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Liu H, Chen Q, Lei L, Zhou W, Huang L, Zhang J, Chen D. Prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances affects leukocyte telomere length in female newborns. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 235:446-452. [PMID: 29310088 DOI: 10.1016/j.envpol.2017.12.095] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Revised: 12/23/2017] [Accepted: 12/24/2017] [Indexed: 05/22/2023]
Abstract
Evidence has shown that leukocyte telomere length (LTL) at birth is related to the susceptibility to various diseases in later life and the setting of newborn LTL is influenced by the intrauterine environment. Perfluoroalkyl and polyfluoroalkyl substances (PFASs), as a kind of persistent organic pollutants, are commonly used in commercial and domestic applications and are capable of crossing the maternal-fetal barrier during pregnancy. We hypothesized that intrauterine exposure to PFASs may affect fetal LTL by increasing oxidative stress. To verify this hypothesis, LTL, concentrations of PFASs and reactive oxygen species (ROS) were measured in umbilical cord blood of 581 newborns from a prospective cohort. Our results showed that there were interactions between PFOS/PFDA and sex on LTL and ROS. The LTL was significantly shorter (0.926 ± 0.053 vs 0.945 ± 0.054, P = .023 for PFOS; 0.919 ± 0.063 vs 0.940 ± 0.059, P = .011 for PFDA) and the ROS levels were extremely higher (252.9 ± 60.5 [M] vs 233.5 ± 53.6 [M], P = .031 for PFOS; 255.2 ± 62.9 [M] vs 232.9 ± 58.3 [M], P = .011 for PFDA) in the female newborns whose PFOS or PFDA concentrations fell in the upmost quartile compared with those in the lowest quartile after adjusting for potential confounders. ROS levels were inversely associated with LTL in female newborns (β = -1.42 × 10-4, P = .022). 13% of the effect of PFOS on female LTL was mediated through ROS approximately by the mediation analyses. However, in male newborns, no relationships among PFASs, ROS and LTL were observed. Our findings suggest a "programming" role of PFASs on fetal telomere biology system in females in intrauterine stage.
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Affiliation(s)
- Han Liu
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qian Chen
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lei Lei
- Department of Obstetrics and Gynecology, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Wei Zhou
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lisu Huang
- Pediatric Department, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Clinical Research Unit, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Zhang
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Dan Chen
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Oxidative stress and oxidative damage in chemical carcinogenesis. Toxicol Appl Pharmacol 2011; 254:86-99. [PMID: 21296097 DOI: 10.1016/j.taap.2009.11.028] [Citation(s) in RCA: 297] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 11/29/2009] [Accepted: 11/29/2009] [Indexed: 12/13/2022]
Abstract
Reactive oxygen species (ROS) are induced through a variety of endogenous and exogenous sources. Overwhelming of antioxidant and DNA repair mechanisms in the cell by ROS may result in oxidative stress and oxidative damage to the cell. This resulting oxidative stress can damage critical cellular macromolecules and/or modulate gene expression pathways. Cancer induction by chemical and physical agents involves a multi-step process. This process includes multiple molecular and cellular events to transform a normal cell to a malignant neoplastic cell. Oxidative damage resulting from ROS generation can participate in all stages of the cancer process. An association of ROS generation and human cancer induction has been shown. It appears that oxidative stress may both cause as well as modify the cancer process. Recently association between polymorphisms in oxidative DNA repair genes and antioxidant genes (single nucleotide polymorphisms) and human cancer susceptibility has been shown.
