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Wei P, Wang Q, Yi T. From fluorescent probes to the theranostics platform. CHINESE J CHEM 2022. [DOI: 10.1002/cjoc.202200122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Peng Wei
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Shanghai Engineering Research Center of Nano‐Biomaterials and Regenerative Medicine, College of Chemistry, Chemical Engineering and Biotechnology Donghua University Shanghai 201620 China
| | - Qing Wang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Shanghai Engineering Research Center of Nano‐Biomaterials and Regenerative Medicine, College of Chemistry, Chemical Engineering and Biotechnology Donghua University Shanghai 201620 China
| | - Tao Yi
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Shanghai Engineering Research Center of Nano‐Biomaterials and Regenerative Medicine, College of Chemistry, Chemical Engineering and Biotechnology Donghua University Shanghai 201620 China
- Department of Chemistry Fudan University Shanghai 200438 China
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Zhao Y, Bao RK, Zhu SY, Talukder M, Cui JG, Zhang H, Li XN, Li JL. Lycopene prevents DEHP-induced hepatic oxidative stress damage by crosstalk between AHR-Nrf2 pathway. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 285:117080. [PMID: 33965855 DOI: 10.1016/j.envpol.2021.117080] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 03/29/2021] [Accepted: 04/01/2021] [Indexed: 05/20/2023]
Abstract
Di (2-ethylhexyl) phthalate (DEHP) is a widespread plasticizer that persists in the environment and can significantly contribute to serious health hazards of liver especially oxidative stress injury. Lycopene (LYC) as a carotenoid has recently gained widespread attention because of antioxidant activity. However, the potential mechanism of DEHP-induced hepatotoxicity and antagonism effect of LYC on it are still unclear. To explore the underlying mechanisms of this hypothesis, the mice were given by gavage with LYC (5 mg/kg) and DEHP (500 or 1000 mg/kg). The data suggested that DEHP caused liver enlargement, reduction of antioxidant activity markers, increase of oxidative stress indicators and disorder of cytochrome P450 enzymes system (CYP450s) homeostasis. DEHP-induced reactive oxygen species (ROS) activated the NF-E2-relatedfactor2 (Nrf2) and nuclear xenobiotic receptors (NXRs) system including Aryl hydrocarbon receptor (AHR), Pregnane X receptor (PXR) and Constitutive androstane receptor (CAR). Interestingly, these disorders and injuries were prevented after LYC treatment. Taken together, DEHP administration resulted in hepatotoxicity including oxidative stress injury and disordered CYP450 system, but these alterations might be ameliorated by LYC via crosstalk between AHR-Nrf2 pathway.
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Affiliation(s)
- Yi Zhao
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China
| | - Rong-Kun Bao
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China
| | - Shi-Yong Zhu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China
| | - Milton Talukder
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China; Department of Physiology and Pharmacology, Faculty of Animal Science and Veterinary Medicine, Patuakhali Science and Technology University, Barishal, 8210, Bangladesh
| | - Jia-Gen Cui
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China
| | - Hao Zhang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China
| | - Xue-Nan Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China; Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, Northeast Agricultural University, Harbin, 150030, PR China; Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, Northeast Agricultural University, Harbin, 150030, PR China
| | - Jin-Long Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China; Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, Northeast Agricultural University, Harbin, 150030, PR China; Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, Northeast Agricultural University, Harbin, 150030, PR China.
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Walker CL, Pomatto LCD, Tripathi DN, Davies KJA. Redox Regulation of Homeostasis and Proteostasis in Peroxisomes. Physiol Rev 2017; 98:89-115. [PMID: 29167332 DOI: 10.1152/physrev.00033.2016] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 06/19/2017] [Accepted: 06/21/2017] [Indexed: 02/08/2023] Open
Abstract
Peroxisomes are highly dynamic intracellular organelles involved in a variety of metabolic functions essential for the metabolism of long-chain fatty acids, d-amino acids, and many polyamines. A byproduct of peroxisomal metabolism is the generation, and subsequent detoxification, of reactive oxygen and nitrogen species, particularly hydrogen peroxide (H2O2). Because of its relatively low reactivity (as a mild oxidant), H2O2 has a comparatively long intracellular half-life and a high diffusion rate, all of which makes H2O2 an efficient signaling molecule. Peroxisomes also have intricate connections to mitochondria, and both organelles appear to play important roles in regulating redox signaling pathways. Peroxisomal proteins are also subject to oxidative modification and inactivation by the reactive oxygen and nitrogen species they generate, but the peroxisomal LonP2 protease can selectively remove such oxidatively damaged proteins, thus prolonging the useful lifespan of the organelle. Peroxisomal homeostasis must adapt to the metabolic state of the cell, by a combination of peroxisome proliferation, the removal of excess or badly damaged organelles by autophagy (pexophagy), as well as by processes of peroxisome inheritance and motility. More recently the tumor suppressors ataxia telangiectasia mutate (ATM) and tuberous sclerosis complex (TSC), which regulate mTORC1 signaling, have been found to regulate pexophagy in response to variable levels of certain reactive oxygen and nitrogen species. It is now clear that any significant loss of peroxisome homeostasis can have devastating physiological consequences. Peroxisome dysregulation has been implicated in several metabolic diseases, and increasing evidence highlights the important role of diminished peroxisomal functions in aging processes.
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Affiliation(s)
- Cheryl L Walker
- Center for Precision Environmental Health and Departments of Molecular & Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas; and Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center and Division of Molecular & Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, The University of Southern California, Los Angeles, California
| | - Laura C D Pomatto
- Center for Precision Environmental Health and Departments of Molecular & Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas; and Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center and Division of Molecular & Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, The University of Southern California, Los Angeles, California
| | - Durga Nand Tripathi
- Center for Precision Environmental Health and Departments of Molecular & Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas; and Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center and Division of Molecular & Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, The University of Southern California, Los Angeles, California
| | - Kelvin J A Davies
- Center for Precision Environmental Health and Departments of Molecular & Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas; and Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center and Division of Molecular & Computational Biology, Department of Biological Sciences of the Dornsife College of Letters, Arts, and Sciences, The University of Southern California, Los Angeles, California
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4
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Interplay between oxidant species and energy metabolism. Redox Biol 2015; 8:28-42. [PMID: 26741399 PMCID: PMC4710798 DOI: 10.1016/j.redox.2015.11.010] [Citation(s) in RCA: 193] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 11/20/2015] [Accepted: 11/25/2015] [Indexed: 02/07/2023] Open
Abstract
It has long been recognized that energy metabolism is linked to the production of reactive oxygen species (ROS) and critical enzymes allied to metabolic pathways can be affected by redox reactions. This interplay between energy metabolism and ROS becomes most apparent during the aging process and in the onset and progression of many age-related diseases (i.e. diabetes, metabolic syndrome, atherosclerosis, neurodegenerative diseases). As such, the capacity to identify metabolic pathways involved in ROS formation, as well as specific targets and oxidative modifications is crucial to our understanding of the molecular basis of age-related diseases and for the design of novel therapeutic strategies. Herein we review oxidant formation associated with the cell's energetic metabolism, key antioxidants involved in ROS detoxification, and the principal targets of oxidant species in metabolic routes and discuss their relevance in cell signaling and age-related diseases. Energy metabolism is both a source and target of oxidant species. Reactive oxygen species are formed in redox reactions in catabolic pathways. Sensitive targets of oxidant species regulate the flux of metabolic pathways. Metabolic pathways and antioxidant systems are regulated coordinately.
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Castellone MD, Langella A, Cantara S, Laurila JP, Laatikainen LE, Bellelli R, Pacini F, Salvatore M, Laukkanen MO. Extracellular superoxide dismutase induces mouse embryonic fibroblast proliferative burst, growth arrest, immortalization, and consequent in vivo tumorigenesis. Antioxid Redox Signal 2014; 21:1460-74. [PMID: 24328532 DOI: 10.1089/ars.2013.5475] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
AIMS Rat sarcoma virus (RAS)-induced tumorigenesis has been suggested to follow a three-stage model consisting of an initial RAS activation, senescence induction, and evasion of p53-dependent senescence checkpoints. While reactive oxygen species act as second messengers in RAS-induced senescence, they are also involved in oncogenic transformation by inducing proliferation and promoting mutations. In the current work, we investigated the role of extracellular superoxide dismutase (SOD3) in RAS-induced senescence and immortalization in vitro and in vivo. We used a mouse embryonic fibroblast (MEF) primary cell model along with immortalized and transformed human cell lines derived from papillary and anaplastic thyroid cancer. RESULTS Based on our data, sod3 RNA interference in H-RasV12-transduced cells markedly inhibited cell growth, while sod3 over-expression in MEFs initially caused a proliferative burst followed by the activation of DNA damage checkpoints, induction of p53-p21 signal transduction, and senescence. Subsequently, sod3-transduced MEF cells developed co-operative p21-p16 down-regulation and acquired transformed cell characteristics such as increased telomerase activity, loss of contact inhibition, growth in low-nutrient conditions, and in vivo tumorigenesis. Interestingly, as previously reported with RAS, we showed a dose-dependent response to SOD3 in vitro and in vivo involving transcriptional and non-transcriptional regulatory mechanisms. INNOVATION SOD3 may mediate H-RasV12-induced initiation of primary cell immortalization. CONCLUSIONS Our results indicate that SOD3 influences growth signaling in primary and cancer cells downstream of the ras oncogene and could serve as a therapy target at an early tumorigenesis phase.
