversions of active UMSBP monomers and inactive oligomers, was challenged here, revealing that the two redox-driven processes are not interrelated. No correlation could be observed between DNA-binding inhibition and UMSBP oligomerization, upon oxidation of UMSBP. Moreover, while the presence of zinc ions was found to be essential for the interaction of UMSBP with DNA, UMSBP oligomerization occurred through zinc-depleted, unfolded zinc finger domains. Site directed mutagenesis analysis of UMSBP suggested that its unique methionine residue, which can be oxidized into methionine sulfoxide, is not involved in the redox-mediated regulation of UMSBP-DNA interactions.
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Affiliation(s)
- Dotan Sela
- Department of Parasitology, Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University, Hadassah Medical School, Jerusalem, Israel
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62
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Sela D, Yaffe N, Shlomai J. Enzymatic Mechanism Controls Redox-mediated Protein-DNA Interactions at the Replication Origin of Kinetoplast DNA Minicircles. J Biol Chem 2008; 283:32034-44. [DOI: 10.1074/jbc.m804417200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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63
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Weitsman GE, Weebadda W, Ung K, Murphy LC. Reactive oxygen species induce phosphorylation of serine 118 and 167 on estrogen receptor alpha. Breast Cancer Res Treat 2008; 118:269-79. [DOI: 10.1007/s10549-008-0221-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Accepted: 10/02/2008] [Indexed: 11/30/2022]
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64
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Quick SK, Shields PG, Nie J, Platek ME, McCann SE, Hutson AD, Trevisan M, Vito D, Modali R, Lehman TA, Seddon M, Edge SB, Marian C, Muti P, Freudenheim JL. Effect modification by catalase genotype suggests a role for oxidative stress in the association of hormone replacement therapy with postmenopausal breast cancer risk. Cancer Epidemiol Biomarkers Prev 2008; 17:1082-7. [PMID: 18483329 DOI: 10.1158/1055-9965.epi-07-2755] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Catalase, a ubiquitous heme enzyme, catalyzes conversion of hydrogen peroxide to water and molecular oxygen, protecting cells from oxidative stress. A C/T polymorphism in the promoter region of the CAT gene (rs1001179) affects transcriptional activity and RBC catalase levels. Oxidative stress may explain the observed increased postmenopausal breast cancer risk associated with hormone replacement therapy (HRT). We examined CAT genotype, HRT, and postmenopausal breast cancer risk in the Western New York Exposures and Breast Cancer case-control study. Cases (n = 616) were women with primary, incident, pathologically confirmed breast cancer. Randomly selected controls (n = 1,082) were frequency matched to cases on age and race. Genotype was assayed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI) adjusted for potential confounders. CAT genotype alone was not associated with breast cancer risk. Ever use of HRT was associated with increased risk (OR, 1.39; 95% CI, 1.11-1.75). The increase with ever use was more pronounced among those with variant CT or TT CAT genotype (OR, 1.88; 95% CI, 1.29-2.75) than among those with CC (OR, 1.15; 95% CI, 0.86-1.54). Similarly, risk associated with >or=5 years of HRT use was greater among those with at least one variant T allele (OR, 2.32; 95% CI, 1.50-3.59). Increased risk was limited to estrogen receptor-positive tumors. Our findings suggest that CAT genotype modifies the effect of HRT use on breast cancer risk and that HRT may affect risk by affecting oxidative stress.
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Affiliation(s)
- Sylvia K Quick
- Department of Social, State University of New York at Buffalo, Buffalo, NY, USA.
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Aiba I, Hossain A, Kuo MT. Elevated GSH level increases cadmium resistance through down-regulation of Sp1-dependent expression of the cadmium transporter ZIP8. Mol Pharmacol 2008; 74:823-33. [PMID: 18556457 DOI: 10.1124/mol.108.046862] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Cadmium is a nonessential toxic metal in mammals. Its toxicity is mainly caused by interactions with cellular proteins that result in protein dysfunction and then disturb normal cellular functions. Glutathione (GSH) has been reported to play a role in cadmium resistance by serving as a cofactor for multidrug resistance protein 1/GS-X pump-mediated cadmium elimination. To further investigate the role of GSH in cadmium toxicity, we carried out a comparative study using small-cell lung cancer-derived cell lines, SR3A, and those that were stably transfected with glutamate cysteine ligase catalytic subunit (GCLC), a rate-limiting enzyme in GSH biosynthesis. These GCLC stably transfected cell lines produced higher levels of GSH and were more resistant to cadmium toxicity than the parental cell line was. The rates of cadmium uptake were reduced in these GCLC-transfected cell lines, which were associated with down-regulation of the cadmium transporter ZIP8/SLC39A8. Further analyses demonstrated that Sp1 binding site at the proximal promoter region of ZIP8 was sensitive to the GSH level and that the expression level of transcription factor Sp1 was reduced by increased GSH levels. We also demonstrated that low concentrations of cadmium exposure down-regulated ZIP8 expression with concomitant reduction of Sp1 expression. Taken together, these results demonstrate the importance of Sp1 in the regulation of ZIP8 expression. More important, our results reveal a new mechanism by which elevated GSH levels confer cadmium resistance by down-regulation of ZIP8 expression through the suppression of Sp1.
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Affiliation(s)
- Isamu Aiba
- Department of Molecular Pathology, M.D. Anderson Cancer Center, Houston, TX 77054, USA
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66
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Pereda J, Escobar J, Sandoval J, Rodríguez JL, Sabater L, Pallardó FV, Torres L, Franco L, Viña J, López-Rodas G, Sastre J. Glutamate cysteine ligase up-regulation fails in necrotizing pancreatitis. Free Radic Biol Med 2008; 44:1599-609. [PMID: 18279677 DOI: 10.1016/j.freeradbiomed.2008.01.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Revised: 01/07/2008] [Accepted: 01/11/2008] [Indexed: 12/22/2022]
Abstract
Glutathione depletion is a key factor in the development of acute pancreatitis. Our aim was to study the regulation of glutamate cysteine ligase, the rate-limiting enzyme in glutathione synthesis, in edematous or necrotizing pancreatitis in rats. Glutathione levels were kept low in necrotizing pancreatitis for several hours, with no increase in protein or mRNA levels of glutamate cysteine ligase subunits, despite binding of RNA polymerase II to their promoters and coding regions. The survival signal pathway mediated by ERK and c-MYC was activated, and c-MYC was recruited to the promoters. The failure in gene up-regulation seems to be due to a marked increase in cytosolic ribonuclease activity. In contrast, in edematous pancreatitis glutathione levels were depleted and rapidly restored, and protein and mRNA expression of glutamate cysteine ligase increased markedly due to enhanced transcription mediated by recruitment of c-MYC, NF-kappaB, and SP-1 to the promoters. No increase in cytosolic ribonuclease activity was found in this case. We propose a novel pathophysiological mechanism to differentiate necrotizing from edematous pancreatitis, which is the inefficient up-regulation of glutamate cysteine ligase caused by increased cytosolic ribonuclease activity in the severe form of the disease. This mechanism would abrogate a rapid recovery of glutathione levels.
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Affiliation(s)
- Javier Pereda
- Department of Physiology, University of Valencia, 46100 Burjasot (Valencia), Spain
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67
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Kang X, Song Z, McClain CJ, Kang YJ, Zhou Z. Zinc supplementation enhances hepatic regeneration by preserving hepatocyte nuclear factor-4alpha in mice subjected to long-term ethanol administration. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 172:916-25. [PMID: 18349129 DOI: 10.2353/ajpath.2008.070631] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Alcoholic liver disease is associated with sustained liver damage and impaired regeneration, as well as significant zinc deficiency. This study was undertaken to examine whether dietary zinc supplementation could improve liver regeneration by increasing the expression of genes involved in hepatic cellular proliferation in a mouse model of alcoholic liver disease. Adult 129S6 mice fed an ethanol-containing liquid diet for 6 months developed alcoholic liver disease as measured by serum alanine transferase activity and histopathological changes. Zinc supplementation to ethanol-exposed mice enhanced liver regeneration as indicated by increased numbers of proliferation cell nuclear antigen (PCNA)-positive and bromodeoxyuridine (BrdU)-labeled hepatocytes. Zinc-enhanced liver regeneration was associated with an increase in hepatocyte nuclear factor-4alpha (HNF-4alpha), a liver-enriched, zinc-finger transcription factor. Studies using cultured HepG2 cells showed that zinc deficiency suppressed cell proliferation and cell proliferation-related proteins, including hepatocyte growth factor (HGF), insulin-like growth factor I (IGF-I), insulin-like growth factor binding protein 1 (IGFBP1), metallothionein (MT), and cyclin D1, as well as HNF-4alpha. HNF-4alpha gene silencing inhibited cell proliferation in association with decreased protein levels of IGF-I, IGFBP1, MT, and cyclin D1. The present study provides evidence that zinc supplementation enhances liver regeneration at least in part by HNF-4alpha through the up-regulation of cell proliferation-related proteins, suggesting that dietary zinc supplementation may have beneficial effects in alcoholic liver disease.
