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Harris KL, Harris KJ, Banks LD, Adunyah SE, Ramesh A. Acceleration of benzo(a)pyrene-induced colon carcinogenesis by Western diet in a rat model of colon cancer. Curr Res Toxicol 2024; 6:100162. [PMID: 38496007 PMCID: PMC10943645 DOI: 10.1016/j.crtox.2024.100162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 03/02/2024] [Accepted: 03/06/2024] [Indexed: 03/19/2024] Open
Abstract
Colorectal cancer (CRC) is the third leading cause of cancer-related mortalities in the USA and around 52,550 people were expected to die from this disease by December 2023. The objective of this study was to investigate the effect of diet type on benzo(a)pyrene [B(a)P]-induced colon cancer in an adult male rat model, the Polyposis In the Rat Colon (PIRC) kindred type. Groups of PIRC rats (n = 10) were fed with AIN-76A regular diet (RD) or Western diet (WD) and received 25, 50 and 100 µg B(a)P/kg body wt. via oral gavage for 60 days. Rats fed diets alone, but no B(a)P, served as controls. After exposure, rats were euthanized; colon and liver samples were analyzed for activation of drug metabolizing enzymes (DMEs) CYP1A1, CYP1B1, SULT and GST. Plasma and tissue samples were analyzed by reverse phase-HPLC for B(a)P metabolites. In addition to these studies, DNA isolated from colon and liver tissues was analyzed for B(a)P-induced DNA adducts by the 32P-postlabeling method using a thin-layer chromatography system. Western diet consumption resulted in a marked increase in DME expression and B(a)P metabolite concentrations in rats that were administered 100 µg/kg B(a)P + WD (p < 0.05) compared to other treatment groups. Our findings demonstrate that WD accelerates the development of colon tumors induced by B(a)P through enhanced biotransformation, and the products of this process (metabolites) were found to bind with DNA and form B(a)P-DNA adducts, which may have given rise to colon polyps characterized by gain in tumor number, sizes, and dysplasia.
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Affiliation(s)
- Kelly L Harris
- Department of Biochemistry, Cancer Biology, Neuroscience & Pharmacology, Meharry Medical College, 1005 D.B. Todd Blvd., Nashville, TN 37208, United States
| | - Kenneth J Harris
- Department of Biochemistry, Cancer Biology, Neuroscience & Pharmacology, Meharry Medical College, 1005 D.B. Todd Blvd., Nashville, TN 37208, United States
| | - Leah D Banks
- Department of Biochemistry, Cancer Biology, Neuroscience & Pharmacology, Meharry Medical College, 1005 D.B. Todd Blvd., Nashville, TN 37208, United States
| | - Samuel E Adunyah
- Department of Biochemistry, Cancer Biology, Neuroscience & Pharmacology, Meharry Medical College, 1005 D.B. Todd Blvd., Nashville, TN 37208, United States
| | - Aramandla Ramesh
- Department of Biochemistry, Cancer Biology, Neuroscience & Pharmacology, Meharry Medical College, 1005 D.B. Todd Blvd., Nashville, TN 37208, United States
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Pilot Metabolome-Wide Association Study of Benzo(a)pyrene in Serum From Military Personnel. J Occup Environ Med 2018; 58:S44-52. [PMID: 27501104 DOI: 10.1097/jom.0000000000000772] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE A pilot study was conducted to test the feasibility of using Department of Defense Serum Repository (DoDSR) samples to study health and exposure-related effects. METHODS Thirty unidentified human serum samples were obtained from the DoDSR and analyzed for normal serum metabolites with high-resolution mass spectrometry and serum levels of free benzo(a)pyrene (BaP) by gas chromatography-mass spectrometry. Metabolic associations with BaP were determined using a metabolome-wide association study (MWAS) and metabolic pathway enrichment. RESULTS The serum analysis detected normal ranges of glucose, selected amino acids, fatty acids, and creatinine. Free BaP was detected in a broad concentration range. MWAS of BaP showed associations with lipids, fatty acids, and sulfur amino acid metabolic pathways. CONCLUSION The results show that the DoDSR samples are of sufficient quality for chemical profiling of DoD personnel.