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Affiliation(s)
- Maria Domenica Castellone
- 1 Department of Molecular Medicine and Medical Biotechnologies, Institute of Experimental Endocrinology and Oncology (CNR), University of Naples Federico II , Naples, Italy
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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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Klaunig JE, Babich MA, Baetcke KP, Cook JC, Corton JC, David RM, DeLuca JG, Lai DY, McKee RH, Peters JM, Roberts RA, Fenner-Crisp PA. PPARα Agonist-Induced Rodent Tumors: Modes of Action and Human Relevance. Crit Rev Toxicol 2008; 33:655-780. [PMID: 14727734 DOI: 10.1080/713608372] [Citation(s) in RCA: 433] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Widely varied chemicals--including certain herbicides, plasticizers, drugs, and natural products--induce peroxisome proliferation in rodent liver and other tissues. This phenomenon is characterized by increases in the volume density and fatty acid oxidation of these organelles, which contain hydrogen peroxide and fatty acid oxidation systems important in lipid metabolism. Research showing that some peroxisome proliferating chemicals are nongenotoxic animal carcinogens stimulated interest in developing mode of action (MOA) information to understand and explain the human relevance of animal tumors associated with these chemicals. Studies have demonstrated that a nuclear hormone receptor implicated in energy homeostasis, designated peroxisome proliferator-activated receptor alpha (PPARalpha), is an obligatory factor in peroxisome proliferation in rodent hepatocytes. This report provides an in-depth analysis of the state of the science on several topics critical to evaluating the relationship between the MOA for PPARalpha agonists and the human relevance of related animal tumors. Topics include a review of existing tumor bioassay data, data from animal and human sources relating to the MOA for PPARalpha agonists in several different tissues, and case studies on the potential human relevance of the animal MOA data. The summary of existing bioassay data discloses substantial species differences in response to peroxisome proliferators in vivo, with rodents more responsive than primates. Among the rat and mouse strains tested, both males and females develop tumors in response to exposure to a wide range of chemicals including DEHP and other phthalates, chlorinated paraffins, chlorinated solvents such as trichloroethylene and perchloroethylene, and certain pesticides and hypolipidemic pharmaceuticals. MOA data from three different rodent tissues--rat and mouse liver, rat pancreas, and rat testis--lead to several different postulated MOAs, some beginning with PPARalpha activation as a causal first step. For example, studies in rodent liver identified seven "key events," including three "causal events"--activation of PPARalpha, perturbation of cell proliferation and apoptosis, and selective clonal expansion--and a series of associative events involving peroxisome proliferation, hepatocyte oxidative stress, and Kupffer-cell-mediated events. Similar in-depth analysis for rat Leydig-cell tumors (LCTs) posits one MOA that begins with PPARalpha activation in the liver, but two possible pathways, one secondary to liver induction and the other direct inhibition of testicular testosterone biosynthesis. For this tumor, both proposed pathways involve changes in the metabolism and quantity of related hormones and hormone precursors. Key events in the postulated MOA for the third tumor type, pancreatic acinar-cell tumors (PACTs) in rats, also begin with PPARalpha activation in the liver, followed by changes in bile synthesis and composition. Using the new human relevance framework (HRF) (see companion article), case studies involving PPARalpha-related tumors in each of these three tissues produced a range of outcomes, depending partly on the quality and quantity of MOA data available from laboratory animals and related information from human data sources.
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Affiliation(s)
- James E Klaunig
- Indiana University School of Medicine, Indianapolis, IN, USA
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8
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Cattley RC, Dietze SR, Richardson FC, Popp JA. Detection of 5-Hydroxymethyl-2′-Deoxyuridine in Dna from Calf Thymus, Hela Cells, and Rat Liver Nuclei. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/07328319008045130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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9
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Prasad L, Husain Khan T, Jahangir T, Sultana S. Chemomodulatory effects of Terminalia chebula against nickel chloride induced oxidative stress and tumor promotion response in male Wistar rats. J Trace Elem Med Biol 2006; 20:233-9. [PMID: 17098582 DOI: 10.1016/j.jtemb.2006.07.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Accepted: 07/07/2006] [Indexed: 11/22/2022]
Abstract
Nickel, a major environmental pollutant is a known potent nephrotoxic agent. In this communication we report the chemopreventive effect of Terminalia chebula on nickel chloride (NiCl(2)) induced renal oxidative stress, toxicity and cell proliferation response in male Wistar rats. Administration of NiCl(2) (250micromoL Ni/kg body weight) to male Wistar rats resulted in an increase in the reduced renal glutathione content (GSH), glutathione-S-transferase (GST), glutathione reductase (GR), lipid peroxidation (LPO), H(2)O(2) generation, blood urea nitrogen (BUN) and serum creatinine with a concomitant decrease in the activity of glutathione peroxidase (p<0.001). Nickel chloride (NiCl(2)) treatment also induced tumor promotion markers, viz., ornithine decarboxylase (ODC) activity and thymidine [(3)H] incorporation into renal DNA (p<0.001). Prophylactic treatment of rats with T. chebula (25mg/kg body weight and 50mg/kg body weight) daily for one week resulted in the diminution of NiCl(2) mediated damage as evident from the down regulation of glutathione content, GST, GR, LPO, H(2)O(2) generation, BUN, serum creatinine, DNA synthesis (p<0.001) and ODC activity (p<0.01) with concomitant restoration of GPx activity. Thus, the present investigation suggests that T. chebula extract could be used as therapeutic agent for cancer prevention as evident from this study where it blocks or suppresses the events associated with chemical carcinogenesis.
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Affiliation(s)
- Lakshmi Prasad
- Section of Chemoprevention and Nutrition Toxicology, Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi 110062, India
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Valko M, Izakovic M, Mazur M, Rhodes CJ, Telser J. Role of oxygen radicals in DNA damage and cancer incidence. Mol Cell Biochem 2005; 266:37-56. [PMID: 15646026 DOI: 10.1023/b:mcbi.0000049134.69131.89] [Citation(s) in RCA: 1021] [Impact Index Per Article: 53.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The development of cancer in humans and animals is a multistep process. The complex series of cellular and molecular changes participating in cancer development are mediated by a diversity of endogenous and exogenous stimuli. One type of endogenous damage is that arising from intermediates of oxygen (dioxygen) reduction - oxygen-free radicals (OFR), which attacks not only the bases but also the deoxyribosyl backbone of DNA. Thanks to improvements in analytical techniques, a major achievement in the understanding of carcinogenesis in the past two decades has been the identification and quantification of various adducts of OFR with DNA. OFR are also known to attack other cellular components such as lipids, leaving behind reactive species that in turn can couple to DNA bases. Endogenous DNA lesions are genotoxic and induce mutations. The most extensively studied lesion is the formation of 8-OH-dG. This lesion is important because it is relatively easily formed and is mutagenic and therefore is a potential biomarker of carcinogenesis. Mutations that may arise from formation of 8-OH-dG involve GC --> TA transversions. In view of these findings, OFR are considered as an important class of carcinogens. The effect of OFR is balanced by the antioxidant action of non-enzymatic antioxidants as well as antioxidant enzymes. Non-enzymatic antioxidants involve vitamin C, vitamin E, carotenoids (CAR), selenium and others. However, under certain conditions, some antioxidants can also exhibit a pro-oxidant mechanism of action. For example, beta-carotene at high concentration and with increased partial pressure of dioxygen is known to behave as a pro-oxidant. Some concerns have also been raised over the potentially deleterious transition metal ion-mediated (iron, copper) pro-oxidant effect of vitamin C. Clinical studies mapping the effect of preventive antioxidants have shown surprisingly little or no effect on cancer incidence. The epidemiological trials together with in vitro experiments suggest that the optimal approach is to reduce endogenous and exogenous sources of oxidative stress, rather than increase intake of anti-oxidants. In this review, we highlight some major achievements in the study of DNA damage caused by OFR and the role in carcinogenesis played by oxidatively damaged DNA. The protective effect of antioxidants against free radicals is also discussed.
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Affiliation(s)
- Marian Valko
- Faculty of Chemical and Food Technology, Slovak Technical University, SK-812 37 Bratislava, Slovakia.
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11
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Valko M, Izakovic M, Mazur M, Rhodes CJ, Telser J. Role of oxygen radicals in DNA damage and cancer incidence. Mol Cell Biochem 2004; 266:37-56. [PMID: 15646026 DOI: 10.1023/b:mcbi.0000049134.69131.89/metrics] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The development of cancer in humans and animals is a multistep process. The complex series of cellular and molecular changes participating in cancer development are mediated by a diversity of endogenous and exogenous stimuli. One type of endogenous damage is that arising from intermediates of oxygen (dioxygen) reduction - oxygen-free radicals (OFR), which attacks not only the bases but also the deoxyribosyl backbone of DNA. Thanks to improvements in analytical techniques, a major achievement in the understanding of carcinogenesis in the past two decades has been the identification and quantification of various adducts of OFR with DNA. OFR are also known to attack other cellular components such as lipids, leaving behind reactive species that in turn can couple to DNA bases. Endogenous DNA lesions are genotoxic and induce mutations. The most extensively studied lesion is the formation of 8-OH-dG. This lesion is important because it is relatively easily formed and is mutagenic and therefore is a potential biomarker of carcinogenesis. Mutations that may arise from formation of 8-OH-dG involve GC --> TA transversions. In view of these findings, OFR are considered as an important class of carcinogens. The effect of OFR is balanced by the antioxidant action of non-enzymatic antioxidants as well as antioxidant enzymes. Non-enzymatic antioxidants involve vitamin C, vitamin E, carotenoids (CAR), selenium and others. However, under certain conditions, some antioxidants can also exhibit a pro-oxidant mechanism of action. For example, beta-carotene at high concentration and with increased partial pressure of dioxygen is known to behave as a pro-oxidant. Some concerns have also been raised over the potentially deleterious transition metal ion-mediated (iron, copper) pro-oxidant effect of vitamin C. Clinical studies mapping the effect of preventive antioxidants have shown surprisingly little or no effect on cancer incidence. The epidemiological trials together with in vitro experiments suggest that the optimal approach is to reduce endogenous and exogenous sources of oxidative stress, rather than increase intake of anti-oxidants. In this review, we highlight some major achievements in the study of DNA damage caused by OFR and the role in carcinogenesis played by oxidatively damaged DNA. The protective effect of antioxidants against free radicals is also discussed.
