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Bhandari D, Zhu Y, Zhang C, Zhu W, Alexandridis A, Etemadi A, Freedman ND, Chang C, Abnet CC, Dawsey SM, Inoue-Choi M, Poustchi H, Pourshams A, Boffetta P, Malekzadeh R, Blount B. Smoke exposure associated with higher urinary benzene biomarker muconic acid (MUCA) in Golestan Cohort Study participants. Biomarkers 2023; 28:637-642. [PMID: 37878492 DOI: 10.1080/1354750x.2023.2276030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 10/22/2023] [Indexed: 10/27/2023]
Abstract
Background. Benzene is a known human carcinogen. Human exposure to benzene can be assessed by measuring trans, trans-muconic acid (MUCA) in urine. Golestan Province in northeastern Iran has been reported to have high incidence of esophageal cancer linked to the use of tobacco products. This manuscript evaluates the urinary MUCA concentrations among the participants of the Golestan Cohort Study (GCS).Methods. We analyzed MUCA concentration in 177 GCS participants' urine samples and performed nonparametric pairwise multiple comparisons to determine statistically significant difference among six different product use groups. Mixed effects model was fitted on 22 participants who exclusively smoked cigarette and 51 participants who were classified as nonusers. The urinary MUCA data were collected at the baseline and approximately five years later, and intraclass correlation coefficient (ICC) was calculated from the model.Results. Compared with nonusers, tobacco smoking was associated with higher urinary MUCA concentrations. Based on the nonparametric test of pairwise multiple comparisons, MUCA concentrations among participants who smoked combusted tobacco products were statistically significantly higher compared to nonusers. Urinary MUCA collected five years apart from the same individuals showed moderate reliability (ICC = 0.41), which was expected given the relatively short half-life (∼6 h) of MUCA.Conclusion. Our study revealed that tobacco smoke was positively associated with increased levels of urinary MUCA concentration, indicating that it is a significant source of benzene exposure among GCS participants.
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Affiliation(s)
- Deepak Bhandari
- Tobacco and Volatiles Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Yuyang Zhu
- Tobacco and Volatiles Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Can Zhang
- Tobacco and Volatiles Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Wanzhe Zhu
- Tobacco and Volatiles Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | - Arash Etemadi
- Metabolic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- Digestive Oncology Research Center, Digestive Diseases Research Institute, Tehran University of Medical Sciences, Tehran
| | - Neal D Freedman
- Metabolic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Cindy Chang
- Center for Tobacco Products, Food and Drug Administration, Silver Spring, MD, USA
| | - Christian C Abnet
- Metabolic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Sanford M Dawsey
- Metabolic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Maki Inoue-Choi
- Metabolic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Hossein Poustchi
- Digestive Oncology Research Center, Digestive Diseases Research Institute, Tehran University of Medical Sciences, Tehran
| | - Akram Pourshams
- Digestive Oncology Research Center, Digestive Diseases Research Institute, Tehran University of Medical Sciences, Tehran
| | - Paolo Boffetta
- Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY, USA
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Reza Malekzadeh
- Digestive Oncology Research Center, Digestive Diseases Research Institute, Tehran University of Medical Sciences, Tehran
| | - Benjamin Blount
- Tobacco and Volatiles Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Shu N, Lorentzen LG, Davies MJ. Reaction of quinones with proteins: Kinetics of adduct formation, effects on enzymatic activity and protein structure, and potential reversibility of modifications. Free Radic Biol Med 2019; 137:169-180. [PMID: 31026584 DOI: 10.1016/j.freeradbiomed.2019.04.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 04/22/2019] [Accepted: 04/22/2019] [Indexed: 01/08/2023]
Abstract
Quinones are a common motif in many biological compounds, and have been linked to tissue damage as they can undergo redox cycling to generate radicals, and/or act as Michael acceptors with nucleophiles, such as protein Cys residues, with consequent adduct formation. The kinetics and consequences of these Michael reactions are poorly characterized. In this study we hypothesized that adduction of protein Cys residues with quinones would be rapid, structure-dependent, quantitatively-significant, and result in altered protein structure and function. Multiple quinones were incubated with glyceraldehyde-3-phosphate dehydrogenase (GAPDH), creatine kinase (CK), papain, bovine (BSA) and human (HSA) serum albumins, with the kinetics of adduction and effects on protein structure and activity determined. Adduction rate constants at Cys residues, which were dependent on the quinone and protein structure, and thiol pKa, are in the range 102-105 M-1 s-1. p-Benzoquinone (BQ) induced dimerization of GAPDH and CK (but not BSA, HSA, or papain) in a dose- and time-dependent manner. Incubation of purified proteins, or cell lysates, with quinones resulted in a rapid loss of GAPDH and CK activity; this loss correlated well with the rate constant for Cys adduction. Glutathione (GSH) reacts competitively with quinones, and could reverse the loss of activity and dimerization of GAPDH and CK. Mass spectrometry peptide mass mapping provided evidence for BQ adduction to GAPDH to specific Cys residues (Cys149, Cys244), whereas all Cys residues in CK were modified. These data suggested that quinones can induce biological effects by rapid and selective formation of adducts with Cys residues in proteins.