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Klaunig JE, Kamendulis LM, Hocevar BA. Oxidative stress and oxidative damage in carcinogenesis. Toxicol Pathol 2009; 38:96-109. [PMID: 20019356 DOI: 10.1177/0192623309356453] [Citation(s) in RCA: 620] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Carcinogenesis is a multistep process involving mutation and the subsequent selective clonal expansion of the mutated cell. Chemical and physical agents including those that induce reative oxygen species can induce and/or modulate this multistep process. Several modes of action by which carcinogens induce cancer have been identified, including through production of reactive oxygen species (ROS). Oxidative damage to cellular macromolecules can arise through overproduction of ROS and faulty antioxidant and/or DNA repair mechanisms. In addition, ROS can stimulate signal transduction pathways and lead to activation of key transcription factors such as Nrf2 and NF-kappaB. The resultant altered gene expression patterns evoked by ROS contribute to the carcinogenesis process. Recent evidence demonstrates an association between a number of single nucleotide polymorphisms (SNPs) in oxidative DNA repair genes and antioxidant genes with human cancer susceptibility. These aspects of ROS biology will be discussed in the context of their relationship to carcinogenesis.
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Affiliation(s)
- James E Klaunig
- Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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Subacute exposure to N-ethyl perfluorooctanesulfonamidoethanol results in the formation of perfluorooctanesulfonate and alters superoxide dismutase activity in female rats. Arch Toxicol 2009; 83:909-24. [PMID: 19544052 DOI: 10.1007/s00204-009-0450-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Accepted: 06/04/2009] [Indexed: 01/24/2023]
Abstract
Perfluorooctanesulfonamides, such as N-ethyl perfluorooctanesulfonamidoethanol (N-EtFOSE), are large scale industrial chemicals but their disposition and toxicity are poorly understood despite significant human exposure. The hypothesis that subacute exposure to N-EtFOSE, a weak peroxisome proliferator, causes a redox imbalance in vivo was tested using the known peroxisome proliferator, ciprofibrate, as a positive control. Female Sprague-Dawley rats were treated orally with N-EtFOSE, ciprofibrate or corn oil (vehicle) for 21 days, and levels of N-EtFOSE and its metabolites as well as markers of peroxisome proliferation and oxidative stress were assessed in serum, liver and/or uterus. The N-EtFOSE metabolite profile in liver and serum was in good agreement with reported in vitro biotransformation pathways in rats and the metabolite levels decreasing in the order perfluorooctanesulfonate >> perfluorooctanesulfonamide ~ N-ethyl perfluorooctanesulfonamidoacetate >> perfluorooctanesulfonamidoethanol approximately N-EtFOSE. Although N-EtFOSE treatment significantly decreased the growth rate, increased relative liver weight and activity of superoxide dismutases (SOD) in liver and uterus (total SOD, CuZnSOD and MnSOD), a metabolic study revealed no differences in the metabolome in serum from N-EtFOSE-treated and control animals. Ciprofibrate treatment increased liver weight and peroxisomal acyl Co-A oxidase activity in the liver and altered antioxidant enzyme activities in the uterus and liver. According to NMR metabolomic studies, ciprofibrate treated animals had altered serum lipid profiles compared to N-EtFOSE-treated and control animals, whereas putative markers of peroxisome proliferation in serum were not affected. Overall, this study demonstrates the biotransformation of N-EtFOSE to PFOS in rats that is accompanied by N-EtFOSE-induced alterations in antioxidant enzyme activity.
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O'Brien ML, Spear BT, Glauert HP. Role of Oxidative Stress in Peroxisome Proliferator-Mediated Carcinogenesis. Crit Rev Toxicol 2008; 35:61-88. [PMID: 15742903 DOI: 10.1080/10408440590905957] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In this review, the evidence about the role of oxidative stress in the induction of hepatocellular carcinomas by peroxisome proliferators is examined. The activation of PPAR-alpha by peroxisome proliferators in rats and mice may produce oxidative stress, due to the induction of enzymes like fatty acyl coenzyme A (CoA) oxidase (AOX) and cytochrome P-450 4A1. The effect of peroxisome proliferators on the antioxidant defense system is reviewed, as is the effect on endpoints resulting from oxidative stress that may be important in carcinogenesis, such as lipid peroxidation, oxidative DNA damage, and transcription factor activation. Peroxisome proliferators clearly inhibit several enzymes in the antioxidant defense system, but studies examining effects on lipid peroxidation and oxidative DNA damage are conflicting. There is a profound species difference in the induction of hepatocellular carcinomas by peroxisome proliferators, with rats and mice being sensitive, whereas species such as nonhuman primates and guinea pigs are not susceptible to the effects of peroxisome proliferators. The possible role of oxidative stress in these species differences is also reviewed. Overall, peroxisome proliferators produce changes in oxidative stress, but whether these changes are important in the carcinogenic process is not clear at this time.