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Affiliation(s)
- Marian Valko
- Faculty of Chemical and Food Technology, Slovak Technical University, SK-812 37 Bratislava, Slovakia.
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12
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Reddy JK. Peroxisome proliferators and peroxisome proliferator-activated receptor alpha: biotic and xenobiotic sensing. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 164:2305-21. [PMID: 15161663 PMCID: PMC1615758 DOI: 10.1016/s0002-9440(10)63787-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Janardan K Reddy
- Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60611, USA.
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13
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Yadetie F, Laegreid A, Bakke I, Kusnierczyk W, Komorowski J, Waldum HL, Sandvik AK. Liver gene expression in rats in response to the peroxisome proliferator-activated receptor-alpha agonist ciprofibrate. Physiol Genomics 2003; 15:9-19. [PMID: 12851464 DOI: 10.1152/physiolgenomics.00064.2003] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Fibrate class hypolipidemic drugs such as ciprofibrate activate the peroxisome proliferator-activated receptor-alpha (PPARalpha), which is involved in processes including lipid metabolism and hepatocyte proliferation in rodents. We examined the effects of ciprofibrate (50 mg/kg body wt per day for 60 days) on liver gene expression in rats using cDNA microarrays. The 60-day dosing period was chosen to elucidate both the metabolic and proliferative actions of this substance, while avoiding confounding effects from the hepatic carcinogenesis seen during more long-term stimulation. Ciprofibrate changed the expression of many genes including previously known PPARalpha agonist-responsive genes involved in processes such as lipid metabolism and inflammatory responses. In addition, many novel candidate genes involved in sugar metabolism, transcription, signal transduction, cell proliferation, and stress responses appeared to be differentially regulated in ciprofibrate-dosed rats. Ciprofibrate also resulted in significant increases in liver weight and hepatocyte proliferation. The cDNA microarray results were confirmed by Northern blot analysis for selected genes. This study thus identifies many genes that appear to be differentially regulated in ciprofibrate-dosed rats, and some of these are potential targets of PPARalpha. The functional diversity of these candidate genes suggests that most of them are likely to be differentially regulated as indirect consequence of the many processes affected by ciprofibrate in rodent liver. Although caution is advisable in the interpretation of genome-wide expression data, the genes identified in the present study provide candidates for further studies that may give new insight into the mechanisms of action of peroxisome proliferators.
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Affiliation(s)
- Fekadu Yadetie
- Department of Cancer Research and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology, N-7489 Trondheim, Norway.
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14
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Seacat AM, Thomford PJ, Hansen KJ, Clemen LA, Eldridge SR, Elcombe CR, Butenhoff JL. Sub-chronic dietary toxicity of potassium perfluorooctanesulfonate in rats. Toxicology 2003; 183:117-31. [PMID: 12504346 DOI: 10.1016/s0300-483x(02)00511-5] [Citation(s) in RCA: 276] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Perfluorooctanesulfonate (PFOS) is a widely disseminated persistent compound found at low (part-per-billion) concentrations in serum and liver samples from humans and fish-eating wildlife. This study investigated the hypotheses that early hepatocellular peroxisomal proliferation and hepatic cellular proliferation are factors in chronic liver response to dietary dosing, that lowering of serum total cholesterol is an early clinical measure of response to treatment, and that liver and serum PFOS concentrations are proportional to dose and cumulative dose after sub-chronic treatment. PFOS was administered in diet as the potassium salt at 0, 0.5, 2.0, 5.0, and 20 parts per million (ppm) to Sprague Dawley rats for 4 or 14 weeks. At 4 weeks, effects included decreased serum glucose and an equivocal (<twofold) increase in hepatic palmitoyl CoA oxidase (PCoAO) activity in 20 ppm dose-group males in one of two assay systems [corrected]. At 14 weeks, the 20 ppm males had increased liver weight, decreased serum cholesterol, increased non-segmented neutrophils, and increased ALT. Relative liver weights and urea nitrogen were increased in both sexes at 14 weeks. Hepatocytic hypertrophy and cytoplasmic vacuolation were observed in the 5 or 20 ppm male and the 20 ppm female dose groups. An increase in hepatic PCoAO activity was not observed at 14 weeks, and the average hepatocyte proliferation index was not increased, although, individual animals had mild increases. Serum and liver PFOS concentrations were proportional to dose and cumulative dose. Serum concentrations were generally higher in females than in males. The liver-to-serum PFOS ratios ranged from approximately 3:1 to 12:1. After 14 weeks, the no-observed-adverse effect level (NOAEL) in males and females was 5 ppm. The NOAEL corresponded to mean serum PFOS concentrations of 44 ppm (microg/ml) in males and 64 ppm in females and mean liver PFOS concentrations of 358 ppm in males and 370 ppm in females. Results for this study: (1) did not provide strong evidence for hepatocellular peroxisomal or cellular proliferation at the doses tested; (2) suggested that lowering of serum total cholesterol may not be the earliest clinically-measurable response to treatment in the rat; and (3) confirmed that serum and liver PFOS concentrations on repeated dosing are proportional to dose and cumulative dose.
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Affiliation(s)
- Andrew M Seacat
- 3M Medical Department, Corporate Toxicology, 3M Center 220-2E-02, Saint Paul, MN 55133, USA
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Peters JM, Rusyn I, Rose ML, Gonzalez FJ, Thurman RG. Peroxisome proliferator-activated receptor alpha is restricted to hepatic parenchymal cells, not Kupffer cells: implications for the mechanism of action of peroxisome proliferators in hepatocarcinogenesis. Carcinogenesis 2000; 21:823-6. [PMID: 10753222 DOI: 10.1093/carcin/21.4.823] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Peroxisome proliferators increase hepatocyte proliferation and cause liver tumors in rodents, yet the mechanism of action is not understood. Based on studies with null mice it is known that peroxisome proliferator-activated receptor-alpha (PPARalpha) is involved. There is also evidence that Kupffer cells play a central role in peroxisome proliferator-induced carcinogenesis, most likely via mechanisms involving increases in superoxide, activation of nuclear factor kappaB and production of tumor necrosis factor-alpha (TNFalpha). However, it is not known whether PPARalpha is constitutively expressed in Kupffer cells. Therefore, the expression of PPAR isoforms in rat Kupffer and parenchymal cells was examined. Kupffer cells and hepatocytes of >99% purity were isolated from rats fed either a control diet or one containing 0.1% WY-14,643 for 1 week. Protein and RNA were obtained and PPAR expression was analyzed using northern and western blots. PPARalpha, PPARbeta and PPARgamma mRNA was detected in purified hepatocytes. In Kupffer cells, mRNA encoding PPARgamma was present while transcripts for PPARalpha and PPARbeta were not detected. Immunoblots were consistent with the results found by northern analysis. Moreover, when Kupffer cells from wild-type or PPARalpha-null mice were treated with WY-14,643 in vitro, superoxide production was similar. Combined, these results show that PPARalpha is expressed in rat parenchymal cells but not in Kupffer cells. These data are consistent with the hypothesis that parenchymal cells respond to Kupffer cell-derived TNFalpha via mechanisms dependent on PPARalpha within the parenchymal cells.
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Affiliation(s)
- J M Peters
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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16
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Rusyn I, Rose ML, Bojes HK, Thurman RG. Novel role of oxidants in the molecular mechanism of action of peroxisome proliferators. Antioxid Redox Signal 2000; 2:607-21. [PMID: 11229371 DOI: 10.1089/15230860050192350] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Peroxisome proliferators are nongenotoxic rodent carcinogens that act as tumor promoters by increasing cell proliferation; however, their precise mechanism of action is not well understood. Oxidative DNA damage caused by leakage of hydrogen peroxide (H2O2) from peroxisomes was hypothesized initially as the mechanism by which these compounds cause liver tumors. It seems unlikely that oxidants of peroxisomal origin explain the mechanism of action of peroxisome proliferators because treatment with these compounds in vivo does not lead to increased H2O2 production. On the other hand, Kupffer cell-derived oxidants, such as superoxide, may play a role in initiating tumor nerosis factor-alpha (TNF-alpha) production that leads to hepatocyte proliferation. Peroxisome proliferators have been shown to activate Kupffer cells both in vitro and in vivo, and the use of Kupffer cell inhibitors such as methyl palmitate and dietary glycine have demonstrated that Kupffer cells are responsible for hepatocyte proliferation by mechanisms involve TNF-alpha. Moreover, peroxisome proliferators activate the transcription factor NF-kappaB, one of the major regulators of TNF-alpha expression, in Kupffer cells. Importantly, activation of NF-kappaB by peroxisome proliferators was shown to be oxidant-dependent, leading to the hypothesis that oxidants of Kupffer cell origin are involved in the mechanism of action. Many of the effects of peroxisome proliferators, including peroxisome induction and hepatomegaly, involve the peroxisome proliferator-activated receptor-alpha (PPARalpha). Recently, it was shown that peroxisome proliferator-induced cell proliferation and tumors require the PPARalpha. However, PPARalpha is not involved in TNF-alpha production by Kupffer cells because it is not expressed in this cell type. How it is involved in liver tumor remains unclear and one possible explanation is that both Kupffer cell TNF-alpha and parenchymal cell PPARalpha are required. Collectively, recent data are consistent with the hypothesis that oxidants play a role in signaling hepatocellular proliferation due to peroxisome proliferators via activation of NF-kappaB and incrase in mitogenic cytokines such as TNF-alpha.