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Affiliation(s)
- Nan Shu
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Lasse G Lorentzen
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark.
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Jurica K, Brčić Karačonji I, Kopjar N, Shek-Vugrovečki A, Cikač T, Benković V. The effects of strawberry tree water leaf extract, arbutin and hydroquinone on haematological parameters and levels of primary DNA damage in white blood cells of rats. JOURNAL OF ETHNOPHARMACOLOGY 2018; 215:83-90. [PMID: 29288828 DOI: 10.1016/j.jep.2017.12.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 11/09/2017] [Accepted: 12/26/2017] [Indexed: 06/07/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Strawberry tree (Arbutus unedo L., Ericaceae) leaves represent a potent source of biologically active compounds and have been used for a long to relieve symptoms of various health impairments and diseases. Two major compounds related to their beneficial activities in animals and humans are arbutin and hydroquinone. AIM OF THE STUDY To establish potential benefit/risk ratio associated with daily oral administration of strawberry tree water leaf extract, arbutin and hydroquinone in doses expected to be non-toxic. MATERIALS AND METHODS We performed a 14-day and a 28-day study on male and female Lewis rats and evaluated main haematological parameters and the effects of treatments on the levels of primary DNA damage in white blood cells (WBC) using the alkaline comet assay. RESULTS Our findings suggest no significant changes in the haematological parameters following prolonged exposure to strawberry tree water leaf extract, arbutin, and hydroquinone. However, hydroquinone causes increased, and extract as well as arbutin decreased WBC count in male rats compared to control after 14 days of treatment. DNA damage measured in WBC of rats treated with all compounds was below 10% of the DNA in the comet tail, which indicates low genotoxicity. The genotoxic potential of strawberry water leaf extract was within acceptable limits and reflected effects of a complex chemical composition upon DNA. We also observed slight gender- and exposure time- related differences in primary DNA damage in the leucocytes of control and treated rats. CONCLUSIONS Future studies should investigate which doses of strawberry tree water leaf extract would be most promising for the potential use as a substitute for bearberry leaves for treatment of urinary infection.
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Affiliation(s)
- Karlo Jurica
- Special Security Operations Directorate, Ministry of the Interior, Zagreb, Croatia
| | | | - Nevenka Kopjar
- Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | | | - Tihana Cikač
- Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Vesna Benković
- Faculty of Science, University of Zagreb, Zagreb, Croatia.
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Olchowik-Grabarek E, Makarova K, Mavlyanov S, Abdullajanova N, Zamaraeva M. Comparative analysis of BPA and HQ toxic impacts on human erythrocytes, protective effect mechanism of tannins (Rhus typhina). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:1200-1209. [PMID: 29082470 PMCID: PMC5766716 DOI: 10.1007/s11356-017-0520-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 10/18/2017] [Indexed: 06/07/2023]
Abstract
Several studies reported that bisphenol A (BPA) and its metabolite hydroquinone (HQ) have adverse effects on human and animal health. In this work, a comparative study of influence of the BPA and HQ, environment pollutants, on human erythrocytes was carried out. It was shown that BPA and HQ to varying extents caused oxidative damage in human erythrocytes: hemolysis, decreased GSH level, and methemoglobin formation. It was demonstrated that hydrolysable tannins 3,6-bis-O-di-O-galloyl-1,2,4-tri-O-galloyl-β-D-glucose (C55H40O34) and 1,2,3,4,6-penta-O-galloyl-β-D-glucose (C41H32O26) (PGG) isolated from the Rhus typhina L. leaves in the range of 1-50 μM concentrations inhibited hemolysis and methemoglobin formation and also increased intracellular reduced glutathione in erythrocytes treated with BPA or HQ. It was revealed by electron paramagnetic resonance (EPR) using 5-doxyl-stearic acid (5-DS) that C55H40O34 and C41H32O26 increased the rigidity of erythrocyte membranes at the depth of 5th carbon atom of the fatty acid hydrocarbon chain. Taken together, these results allow to conclude that tannins from the Rhus typhina L. leaves protect erythrocytes from oxidative stress caused by BPA or HQ both due to their antioxidant activity as well as their interaction with the erythrocyte membrane components.