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Kim MS, Min HG, Koo N, Park J, Lee SH, Bak GI, Kim JG. The effectiveness of spent coffee grounds and its biochar on the amelioration of heavy metals-contaminated water and soil using chemical and biological assessments. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2014; 146:124-130. [PMID: 25242543 DOI: 10.1016/j.jenvman.2014.07.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 06/30/2014] [Accepted: 07/03/2014] [Indexed: 05/22/2023]
Abstract
Spent coffee grounds (SCG) and charred spent coffee grounds (SCG-char) have been widely used to adsorb or to amend heavy metals that contaminate water or soil and their success is usually assessed by chemical analysis. In this work, the effects of SCG and SCG-char on metal-contaminated water and soil were evaluated using chemical and biological assessments; a phytotoxicity test using bok choy (Brassica campestris L. ssp. chinensis Jusl.) was conducted for the biological assessment. When SCG and SCG-char were applied to acid mine drainage, the heavy metal concentrations were decreased and the pH was increased. However, for SCG, the phytotoxicity increased because a massive amount of dissolved organic carbon was released from SCG. In contrast, SCG-char did not exhibit this phenomenon because any easily released organic matter was removed during pyrolysis. While the bioavailable heavy metal content decreased in soils treated with SCG or SCG-char, the phytotoxicity only rose after SCG treatment. According to our statistical methodology, bioavailable Pb, Cu and As, as well as the electrical conductivity representing an increase in organic content, affected the phytotoxicity of soil. Therefore, applying SCG during environment remediation requires careful biological assessments and evaluations of the efficiency of this remediation technology.
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Affiliation(s)
- Min-Suk Kim
- Division of Environmental Science and Ecological Engineering, College of Life and Environmental Sciences, Korea University, Seoul 136-713, Republic of Korea
| | - Hyun-Gi Min
- Division of Environmental Science and Ecological Engineering, College of Life and Environmental Sciences, Korea University, Seoul 136-713, Republic of Korea
| | - Namin Koo
- Division of Forest Soil & Water Conservation, Korea Forest Research Institute, Seoul 130-712, Republic of Korea
| | - Jeongsik Park
- Environmental Safety Team, Chemistry Environmental Headquarter, Korea Testing & Research Institute, Gimpo-si 415-873, Republic of Korea
| | - Sang-Hwan Lee
- Technology Research Center, Mine Reclamation Corporation, Cheonan-si 331-800, Republic of Korea
| | - Gwan-In Bak
- Technology Research Center, Mine Reclamation Corporation, Cheonan-si 331-800, Republic of Korea
| | - Jeong-Gyu Kim
- Division of Environmental Science and Ecological Engineering, College of Life and Environmental Sciences, Korea University, Seoul 136-713, Republic of Korea.
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Uno S, Sakurai K, Nebert DW, Makishima M. Protective role of cytochrome P450 1A1 (CYP1A1) against benzo[a]pyrene-induced toxicity in mouse aorta. Toxicology 2014; 316:34-42. [PMID: 24394547 DOI: 10.1016/j.tox.2013.12.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 12/19/2013] [Accepted: 12/22/2013] [Indexed: 12/20/2022]
Abstract
Benzo[a]pyrene (BaP) is an environmental pollutant produced by combustive processes, such as cigarette smoke and coke ovens, and is implicated in the pathogenesis of atherosclerosis. Cytochrome P450 1A1 (CYP1A1) plays a role in both metabolic activation and detoxication of BaP in a context-dependent manner. The role of CYP1A1 in BaP-induced toxicity in aorta remains unknown. First, we fed Apoe⁻/⁻ mice an atherogenic diet plus BaP and found that oral BaP-enhanced atherosclerosis is associated with increased reactive oxygen species (ROS) and inflammatory markers, such as plasma tumor necrosis factor levels and aortic mRNA expression of vascular endothelial growth factor A (Vegfa). We next examined the effect of an atherogenic diet plus BaP on ROS and inflammatory markers in Cyp1a1⁻/⁻ mice. Although this treatment was not sufficient to induce atherosclerotic lesions in Cyp1a1⁻/⁻ mice, plasma antioxidant levels were decreased in Cyp1a1⁻/⁻ mice even in the absence of BaP treatment. The atherogenic diet plus BaP effectively elevated plasma ROS levels and expression of atherosclerosis-related genes, specifically Vegfa, in Cyp1a1⁻/⁻ mice compared with wild-type mice. BaP treatment increased Vegfa mRNA levels in mouse embryonic fibroblasts from Cyp1a1⁻/⁻ mice but not from wild-type mice. BaP-induced DNA adduct formation was increased in the aorta of Cyp1a1⁻/⁻ mice, but not wild-type or Apoe⁻/⁻ mice, and the atherogenic diet decreased BaP-induced DNA adducts in Cyp1a1⁻/⁻ mice compared with mice on a control diet. These data suggest that ROS production contributes to BaP-exacerbated atherosclerosis and that CYP1A1 plays a protective role against oral BaP toxicity in aorta.