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Affiliation(s)
- I Rusyn
- Department of Pharmacology and Curriculum in Toxicology, University of North Carolina, Chapel Hill 27599-7365, USA.
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17
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Maloney EK, Waxman DJ. trans-Activation of PPARalpha and PPARgamma by structurally diverse environmental chemicals. Toxicol Appl Pharmacol 1999; 161:209-18. [PMID: 10581215 DOI: 10.1006/taap.1999.8809] [Citation(s) in RCA: 272] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A large number of industrial chemicals and environmental pollutants, including trichloroethylene (TCE), di(2-ethylhexyl)phthalate (DEHP), perfluorooctanoic acid (PFOA), and various phenoxyacetic acid herbicides, are nongenotoxic rodent hepatocarcinogens whose human health risk is uncertain. Rodent model studies have identified the receptor involved in the hepatotoxic and hepatocarcinogenic actions of these chemicals as peroxisome proliferator-activated receptor alpha (PPARalpha), a nuclear receptor that is highly expressed in liver. Humans exhibit a weak response to these peroxisome proliferator chemicals, which in part results from the relatively low level of PPARalpha expression in human liver. Cell transfection studies were carried out to investigate the interactions of peroxisome proliferator chemicals with PPARalpha, cloned from human and mouse, and with PPARgamma, a PPAR isoform that is highly expressed in multiple human tissues and is an important regulator of physiological processes such as adipogenesis and hematopoiesis. With three environmental chemicals, TCE, perchloroethylene, and DEHP, PPARalpha was found to be activated by metabolites, but not by the parent chemical. A decreased sensitivity of human PPARalpha compared to mouse PPARalpha to trans-activation was observed with some (Wy-14, 643, PFOA), but not other, peroxisome proliferators (TCE metabolites, trichloroacetate and dichloroacetate; and DEHP metabolites, mono[2-ethylhexyl]phthalate and 2-ethylhexanoic acid). Investigation of human and mouse PPARgamma revealed the transcriptional activity of this receptor to be stimulated by mono(2-ethylhexyl)phthalate, a DEHP metabolite that induces developmental and reproductive organ toxicities in rodents. This finding suggests that PPARgamma, which is highly expressed in human adipose tissue, where many lipophilic foreign chemicals tend to accumulate, as well as in colon, heart, liver, testis, spleen, and hematopoietic cells, may be a heretofore unrecognized target in human cells for a subset of industrial and environmental chemicals of the peroxisome proliferator class.
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Affiliation(s)
- E K Maloney
- Division of Cell and Molecular Biology, Boston University, Boston, Massachusetts, 02215, USA
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18
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Fiander H, Schneider H. Compounds that induce isoforms of glutathione S-transferase with properties of a critical enzyme in defense against oxidative stress. Biochem Biophys Res Commun 1999; 262:591-5. [PMID: 10471368 DOI: 10.1006/bbrc.1999.1262] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Compounds that upregulate enzymes that play critical roles in protection against free radical damage might be useful in treating diseases in which free radicals are pathological. To identify critical enzymes and their upregulators, compounds that were not free radical scavengers were screened for the ability to increase the IC(50) of the human neuronal cell line IMR-32 for hydrogen peroxide. Subsequently, enzymes upregulated by compounds that increased the IC(50) were identified. All of the compounds identified that increased the IC(50) also increased the specific activity of glutathione S-transferase (GST). In addition, compound-caused increases in the specific activity of GST correlated with compound-caused increases in the IC(50), the expected behaviour if GST was a critical enzyme. The GST isoform composition changed on upregulation, suggesting the upregulation of isoforms with anti-free radical activities. Structural features of compounds concurrently increasing the IC(50) and upregulating GST were identified.
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Affiliation(s)
- H Fiander
- National Research Council of Canada, Institute for Biological Sciences, Ottawa, Ontario, K1A 0R6, Canada
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19
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Fukamachi Y, Karasaki Y, Sugiura T, Itoh H, Abe T, Yamamura K, Higashi K. Zinc suppresses apoptosis of U937 cells induced by hydrogen peroxide through an increase of the Bcl-2/Bax ratio. Biochem Biophys Res Commun 1998; 246:364-9. [PMID: 9610364 DOI: 10.1006/bbrc.1998.8621] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Treatment of human premonocytic U937 cells with 500 microM H2O2 for 1h followed by 4h incubation in fresh medium to allow the cells to execute apoptotic processes caused DNA fragmentation. However, in the presence of 1mM ZnSO4 throughout the incubation, DNA ladder formation was markedly inhibited. Hydrogen peroxide treatment for 1h with or without zinc increased both Bcl-2 and Bax proteins. However, only Bax protein decreased to basal levels in the presence of zinc during the following 4h incubation, resulting in an increase of the Bcl-2/Bax ratio and prevention of apoptosis. Treatment of U937 cells with 1mM ZnSO4 alone also decreased the levels of Bax protein. Furthermore, we observed that zinc completely inhibited the activation of CPP32 by H2O2, while no significant changes of ICE activities occurred with either H2O2 and/or zinc. These results indicate that the suppression of H2O2-induced apoptosis by zinc is mediated through an increase of the Bcl-2/Bax ratio, which occurs upstream from the activation of CPP32.
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Affiliation(s)
- Y Fukamachi
- Department of Biochemistry, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
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20
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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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21
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Affiliation(s)
- M S Rao
- Department of Pathology, Northwestern University, Medical School, Chicago, Illinois 60611, USA
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22
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Nilakantan V, Li Y, Glauert HP, Spear BT. Increased liver-specific catalase activity in transgenic mice. DNA Cell Biol 1996; 15:625-30. [PMID: 8769564 DOI: 10.1089/dna.1996.15.625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Catalase is the major peroxisomal H2O2-detoxifying enzyme and is thought to be critical in maintaining low H2O2 levels within a cell. It has been proposed that increased H2O2 levels may be involved in oxidative DNA damage and tumor promotion induced by peroxisome proliferators and other xenobiotics. To develop a mouse model system to address this issue, we have generated transgenic mice that exhibit a three- to four-fold increase in liver catalase levels. The activities of fatty acyl coenzyme A (CoA) oxidase and lauric acid hydroxylase were unchanged in transgenic mice, demonstrating that elevated catalase levels did not alter the activity of these other peroxisome proliferator-induced enzymes that produce active oxygen. These mice should help elucidate the role of H2O2 in cellular events mediated by peroxisome proliferators and other xenobiotics.
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Affiliation(s)
- V Nilakantan
- Graduate Center for Toxicology, University of Kentucky, Lexington 40506, USA
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23
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Steroid Hormones and other Physiologic Regulators of Liver Cytochromes P450: Metabolic Reactions and Regulatory Pathways. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s1569-2558(08)60349-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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24
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Shaw S, Naegeli P, Etter JD, Weidmann P. Role of intracellular signalling pathways in hydrogen peroxide-induced injury to rat glomerular mesangial cells. Clin Exp Pharmacol Physiol 1995; 22:924-33. [PMID: 8846514 DOI: 10.1111/j.1440-1681.1995.tb02328.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
1. Brief exposure of cultured rat glomerular mesangial cells (GMC) to H2O2 in nominally bicarbonate-free solution induced a rapid dose dependent, dantrolene-inhibitable increase in intracellular free Ca2+ from 65 +/- 6 to 203 +/- 14 nmol/L and a prolonged release of [14C]-arachidonic acid [14C]-AA which preceded the onset of cell membrane damage assessed by trypan-blue uptake. 2. Ca2+ responses were potentiated in HCO3-/CO2 containing buffers and reached values of 1145 +/- 100 nmol/L at 1 mmol/L H2O2. In HCO3-/CO2 solutions, but not HEPES buffer, H2O2-induced Ca2+ increases were markedly attenuated by verapamil (100 mumol/L) or removal of extracellular calcium. 3. Enhanced release of [14C]-AA was partially attenuated by inhibitors of key intracellular signalling mechanisms including the phospholipase-A2 (PLA2) inhibitor mepacrine (100 mumol/L), the NADPH oxidase inhibitor diphenyliodonium (10 mumol/L), the mitochondrial calcium-cycling inhibitor ruthenium red (10 mumol/L) and the iron chelator dipyridyl (100 mumol/L). Release was unaffected by protein kinase C inhibition with H7 (100 mumol/L), inositol triphosphate antagonism with neomycin (1 mmol/L) or overnight treatment with the G-protein antagonist pertussis toxin (5 micrograms/mL). 4. Several structurally diverse lipoxygenase inhibitors, including esculetin, baicalein and phenidone, over the dose range 1-100 mumol/L, also prevented [14C]-AA release and markedly protected against cell membrane damage. No drug directly scavenged H2O2 assessed by UV absorption. 5. These results indicate that H2O2 activates in GMC a complex series of interrelated pathological mechanisms which in turn contribute to a prolongation of oxidative damage beyond the time of the initial exposure. These include an increase in intracellular calcium which, depending upon conditions, appears to be mediated by release from intracellular stores as well as Ca2+ entry from the extracellular space. In turn there is a sustained release of arachidonic acid, which may partly depend on prolonged activation of PLA2 but not phospholipase C. 6. Release of [14C]-AA could be attenuated by inhibitors of NADPH oxidase, mitochondrial calcium-cycling, iron chelators and a structurally diverse range of lipoxygenase inhibitors in association with protection from H2O2-mediated cell membrane damage.