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Affiliation(s)
- Ewa Olchowik-Grabarek
- Department of Biophysics, University of Bialystok, Ciolkowskiego 1J, 15-245, Bialystok, Poland
| | - Katerina Makarova
- Department of Physical Chemistry, Faculty of Pharmacy, The Medical University of Warsaw, Banacha 1, 02-097, Warsaw, Poland
| | - Saidmukhtar Mavlyanov
- Institute of Bioorganic Chemistry, Academy of Science of Uzbekistan, Abdullaev 83, Tashkent, Uzbekistan, 100125
| | - Nodira Abdullajanova
- Institute of Bioorganic Chemistry, Academy of Science of Uzbekistan, Abdullaev 83, Tashkent, Uzbekistan, 100125
| | - Maria Zamaraeva
- Department of Biophysics, University of Bialystok, Ciolkowskiego 1J, 15-245, Bialystok, Poland.
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Abstract
Bioactive electrophiles generated from the oxidation of endogenous and exogenous compounds are a contributing factor in numerous disease states. Their toxicity is largely attributed to the covalent modification of cellular nucleophiles, including protein and DNA. With regard to protein modification, the side-chains of Cys, His, Lys, and Arg residues are critical targets. This results in the generation of undesired protein post-translational modifications (PTMs) that can trigger dire cellular consequences. Notably, histones are Lys- and Arg-rich proteins, providing a fertile source for adduction by both exogenous and endogenous electrophiles. The regulation of histone PTMs plays a critical role in the regulation of chromatin structure and thus gene expression. This perspective focuses on the role of electrophilic protein adduction within the context of chromatin and its potential consequences on cellular law and order.
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Affiliation(s)
- James J Galligan
- Department of Biochemistry, ‡Department of Chemistry, Vanderbilt University School of Medicine , Nashville, Tennessee 37232-0146, United States
| | - Lawrence J Marnett
- Department of Biochemistry, ‡Department of Chemistry, Vanderbilt University School of Medicine , Nashville, Tennessee 37232-0146, United States
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Li Y, Jongberg S, Andersen ML, Davies MJ, Lund MN. Quinone-induced protein modifications: Kinetic preference for reaction of 1,2-benzoquinones with thiol groups in proteins. Free Radic Biol Med 2016; 97:148-157. [PMID: 27212016 DOI: 10.1016/j.freeradbiomed.2016.05.019] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 05/11/2016] [Accepted: 05/18/2016] [Indexed: 12/23/2022]
Abstract
Oxidation of polyphenols to quinones serves as an antioxidative mechanism, but the resulting quinones may induce damage to proteins as they react through a Michael addition with nucleophilic groups, such as thiols and amines to give protein adducts. In this study, rate constants for the reaction of 4-methylbenzoquinone (4MBQ) with proteins, thiol and amine compounds were determined under pseudo first-order conditions by UV-vis stopped-flow spectrophotometry. The chemical structures of the adducts were identified by LC-ESI-MS/MS. Proteins with free thiols were rapidly modified by 4MBQ with apparent second order rate constants, k2 of (3.1±0.2)×10(4)M(-1)s(-1) for bovine serum albumin (BSA) and (4.8±0.2)×10(3)M(-1)s(-1) for human serum albumin at pH 7.0. These values are at least 12-fold greater than that for α-lactalbumin (4.0±0.2)×10(2)M(-1)s(-1), which does not contain any free thiols. Reaction of Cys-34 of BSA with N-ethylmaleimide reduced the thiol concentration by ~59%, which resulted in a decrease in k2 by a similar percentage, consistent with rapid adduction at Cys-34. Reaction of 4MBQ with amines (Gly, Nα-acetyl-l-Lys, Nε-acetyl-l-Lys and l-Lys) and the guanidine group of Nα-acetyl-l-Arg was at least 5×10(5) slower than with low-molecular-mass thiols (l-Cys, Nα-acetyl-l-Cys, glutathione). The thiol-quinone interactions formed colorless thiol-phenol products via an intermediate adduct, while the amine-quinone interactions generated colored amine-quinone products that require oxygen involvement. These data provide strong evidence for rapid modification of protein thiols by quinone species which may be of considerable significance for biological and food systems.