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Affiliation(s)
- Shigeyuki Uno
- Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, Itabashi-ku, Tokyo 173-8610, Japan
| | - Kenichi Sakurai
- Division of Breast and Endocrine Surgery, Department of Surgery, Nihon University School of Medicine, Itabashi-ku, Tokyo 173-8610, Japan
| | - Daniel W Nebert
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, P.O. Box 670056, Cincinnati, OH 45267-0056, USA
| | - Makoto Makishima
- Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, Itabashi-ku, Tokyo 173-8610, Japan.
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Diggs DL, Myers JN, Banks LD, Niaz MS, Hood DB, Roberts LJ, Ramesh A. Influence of dietary fat type on benzo(a)pyrene [B(a)P] biotransformation in a B(a)P-induced mouse model of colon cancer. J Nutr Biochem 2013; 24:2051-63. [PMID: 24231098 PMCID: PMC3904801 DOI: 10.1016/j.jnutbio.2013.07.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 07/06/2013] [Accepted: 07/17/2013] [Indexed: 02/06/2023]
Abstract
In the US alone, around 60,000 lives/year are lost due to colon cancer. Diet and environment have been implicated in the development of sporadic colon tumors. The objective of this study was to determine how dietary fat potentiates the development of colon tumors through altered B(a)P biotransformation, using the Adenomatous polyposis coli with Multiple intestinal neoplasia mouse model. Benzo(a)pyrene was administered to mice through tricaprylin, and unsaturated (USF; peanut oil) and saturated (SF; coconut oil) fats at doses of 50 and 100 μg/kg via oral gavage over a 60-day period. Blood, colon, and liver were collected at the end of exposure period. The expression of B(a)P biotransformation enzymes [cytochrome P450 (CYP)1A1, CYP1B1 and glutathione-S-transferase] in liver and colon were assayed at the level of protein, mRNA and activities. Plasma and tissue samples were analyzed by reverse phase high-performance liquid chromatography for B(a)P metabolites. Additionally, DNA isolated from colon and liver tissues was analyzed for B(a)P-induced DNA adducts by the (32)P-postlabeling method using a thin-layer chromatography system. Benzo(a)pyrene exposure through dietary fat altered its metabolic fate in a dose-dependent manner, with 100 μg/kg dose group registering an elevated expression of B(a)P biotransformation enzymes, and greater concentration of B(a)P metabolites, compared to the 50 μg/kg dose group (P<.05). This effect was more pronounced for SF group compared to USF group (P<.05). These findings establish that SF causes sustained induction of B(a)P biotransformation enzymes and extensive metabolism of this toxicant. As a consequence, B(a)P metabolites were generated to a greater extent in colon and liver, whose concentrations also registered a dose-dependent increase. These metabolites were found to bind with DNA and form B(a)P-DNA adducts, which may have contributed to colon tumors in a subchronic exposure regimen.
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Affiliation(s)
- Deacqunita L. Diggs
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208
| | - Jeremy N. Myers
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208
| | - Leah D. Banks
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208
| | - Mohammad S. Niaz
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208
| | - Darryl B. Hood
- Department of Neuroscience and Pharmacology, Meharry Medical College,Nashville, TN 37208
| | - L. Jackson Roberts
- Departments of Pharmacology and Medicine, Pathology, Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Aramandla Ramesh
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208
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Wilk A, Waligórski P, Lassak A, Vashistha H, Lirette D, Tate D, Zea AH, Koochekpour S, Rodriguez P, Meggs LG, Estrada JJ, Ochoa A, Reiss K. Polycyclic aromatic hydrocarbons-induced ROS accumulation enhances mutagenic potential of T-antigen from human polyomavirus JC. J Cell Physiol 2013; 228:2127-38. [PMID: 23558788 DOI: 10.1002/jcp.24375] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 03/28/2013] [Indexed: 01/28/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are the products of incomplete combustion of organic materials, which are present in cigarette smoke, deep-fried food, and in natural crude oil. Since PAH-metabolites form DNA adducts and cause oxidative DNA damage, we asked if these environmental carcinogens could affect transforming potential of the human Polyomavirus JC oncoprotein, T-antigen (JCV T-antigen). We extracted DMSO soluble PAHs from Deepwater Horizon oil spill in the Gulf of Mexico (oil-PAHs), and detected several carcinogenic PAHs. The oil-PAHs were tested in exponentially growing cultures of normal mouse fibroblasts (R508), and in R508 stably expressing JCV T-antigen (R508/T). The oil-PAHs were cytotoxic only at relatively high doses (1:50-1:100 dilution), and at 1:500 dilution the growth and cell survival rates were practically unaffected. This non-toxic dose triggered however, a significant accumulation of reactive oxygen species (ROS), caused oxidative DNA damage and the formation of DNA double strand breaks (DSBs). Although oil-PAHs induced similar levels of DNA damage in R508 and R508/T cells, only T-antigen expressing cells demonstrated inhibition of high fidelity DNA repair by homologous recombination (HRR). In contrast, low-fidelity repair by non-homologous end joining (NHEJ) was unaffected. This potential mutagenic shift between DNA repair mechanisms was accompanied by a significant increase in clonal growth of R508/T cells chronically exposed to low doses of the oil-PAHs. Our results indicate for the first time carcinogenic synergy in which oil-PAHs trigger oxidative DNA damage and JCV T-antigen compromises DNA repair fidelity.