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Affiliation(s)
- S Shaw
- Medizinische Universitäts, Poliklinik, Bern, Switzerland
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25
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Soames AR, Foster JR. Juxtaposition of peroxisomes and chromosomes in mitotic hepatocytes following methyl clofenapate administration to rats. Int J Exp Pathol 1994; 75:405-14. [PMID: 7734330 PMCID: PMC2001926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Administration of 25 mg/kg/day methyl clofenapate to Alpk/APfSD rats for up to 4 days gave rise to hepatomegaly resulting from a combination of hepatocyte hyperplasia, mainly in the periportal region of the lobule, and centrilobular cell hypertrophy. In hepatocytes undergoing mitosis there was a redistribution of dense vesicles and some peroxisomes to the perinuclear region of the cytoplasm. With increasing length of exposure to methyl clofenapate the number of peroxisomes located in this region during mitosis increased. Chromosomes observed by electron microscopy were seen to lie in close apposition to these organelles. Immunocytochemical localization of the Phase II conjugating enzymes glutathione-S transferase B, C and E showed a dramatic reduction and redistribution of those enzymes in mitotic cells and their absence in the region of the chromosomes. These events may increase the vulnerability of DNA to damage in specific cells.
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Affiliation(s)
- A R Soames
- Pathology Section, Zeneca Central Toxicology Laboratory, Alderley Park, Macclesfield, UK
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26
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Ashby J, Brady A, Elcombe CR, Elliott BM, Ishmael J, Odum J, Tugwood JD, Kettle S, Purchase IF. Mechanistically-based human hazard assessment of peroxisome proliferator-induced hepatocarcinogenesis. Hum Exp Toxicol 1994; 13 Suppl 2:S1-117. [PMID: 7857698 DOI: 10.1177/096032719401300201] [Citation(s) in RCA: 227] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In this review we have evaluated the relationship between peroxisome proliferation and hepatocarcinogenesis. To do so, we identified all chemicals known to produce peroxisome proliferation and selected those for which there are data (on peroxisome proliferation and hepatocarcinogenesis) which meet certain criteria chosen to facilitate comparison of these phenomena. The summarised data and definition of the methodology used has been collected in appendices. These comparisons enabled us to evaluate the relationship between these phenomena using reliable data. As there is a good correlation between them, we further explored the mechanisms of action that have been proposed (direct genotoxic activity, production of hydrogen peroxide, cell proliferation and receptor activation). The relationship between these events in other species, including humans, was also reviewed and finally an overview of the assessment of human hazard is presented in section IX. Some of the first chemicals which were shown to produce peroxisome proliferation were also hepatocarcinogens whose carcinogenicity could not be readily explained by genotoxic activity. This raised the suggestion that the unusual phenomenon of peroxisome proliferation was intricately linked to the carcinogenic activity of these agents. Three questions have exercised the attention of regulatory, industrial and academic toxicology since then; are chemicals which elicit peroxisome proliferation in the liver actually a coherent class of chemical carcinogens?; does the early biological phenomenon of peroxisome proliferation have real predictive value for and mechanistic association with rodent carcinogenesis?; and what hazard/risk do these agents pose to humans that may be exposed to them? Whether peroxisome proliferators are indeed a discrete class of rodent carcinogens would appear to be the single, most important question. If so, then the assumptions and procedures relevant to human hazard and risk assessment should be applied to the class and should be essentially generic; if not, each chemical should be considered independently. Our critical analysis of the published data for over 70 agents which have been shown to possess intrinsic ability to induce peroxisome proliferation in the livers of rodents has led to the conclusion that there exists a strong correlation between peroxisome proliferation as n early effect in the liver and hepatocarcinogenicity in chronic exposure studies. An almost perfect correlation was observed between the induction of peroxisomes in the rodent liver and the eventual appearance of tumours following chronic exposure The few exceptions to this were largely explainable (section II).(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- J Ashby
- Zeneca Ltd, Central Toxicology Laboratory, Macclesfield, Cheshire, UK
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27
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Demoz A, Svardal A, Berge RK. Relationship between peroxisome-proliferating sulfur-substituted fatty acid analogs, hepatic lipid peroxidation and hydrogen peroxide metabolism. Biochem Pharmacol 1993; 45:257-9. [PMID: 8424818 DOI: 10.1016/0006-2952(93)90400-q] [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: 01/30/2023]
Abstract
The effect of the administration of three peroxisome-proliferating sulfur-substituted fatty acid analogs on hepatic antioxidant status and lipid peroxidation was studied in rats. After 14 days of treatment, the ratio of induction of peroxisomal fatty acyl-CoA oxidase to catalase was 4.2 and 3.5 in rats treated with 1,10 bis-(carboxymethylthio)decane (BCMTD) and 1-mono (carboxymethylthio)tetradecane (CMTTD), respectively, while the corresponding ratio was 1.3 in 1-mono (carboxyethylthio)tetradecane (CETTD)-treated rats. As compared to the controls an increase in hepatic hydrogen peroxide content was noted in BCMTD- and CMTTD-treated rats, but not CETTD-treated rats. Hepatic lipid peroxidation was increased in all the three treatment groups in a manner not related to the potency of the compounds to induce the peroxisomal hydrogen peroxide metabolizing enzymes. Hepatic glutathione content increased while the activities of its associated enzymes such as glutathione transferase, glutathione peroxidase and glutathione reductase decreased in all the treated rats. Taken together, our data show a relationship between the levels of hydrogen peroxide and lipid peroxidation in rat livers treated with BCMTD and CMTTD. However, increased hepatic lipid peroxidation in CETTD-treated rats cannot be accounted for by the changes in the peroxisomal enzymes.
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Affiliation(s)
- A Demoz
- University of Bergen, Institute of Clinical Biology, Norway
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28
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Demoz A, Willumsen N, Berge RK. Eicosapentaenoic acid at hypotriglyceridemic dose enhances the hepatic antioxidant defense in mice. Lipids 1992; 27:968-71. [PMID: 1487958 DOI: 10.1007/bf02535573] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The effect of oral administration of purified (95%) eicosapentaenoic acid on serum lipids, hepatic peroxisomal enzymes, antioxidant enzymes and lipid peroxidation was compared with that of palmitic acid fed mice and corresponding controls. After 10 d, a dose of 1000 mg eicosapentaenoic acid per day/kg body weight lowered serum triglycerides by 45%, while no significant change in serum cholesterol level was noted in comparison to palmitic acid fed mice and controls. Hepatic acyl-CoA oxidase and catalase activities increased by 50% and 30%, respectively, in the eicosapentaenoic acid fed group. In addition, the hepatic reduced glutathione content and the activities of glutathione transferase, glutathione peroxidase and glutathione reductase, increased significantly during eicosapentaenoic acid treatment. The levels of hepatic lipid peroxides were lower after eicosapentaenoic acid feeding, while no significant change was noted in the palmitic acid fed mice when compared to the controls. Taken together, the present data demonstrate for the first time that at hypolipidemic doses eicosapentaenoic acid feeding i) enhances the hepatic antioxidant defense, and ii) does not cause a significant differential induction of the two peroxisomal enzymes, acyl-CoA oxidase and catalase, as was noted after administration of hypolipidemic peroxisome proliferating compounds, such as clofibrate in rodents.
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Affiliation(s)
- A Demoz
- Laboratory of Clinical Biochemistry, University of Bergen, Haukeland Sykehus, Norway
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29
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Sundseth S, Waxman D. Sex-dependent expression and clofibrate inducibility of cytochrome P450 4A fatty acid omega-hydroxylases. Male specificity of liver and kidney CYP4A2 mRNA and tissue-specific regulation by growth hormone and testosterone. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50613-5] [Citation(s) in RCA: 151] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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30
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Hsieh LL, Shinozuka H, Weinstein IB. Changes in expression of cellular oncogenes and endogenous retrovirus-like sequences during hepatocarcinogenesis induced by a peroxisome proliferator. Br J Cancer 1991; 64:815-20. [PMID: 1931600 PMCID: PMC1977482 DOI: 10.1038/bjc.1991.406] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Previous studies have demonstrated that BR-931, a hepatic peroxisome proliferator, can induce liver tumours in mice and rats. Since alterations in gene expression may play a critical role in multistage hepatocarcinogenesis, the present studies examined the expression of the c-myc, c-H-ras, epidermal growth factor (EGF) receptor and ODC (ornithine decarboxylase) genes, as well as endogenous retrovirus-like sequences, in F344 rat liver during the first 8 weeks of feeding a 0.16% Br931 diet and in liver tumours induced by chronic feeding of this diet. Northern blot analysis of poly A + liver RNA samples showed an increase in the level of RNAs homologous to rat leukaemia virus (RaLV) but no significant change in the level of 30S-retrovirus related RNAs in the liver RNA samples obtained from rats during the first 8 weeks of feeding the diet containing BR931. An increase in the levels of c-myc, c-H-ras and ODC transcripts was also seen in the liver RNA samples from the treated rats. Of particular interest was a decrease in the abundance of EGF receptor transcripts in the liver RNA samples from rats fed the BR931 diet. Increased levels of RaLV, c-myc, and ODC RNAs were also seen in the tumours induced by BR931, but this was not the case for 30S and c-H-ras. The liver tumour samples also showed a decrease in EGF receptor RNA. These changes in cellular levels of specific RNAs resemble, in several respect, those we previously described in rodent liver during regeneration and tumour promotion, and also those seen in rodent hepatomas induced by other agents. Therefore, they may reflect a common profile of gene expression relevant to liver proliferation and carcinogenesis.