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Affiliation(s)
- Michelle L O'Brien
- Graduate Centerfor Toxicology, University of Kentucky, Lexington, Kentucky 40506-0054, USA
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Nishimura J, Dewa Y, Okamura T, Muguruma M, Jin M, Saegusa Y, Umemura T, Mitsumori K. Possible involvement of oxidative stress in fenofibrate-induced hepatocarcinogenesis in rats. Arch Toxicol 2008; 82:641-54. [PMID: 18253720 DOI: 10.1007/s00204-007-0278-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Accepted: 12/20/2007] [Indexed: 12/16/2022]
Abstract
To clarify whether oxidative stress is involved in the development of hepatocellular preneoplastic foci induced by fenofibrate (FF), a peroxisome proliferator-activated receptor alpha agonist, male F344/N rats were fed a diet containing 6,000, 3,000, or 0 ppm of FF for 13 weeks after N-diethylnitrosamine initiation. Two-third partial hepatectomy was performed 1 week after the FF treatment. Histopathologically, the number of hepatocellular altered foci significantly increased in the FF-treated groups with a concomitant increase in the number of hepatocytes positive for anti-Ki-67 antibody, but the number and area of glutathione S-transferase placental form (GST-P)-positive foci decreased in these groups, as compared to those in the controls. Microarray analysis or quantitative real-time reverse transcription-polymerase chine reaction demonstrated the significant up-regulations of Aco and Cyp4a1 (genes related to lipid metabolism); Gpx2, Yc2, Cat, Cyp2b15, and Ugt1a6 (metabolic oxidative stress-related genes); Apex1, Mgmt, Xrcc5, Nbn, and Gadd45a (DNA repair-related genes); and Ccnd1 (cell cycle-related genes) in the FF-treated groups, and the significant down-regulations of Cyp1a2, Gsta2, Gstm2, and Gstm3 (phase I or II metabolism-related genes); Mlh1 and Top1 (DNA repair-related genes); and Cdkn1a, Cdkn1b, Chek2, and Gadd45b (cell cycle/apoptosis-related genes) in these rats. FF-treatment increased the activity of enzymes such as carnitine acetyltransferase, carnitine palmitoyltransferase, fatty acyl-CoA oxidizing system, and catalase in the liver, but not superoxide dismutase in the liver. In addition, 8-OHdG level in liver DNA, lipofuscin deposition in hepatocytes, and in vitro reactive oxygen species production in microsomes significantly increased due to FF treatment. These results suggest that oxidative stress is involved in the development of FF-induced hepatocellular preneoplastic foci in rats.
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Affiliation(s)
- Jihei Nishimura
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo, Japan.