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Affiliation(s)
- Xinqin Kang
- Department of Medicine, University of Louisville School of Medicine, 511 South Floyd Street, Louisville, KY 40292, USA
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Rao AK, Ziegler YS, McLeod IX, Yates JR, Nardulli AM. Effects of Cu/Zn superoxide dismutase on estrogen responsiveness and oxidative stress in human breast cancer cells. Mol Endocrinol 2008; 22:1113-24. [PMID: 18258688 DOI: 10.1210/me.2007-0381] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The effects of estrogen on gene expression in mammary cells are mediated by interaction of the estrogen receptor (ER) with estrogen response elements in target DNA. Whereas the ER is the primary initiator of transcription, the recruitment of coregulatory proteins to the DNA-bound receptor influences estrogen responsiveness. To better understand how estrogen alters gene expression, we identified proteins associated with the DNA-bound ERalpha. Surprisingly, the antioxidant enzyme Cu/Zn superoxide dismutase (SOD1), which is known primarily as a scavenger of superoxide, was associated with the DNA-bound receptor. We have now demonstrated that SOD1 interacts with ERalpha from MCF-7 cell nuclear extracts and with purified ERalpha and that SOD1 enhances binding of ERalpha to estrogen response element-containing DNA. Although SOD1 decreases transcription of an estrogen-responsive reporter plasmid in transiently transfected U2 osteosarcoma cells, RNA interference assays demonstrate that SOD1 is required for effective estrogen responsiveness of the endogenous pS2, progesterone receptor, cyclin D1, and Cathepsin D genes in MCF-7 breast cancer cells. Furthermore, ERalpha and SOD1 are associated with regions of the pS2 and progesterone receptor genes involved in conferring estrogen-responsive gene expression. Interestingly, when MCF-7 cells are exposed to 17beta-estradiol and superoxide generated by addition of potassium superoxide (KO2) to the cell medium, SOD1 levels are increased and tyrosine nitration, which is an indicator of oxidative stress-induced protein damage, is significantly diminished. Our studies have identified a new role for SOD1 in regulating estrogen-responsive gene expression and suggest that the 17beta-estradiol- and KO2-induced increase in SOD1 may play a role in the survival of breast cancer cells and the progression of mammary tumors.
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Affiliation(s)
- Abhi K Rao
- Department of Cellular and Development Biology, University of Illinois at Urbana, Urbana, Illinois 61801, USA
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69
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Elliot S, Catanuto P, Fernandez P, Espinosa-Heidmann D, Karl M, Korach K, Cousins SW. Subtype specific estrogen receptor action protects against changes in MMP-2 activation in mouse retinal pigmented epithelial cells. Exp Eye Res 2008; 86:653-60. [PMID: 18313050 DOI: 10.1016/j.exer.2008.01.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Revised: 01/03/2008] [Accepted: 01/09/2008] [Indexed: 10/22/2022]
Abstract
Eyes with age-related macular degeneration (AMD) demonstrate accumulation of specific deposits and extracellular matrix (ECM) molecules under the retinal pigment epithelium (RPE). AMD is about two times more prevalent in aging postmenopausal women. Therefore we studied whether 17beta-estradiol (E(2)) modulates the expression and activity of the trimolecular complex (MMP-2, TIMP-2 and MMP-14), molecules which are of major importance for ECM turnover in RPE. We used cell lines isolated from estrogen receptor knockout mice (ERKO) to determine which ER (estrogen receptor) subtype was important for ECM regulation in RPE cells. We found that mouse RPE sheets had higher baseline MMP-2 activity in the presence of ERbeta. This correlated with higher MMP-2 activity in RPE cell lines isolated from ERKOalpha mice. Exposure to E(2) increased MMP-2 activity in mouse RPE cell lines. In addition E(2) increased transcriptional activation of the MMP-2 promoter through a functional Sp1 site which required the presence of ERbeta, but not ERalpha. E(2) also maintained levels of pro MMP-2, and MMP-14 and TIMP-2 activity after oxidant injury. Since the direct effects of E(2) on MMP-2 transcriptional activation and the regulation of the trimolecular complex after oxidant-induced injury requires ERbeta, this receptor subtype may have a role as a potential therapeutic target to prevent changes in activation of MMP-2.
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Affiliation(s)
- Sharon Elliot
- Laboratory on Sex and Gender Differences in Health and Disease, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
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70
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Wei M, Fabrizio P, Hu J, Ge H, Cheng C, Li L, Longo VD. Life span extension by calorie restriction depends on Rim15 and transcription factors downstream of Ras/PKA, Tor, and Sch9. PLoS Genet 2007; 4:e13. [PMID: 18225956 PMCID: PMC2213705 DOI: 10.1371/journal.pgen.0040013] [Citation(s) in RCA: 349] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Accepted: 12/10/2007] [Indexed: 01/20/2023] Open
Abstract
Calorie restriction (CR), the only non-genetic intervention known to slow aging and extend life span in organisms ranging from yeast to mice, has been linked to the down-regulation of Tor, Akt, and Ras signaling. In this study, we demonstrate that the serine/threonine kinase Rim15 is required for yeast chronological life span extension caused by deficiencies in Ras2, Tor1, and Sch9, and by calorie restriction. Deletion of stress resistance transcription factors Gis1 and Msn2/4, which are positively regulated by Rim15, also caused a major although not complete reversion of the effect of calorie restriction on life span. The deletion of both RAS2 and the Akt and S6 kinase homolog SCH9 in combination with calorie restriction caused a remarkable 10-fold life span extension, which, surprisingly, was only partially reversed by the lack of Rim15. These results indicate that the Ras/cAMP/PKA/Rim15/Msn2/4 and the Tor/Sch9/Rim15/Gis1 pathways are major mediators of the calorie restriction-dependent stress resistance and life span extension, although additional mediators are involved. Notably, the anti-aging effect caused by the inactivation of both pathways is much more potent than that caused by CR. Reduction in calorie intake is a well-established intervention that extends the life span of a variety of biological model organisms studied. Calorie restriction also delays and attenuates age-related changes in primates, although its longevity-promoting effect has not been demonstrated. Here, we utilized a single cell organism, baker's yeast, to examine the role of evolutionarily conserved genes in life span regulation and their involvement in calorie restriction. The yeast mutants lacking Ras2, Tor1, or Sch9 are long-lived. The anti-aging effect observed in these mutants depends on the protein Rim15 and several key regulators of gene expression that are essential in inducing cellular protection under stress. The beneficial effects of calorie restriction are much smaller in yeast that are missing these proteins, indicating their essential role in promoting longevity. Our study also showed that by combining the genetic manipulation and calorie restriction intervention, yeast can reach a life span ten times that of those grown under standard conditions. This extreme longevity requires Rim15 and also depends on other yet-to-be identified mechanisms. Our findings provided new leads that may help to elucidate the mechanisms underlying the anti-aging effect of calorie restriction in mammals.