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Affiliation(s)
- Anna Wilk
- Neurological Cancer Research at Stanley S Scott Cancer Center, New Orleans, Louisiana, USA
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Qiu C, Cheng S, Xia Y, Peng B, Tang Q, Tu B. Effects of subchronic benzo(a)pyrene exposure on neurotransmitter receptor gene expression in the rats hippocampus related with spatial learning and memory change. Toxicology 2011; 289:83-90. [DOI: 10.1016/j.tox.2011.07.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Revised: 07/18/2011] [Accepted: 07/28/2011] [Indexed: 10/17/2022]
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La Merrill M, Stein CR, Landrigan P, Engel SM, Savitz DA. Prepregnancy body mass index, smoking during pregnancy, and infant birth weight. Ann Epidemiol 2011; 21:413-20. [PMID: 21421328 PMCID: PMC3090467 DOI: 10.1016/j.annepidem.2010.11.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 11/23/2010] [Accepted: 11/30/2010] [Indexed: 11/23/2022]
Abstract
PURPOSE Smoking during pregnancy is strongly associated with increased risk of small for gestational age (SGA) and low birth weight, whereas elevated prepregnancy body mass index (BMI) is associated with a decreased risk of SGA and greater birth weight. We investigated the combined effect of prenatal smoking and prepregnancy BMI on risk of SGA and on birth weight. METHODS A total of 34,928 singleton, term pregnancies in residents of New York City between 1995 and 2003 were evaluated in multivariable regression models of birth weight and risk of SGA. RESULTS Increasing prepregnancy BMI reduced the risk of SGA and increased birth weight. The effect of prenatal smoking on birth weight and SGA diminished in women as their prepregnancy BMI increased, such that prenatal smoking did not significantly impact the risk of SGA among women who were overweight or obese before pregnancy. Prenatal smoking decreased mean birth weight by 187 g (95% confidence interval [CI] -337, -37) among underweight women, by 129 g(95% CI -170, -87) among normal weight women, by 46 g (95% CI -113, +20) among overweight women, and by 75 g (95% CI -162, +11) among obese women. CONCLUSIONS This study suggests that the effect of smoking during pregnancy on SGA and birth weight is present in underweight and normal weight women but markedly reduced among obese and overweight women.
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Affiliation(s)
- Michele La Merrill
- Department of Preventive Medicine, Mount Sinai School of Medicine, New York, NY.
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Dimitrova-Shumkovska J, Veenman L, Ristoski T, Leschiner S, Gavish M. Dimethylbenz[α]anthracene induces oxidative stress and reduces the binding capacity of the mitochondrial 18-kDa translocator protein in rat aorta. Drug Chem Toxicol 2010; 33:337-47. [DOI: 10.3109/01480540903483441] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Walker SA, Ramesh A. RELATIONSHIP BETWEEN DIETARY FAT TYPE AND METABOLIC FATE OF FLUORANTHENE IN F-344 RATS. Polycycl Aromat Compd 2009. [DOI: 10.1080/10406630903127069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Knaapen AM, Curfs DM, Pachen DM, Gottschalk RW, de Winther MPJ, Daemen MJ, Van Schooten FJ. The environmental carcinogen benzo[a]pyrene induces expression of monocyte-chemoattractant protein-1 in vascular tissue: a possible role in atherogenesis. Mutat Res 2007; 621:31-41. [PMID: 17376491 DOI: 10.1016/j.mrfmmm.2006.12.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Revised: 12/12/2006] [Accepted: 12/13/2006] [Indexed: 01/07/2023]
Abstract
Exposure to carcinogenic polycyclic aromatic hydrocarbons (PAHs) has been implicated in the aetiology of atherosclerosis. Previously we showed that chronic exposure of ApoE-/- mice to the prototype PAH benzo[a]pyrene (B[a]P) causes enhanced progression of atherosclerosis, which was characterised by an increased inflammatory cell content in the atherosclerotic plaques. The aim of the present study was to evaluate the effect of B[a]P on vascular expression of monocyte-chemoattractant protein 1 (MCP-1), which is a crucial molecule promoting the recruitment of monocytes into atherosclerotic lesions. We hypothesised that B[a]P-induced expression of MCP-1 is mediated through aryl hydrocarbon receptor (AhR) activation. Initially