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Ryu JY, Lee E, Kim HJ, Park H, Im JY, Kim J, Han SY, Kang IH, Park KL, Kim HS. Alterations of di( n-butyl)phthalate-induced oxidative stress in the testis of hypothyroid rats. TOXICOLOGICAL & ENVIRONMENTAL CHEMISTRY 2008; 90:113-126. [DOI: 10.1080/02772240701284451] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/14/2024]
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Sánchez-Pérez Y, Carrasco-Legleu C, García-Cuellar C, Pérez-Carreón J, Hernández-García S, Salcido-Neyoy M, Alemán-Lazarini L, Villa-Treviño S. Oxidative stress in carcinogenesis. Correlation between lipid peroxidation and induction of preneoplastic lesions in rat hepatocarcinogenesis. Cancer Lett 2005; 217:25-32. [PMID: 15596293 DOI: 10.1016/j.canlet.2004.07.019] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2004] [Revised: 07/01/2004] [Accepted: 07/06/2004] [Indexed: 11/24/2022]
Abstract
Oxidative stress during carcinogen metabolism seems to participate in liver tumor production in the rat. N-diethylnitrosamine is an important carcinogen used in liver cancer animal models. This indirect alkylating agent produces DNA-ethyl adducts and oxidative stress. In contrast, N-ethyl-N-nitrosourea, a direct mutagen, which generates DNA-ethyl adducts, does not produce liver tumors in rat unless it is given under oxidative stress conditions such as partial hepatectomy or phenobarbital treatment. To gain insight into the relation between oxidative stress and hepatocarcinogenicity, the induction of preneoplastic liver lesions was compared among three different initiation protocols related to the initiation-promotion-resistant hepatocyte model. In addition, liver lipid peroxidation levels, determined as thiobarituric acid reactive substances were studied early during the initiation stage. Rats initiated with N-ethyl-N-nitrosourea, 25 days after treatment developed fewer and smaller gamma-glutamyl transpeptidase positive preneoplastic lesions than rats initiated with N-diethylnitrosamine. A pre-treatment with the antioxidant quercetin 1 h before N-diethylnitrosamine initiation, significantly prevented development of gamma-glutamyl transpeptidase-positive lesions. Increased lipid peroxidation levels were induced with N-diethylnitrosamine from 3 to 24 h after initiation, while N-ethyl-N-nitrosourea did not induce increments, and importantly, pre-treatment with quercetin decreased lipid peroxidation induced by N-diethylnitrosamine. These results show correlation between lipid peroxidation and hepatocarcinogenicity and support the important role of oxidative stress on liver carcinogenesis.
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Affiliation(s)
- Yesennia Sánchez-Pérez
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Av. IPN No. 2508 Col. San Pedro Zacatenco, México 14, DF, CP 07360, Mexico
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9
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Seo KW, Kim KB, Kim YJ, Choi JY, Lee KT, Choi KS. Comparison of oxidative stress and changes of xenobiotic metabolizing enzymes induced by phthalates in rats. Food Chem Toxicol 2004; 42:107-14. [PMID: 14630134 DOI: 10.1016/j.fct.2003.08.010] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Phthalates are widely used as a plasticizer and cause a peroxisome proliferation. Peroxisome proliferators (PPs), such as di-2-ethylhexyl phthalate (DEHP) and clofibrate (CF) are known to have a hepatocarcinogenic potential in rodents. It has been proposed that these PPs may cause hepatocellular cancer by an oxidative damage-mediated mechanism(s). The primary purpose of this study is to find whether there is a difference between the oxidative damage by hepatocarcinogenic PPs (DEHP and CF) and the oxidative damage by weak PPs [di-n-butyl phthalate (DBP) and n-butylbenzyl phthalate (BBP)]. The second purpose is to investigate if phthalates can affect the phase I/phase II enzymes, and if the effect of PPs on metabolizing enzymes correlates with peroxisome proliferation or not. After rats were treated with PPs (DEHP, DBP and BBP; 50, 200, 1000 mg/kg, CF; 100 mg/kg, p.o., for 14 days), the activities of metabolizing enzymes and peroxisomal enzymes were investigated, and the oxidative damage was measured using 8-hydroxydeoxyguanosine (8-OHdG) in the DNA and malonedialdehyde (MDA) in the livers. These four PPs significantly increased the relative liver weights, palmitoyl-CoA oxidation and activity of carnitine acetyltransferase. DEHP was found to be the most potent PP among three phthalates. A dramatic and dose-dependent increase in hepatic MDA levels was observed in CF (100 mg/kg), DEHP (>or=50 mg/kg), DBP and BBP (>or=200 mg/kg) groups. However, the 8-OHdG in hepatic DNA was increased only in DEHP (1000 mg/kg) and CF groups. Activities of cytochrome p4501A1, 1A2, 3A4, UDP-glucuronosyl transferase and glutathione S-transferase were decreased overall by PPs, but there is no correlation between the inhibitory effect on metabolizing enzymes and the peroxisome proliferation. These results indicate that 8-OHdG positively correlates with carcinogenic potential of PPs, but other factors as well as peroxisomal H(2)O(2) could be involved in the generation of 8-OHdG and the carcinogenesis of PPs. The present findings also demonstrate that the effect of PPs on xenobiotic metabolizing enzymes may be independent of the peroxisome proliferation and the oxidative stress. Thus it is possible that the PPs affect the hepatic toxification/detoxification capacity even in humans.