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Affiliation(s)
- Min Wei
- Andrus Gerontology Center, University of Southern California, Los Angeles, California, United States of America
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71
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Folate deficiency enhances arsenic effects on expression of genes involved in epidermal differentiation in transgenic K6/ODC mouse skin. Toxicology 2007; 241:134-45. [DOI: 10.1016/j.tox.2007.08.094] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Revised: 08/23/2007] [Accepted: 08/27/2007] [Indexed: 11/24/2022]
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72
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Wang J, Xu Z, Fang H, Duhart HM, Patterson TA, Ali SF. Gene expression profiling of MPP+-treated MN9D cells: A mechanism of toxicity study. Neurotoxicology 2007; 28:979-87. [PMID: 17475336 DOI: 10.1016/j.neuro.2007.02.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Revised: 02/22/2007] [Accepted: 02/27/2007] [Indexed: 01/06/2023]
Abstract
Parkinson's disease (PD) is a common neurodegenerative disease characterized by progressive loss of midbrain dopaminergic neurons with unknown etiology. MPP+ (1-methyl-4-phenylpyridinium) is the active metabolite of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which induces Parkinson's-like syndromes in humans and animals. MPTP/MPP+ treatment produces selective dopaminergic neuronal degeneration, therefore, these agents are commonly used to study the pathogenesis of PD. However, the mechanisms of their toxicity have not been elucidated. In order to gain insights into MPP+-induced neurotoxicity, a gene expression microarray study was performed using a midbrain-derived dopaminergic neuronal cell line, MN9D. Utilizing a two-color reference design, Agilent mouse oligonucleotide microarrays were used to examine relative gene expression changes in MN9D cells treated with 40microM MPP+ compared with controls. Bioinformatics tools were used for data evaluation. Briefly, raw data were imported into the NCTR ArrayTrack database, normalized using a Lowess method and data quality was assessed. The Student's t-test was used to determine significant changes in gene expression (set as p<0.05, fold change >1.5). Gene Ontology for Function Analysis (GOFFA) and Ingenuity Pathway Analysis were employed to analyze the functions and roles of significant genes in biological processes. Of the 51 significant genes identified, 44 were present in the GOFFA or Ingenuity database. These data indicate that multiple pathways are involved in the underlying mechanisms of MPP+-induced neurotoxicity, including apoptosis, oxidative stress, iron binding, cellular metabolism, and signal transduction. These data also indicate that MPP+-induced toxicity shares common molecular mechanisms with the pathogenesis of PD and further pathway analyses will be conducted to explore these mechanisms.
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Affiliation(s)
- Jianyong Wang
- Neurochemistry Laboratory, Division of Neurotoxicology, HFT-132, National Center for Toxicological Research/FDA, 3900 NCTR Road, Jefferson, AR 72079, USA
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73
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Vasto S, Mocchegiani E, Candore G, Listì F, Colonna-Romano G, Lio D, Malavolta M, Giacconi R, Cipriano C, Caruso C. Inflammation, genes and zinc in ageing and age-related diseases. Biogerontology 2007; 7:315-27. [PMID: 16972155 DOI: 10.1007/s10522-006-9046-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Lifelong antigenic burden determines a condition of chronic inflammation, with increased lymphocyte activation and pro-inflammatory cytokine production. A large number of studies have documented changes in Zn metabolism in experimental animal models of acute and chronic inflammation and in human chronic inflammatory diseases. In particular, modification of zinc plasma concentration as well as intracellular disturbance of antioxidant intracellular pathways have been found associated to age-related inflammatory diseases, like atherosclerosis. Zinc deficiency is extremely diffused in aged people that are educated to avoid meat and other high Zn-content foods due to fear of cholesterol. Rather, they increase consumption of refined wheat products that lack of Zn, magnesium and other critical nutrients in consequence of refining process. On the other hand, plasma concentration of metallic ions like Zn is influenced by pro-inflammatory cytokines production. A major target of Zn may be NF-kB, a transcription factor critical for the expression of many pro-inflammatory cytokines whose production is finely regulated by extra- and intracellular activating and inhibiting factors interacting with regulatory elements on cytokine genes. Moreover, this factor is regulated by the expression of specific cellular genes involved in inflammation. So it is not surprising that Zn deficiency is constantly observed in aged patients affected by infectious diseases. On the other hand, cytokine genes are highly polymorphic and some of these polymorphisms have been found associated to age-related diseases as atherosclerosis. Therefore, Zn deficiency in individuals genetically predisposed to a dis-regulation of inflammation response, may play a crucial role, in causing adverse events and in reducing the probability of a successful aging.
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Affiliation(s)
- Sonya Vasto
- Department of Pathobiology and Biomedical Methodology, Palermo University, Corso Tukory 211, 90134, Palermo , Italy
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74
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Abstract
The development of atherosclerosis is influenced by genetic, lifestyle and nutritional risk factors. Zn and metallothionein deficiency can enhance oxidative-stress-related signalling processes in endothelial cells, and since changes in available plasma Zn may affect the Zn status of the endothelium, Zn deficiency could be a risk factor for IHD. Although the association of Zn with many proteins is essential for their function, three key signalling processes are highlighted as being principal targets for the effect of Zn deficiency: the activation of NF-κB, the activation of caspase enzymes and the signalling of NO. The need to develop a reliable indicator of Zn status is critical to any epidemiological approach for studying the relationship between Zn status and disease incidence. Studies using appropriate animal models and investigating how the plasma Zn pool influences endothelial intracellular labile Zn would be helpful in appreciating the importance of Zn deficiency in atherogenesis.
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Affiliation(s)
- John H Beattie
- Division of Cellular Integrity, Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, Scotland, UK.
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75
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Xiao GS, Jin YS, Lu QY, Zhang ZF, Belldegrun A, Figlin R, Pantuck A, Yen Y, Li F, Rao J. Annexin-I as a potential target for green tea extract induced actin remodeling. Int J Cancer 2007; 120:111-20. [PMID: 17019707 DOI: 10.1002/ijc.22164] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Using a multistep human urothelial model, we previously showed that green tea extract (GTE) selectively modulates actin remodeling in transformed cells (MC-T11), which resulted in increased cell adhesion and reduced cell motility (Lu et al., Clin Cancer Res 2005;11:1675-83). This study further analyzed which actin binding proteins (ABPs) might be involved in this process. Proteomic profiles of GTE treated and untreated MC-T11 cells using two-dimensional gel electrophoresis coupled with liquid chromatography tandem mass spectrometry (LC/MS/MS) and matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) identified 20 GTE-induced proteins. Among them, 3 were ABPs (tropomodulin, cofilin and annexin-I), and only annexin-I showed a dose- and time-dependent expression. The increased annexin-I correlated with actin remodeling, and was the result of transcription level up-regulation, as determined by RT-PCR, pull-down immunoblot and siRNA analyses. 5-Azacytidine, a DNA methylation inhibitor, exhibited no effect on annexin-I expression when used alone, but had an additive effect for GTE-induced annexin-I expression. Immunohistochemistry of bladder cancer tissue array showed a decrease of annexin-I expression in carcinoma in situ and low grade papillary carcinoma (n = 32, 0% positive) compared to nontumor urothelium (n = 18, 89% positive) (p < 0.001 by Fisher exact test), but increased in some (6 of 15, 40%) high-grade tumors. Together, GTE induced annexin-I expression plays a role in regulating actin remodeling and decreased annexin-I expression is a common event in early stage of bladder cancer development.
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Affiliation(s)
- Gui-Shan Xiao
- Department of Clinic Molecular Pharmacology, Comprehensive Cancer Center at City of Hope National Medical Center, Duarte, California, USA
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76
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Yang J, Yan B. Photochemotherapeutic agent 8-methoxypsoralen induces cytochrome P450 3A4 and carboxylesterase HCE2: evidence on an involvement of the pregnane X receptor. Toxicol Sci 2006; 95:13-22. [PMID: 17003103 PMCID: PMC4114574 DOI: 10.1093/toxsci/kfl120] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
8-Methoxypsoralen (8-MOP) is a prototype photochemotherapeutic agent and used to treat various skin disorders such as psoriasis and cutaneous T-cell lymphoma. Animal studies demonstrate that repeated treatment with 8-MOP markedly increases the capacity of drug metabolism. In this study, we report that 8-MOP is a potent inducer of cytochrome P450 3A4 (CYP3A4) and carboxylesterase 2 (HCE2), two major human enzymes that catalyze oxidative and hydrolytic reactions, respectively. In human primary hepatocytes, 8-MOP markedly induced the expression of CYP3A4 (approximately sixfold) and HCE2 (approximately threefold) and the induction occurred in a concentration-dependent manner (0-50 microM). RNA interference of the expression of the pregnane X receptor (PXR) proportionally decreased the induction. In a reporter assay, 8-MOP stimulated both CYP3A4 and HCE2 promoters, and the stimulation was enhanced by cotransfection of PXR. Several natural variants of PXR differed markedly from the wild-type receptor in responding to 8-MOP. In addition to human PXR (hPXR), 8-MOP activated rat PXR, and the activation was comparable to that of hPXR (EC(50) = approximately 14 microM). PXR is recognized as a master regulator of the genes encoding drug-metabolizing enzymes and transporters. The involvement of PXR in 8-MOP induction suggests that this chemotherapeutic agent causes a broader range of drug-drug interactions, and the differential activation of certain PXR variants suggests that the magnitude of the interactions varies from person to person.