we performed in vivo studies showing that acute treatment with B[a]P induces MCP-1 gene expression in aortic tissue of ApoE-/- mice. These observations could be confirmed by in vitro studies with human endothelial cells (RF24 cell line and primary HUVEC), showing a dose- and time-dependent increase in MCP-1 expression upon exposure to B[a]P. This was paralleled by an induction of cytochrome P450 1A1 and 1B1, indicating Ah receptor activation. No increased gene expression (MCP-1, CYP1A1 and 1B1) was found upon incubation with the structural isomer benzo[e]pyrene, which is a weak AhR agonist. Moreover, B[a]P-induced MCP-1 gene and protein expression was inhibited by co-treatment with the AhR antagonist alpha-naphthoflavone. In addition to its effect on basal gene expression, we showed that B[a]P significantly enhanced TNFalpha-induced expression of MCP-1. We were unable to block B[a]P-induced MCP-1 expression by antioxidant treatment. In contrast, we found that addition of N-acetylcysteine or vitamin C enhanced transcription of MCP-1 by B[a]P. In conclusion, our studies revealed potent vascular pro-inflammatory effects of B[a]P, as evidenced by AhR-mediated induction of MCP-1. These observations further contribute to the concept that induction of inflammation is a crucial process in PAH-enhanced atherogenesis.
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Affiliation(s)
- Ad M Knaapen
- Department of Health Risk Analysis and Toxicology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), The Netherlands.
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Curfs DMJ, Knaapen AM, Pachen DMFA, Gijbels MJJ, Lutgens E, Smook MLF, Kockx MM, Daemen MJAP, van Schooten FJ. Polycyclic aromatic hydrocarbons induce an inflammatory atherosclerotic plaque phenotype irrespective of their DNA binding properties. FASEB J 2005; 19:1290-2. [PMID: 15939734 DOI: 10.1096/fj.04-2269fje] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Although it has been demonstrated that carcinogenic environmental polycyclic aromatic hydrocarbons (PAHs) cause progression of atherosclerosis, the underlying mechanism remains unclear. In the present study, we aimed to investigate whether DNA binding events are critically involved in the progression of PAH-mediated atherogenesis. Apolipoprotein E knockout mice were orally (24 wk, once/wk) exposed to 5 mg/kg benzo[a]pyrene (B[a]P), or its nonmutagenic, noncarcinogenic structural isoform benzo[e]pyrene (B[e]P). 32P-postlabeling of lung tissue confirmed the presence of promutagenic PAH-DNA adducts in B[a]P-exposed animals, whereas in B[e]P-exposed and vehicle control animals, these adducts were undetectable. Morphometrical analysis showed that both B[a]P and B[e]P caused an increase in plaque size, whereas location or number of plaques was unaffected. Immunohistochemistry revealed no differences in oxidative DNA damage (8-OHdG) or apoptosis in the plaques. Also plasma lipoprotein levels remained unchanged after PAH-exposure. However, T lymphocytes were increased > or =2-fold in the plaques of B[a]P- and B[e]P-exposed animals. Additionally, B[a]P and to a lesser extent B[e]P exposure resulted in increased TGFbeta protein levels in the plaques, that was mainly localized in the plaque macrophages. In vitro studies using the murine macrophage like RAW264.7 cells showed that inhibition of TGFbeta resulted in decreased tumor necrosis factor (TNF) alpha release, suggesting that enhanced TGFbeta expression in the plaque macrophages contributes to the proinflammatory effects in the vessel wall. In general, this inflammatory reaction in the plaques appeared to be a local response since peripheral blood cell composition (T cells, B cells, granulocytes, and macrophages) was not changed upon PAH exposure. In conclusion, we showed that both B[a]P and B[e]P cause progression of atherosclerosis, irrespective of their DNA binding properties. Moreover, our data revealed a possible novel mechanism of PAH-mediated atherogenesis, which likely involves a TGFbeta-mediated local inflammatory reaction in the vessel wall.
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Affiliation(s)
- Daniëlle M J Curfs
- Department of Health Risk Analysis and Toxicology, University of Maastricht, Maastricht, The Netherlands
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