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Affiliation(s)
- Kyung Won Seo
- Toxicology Department, National Institute of Toxicological Research, Korea Food and Drug Administration, 5 Nokbundong, Eunpyunggu, Seoul 122-704, South Korea.
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Chen LC, Tatum V, Glauert HP, Chow CK. Peroxisome proliferator perfluorodecanoic acid alters glutathione and related enzymes. J Biochem Mol Toxicol 2001; 15:107-13. [PMID: 11284052 DOI: 10.1002/jbt.6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Previously we have shown that treatment with the peroxisome proliferator perfluorodecanoic acid (PFDA) significantly increased hepatic reduced glutathione (GSH) content without altering the activity of selenium-glutathione peroxidase. In this study we examined some potential mechanisms by which PFDA treatment increases GSH levels. Male Sprague-Dawley rats were given a single injection of 0, 8.8, 17.5, and 35 mg PFDA in corn oil per kg body weight. Twelve days later the effects of PFDA on the activities of enzymes associated with GSH synthesis, utilization, and regeneration were assessed. The results showed that in a dose-dependent manner, PFDA treatment significantly decreased the activity of gamma-glutamylcysteine synthetase, while the activities of NADPH-generating enzymes, malic enzyme, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase were increased. PFDA treatment also dose dependently decreased cytosolic, but not microsomal, glutathione S-transferase activity, and the activity of glutathione reductase was decreased by the highest dose of PFDA. The data obtained suggest that increased hepatic GSH levels following PFDA treatment may result from increased regeneration and/or decreased utilization.
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Affiliation(s)
- L C Chen
- Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40506-0054, USA
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Qu B, Li QT, Wong KP, Ong CN, Halliwell B. Mitochondrial damage by the "pro-oxidant" peroxisomal proliferator clofibrate. Free Radic Biol Med 1999; 27:1095-102. [PMID: 10569642 DOI: 10.1016/s0891-5849(99)00143-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Clofibrate is a peroxisome proliferator that can cause hepatic cancer in rodents. It has been suggested that oxidative damage is involved in this hepatocarcinogenesis, although the data are conflicting. We confirmed that clofibrate causes oxidative damage in nuclei from the livers of mice treated with this substance, measured both as protein carbonyls and levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in DNA. In addition, clofibrate also affects mitochondria, causing elevated levels of carbonyls and 8-OHdG, increased state 4 respiration and decreased adenosine triphosphatase (ATPase) activity. No evidence for clofibrate-induced lipid peroxidation in mitochondria was obtained. We propose that mitochondria may be a major target of injury and a source of oxidative stress in clofibrate-treated animals.