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MESH Headings
- Adult
- Aged
- Animals
- Carboxylesterase/biosynthesis
- Carboxylesterase/genetics
- Cell Line, Tumor
- Cytochrome P-450 CYP3A
- Cytochrome P-450 Enzyme System/biosynthesis
- Cytochrome P-450 Enzyme System/genetics
- Dose-Response Relationship, Drug
- Enzyme Induction/drug effects
- Female
- Genes, Reporter
- Hepatocytes/drug effects
- Hepatocytes/enzymology
- Humans
- Luciferases
- Male
- Methoxsalen/toxicity
- Photosensitizing Agents/toxicity
- Pregnane X Receptor
- Promoter Regions, Genetic/drug effects
- Promoter Regions, Genetic/genetics
- RNA Interference
- RNA, Messenger/metabolism
- Rats
- Receptors, Steroid/drug effects
- Receptors, Steroid/genetics
- Receptors, Steroid/metabolism
- Recombinant Fusion Proteins/drug effects
- Recombinant Fusion Proteins/metabolism
- Transcription, Genetic/drug effects
- Transfection
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Affiliation(s)
- Jian Yang
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island 02881
- Department of Pharmacology, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Bingfang Yan
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island 02881
- To whom correspondence should be addressed. Fax: (401) 874-5787.
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77
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Alderson NL, Wang Y, Blatnik M, Frizzell N, Walla MD, Lyons TJ, Alt N, Carson JA, Nagai R, Thorpe SR, Baynes JW. S-(2-Succinyl)cysteine: a novel chemical modification of tissue proteins by a Krebs cycle intermediate. Arch Biochem Biophys 2006; 450:1-8. [PMID: 16624247 DOI: 10.1016/j.abb.2006.03.005] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2006] [Revised: 03/02/2006] [Accepted: 03/04/2006] [Indexed: 01/05/2023]
Abstract
S-(2-Succinyl)cysteine (2SC) has been identified as a chemical modification in plasma proteins, in the non-mercaptalbumin fraction of human plasma albumin, in human skin collagen, and in rat skeletal muscle proteins and urine. 2SC increases in human skin collagen with age and is increased in muscle protein of diabetic vs. control rats. The concentration of 2SC in skin collagen and muscle protein correlated strongly with that of the advanced glycation/lipoxidation end-product (AGE/ALE), N(epsilon)-(carboxymethyl)lysine (CML). 2SC is formed by a Michael addition reaction of cysteine sulfhydryl groups with fumarate at physiological pH. Fumarate, but not succinate, inactivates the sulfhydryl enzyme, glyceraldehyde-3-phosphate dehydrogenase in vitro, in concert with formation of 2SC. 2SC is the first example of spontaneous chemical modification of protein by a metabolic intermediate in the Krebs cycle. These observations identify fumarate as an endogenous electrophile and suggest a role for fumarate in regulation of metabolism.
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MESH Headings
- Animals
- Anticarcinogenic Agents/pharmacology
- Citric Acid Cycle/drug effects
- Collagen/metabolism
- Cysteine/analogs & derivatives
- Cysteine/analysis
- Cysteine/chemistry
- Cysteine/metabolism
- Diabetes Mellitus, Experimental/metabolism
- Female
- Fumarates/pharmacology
- Glycation End Products, Advanced/analysis
- Glycation End Products, Advanced/metabolism
- Glyceraldehyde-3-Phosphate Dehydrogenases/metabolism
- Humans
- Insulin/analysis
- Insulin/metabolism
- Insulin, Long-Acting
- Insulin, Regular, Human
- Muscle Proteins/metabolism
- Protein Processing, Post-Translational/drug effects
- Protein Processing, Post-Translational/physiology
- Radiation-Protective Agents/pharmacology
- Rats
- Rats, Sprague-Dawley
- Serum Albumin/analysis
- Serum Albumin/metabolism
- Serum Albumin, Human
- Skin/metabolism
- Succinic Acid/pharmacology
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Affiliation(s)
- Nathan L Alderson
- Department of Chemistry and Biochemistry, University of South Carolina, USA
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78
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Hao G, Derakhshan B, Shi L, Campagne F, Gross SS. SNOSID, a proteomic method for identification of cysteine S-nitrosylation sites in complex protein mixtures. Proc Natl Acad Sci U S A 2006; 103:1012-7. [PMID: 16418269 PMCID: PMC1347989 DOI: 10.1073/pnas.0508412103] [Citation(s) in RCA: 286] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Reversible addition of NO to Cys-sulfur in proteins, a modification termed S-nitrosylation, has emerged as a ubiquitous signaling mechanism for regulating diverse cellular processes. A key first-step toward elucidating the mechanism by which S-nitrosylation modulates a protein's function is specification of the targeted Cys (SNO-Cys) residue. To date, S-nitrosylation site specification has been laboriously tackled on a protein-by-protein basis. Here we describe a high-throughput proteomic approach that enables simultaneous identification of SNO-Cys sites and their cognate proteins in complex biological mixtures. The approach, termed SNOSID (SNO Site Identification), is a modification of the biotin-swap technique [Jaffrey, S. R., Erdjument-Bromage, H., Ferris, C. D., Tempst, P. & Snyder, S. H. (2001) Nat. Cell. Biol. 3, 193-197], comprising biotinylation of protein SNO-Cys residues, trypsinolysis, affinity purification of biotinylated-peptides, and amino acid sequencing by liquid chromatography tandem MS. With this approach, 68 SNO-Cys sites were specified on 56 distinct proteins in S-nitrosoglutathione-treated (2-10 microM) rat cerebellum lysates. In addition to enumerating these S-nitrosylation sites, the method revealed endogenous SNO-Cys modification sites on cerebellum proteins, including alpha-tubulin, beta-tubulin, GAPDH, and dihydropyrimidinase-related protein-2. Whereas these endogenous SNO proteins were previously recognized, we extend prior knowledge by specifying the SNO-Cys modification sites. Considering all 68 SNO-Cys sites identified, a machine learning approach failed to reveal a linear Cys-flanking motif that predicts stable transnitrosation by S-nitrosoglutathione under test conditions, suggesting that undefined 3D structural features determine S-nitrosylation specificity. SNOSID provides the first effective tool for unbiased elucidation of the SNO proteome, identifying Cys residues that undergo reversible S-nitrosylation.
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Affiliation(s)
- Gang Hao
- Department of Pharmacology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA
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79
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Potashkin JA, Meredith GE. The role of oxidative stress in the dysregulation of gene expression and protein metabolism in neurodegenerative disease. Antioxid Redox Signal 2006; 8:144-51. [PMID: 16487048 DOI: 10.1089/ars.2006.8.144] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
There are few examples for which the genetic basis for neurodegenerative disease has been identified. For the majority of these disorders, the key to their understanding lies in knowledge of the molecular changes that contribute to altered gene expression and the translational modification of the protein products. Environmental factors play a role in the development and chronicity of neurodegenerative disorders. Environmental stimuli such as hypoxia, toxins, or heavy metals, increase production of reactive oxygen species and lower energy reserves. Chronic exposure to oxidative radicals can adversely affect gene expression and proteolysis. This review summarizes what is currently known about some of the changes in gene expression and protein metabolism that occur after oxidative stress which contribute to neurodegeneration, and reveals areas where more research is clearly needed.