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Affiliation(s)
- L L Hsieh
- Comprehensive Cancer Center, School of Public Health, Columbia University, New York, New York 10032
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31
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Hagiwara A, Tamano S, Ogiso T, Asakawa E, Fukushima S. Promoting effect of the peroxisome proliferator, clofibrate, but not di(2-ethylhexyl)phthalate, on urinary bladder carcinogenesis in F344 rats initiated by N-butyl-N-(4-hydroxybutyl)nitrosamine. Jpn J Cancer Res 1990; 81:1232-8. [PMID: 2125992 PMCID: PMC5918008 DOI: 10.1111/j.1349-7006.1990.tb02684.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The modifying potential of clofibrate and di(2-ethylhexyl)phthalate (DEHP) on second stage, N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN)-initiated urinary bladder carcinogenesis was investigated in male F344 rats, using a uracil-accelerated transitional cell proliferation model. Six-week-old animals received 0.05% BBN in their drinking water for 4 weeks and then clofibrate (1.0, 0.5, and 0.25%) and DEHP (1.2, 0.6, and 0.3%) were given during experimental weeks 5-8 and weeks 12-20. Uracil was administered during weeks 9-11 at a dietary level of 3.0%. Control rats were treated with BBN and uracil without peroxisome proliferator. Surviving animals were killed at the end of week 20 of the experiment, when the densities of putative preneoplastic, papillary or nodular (PN) hyperplasias (numbers per 10 cm of basement membrane) were significantly increased in all clofibrate-treated, but not the DEHP groups. The incidences of PN hyperplasia were similar in both treated animals and controls. In a second experiment, rats fed diets containing 1.0% clofibrate or 1.2% DEHP were assessed for levels of DNA synthesis in urinary bladder epithelium by 5-bromo-2-deoxyuridine immunohistochemistry. Numbers of labeled nuclei remained within normal levels, and no proliferative changes were evident. Thus, the present experiments indicated that while clofibrate, but not DEHP, exerts weak enhancing effects on BBN-initiated urinary bladder carcinogenesis in rats this is not associated with increased levels of DNA synthesis in the affected epithelium.
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Affiliation(s)
- A Hagiwara
- First Department of Pathology, Nagoya City University Medical School
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32
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Mikalsen SO, Kaalhus O, Reith A, Sanner T. Role of catalase and oxidative stress in hepatic peroxisome proliferator-induced morphological transformation of Syrian hamster embryo cells. Int J Cancer 1990; 46:950-7. [PMID: 2172174 DOI: 10.1002/ijc.2910460533] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Several hepatic peroxisome proliferators (HHPs) such as di(2-ethylhexyl)phthalate (DEHP), mono(2-ethylhexyl)-phthalate, clofibrate and tiadenol, induce morphological transformation of Syrian hamster embryo (SHE) cells in vitro. According to one hypothesis, the hepatocarcinogenic effect of HPPs is caused by an oxidative stress due to increased H2O2-production from the strongly induced peroxisomal beta-oxidation of fatty acids. Thus, increased transformation frequencies by HPPs should be obtained when catalase was inhibited by 3-amino-1,2,4-triazole (amitrole). However, co-exposure to HPPs and amitrole did not enhance the transformation frequencies for any of the HPPs. The sensitivity of SHE cells for oxidative agents was studied by using menadione and H2O2. Menadione only induced transformation at a toxic concentration, while H2O2 induced transformation at non-toxic concentrations. To study the generation of oxidative radicals in SHE cells, electron spin resonance was employed. No oxidative radical formation was detected in tiadenol- or DEHP-exposed SHE cells. When menadione or H2O2 were added during the measurements, oxidative radicals were found. A transmission electron microscopic study showed a small number of peroxisomes, and did not reveal any increase in the number of peroxisomes in clofibrate-treated SHE cells.
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Affiliation(s)
- S O Mikalsen
- Laboratory for Environmental and Occupational Cancer, Institute for Cancer Research, Norwegian Radium Hospital, Oslo
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Baumgart E, Völkl A, Pill J, Fahimi HD. Proliferation of peroxisomes without simultaneous induction of the peroxisomal fatty acid beta-oxidation. FEBS Lett 1990; 264:5-9. [PMID: 2338145 DOI: 10.1016/0014-5793(90)80750-d] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Marked proliferation of rat hepatic peroxisomes is observed after treatment with a new potent hypolipidemic drug BM 15766, as well as after bezafibrate. Whereas the relative specific activity of the peroxisomal fatty acid beta-oxidation system is not affected by BM 15766 it is significantly increased after bezafibrate. This is also confirmed by immunoblot analysis of individual beta-oxidation enzymes in highly purified peroxisome fractions. These observations suggest that peroxisome proliferation and the induction of the fatty acid beta-oxidation are regulated separately.
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Affiliation(s)
- E Baumgart
- Department of Anatomy and Cell Biology II, University of Heidelberg, FRG
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34
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Takagi A, Sai K, Umemura T, Hasegawa R, Kurokawa Y. Significant increase of 8-hydroxydeoxyguanosine in liver DNA of rats following short-term exposure to the peroxisome proliferators di(2-ethylhexyl)phthalate and di(2-ethylhexyl)adipate. Jpn J Cancer Res 1990; 81:213-5. [PMID: 2112523 PMCID: PMC5918022 DOI: 10.1111/j.1349-7006.1990.tb02551.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
8-Hydroxydeoxyguanosine (8-OH-dG) levels were examined in liver and kidney DNA after di(2-ethylhexyl)phthalate (DEHP), di(2-ethylhexyl)adipate (DEHA) and phthalic anhydride administration to male 6-week-old F-344 rats in the diet at concentrations of 1.2, 2.5 and 1.5%, respectively. Significant increases in 8-OH-dG levels were observed only in the liver (target organ of DEHP and DEHA carcinogenesis) DNA after 1 and 2 weeks of treatment with DEHP and DEHA, respectively. The results suggest the involvement of oxidative DNA damage in hepatocarcinogenesis by peroxisome proliferators.
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Affiliation(s)
- A Takagi
- Division of Toxicology, National Institute of Hygienic Sciences, Tokyo
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35
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Glauert HP, Beaty MM, Clark TD, Greenwell WS, Chow CK. Effect of dietary selenium on the induction of altered hepatic foci and hepatic tumors by the peroxisome proliferator ciprofibrate. Nutr Cancer 1990; 14:261-71. [PMID: 2084622 DOI: 10.1080/01635589009514102] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The purpose of this study was to determine if the dietary antioxidant selenium could inhibit hepatocarcinogenesis induced by peroxisome proliferators, which are hypothesized to induce tumors by increased production of hydrogen peroxide or other reactive oxygen species. Rats were fed diets containing the peroxisome proliferator ciprofibrate and one of three concentrations (0.04, 0.2, or 1.0 ppm) of selenium for 6 or 21 months. The incidence of hepatic tumors and the number and volume of gamma-glutamyl transpeptidase-positive, ATPase-negative, glucose-6-phosphatase-negative, and glucose-6-phosphatase-positive foci at 21 months were lower in rats fed higher levels of selenium (no foci or tumors were seen at 6 mo). Indices of oxidative damage in the liver (thiobarbituric acid reactants, conjugated dienes, and lipid-soluble fluorescence products), however, were not decreased in rats fed the high-selenium diet. Therefore, selenium was protective against ciprofibrate-induced hepatocarcinogenesis, but not by reducing the degree of oxidative damage. The liver selenium and glutathione concentrations, and liver selenium-dependent glutathione peroxidase activity, increased as dietary selenium increased. Therefore, inhibition of carcinogenesis by selenium was correlated with increased levels of glutathione and glutathione peroxidase, but these did not inhibit the indices of oxidative damage. Peroxisomal beta-oxidation also increased with the dietary selenium content; it therefore does not appear to be a factor in the inhibition of hepatocarcinogenesis in rats fed higher levels of selenium.
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Affiliation(s)
- H P Glauert
- Department of Nutrition and Food Science, Veterans Administration Hospital, University of Kentucky, Lexington 40506
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Abstract
1. The structures of mammalian cytochrome P-450 isoenzymes have been compared with respect to micro-sequence heterogeneity and their haem-binding cysteinyl peptides. 2. Mechanisms of induction of several P450 gene families are described including transcriptional activation and mRNA stabilization in cytochrome P450 I, II and IV families. 3. The tissue expression and substrate specificity of the cytochrome P450 IV family in liver, kidney and lung have been discussed. 4. The role of hepatic cytochrome P450 IVA1 induction in peroxisome proliferation is presented, and emphasis placed on the identification of susceptible and non-susceptible species.