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Affiliation(s)
- B Qu
- Department of Biochemistry, National University of Singapore, Singapore
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12
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Loft S, Deng XS, Tuo J, Wellejus A, Sørensen M, Poulsen HE. Experimental study of oxidative DNA damage. Free Radic Res 1998; 29:525-39. [PMID: 10098457 DOI: 10.1080/10715769800300571] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Animal experiments allow the study of oxidative DNA damage in target organs and the elucidation of dose-response relationships of carcinogenic and other harmful chemicals and conditions as well as the study of interactions of several factors. So far the effects of more than 50 different chemical compounds have been studied in animal experiments mainly in rats and mice, and generally with measurement of 8-oxodG with HPLC-EC. A large number of well-known carcinogens induce 8-oxodG formation in liver and/or kidneys. Moreover several animal studies have shown a close relationship between induction of dative DNA damage and tumour formation. In principle the level of oxidative DNA damage in an organ or cell may be studied by measurement of modified bases in extracted DNA by immunohistochemical visualisation, and from assays of strand breakage before and after treatment with repair enzymes. However, this level is a balance between the rates of damage and repair. Until the repair rates and capacity can be adequately assessed the rate of damage can only be estimated from the urinary excretion of repair products albeit only as an average of the entire body. A number of model compounds have been used to induce oxidative DNA damage in experimental animals. The hepatocarcinogen 2-nitropropane induces up to 10-fold increases in 8-oxodG levels in rat liver DNA. The level of 8-oxodG is also increased in kidneys and bone marrow but not in the testis. By means of 2-nitropropane we have shown correspondence between the increases in 8-oxodG in target organs and the urinary excretion of 8-oxodG and between 8-oxodG formation and the comet assay in bone marrow as well potent preventive effects of extracts of Brussels sprouts. Others have shown similar effects of green tea extracts and its components. Drawbacks of the use of 2-nitropropane as a model for oxidative DNA damage relate particularly to formation of 8-aminoguanine derivatives that may interfere with HPLC-EC assays and have unknown consequences. Other model compounds for induction of oxidative DNA damage, such as ferric nitriloacetate, iron dextran, potassium bromate and paraquat, are less potent and/or more organ specific. Inflammation and activation of an inflammatory response by phorbol esters or E. coli lipopolysaccharide (LPS) induce oxidative DNA damage in many target cells and enhance benzene-induced DNA damage in mouse bone marrow. Experimental studies provide powerful tools to investigate agents inducing and preventing oxidative damage to DNA and its role in carcinogenesis. So far, most animal experiments have concerned 8-oxodG and determination of additional damaged bases should be employed. An ideal animal model for prevention of oxidative DNA damage has yet to he developed.
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Affiliation(s)
- S Loft
- Institute of Public Health, Department of Clinical Pharmacology, Rigshospitalet; University of Copenhagen, Denmark.
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Nilakantan V, Spear BT, Glauert HP. Effect of the peroxisome proliferator ciprofibrate on lipid peroxidation and 8-hydroxydeoxyguanosine formation in transgenic mice with elevated hepatic catalase activity. Free Radic Biol Med 1998; 24:1430-6. [PMID: 9641260 DOI: 10.1016/s0891-5849(98)00007-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Peroxisome proliferators are a group of non-genotoxic hepatic carcinogens which have been proposed to act by increasing oxidative damage in the liver. To test this hypothesis, we have produced a transgenic mouse line that has elevated catalase activity specifically in the liver. In this study, we have examined if catalase overexpression influences the induction of lipid peroxidation or oxidative DNA damage, two mechanisms which have been hypothesized to be important in the carcinogenesis by peroxisome proliferators. Transgenic mice or non-transgenic litter mates were fed either 0.01% ciprofibrate or a control diet for 21 days. The activities of fatty acyl CoA oxidase and lauric acid hydroxylase were not significantly affected by catalase overexpression, although the ratio of fatty acyl CoA oxidase to catalase was significantly decreased in transgenic animals. Hepatic lipid peroxidation was estimated by quantifying the concentrations of malondialdehyde and conjugated dienes. Ciprofibrate treatment did not affect either endpoint, but catalase overexpression increased the concentrations of malondialdehyde (in untreated mice only) and conjugated dienes (in both untreated and ciprofibrate-fed mice). Oxidative DNA damage was estimated by quantifying 8-hydroxydeoxyguanosine (8-OHdG) by high-performance liquid chromatography/electrochemical detection. Ciprofibrate treatment significantly increased hepatic 8-OHdG concentrations, in agreement with several previous studies, but catalase overexpression did not significantly affect them, although 8-OHdG concentrations were decreased 50% in untreated mice. These results imply that the metabolism of hydrogen peroxide by catalase is not an important factor in the development of hepatic lipid peroxidation. The decrease in hepatic 8-OHdG in untreated transgenic mice and the increase seen after ciprofibrate administration imply that hydrogen peroxide is important in the formation of 8-OHdG. While the lack of decreased 8-OHdG levels in ciprofibrate-treated transgenic mice does not support this conclusion, it is possible that catalase levels were not sufficiently high to affect this endpoint. Transgenic mice with higher hepatic catalase activities may be required to resolve this issue.