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Affiliation(s)
- Judith A Potashkin
- Department of Cellular and Molecular Pharmacology, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
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80
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Abstract
Alcoholic liver disease (ALD) is associated with decreases in zinc (Zn) and its major binding protein, metallothionein (MT), in the liver. Studies using animal models have shown that Zn supplementation prevents alcohol-induced liver injury under both acute and chronic alcohol exposure conditions. There are hepatic and extrahepatic actions of Zn in the prevention of alcoholic liver injury. Zn supplementation attenuates ethanol-induced hepatic Zn depletion and suppresses ethanol-elevated cytochrome P450 2E1 (CYP2E1) activity, but increases the activity of alcohol dehydrogenase in the liver; an action that is likely responsible for Zn suppression of alcohol-induced oxidative stress. Zn also enhances glutathione-related antioxidant capacity in the liver. At the cellular level, Zn inhibits alcohol-induced hepatic apoptosis partially through suppression of the Fas/FasL-mediated pathway. Zn supplementation preserves intestinal integrity and prevents endotoxemia, leading to inhibition of endotoxin-induced tumor necrosis factor-alpha (TNF-alpha) production in the liver. Zn also directly inhibits the signaling pathway involved in endotoxin-induced TNF-alpha production. These hepatic and extrahepatic effects of Zn are independent of MT. However, low levels of MT in the liver sensitize the organ to alcohol-induced injury, and elevation of MT enhances the endogenous Zn reservoir and makes Zn available when oxidative stress is imposed. Zn has a high potential to be developed as an effective agent in the prevention and treatment of ALD.
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Affiliation(s)
- Y James Kang
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA.
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81
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Abstract
Zinc (Zn) deficiency, a frequent condition in human populations, induces oxidative stress and subsequently activates/inhibits oxidant-sensitive transcription factors that can affect cell function, proliferation and survival leading to disease. Zn deficiency-triggered oxidative stress could affect cell signaling, including: (1) transcription factors containing Zn finger motifs, and (2) other oxidant-sensitive transcription factors (NF-kappaB and AP-1). The Zn finger motif in the Zn finger transcription factors is mainly a DNA binding domain. Cysteine residues coordinate the Zn ion folding structural domains that participate in intermolecular interactions. Oxidative stress can impair the DNA-binding activity of Zn finger transcription factor, by oxidizing the cysteine residues and therefore altering the secondary structure of the protein. AP-1 is generally activated in Zn deficiency that can occur secondary to an increase in cellular H(2)O(2), followed by activation of MAPKs p38 and JNK. The role of AP-1 in Zn deficiency-associated pathology remains to be established. The cytosolic steps of the NF-kappaB cascade are activated by oxidants in Zn deficiency. However, an impaired nuclear transport of the active transcription factor leads to a low expression of NF-kappaB-dependent genes that could be involved in multiple aspects of Zn deficiency associated pathology. In summary, Zn deficiency induces oxidative stress that can both, lead to tissue oxidative damage and/or to the modulation of select signaling cascades. Their role in the pathology of Zn deficiency remains to be defined.
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Affiliation(s)
- Patricia I Oteiza
- Department of Nutrition, University of California, Davis, CA 95616, USA.
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82
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Loeken MR. Current perspectives on the causes of neural tube defects resulting from diabetic pregnancy. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2005; 135C:77-87. [PMID: 15800853 DOI: 10.1002/ajmg.c.30056] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Maternal diabetes increases the risk for neural tube, and other, structural defects. The mother may have either type 1 or type 2 diabetes, but the diabetes must be existing at the earliest stages of pregnancy, during which organogenesis occurs. Abnormally high glucose levels in maternal blood, which leads to increased glucose transport to the embryo, is responsible for the teratogenic effects of maternal diabetes. Consequently, expression of genes that control essential developmental processes is disturbed. In this review, some of the biochemical pathways by which excess glucose metabolism disturbs neural tube formation are discussed. Research from the author's laboratory has shown that expression of Pax3, a gene required for neural tube closure, is significantly reduced by maternal diabetes, and this is associated with significantly increased neural tube defects (NTD). Pax3 encodes a transcription factor that has recently been shown to inhibit p53-dependent apoptosis. Evidence in support of this model, in which excess glucose metabolism inhibits expression of Pax3, thereby derepressing p53-dependent apoptosis of neuroepithelium and leading to NTD will be discussed.
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Affiliation(s)
- Mary R Loeken
- Section on Developmental and Stem Cell Biology at Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA.
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83
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Chou WC, Chen HY, Yu SL, Cheng L, Yang PC, Dang CV. Arsenic suppresses gene expression in promyelocytic leukemia cells partly through Sp1 oxidation. Blood 2005; 106:304-10. [PMID: 15761015 PMCID: PMC1895131 DOI: 10.1182/blood-2005-01-0241] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The mechanism by which arsenic dramatically affects gene expression remains poorly understood. Here we report that prolonged exposure of acute promyelocytic leukemia NB4 cells to low levels of arsenic trioxide increased the expression of a set of genes responsible for reactive oxygen species (ROS) production. We hypothesize that arsenic-induced ROS in turn contribute partially to altered gene expression. To identify genes responsive to arsenic-induced ROS, we used microarray gene expression analysis and identified genes that responded to arsenic and hydrogen peroxide but whose response to arsenic was reversed by an ROS scavenger, N-acetyl-L-cysteine. We found that 26% of the genes significantly responsive to arsenic might have been directly altered by ROS. We further explored the mechanisms by which ROS affects gene regulation and found that the Sp1 transcription factor was oxidized by arsenic treatment, with a corresponding decrease in its in situ binding on the promoters of 3 genes, hTERT, C17, and c-Myc, whose expressions were significantly suppressed. We conclude that ROS contributed partly to arsenic-mediated gene regulation and that Sp1 oxidation contributed to gene suppression by arsenic-induced ROS.
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Affiliation(s)
- Wen-Chien Chou
- Department of Laboratory Medicine, National Taiwan University Hospital,
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84
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Felty Q, Roy D. Estrogen, mitochondria, and growth of cancer and non-cancer cells. J Carcinog 2005; 4:1. [PMID: 15651993 PMCID: PMC548143 DOI: 10.1186/1477-3163-4-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2004] [Accepted: 01/15/2005] [Indexed: 02/07/2023] Open
Abstract
In this review, we discuss estrogen actions on mitochondrial function and the possible implications on cell growth. Mitochondria are important targets of estrogen action. Therefore, an in-depth analysis of interaction between estrogen and mitochondria; and mitochondrial signaling to nucleus are pertinent to the development of new therapy strategies for the treatment of estrogen-dependent diseases related to mitochondrial disorders, including cancer.
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Affiliation(s)
- Quentin Felty
- Department of Environmental Health Sciences, University of Alabama at Birmingham, Birmingham, AL, 35294-0022 USA
| | - Deodutta Roy
- Department of Environmental Health Sciences, University of Alabama at Birmingham, Birmingham, AL, 35294-0022 USA
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85
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Felty Q, Roy D. Mitochondrial signals to nucleus regulate estrogen-induced cell growth. Med Hypotheses 2005; 64:133-41. [PMID: 15533631 DOI: 10.1016/j.mehy.2003.12.056] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2003] [Accepted: 12/18/2003] [Indexed: 10/26/2022]
Abstract
Classical genomic and non-genomic signaling pathways mediated by nuclear and cell membrane estrogen receptors are considered to contribute to estrogen-induced cell proliferation. Here we propose that mitochondrial signals to the nucleus regulate estrogen-induced progression of the cell cycle. The influence of estrogen on mitochondrial oxidative phosphorylation and mitochondrial gene transcription support the idea that mitochondria are significant targets of estrogen. Mitochondria are the major source of reactive oxygen species (ROS) in epithelial cells. Estrogen redox cycling within mitochondria also generates ROS. Antioxidants inhibit estrogen-induced cell growth. A-Raf, Akt, PKC, MEK, ERK, and transcription factors AP-1, NF-kappaB, and CREB are targets of both estrogen and ROS. We provide four lines of evidence in support of our hypothesis that estrogen-induced mitochondrial ROS stimulate redox sensor kinase A-Raf, Akt or PKC, which, in turn, activate transcription factors NF-kappaB, CREB, or AP-1 via the MEK/ERK pathway. Thus, estrogen-induced mitochondrial ROS leading to the activation of cell cycle genes containing AP-1, NF-kappaB, or CREB response elements are involved in the progression of the cell cycle of the estrogen-dependent cells. Our novel concept will contribute to the development of new targets in the prevention and control of estrogen-induced disease including cancer.