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Affiliation(s)
- G G Gibson
- University of Surrey, Department of Biochemistry, UK
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Conway JG, Cattley RC, Popp JA, Butterworth BE. Possible mechanisms in hepatocarcinogenesis by the peroxisome proliferator di(2-ethylhexyl)phthalate. Drug Metab Rev 1989; 21:65-102. [PMID: 2696637 DOI: 10.3109/03602538909029956] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- J G Conway
- Chemical Industry Institute of Toxicology, Research Triangle Park, North Carolina 27709
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Rao MS, Reddy JK. The relevance of peroxisome proliferation and cell proliferation in peroxisome proliferator-induced hepatocarcinogenesis. Drug Metab Rev 1989; 21:103-10. [PMID: 2696631 DOI: 10.3109/03602538909029957] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- M S Rao
- Department of Pathology, Northwestern University Medical School, Chicago, Illinois 60611
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Lazo O, Contreras M, Hashmi M, Stanley W, Irazu C, Singh I. Peroxisomal lignoceroyl-CoA ligase deficiency in childhood adrenoleukodystrophy and adrenomyeloneuropathy. Proc Natl Acad Sci U S A 1988; 85:7647-51. [PMID: 3174658 PMCID: PMC282249 DOI: 10.1073/pnas.85.20.7647] [Citation(s) in RCA: 155] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We previously reported that in childhood adrenoleukodystrophy (C-ALD) and adrenomyeloneuropathy (AMN), the peroxisomal beta-oxidation system for very long chain (greater than C22) fatty acids is defective. To further define the defect in these two forms of X chromosome-linked ALD, we examined the oxidation of [1-14C]lignoceric acid (n-tetracosanoic acid, C24:0) and [1-14C]lignoceroyl-CoA (substrates for the first and second steps of beta-oxidation, respectively). The oxidation rates of lignoceric acid in C-ALD and AMN were 43% and 36% of control values, respectively, whereas the oxidation rate of lignoceroyl-CoA was 109% (C-ALD) and 106% (AMN) of control values, respectively. On the other hand, the oxidation rates of palmitic acid (n-hexadecanoic acid) and palmitoyl-CoA in C-ALD and AMN were similar to the control values. These results suggest that lignoceroyl-CoA ligase activity may be impaired in C-ALD and AMN. To identify the specific enzymatic deficiency and its subcellular localization in C-ALD and AMN, we established a modified procedure for the subcellular fractionation of cultured skin fibroblasts. Determination of acyl-CoA ligase activities provided direct evidence that lignoceroyl-CoA ligase is deficient in peroxisomes while it is normal in mitochondrial and microsomes. Moreover, the normal oxidation of lignoceroyl-CoA as compared with the deficient oxidation of lignoceric acid in isolated peroxisomes also supports the conclusion that peroxisomal lignoceroyl-CoA ligase is impaired in both C-ALD and AMN. Palmitoyl-Coa ligase activity was found to be normal in peroxisomes as well as in mitochondria and microsomes. This normal peroxisomal palmitoyl-CoA ligase activity as compared with the deficient activity of lignoceroyl-CoA ligase in C-ALD and AMN suggests the presence of two separate acyl-CoA ligases for palmitic and lignoceric acids in peroxisomes. These data clearly demonstrate that the pathognomonic accumulation of very long chain fatty acids in C-ALD and AMN is due to a deficiency of peroxisomal very long chain (lignoceric acid) acyl-CoA ligase.
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Affiliation(s)
- O Lazo
- Department of Pediatrics, Medical University of South Carolina, Charleston 29425
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Hyslop PA, Hinshaw DB, Halsey WA, Schraufstätter IU, Sauerheber RD, Spragg RG, Jackson JH, Cochrane CG. Mechanisms of oxidant-mediated cell injury. The glycolytic and mitochondrial pathways of ADP phosphorylation are major intracellular targets inactivated by hydrogen peroxide. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(19)77928-9] [Citation(s) in RCA: 467] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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41
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Bentley P, Bieri F, Muakkassah-Kelly S, Stäubli W, Waechter F. Mechanisms of Tumor Induction by Peroxisome Proliferators. Arch Toxicol 1988. [DOI: 10.1007/978-3-642-73113-6_39] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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42
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Singh Y, Liu GA, Krishna G. Valproic acid-induced increase in carnitine acetyltransferase in rat hepatocytes is not due to an induction of peroxisomes. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH 1987; 22:459-69. [PMID: 3121863 DOI: 10.1080/15287398709531085] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Valproic acid induced a dose-dependent increase in carnitine acetyltransferase (CAT) activity in rat hepatic mitochondrial fractions isolated by differential centrifugation. An increase in CAT and carnitine palmitoyltransferase (CPT) also occurred in cultured rat hepatocytes in a concentration-and time-dependent fashion. A maximal increase of 8-fold in the activity of CAT and 2-fold in the activity of CPT was induced by 3 mM valproic acid in 72 h. Valproic acid had no effect on cytochrome P-450 levels in cultured rat hepatocytes. Electron-microscopic examination of rat hepatocytes showed that there was no increase in the number of peroxisomes but there was a marked proliferation of mitochondria in parallel with an increase in glutathione level and succinic dehydrogenase in the liver cells after incubation with valproic acid in vitro.
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Affiliation(s)
- Y Singh
- Section on Drug-Tissue Interaction, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892
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Butterworth BE, Loury DJ, Smith-Oliver T, Cattley RC. The potential role of chemically induced hyperplasia in the carcinogenic activity of the hypolipidemic carcinogens. Toxicol Ind Health 1987; 3:129-49. [PMID: 3303446 DOI: 10.1177/074823378700300210] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Di(2-ethylhexyl)phthalate (DEHP) is a widely used plasticizing agent resulting in substantial human exposure and environmental contamination. In a chronic bioassay, high doses of DEHP induced hepatocellular carcinomas in female Fischer-344 rats and male and female B6C3F1 mice. Thus, there is considerable concern as to the species specificity, mechanism of action, and human risk assessment of DEHP. DEHP belongs to a class of agents described as hypolipidemic hepatocarcinogens. These chemicals share the ability to induce hepatic peroxisomal proliferation and range from very weak to very potent hepatocarcinogens. Unlike most identified carcinogens, the hypolipidemic carcinogens lack DNA reactivity in sensitive cell culture systems such as the Ames test. It has been proposed that active oxygen radicals, produced as a result of peroxisomal proliferation, induce DNA damage. While this is an attractive hypothesis, no genotoxic activity has been observed in hepatocytes with peroxisomal proliferation in treated animals. Another biological activity shared by this class of compounds is their ability to stimulate liver growth or hyperplasia. This additive hyperplasia results from direct mitogenic stimulation rather than regenerative growth following liver toxicity. This hyperplasia can be dramatic, with liver to body weight ratios from treated animals reaching two to three times normal. The degree of induced hyperplasia correlates well with the carcinogenic potency of these agents, whereas genotoxicity does not correlate at all. Increased cellular growth may result in spontaneous mutational events or promotional effects. While some feedback mechanism eventually inhibits liver growth, it is possible that key genes related to the regulation of cellular growth and cancer remain stimulated during continued administration of the chemical. Thus, determination of hyperplastic activity represents an attractive first-step approach to the short-term detection and study of the mode of action of nongenotoxic carcinogens.
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Feller DR, Singh Y, Shirhatti VR, Kocarek TA, Liu CT, Krishna G. Characterization of ciprofibrate and clofibric acid as peroxisomal proliferators in primary cultures of rat hepatocytes. Hepatology 1987; 7:508-16. [PMID: 3570161 DOI: 10.1002/hep.1840070316] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We have determined the comparative activities of peroxisomal proliferators, ciprofibrate and clofibric acid on various hepatic parameters associated with endoplasmic reticulum, mitochondria and peroxisomes in primary cultures of rat hepatocytes. We have measured the activities of carnitine acetyltransferase and fatty acylCoA oxidase, and the amount of 60 and 80 kD polypeptides as biochemical markers of the peroxisomal function; laurate hydroxylase and cytochrome P-450 as markers of the endoplasmic reticulum; and carnitine palmitoyltransferase as a marker of mitochondria in primary cultures of hepatocytes. Ciprofibrate (0.01 to 0.3 mM) and clofibric acid (0.1 to 3 mM) produced similar changes in several components of cultured hepatocytes within 72 hr. Increases of protein (18 and 11%), carnitine palmitoyltransferase (23 and 97%), cytochrome P-450 (37 and 49%), carnitine acetyltransferase (484 and 614%), fatty acylCoA oxidase (529 and 931%) and laurate hydroxylase (624 and 671%) were obtained in hepatocytes after a 72-hr exposure to 0.1 mM ciprofibrate and 1.0 mM clofibric acid, respectively. In cultured hepatocytes, ciprofibrate was about 30-fold more active than clofibric acid for the stimulation of carnitine acetyltransferase, laurate hydroxylase and fatty acylCoA oxidase activities. Ciprofibrate was also more potent than clofibric acid as an inducer of the 60 and 80 kD proteins in hepatocytes. The maximal drug-induced increases in carnitine acetyltransferase activity were not additive, and the induction of carnitine acetyltransferase by ciprofibrate was blocked by addition (1 micrograms per ml) of cycloheximide or actinomycin D. Changes in protein and RNA synthesis preceded the drug-induced increases of carnitine acetyltransferase activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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Bentley P, Bieri F, Mitchell F, Waechter F, Stäubli W. Investigations on the mechanism of liver tumour induction by peroxisome proliferators. ARCHIVES OF TOXICOLOGY. SUPPLEMENT. = ARCHIV FUR TOXIKOLOGIE. SUPPLEMENT 1987; 10:157-61. [PMID: 3495251 DOI: 10.1007/978-3-642-71617-1_14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Further understanding of the mechanism by which peroxisome proliferators induce liver tumours is essential to assessing the risks of such compounds to exposed humans. To this end the effects of nafenopin upon the liver have been investigated. Nafenopin was shown to induce certain drug metabolising enzymes, but sub-cellular fractions from induced animals did not form reactive metabolites which could be detected as mutagens. Nafenopin treatment slightly increased the rate of alkaline elution of hepatic nuclear DNA from polycarbonate filters. However, simultaneous administration of sodium glycolate to stimulate H2O2 production or pyrazole to inhibit catalase activity had no further effects. These findings demonstrate that nafenopin is not activated to a mutagen and argue against the hypothesis that indirect DNA damage as a result of excess H2O2 production is responsible for tumour induction.