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Affiliation(s)
- V Nilakantan
- Graduate Center for Toxicology, University of Kentucky, Lexington 40506-0054, USA
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Kasai H. Analysis of a form of oxidative DNA damage, 8-hydroxy-2'-deoxyguanosine, as a marker of cellular oxidative stress during carcinogenesis. Mutat Res 1997; 387:147-63. [PMID: 9439711 DOI: 10.1016/s1383-5742(97)00035-5] [Citation(s) in RCA: 816] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
8-hydroxy-2'-deoxyguanosine (8-OH-dG) was first reported in 1984 as a major form of oxidative DNA damage product by heated sugar, Fenton-type reagents and X-irradiation in vitro. 8-OH-dG has been detected in cellular DNA using an HPLC-ECD method in many laboratories. Analyses of 8-OH-dG in animal organ DNA after the administration of oxygen radical-forming chemicals will be useful for assessments of their carcinogenic risk. Its analysis in human leucocyte DNA and in urine is a new approach to the assessment of an individual's cancer risk due to oxidative stress. The increase of the 8-OH-dG level in the cellular DNA, detected by HPLC-ECD method, was supported by its immunochemical detection and its enhanced repair activity. The validity of the general use of 8-OH-dG as a marker of cellular oxidative stress is discussed.
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Affiliation(s)
- H Kasai
- Department of Environmental Oncology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Kitakyushu, Japan.
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Muna ZA, Doudin K, Songstad J, Ulvik RJ, Berge RK. Tetradecylthioacetic acid inhibits the oxidative modification of low density lipoprotein and 8-hydroxydeoxyguanosine formation in vitro. Arterioscler Thromb Vasc Biol 1997; 17:3255-62. [PMID: 9409320 DOI: 10.1161/01.atv.17.11.3255] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Oxidative modification of low-density lipoprotein (LDL) is thought to play a key role in the formation of foam cells and in initiation and progression of atherosclerotic plaque. The hypolipidemic 3-thia fatty acids contain a sulfur atom and might therefore possess reducing (antioxidant) properties. Consequently, the effects of 3-thia fatty acids on the susceptibility of LDL particles to undergo oxidative modification in vitro were studied. Tetradecylthioacetic acid (TTA), incorporated into the LDL particle and increased the lag time of copper ion induced LDL oxidation in a dose-dependent manner, 80 mumol/L TTA reduced the generation of lipid peroxides during copper ion induced LDL oxidation (for 2 hours) by 100%, 2,2'-azobis-(2,4-dimethylvaleronitrile) induced LDL oxidation by 64%, and 2,2'-azobis-(2-amidinopropane hydrochloride) induced LDL oxidation (for 6 hours) by 21%. The electrophoretic mobility of the oxidized LDL was reduced by TTA in both copper ion and azo-compounds initiated oxidation. This fatty acid analogue was effectively able to reduce in a dose dependent manner the formation of 8-hydroxydeoxyguanosine from 2-deoxyguanosine with ascorbic acid as the radical producer. TTA bound copper(II) ions and did not reduce copper(II) to copper(I). It failed to scavenge the 1,1-diphenyl-2-picrylhydrazyl radicals. The results suggest that the modification of LDL in the lipid and protein moieties can be significantly reduced by TTA. This acid may exert its antioxidant effect partially through metal ion binding and through free radical scavenging.
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Affiliation(s)
- Z A Muna
- Department of Clinical Biology, University of Bergen, Haukeland University Hospital, Norway.