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Affiliation(s)
- Quentin Felty
- Department of Environmental Health Sciences, University of Alabama at Birmingham, Birmingham, AL 35294-0022, USA
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86
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Shilo S, Aharoni-Simon M, Tirosh O. Selenium attenuates expression of MnSOD and uncoupling protein 2 in J774.2 macrophages: molecular mechanism for its cell-death and antiinflammatory activity. Antioxid Redox Signal 2005; 7:276-86. [PMID: 15650415 DOI: 10.1089/ars.2005.7.276] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Selenium can activate cell death. However, the mechanism of action is not yet fully defined. We hypothesized that selenium may impede mitochondrial superoxide dismutation to H2O2 and O2, leading to cell death in macrophages and that this effect may be relevant to antiinflammatory treatment by selenium. In this study, the mechanism of action of selenium was investigated in nonactivated and activated (immune-stimulated) J774.2 macrophages. Sodium selenite treatment decreased dichlorodihydrofluorescein-reacting intracellular reactive oxygen species (ROS) (mainly peroxides and hydroxyl radicals), with no correlation to glutathione peroxidase activity. However, selenite decreased the transcription and expression of manganese superoxide dismutase (MnSOD) and uncoupling protein 2 (UCP2). This cellular effect was due to inhibition of specificity protein-1 (Sp1) binding to its DNA binding site. Following immune stimulation of macrophages using lipopolysaccharides plus interferon-gamma, MnSOD was up-regulated. Activated macrophages showed higher mitochondrial membrane potential, intracellular ROS levels, and cellular resistance to cell death. Selenite treatment attenuated all of these parameters. Selenite prevented nuclear factor-kappaB (NF-kappaB) activation as a mechanism of its inhibitory activity on MnSOD expression in the immune-stimulated cells. In addition, overexpression of human MnSOD protected against death induced by selenite treatment. It is therefore concluded that selenium at high nanomolar to low micromolar concentrations shifts the balance between inflammatory response and cell death toward the latter, through a direct effect on the transcription factors Sp1 and NF-kappaB, and down-regulation of MnSOD and UCP2.
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Affiliation(s)
- Shani Shilo
- The School of Nutritional Sciences, Institute of Biochemistry, Food Science and Nutrition, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovet, Israel
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87
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Onn I, Milman-Shtepel N, Shlomai J. Redox potential regulates binding of universal minicircle sequence binding protein at the kinetoplast DNA replication origin. EUKARYOTIC CELL 2004; 3:277-87. [PMID: 15075258 PMCID: PMC387648 DOI: 10.1128/ec.3.2.277-287.2004] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Kinetoplast DNA, the mitochondrial DNA of the trypanosomatid Crithidia fasciculata, is a remarkable structure containing 5,000 topologically linked DNA minicircles. Their replication is initiated at two conserved sequences, a dodecamer, known as the universal minicircle sequence (UMS), and a hexamer, which are located at the replication origins of the minicircle L- and H-strands, respectively. A UMS-binding protein (UMSBP), binds specifically the conserved origin sequences in their single stranded conformation. The five CCHC-type zinc knuckle motifs, predicted in UMSBP, fold into zinc-dependent structures capable of binding a single-stranded nucleic acid ligand. Zinc knuckles that are involved in the binding of DNA differ from those mediating protein-protein interactions that lead to the dimerization of UMSBP. Both UMSBP DNA binding and its dimerization are sensitive to redox potential. Oxidation of UMSBP results in the protein dimerization, mediated through its N-terminal domain, with a concomitant inhibition of its DNA-binding activity. UMSBP reduction yields monomers that are active in the binding of DNA through the protein C-terminal region. C. fasciculata trypanothione-dependent tryparedoxin activates the binding of UMSBP to UMS DNA in vitro. The possibility that UMSBP binding at the minicircle replication origin is regulated in vivo by a redox potential-based mechanism is discussed.
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Affiliation(s)
- Itay Onn
- Department of Parasitology, The Kuvin Center for the Study of Infectious and Tropical Diseases, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
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88
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Hamatani T, Falco G, Carter MG, Akutsu H, Stagg CA, Sharov AA, Dudekula DB, VanBuren V, Ko MSH. Age-associated alteration of gene expression patterns in mouse oocytes. Hum Mol Genet 2004; 13:2263-78. [PMID: 15317747 DOI: 10.1093/hmg/ddh241] [Citation(s) in RCA: 387] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Decreasing oocyte competence with maternal aging is a major factor in human infertility. To investigate the age-dependent molecular changes in a mouse model, we compared the expression profiles of metaphase II oocytes collected from 5- to 6-week-old mice with those collected from 42- to 45-week-old mice using the NIA 22K 60-mer oligo microarray. Among approximately 11,000 genes whose transcripts were detected in oocytes, about 5% (530) showed statistically significant expression changes, excluding the possibility of global decline in transcript abundance. Consistent with the generally accepted view of aging, the differentially expressed genes included ones involved in mitochondrial function and oxidative stress. However, the expression of other genes involved in chromatin structure, DNA methylation, genome stability and RNA helicases was also altered, suggesting the existence of additional mechanisms for aging. Among the transcripts decreased with aging, we identified and characterized a group of new oocyte-specific genes, members of the human NACHT, leucine-rich repeat and PYD-containing (NALP) gene family. These results have implications for aging research as well as for clinical ooplasmic donation to rejuvenate aging oocytes.
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Affiliation(s)
- Toshio Hamatani
- Developmental Genomics and Aging Section, Laboratory of Genetics, National Institute on Aging, National Institutes of Health, 333 Cassell Drive, Suite 3000, Baltimore, MD 21224, USA
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89
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Evans MD, Cooke MS. Factors contributing to the outcome of oxidative damage to nucleic acids. Bioessays 2004; 26:533-42. [PMID: 15112233 DOI: 10.1002/bies.20027] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Oxidative damage to DNA appears to be a factor in cancer, yet explanations for why highly elevated levels of such lesions do not always result in cancer remain elusive. Much of the genome is non-coding and lesions in these regions might be expected to have little biological effect, an inference supported by observations that there is preferential repair of coding sequences. RNA has an important coding function in protein synthesis, and yet the consequences of RNA oxidation are largely unknown. Some non-coding nucleic acid is functional, e.g. promoters, and damage to these sequences may well have biological consequences. Similarly, oxidative damage to DNA may promote microsatellite instability, inhibit methylation and accelerate telomere shortening. DNA repair appears pivotal to the maintenance of genome integrity, and genetic alterations in repair capacity, due to single nucleotide polymorphisms or mutation, may account for inter-individual differences in cancer susceptibility. This review will survey these aspects of oxidative damage to nucleic acids and their implication for disease.
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Affiliation(s)
- Mark D Evans
- Genome Instability Group, Department of Cancer Studies and Molecular Medicine, University of Leicester, UK.