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46
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Hawkins JM, Jones WE, Bonner FW, Gibson GG. The effect of peroxisome proliferators on microsomal, peroxisomal, and mitochondrial enzyme activities in the liver and kidney. Drug Metab Rev 1987; 18:441-515. [PMID: 3286171 DOI: 10.3109/03602538708994130] [Citation(s) in RCA: 185] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- J M Hawkins
- Biochemistry Department, University of Surrey, England, U.K
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47
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Hyslop PA, Hinshaw DB, Schraufstätter IU, Sklar LA, Spragg RG, Cochrane CG. Intracellular calcium homeostasis during hydrogen peroxide injury to cultured P388D1 cells. J Cell Physiol 1986; 129:356-66. [PMID: 3782310 DOI: 10.1002/jcp.1041290314] [Citation(s) in RCA: 102] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The effects of exposure of cultured P388D1 cells to H2O2 on intracellular free calcium ([Ca++]i) was investigated utilizing the intracellular fluorescent calcium chelator "Quin 2." [Ca++]i rose from approximately 150 nM to greater than 2 microM over a time course that was strongly dependent on the concentration of H2O2 used (5 X 10(-5) to 5 X 10(-3) M). After exposure of P388D1 cells to 5 X 10(-3) M H2O2, Quin 2 was fully saturated between 15 and 30 min exposure. During this time, no apparent change in the rate of equilibration of 45Ca++ from the extracellular medium could be detected, whereas in cells preloaded with 45Ca, net 45Ca was lost from the cells at a greater rate than controls. Measurements of total cellular calcium by atomic absorption spectroscopy confirmed that there was a net loss of calcium from the cells during the first 30 min. At time points greater than 45 min after exposure to H2O2 the influx of extracellular 45Ca and net intracellular Ca++, Na+ and K+ rapidly increased. Half times for H2O2 catabolism by the cells varied from about 8 min at 5.0 X 10(-4) M H2O2 to 14.0 min at 5.0 X 10(-3) M. When the total [Ca++]i-buffering capacity of the Quin 2 pool was varied by increasing the loading of intracellular Quin 2 by 68-fold (1.1 X 10(2) - 7.6 X 10(3) amol per cell), the rate of rise of [Ca++]i was depressed by only 1.6-fold following exposure to 5 mM H2O2. During the rise of intracellular [Ca++]i, cell morphology was observed by both light and scanning electron microscopy and revealed that "surface blebs" appeared during this phase of injury. Both the rise in [Ca++]i and "blebbing" were observable before any loss in cell viability was detected by either loss of Trypan blue exclusion or loss of preloaded 51Cr from the cells. From these results we conclude the following, H2O2 exposure induces a dose-dependent disturbance of intracellular calcium homeostatis; the rise in [Ca++]i is mediated by exposure to H2O2 in the early phase of the injury, and is not dependent on the continuing presence of the oxidant; the rate of rise of [Ca++]i is largely independent of the quantity of calcium mobilized to the Quin 2 pool; during the early phase (less than 30 min) of rise of [Ca++]i, only intracellular calcium is involved in the response; these events occur concomitantly with gross morphological changes to the plasma membrane.(ABSTRACT TRUNCATED AT 400 WORDS)
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48
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Reddy JK, Goel SK, Nemali MR, Carrino JJ, Laffler TG, Reddy MK, Sperbeck SJ, Osumi T, Hashimoto T, Lalwani ND. Transcription regulation of peroxisomal fatty acyl-CoA oxidase and enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase in rat liver by peroxisome proliferators. Proc Natl Acad Sci U S A 1986; 83:1747-51. [PMID: 3456610 PMCID: PMC323161 DOI: 10.1073/pnas.83.6.1747] [Citation(s) in RCA: 237] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The structurally diverse peroxisome proliferators ciprofibrate, clofibrate, and bis(2-ethylhexyl) phthalate [(EtHx)2 greater than Pht] increase the activities of hepatic catalase and peroxisomal fatty acid beta-oxidation enzymes in conjunction with profound proliferation of peroxisomes in hepatocytes. In order to delineate the level at which these enzymes are induced in the liver, the transcriptional activity of specific genes for fatty acyl-CoA oxidase (FAOxase) and enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase bifunctional enzyme (PBE), the first two enzymes of the peroxisomal beta-oxidation system, and for catalase were measured in isolated hepatocyte nuclei obtained from male rats following a single intragastric dose of ciprofibrate, clofibrate, or (EtHx)2 greater than Pht. All three peroxisome proliferators rapidly increased the rate of FAOxase and PBE gene transcription in liver, with near maximal rates (9-15 times control) reached by 1 hr and persisting until at least 16 hr after administration of the compound. FAOxase and PBE mRNA levels, measured by blot-hybridization analysis and FAOxase and PBE protein content, analyzed by immunoblotting, increased concurrently up to at least 16 hr following a single dose of peroxisome proliferator. The catalase mRNA level increased about 1.4-fold, but the transcription rate of the catalase gene was not significantly affected. The results show that the peroxisome proliferators clofibrate, ciprofibrate, and (EtHx)2 greater than Pht selectively increase the rate of transcription of peroxisomal fatty acid beta-oxidation enzyme genes. Whether the transcriptional effects are mediated by peroxisome proliferator-receptor complexes remains to be elucidated.
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49
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Reddy JK, Reddy MK, Usman MI, Lalwani ND, Rao MS. Comparison of hepatic peroxisome proliferative effect and its implication for hepatocarcinogenicity of phthalate esters, di(2-ethylhexyl) phthalate, and di(2-ethylhexyl) adipate with a hypolipidemic drug. ENVIRONMENTAL HEALTH PERSPECTIVES 1986; 65:317-327. [PMID: 3709457 PMCID: PMC1474684 DOI: 10.1289/ehp.8665317] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Peroxisome proliferation is inducible in hepatocytes of rodent and nonrodent species by structurally dissimilar hypolipidemic drugs and certain phthalate ester plasticizers. The induction of peroxisome proliferation appears to be a tissue specific response limited largely to the hepatocyte. Peroxisome proliferation is associated with increases in the activity of the H2O2-generating peroxisomal fatty acid beta-oxidation system and in the amount of peroxisome proliferation-associated 80,000 MW polypeptide (PPA-80). Chronic administration of these non-DNA damaging and nonmutagenic peroxisome proliferators to rats and mice results in the development of hepatocellular carcinomas. Comparative morphometric and biochemical data from rats treated with varying dose levels of ciprofibrate, a hypolipidemic drug, and di(2-ethylhexyl) phthalate, and di(2-ethylhexyl) adipate, the widely used plasticizers, indicate that the hepatocarcinogenic potency of these agents is correlatable with their ability to induce peroxisome proliferation, peroxisomal beta-oxidation and PPA-80. Available evidence strongly favors the role of peroxisome proliferation-associated oxidative stress in the induction of liver tumors by peroxisome proliferators.
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50
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Lillehaug JR, Berge RK. The tumour promoter 12-O-tetradecanoylphorbol-13-acetate increases the activities of some peroxisome-associated enzymes in in vitro cell culture. Br J Cancer 1986; 53:121-7. [PMID: 2868750 PMCID: PMC2001463 DOI: 10.1038/bjc.1986.17] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
A study was conducted on the effects of 12-O-tetradecanoyl-phorbol-13-acetate (TPA) on peroxisomal enzyme activities in mouse embryo fibroblasts C3H/10T1/2 C18 cells and chemically transformed C3H/10T1/2 MCA16 cells. TPA is a potent tumour promoter and treatment with this compound of the two cell lines induced peroxisomal fatty acid beta-oxidation, carnitine acetyltransferase, palmitoyl-CoA hydrolase, and catalase activities after 240 h of treatment. Stimulation of the corresponding enzyme activities was dose-related and cycloheximide inhibited the TPA-induced enzyme activities, except that of carnitine acetyltransferase. The MCA16 cells appeared to be more sensitive than the C18 cells in inducing peroxisome-associated enzyme activities after TPA treatment. The activities of the microsomal marker, NADPH-cytochrome c reductase and the mitochondrial marker, glutamate dehydrogenase were not enhanced by TPA treatment. The results indicate that TPA has peroxisomal effects and may be classified as a peroxisome proliferator.
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