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16
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Voskoboinik I, Ooi SG, Drew R, Ahokas JT. Peroxisome proliferators increase the formation of BPDE-DNA adducts in isolated rat hepatocytes. Toxicology 1997; 122:81-91. [PMID: 9274804 DOI: 10.1016/s0300-483x(97)00083-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Peroxisome proliferators are known to modulate the activity of xenobiotic-metabolising enzymes, including glutathione S-transferase (GST) and cytochrome P-450 (CYP). In this study the effect of peroxisome proliferators silvex and di(2-ethylhexyl)phthalate (DEHP) on the formation of (+)-anti-benzo(a)pyrene -7,8-dihydrodiol-9,10-epoxide (BPDE)-DNA adducts from a proximate mutagen and carcinogen (-)-transbenzo(a)pyrene-7,8-dihydrodiol (BPDD) has been investigated. Rat CYP1A1 metabolises BPDD to mutagenic BPDE, which may form DNA adducts or, alternatively, be detoxified by hydrolysis or glutathione conjugation. In this experiment the formation of BPDE-DNA adducts was significantly increased in hepatocytes isolated from all silvex treated rats and two out of four DEHP treated rats (14 day treatment). The activity of CYP1A1 was increased whereas GST was reduced by the peroxisome proliferator silvex. These changes were more significant than those induced by DEHP. We have hypothesised that the formation of BPDE-DNA adducts was primarily due to the increased BPDD activation to BPDE versus reduced detoxication of BPDE. Other hepatic changes induced by the peroxisome proliferators, e.g. peroxisome proliferation per se and increased mitotic activity of the liver could have an effect on the outcome of BPDD exposure.
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Affiliation(s)
- I Voskoboinik
- Key Centre for Applied and Nutritional Toxicology, RMIT-University, Melbourne, Victoria, Australia
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17
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Soliman MS, Cunningham ML, Morrow JD, Roberts LJ, Badr MZ. Evidence against peroxisome proliferation-induced hepatic oxidative damage. Biochem Pharmacol 1997; 53:1369-74. [PMID: 9214698 DOI: 10.1016/s0006-2952(97)87956-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
It has been proposed that nongenotoxic peroxisome proliferators may cause hepatocellular cancer by an oxidative damage-mediated mechanism(s). The argument for this hypothesis is based mainly on the noted ability of peroxisome proliferators to induce significantly H2O2-producing peroxisomal beta-oxidation while causing a minimal induction of H2O2-degrading catalase. The recent discovery, accurate determination, and use of isoprostanes as a sensitive indicator of oxidative damage prompted us to investigate whether induction of hepatic peroxisomal beta-oxidation in male B6C3F1 mice is accompanied by elevated levels of isoprostanes in those livers. The data show that while 7 days of feeding mice a diet containing 100 ppm [4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio]acetic acid (WY-14,643) increased peroxisomal beta-oxidation by 16-fold and catalase activity by only 2-fold, hepatic levels of esterified F2-isoprostanes were not altered. These levels were 2.8 +/- 0.5 ng/g liver in control mice and 2.4 +/- 0.1 ng/g liver in mice fed the experimental diet for 7 days. Consequently, it is concluded that oxidative stress does not appear to occur in response to peroxisome proliferation, as evidenced by the lack of increase in hepatic levels of F2-isoprostanes in livers of mice treated with the potent peroxisome proliferator WY-14,643.
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Affiliation(s)
- M S Soliman
- Division of Pharmacology, University of Missouri-Kansas City, 64108, U.S.A
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18
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Nilakantan V, Li Y, Spear BT, Glauert HP. Increased liver-specific expression of catalase in transgenic mice. Ann N Y Acad Sci 1996; 804:542-53. [PMID: 8993572 DOI: 10.1111/j.1749-6632.1996.tb18644.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- V Nilakantan
- Graduate Center for Toxicology, University of Kentucky, Lexington 40506, USA
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