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90
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Benderdour M, Charron G, Comte B, Ayoub R, Beaudry D, Foisy S, Deblois D, Des Rosiers C. Decreased cardiac mitochondrial NADP+-isocitrate dehydrogenase activity and expression: a marker of oxidative stress in hypertrophy development. Am J Physiol Heart Circ Physiol 2004; 287:H2122-31. [PMID: 15271667 DOI: 10.1152/ajpheart.00378.2004] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Mitochondrial dysfunction subsequent to increased oxidative stress and alterations in energy metabolism is considered to play a role in the development of cardiac hypertrophy and its progression to failure, although the sequence of events remains to be elucidated. This study aimed at characterizing the impact of hypertrophy development on the activity and expression of mitochondrial NADP+-isocitrate dehydrogenase (mNADP+-ICDH), a metabolic enzyme that controls redox and energy status. We expanded on our previous finding of its inactivation through posttranslational modification by the lipid peroxidation product 4-hydroxynonenal (HNE) in 7-wk-old spontaneously hypertensive rat (SHR) hearts before hypertrophy development (Benderdour et al. J Biol Chem 278: 45154-45159, 2003). In this study, we used 7-, 15-, and 30-wk-old SHR and Sprague-Dawley (SD) rats with abdominal aortic coarctation. Compared with age-matched control Wistar-Kyoto (WKY) rats, SHR hearts showed a significant 25% decrease of mNADP+-ICDH activity, which preceded in time 1) the decline in its protein and mRNA expression levels (between 10% and 35%) and 2) the increase in hypertrophy markers. The chronic and persistent loss of mNADP+-ICDH activity in SHR was associated with enhanced tissue accumulation of HNE-mNADP+-ICDH and total HNE-protein adducts at all ages and contrasted with the profile of changes in the activity of other mitochondrial enzymes involved in antioxidant or energy metabolism. Two-way ANOVA of the data also revealed a significant effect of age on most parameters measured in SHR and WKY hearts. The mNADP+-ICDH activity, protein, and mRNA expression were reduced between 25% and 35% in coarctated SD rats and were normalized by treatment of SHR or coarctated SD rats with renin-angiotensin system inhibitors, which prevented or attenuated hypertrophy. Altogether, our data show that cardiac mNADP+-ICDH activity and expression are differentially and sequentially affected in hypertrophy development and, to a lesser extent, with aging. Decreased cardiac mNADP+-ICDH activity, which is attributed at least in part to HNE adduct formation, appears to be a relevant early and persistent marker of mitochondrial oxidative stress-related alterations in hypertrophy development. Potentially, this could also contribute to the aetiology of cardiomyopathy.
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Affiliation(s)
- Mohamed Benderdour
- Department of Nutrition, University of Montreal, Montreal, Quebec, Canada H1T 1C8
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91
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Conour JE, Graham WV, Gaskins HR. A combined in vitro/bioinformatic investigation of redox regulatory mechanisms governing cell cycle progression. Physiol Genomics 2004; 18:196-205. [PMID: 15138307 DOI: 10.1152/physiolgenomics.00058.2004] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The intracellular reduction-oxidation (redox) environment influences cell cycle progression; however, underlying mechanisms are poorly understood. To examine potential mechanisms, the intracellular redox environment was characterized per cell cycle phase in Chinese hamster ovary fibroblasts via flow cytometry by measuring reduced glutathione (GSH), reactive oxygen species (ROS), and DNA content with monochlorobimane, 2',7'-dichlorohydrofluorescein diacetate (H2DCFDA), and DRAQ5, respectively. GSH content was significantly greater in G2/M compared with G1 phase cells, whereas GSH was intermediate in S phase cells. ROS content was similar among phases. Together, these data demonstrate that G2/M cells are more reduced than G1 cells. Conventional approaches to define regulatory mechanisms are subjective in nature and focus on single proteins/pathways. Proteome databases provide a means to overcome these inherent limitations. Therefore, a novel bioinformatic approach was developed to exhaustively identify putative redox-regulated cell cycle proteins containing redox-sensitive protein motifs. Using the InterPro (http://www.ebi.ac.uk/interpro/) database, we categorized 536 redox-sensitive motifs as: 1) active/functional-site cysteines, 2) electron transport, 3) heme, 4) iron binding, 5) zinc binding, 6) metal binding (non-Fe/Zn), and 7) disulfides. Comparing this list with 1,634 cell cycle-associated proteins from Swiss-Prot and SpTrEMBL (http://us.expasy.org/sprot/) revealed 92 candidate proteins. Three-fourths (69 of 92) of the candidate proteins function in the central cell cycle processes of transcription, nucleotide metabolism, (de)phosphorylation, and (de)ubiquitinylation. The majority of oxidant-sensitive candidate proteins (68.9%) function during G2/M phase. As the G2/M phase is more reduced than the G1 phase, oxidant-sensitive proteins may be temporally regulated by oscillation of the intracellular redox environment. Combined with evidence of intracellular redox compartmentalization, we propose a spatiotemporal mechanism that functionally links an oscillating intracellular redox environment with cell cycle progression.
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Affiliation(s)
- J E Conour
- Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801, USA
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92
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Reiterer G, Toborek M, Hennig B. Peroxisome proliferator activated receptors alpha and gamma require zinc for their anti-inflammatory properties in porcine vascular endothelial cells. J Nutr 2004; 134:1711-5. [PMID: 15226458 DOI: 10.1093/jn/134.7.1711] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Zinc is an essential structural component of various proteins and is crucial for the integrity of the vascular endothelium. The present study focused on the effect of zinc deficiency on the anti-inflammatory properties of peroxisome proliferator activated receptor (PPAR) alpha and gamma agonists. Porcine pulmonary-arterial endothelial cells were deprived from zinc by chelator N,N,N',N'-tetrakis (2-pyridylmethyl)ethylene diamine. Cells were exposed to TNF-alpha for 2 h following pretreament with the PPARalpha agonists fenofibrate or ciprofibrate or the PPARgamma agonists thiazolidinedione or troglitazone. The inflammatory response was tested by measuring nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) binding activities as well as by measuring mRNA expression levels of inflammatory genes, such as vascular cell adhesion molecule-1 (VCAM-1) and IL-6. All PPAR agonists tested lost their potency to downregulate the TNF-alpha-induced inflammatory response in zinc-deficient cells. However, if zinc was added back, all PPAR agonists significantly downregulated the TNF-alpha-mediated induction of inflammatory transcription factors NF-kappaB and AP-1 and significantly reduced the expression of their target genes, VCAM-1 and IL-6. We therefore hypothesize that zinc is required for the PPARalpha and -gamma DNA binding activity. Indeed, zinc deficiency significantly reduced the agonist-induced binding activity of PPARalpha and -gamma to the PPAR response element. Our data demonstrate the importance of zinc in PPAR signaling and the requirement of zinc for the anti-inflammatory properties of PPARalpha and -gamma agonists.
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Affiliation(s)
- Gudrun Reiterer
- Graduate Center for Nutritional Sciences, College of Agriculture, University of Kentucky, Lexington, KY 40546-0215, USA
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93
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Graf PCF, Martinez-Yamout M, VanHaerents S, Lilie H, Dyson HJ, Jakob U. Activation of the Redox-regulated Chaperone Hsp33 by Domain Unfolding. J Biol Chem 2004; 279:20529-38. [PMID: 15023991 DOI: 10.1074/jbc.m401764200] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The molecular chaperone Hsp33 in Escherichia coli responds to oxidative stress conditions with the rapid activation of its chaperone function. On its activation pathway, Hsp33 progresses through three major conformations, starting as a reduced, zinc-bound inactive monomer, proceeding through an oxidized zinc-free monomer, and ending as a fully active oxidized dimer. While it is known that Hsp33 senses oxidative stress through its C-terminal four-cysteine zinc center, the nature of the conformational changes in Hsp33 that must take place to accommodate this activation process is largely unknown. To investigate these conformational rearrangements, we constructed constitutively monomeric Hsp33 variants as well as fragments consisting of the redox regulatory C-terminal domain of Hsp33. These proteins were studied by a combination of biochemical and NMR spectroscopic techniques. We found that in the reduced, monomeric conformation, zinc binding stabilizes the C terminus of Hsp33 in a highly compact, alpha-helical structure. This appears to conceal both the substrate-binding site as well as the dimerization interface. Zinc release without formation of the two native disulfide bonds causes the partial unfolding of the C terminus of Hsp33. This is sufficient to unmask the substrate-binding site, but not the dimerization interface, rendering reduced zinc-free Hsp33 partially active yet monomeric. Critical for the dimerization is disulfide bond formation, which causes the further unfolding of the C terminus of Hsp3 and allows the association of two oxidized Hsp33 monomers. This then leads to the formation of active Hsp33 dimers, which are capable of protecting cells against the severe consequences of oxidative heat stress.
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Affiliation(s)
- Paul C F Graf
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, 830 N. University, Ann Arbor, MI 48109-1048, USA
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94
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Bae JB, Park JH, Hahn MY, Kim MS, Roe JH. Redox-dependent Changes in RsrA, an Anti-sigma Factor in Streptomyces coelicolor: Zinc Release and Disulfide Bond Formation. J Mol Biol 2004; 335:425-35. [PMID: 14672653 DOI: 10.1016/j.jmb.2003.10.065] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
sigmaR is a sigma factor for transcribing genes to defend cells against oxidative stresses in the antibiotic-producing bacterium Streptomyces coelicolor. The availability of sigmaR is regulated by RsrA, an anti-sigma factor, whose sigmaR-binding activity is regulated by redox changes in the environment, via thiol-disulfide exchange. We found that reduced RsrA contains zinc in a stoichiometric amount, whereas oxidized form has very little: 1 mol of zinc per mol of RsrA was released upon oxidation as monitored by a chromogenic Zn-chelator, 4-(2-pyridylazo)-resorcinol (PAR). Measurement of zinc bound in several RsrA mutants of various cysteine and histidine substitutions suggested that C3, H7, C41, and C44 serve as zinc-binding sites. The zinc-binding and sigmaR-binding activities of mutant proteins did not coincide, suggesting that zinc might not be absolutely required for the anti-sigma activity of RsrA. Zn-free apo-RsrA bound sigmaR and inhibited sigmaR-dependent transcription in vitro. Compared with Zn-RsrA, the anti-transcription activity of apo-RsrA was about threefold lower and its sigmaR-binding affinity decreased by about ninefold when measured by surface plasmon resonance analysis. Apo-RsrA was more sensitive to protease, suggesting that zinc allows RsrA to maintain a more compact structure, optimized for binding sigmaR. The cysteine pairs that form disulfide bonds were determined by MALDI-TOF mass spectrometry, revealing formation of the critical disulfide bond between C11 and one of the essential cysteine residues C41 or 44, most likely C44. An improved model for the mechanism of redox-modulation of RsrA was presented.
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Affiliation(s)
- Jae-Bum Bae
- School of Biological Sciences and Institute of Microbiology, Seoul National University, 151-742, Seoul, South Korea
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95
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Giles NM, Giles GI, Holley JE, Gutowski NJ, Jacob C. Targeting oxidative stress-related diseases: organochalcogen catalysts as redox sensitizers. Biochem Pharmacol 2003; 66:2021-8. [PMID: 14599560 DOI: 10.1016/s0006-2952(03)00544-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Tumor cells proliferate under conditions of oxidative stress. A novel therapeutic approach would be to enhance the cellular effects of the reactive oxygen species formed under these conditions by supplementation with a redox catalyst. This provides a means to target and specifically destroy cancer cells via oxidation of redox-sensitive proteins, such as transcription factors, while leaving cells with a normal redox balance largely unaffected. We have previously reported a preliminary observation on the effects of pro-oxidant catalysts that enhance cancer cell death. This paper presents a detailed in vitro investigation into the mechanism of action of synthetic glutathione peroxidase mimics on a model Sp1 transcription factor peptide. The structure and redox potential of these mimics correlate with their ability to catalyze the oxidation of this zinc-binding motif by H(2)O(2) and these compounds promise therapeutic potential by promoting H(2)O(2)-induced PC12 cell death.
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Affiliation(s)
- Niroshini M Giles
- School of Biological and Chemical Sciences, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
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96
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97
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Xiao GG, Wang M, Li N, Loo JA, Nel AE. Use of proteomics to demonstrate a hierarchical oxidative stress response to diesel exhaust particle chemicals in a macrophage cell line. J Biol Chem 2003; 278:50781-90. [PMID: 14522998 DOI: 10.1074/jbc.m306423200] [Citation(s) in RCA: 281] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Epidemiological studies demonstrate an association between short term exposure to ambient particulate matter (PM) and cardiorespiratory morbidity and mortality. Although the biological mechanisms of these adverse effects are unknown, emerging data suggest a key role for oxidative stress. Ambient PM and diesel exhaust particles (DEP) contain redox cycling organic chemicals that induce pro-oxidative and pro-inflammatory effects in the lung. These responses are suppressed by N-acetylcysteine (NAC), which directly complexes to electrophilic DEP chemicals and exert additional antioxidant effects at the cellular level. A proteomics approach was used to study DEP-induced responses in the macrophage cell line, RAW 264.7. We demonstrate that in the dose range 10-100 microg/ml, organic DEP extracts induce a progressive decline in the cellular GSH/GSSG ratio, in parallel with a linear increase in newly expressed proteins on the two-dimensional gel. Using matrix-assisted laser desorption ionization time-of-flight mass spectrometry and electrospray ionization-liquid chromatography/mass spectrometry/mass spectrometry analysis, 32 newly induced/NAC-suppressed proteins were identified. These include antioxidant enzymes (e.g. heme oxygenase-1 and catalase), pro-inflammatory components (e.g. p38MAPK and Rel A), and products of intermediary metabolism that are regulated by oxidative stress. Heme oxygenase-1 was induced at low extract dose and with minimal decline in the GSH/GSSG ratio, whereas MAP kinase activation required a higher chemical dose and incremental levels of oxidative stress. Moreover, at extract doses >50 microg/ml, there is a steep decline in cellular viability. These data suggest that DEP induce a hierarchical oxidative stress response in which some of these proteins may serve as markers for oxidative stress during PM exposures.
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Affiliation(s)
- Gary Guishan Xiao
- Keck Functional Proteomics Center, Department of Biochemistry and Biological Chemistry, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, USA
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98
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Abstract
Two billion years of aerobic evolution have resulted in mammalian cells and tissues that are extremely oxygen-dependent. Exposure to oxygen tensions outside the relatively narrow physiological range results in cellular stress and toxicity. Consequently, hypoxia features prominently in many human diseases, particularly those associated with blood and vascular disorders, including all forms of anemia and ischemia. Bioenergetic enzymes have evolved both acute and chronic oxygen sensing mechanisms to buffer changes of oxygen tension; at normal P(O) oxidative phosphorylation is the principal energy supply for eukaryotic cells, but when the P(O) falls below a critical mark metabolic switches turn off mitochondrial electron transport and activate anaerobic glycolysis. Without this switch cells would suffer an immediate energy deficit and death at low P(O). An intriguing feature of the switching is that the same conditions that regulate energy metabolism also regulate bioenergetic genes, so that enzyme activity and transcription are regulated simultaneously, albeit with different time courses and signaling pathways. In this review we explore the pathways mediating hypoxia-regulated glycolytic enzyme gene expression, focusing on their atavistic traits and evolution.
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Affiliation(s)
- Keith A Webster
- Department of Molecular and Cellular Pharmacology, University of Miami Medical Center, Miami, FL 33136, USA.
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99
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Giles NM, Watts AB, Giles GI, Fry FH, Littlechild JA, Jacob C. Metal and redox modulation of cysteine protein function. CHEMISTRY & BIOLOGY 2003; 10:677-93. [PMID: 12954327 DOI: 10.1016/s1074-5521(03)00174-1] [Citation(s) in RCA: 321] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In biological systems, the amino acid cysteine combines catalytic activity with an extensive redox chemistry and unique metal binding properties. The interdependency of these three aspects of the thiol group permits the redox regulation of proteins and metal binding, metal control of redox activity, and ligand control of metal-based enzyme catalysis. Cysteine proteins are therefore able to act as "redox switches," to sense concentrations of oxidative stressors and unbound zinc ions in the cytosol, to provide a "storage facility" for excess metal ions, to control the activity of metalloproteins, and to take part in important regulatory and signaling pathways. The diversity of cysteine's multiple roles in vivo is equally as fascinating as it is promising for future biochemical and pharmacological research.
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Affiliation(s)
- Niroshini M Giles
- School of Biological and Chemical Sciences, University of Exeter, Stocker Road, EX4 4QD, Exeter, United Kingdom
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100
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Abstract
Cellular compartments differ dramatically in their redox potentials. This translates directly into variations in the extent of disulfide bond formation within proteins, depending on their cellular localization. It has long been assumed that proteins that are present in the reducing environment of the cytosol do not possess disulfide bonds. The recent discovery of a number of cytosolic proteins that use specific and reversible disulfide bond formation as a functional switch suggests that this view needs to be revised. Oxidative stress-induced disulfide bond formation appears to be the main strategy to adjust the protein activity of the oxidative stress transcription factors Yap1 and OxyR, the molecular chaperone Hsp33, and the anti-sigma factor RsrA. This elegant and rapid regulation allows the cells to respond quickly to environmental changes that manifest themselves in the accumulation of reactive oxygen species.
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Affiliation(s)
- Katrin Linke
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
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