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Affiliation(s)
- Yuting Li
- School of Food Science and Technology, South China University of Technology, 381 Wushan Road, Tianhe District, Guangzhou 510640, China; Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 30, 1958 Frederiksberg, Denmark; Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou, China.
| | - Sisse Jongberg
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 30, 1958 Frederiksberg, Denmark.
| | - Mogens L Andersen
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 30, 1958 Frederiksberg, Denmark.
| | - Michael J Davies
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark.
| | - Marianne N Lund
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 30, 1958 Frederiksberg, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark.
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Barata-Silva C, Mitri S, Pavesi T, Saggioro E, Moreira JC. Benzeno: reflexos sobre a saúde pública, presença ambiental e indicadores biológicos utilizados para a determinação da exposição. ACTA ACUST UNITED AC 2014. [DOI: 10.1590/1414-462x201400040006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
O uso indiscriminado de um número cada vez maior de substâncias químicas vem aumentando e a contaminação ambiental associada tem trazido sérias consequências para o sistema público de saúde devido à elevação de danos para a saúde humana. Uma das substâncias que desperta grande interesse devido à contaminação contemporânea é o benzeno, composto aromático classificado pela International Agency for Research on Cancer como reconhecidamente carcinogênico para humanos. O objetivo do presente estudo foi elaborar e discutir um panorama sobre a contaminação por benzeno, seu metabolismo, consequências para a saúde e sua determinação ambiental e biológica a partir de informações existentes na literatura científica. O levantamento de dados possibilitou o acesso a mais de 200 artigos científicos tanto de âmbito nacional quanto internacional, demonstrando a atualidade do tema e a necessidade de minimização da exposição humana a essa substância. A maioria preocupa-se em explorar o metabolismo e investigar indicadores de exposição, muitos já amplamente estudados e com sérias limitações. Contudo, um crescente número de pesquisadores estão empenhados em elucidar fatores relacionados à suscetibilidade e à interferência da exposição no material genético e proteico. Indicadores de exposição inovadores têm sido propostos com o objetivo de complementar as lacunas de informações anteriormente obtidas, contribuindo para o delineamento da estrutura da biologia de sistemas orgânicos frente à exposição ao benzeno.
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Rankin GO, Sweeney A, Racine C, Ferguson T, Preston D, Anestis DK. 4-Amino-2-chlorophenol: Comparative in vitro nephrotoxicity and mechanisms of bioactivation. Chem Biol Interact 2014; 222:126-32. [PMID: 25446496 DOI: 10.1016/j.cbi.2014.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 08/29/2014] [Accepted: 10/06/2014] [Indexed: 11/27/2022]
Abstract
Chlorinated anilines are nephrotoxicants both in vivo and in vitro. The mechanism of chloroaniline nephrotoxicity may occur via more than one mechanism, but aminochlorophenol metabolites appear to contribute to the adverse in vivo effects. The purpose of this study was to compare the nephrotoxic potential of 4-aminophenol (4-AP), 4-amino-2-chlorophenol (4-A2CP), 4-amino-3-chlorophenol (4-A3CP) and 4-amino-2,6-dichlorophenol (4-A2,6DCP) using isolated renal cortical cells (IRCC) from male Fischer 344 rats as the model and to explore renal bioactivation mechanisms for 4-A2CP. For these studies, IRCC (∼4×10(6)cells/ml) were incubated with an aminophenol (0.5 or 1.0mM) or vehicle for 60min at 37°C with shaking. In some experiments, cells were pretreated with an antioxidant or cytochrome P450 (CYP), flavin-containing monooxygenase (FMO), peroxidase or cyclooxygenase inhibitor prior to 4-A2CP (1.0mM). Lactate dehydrogenase (LDH) release served as a measure of cytotoxicity. The order of decreasing nephrotoxic potential in IRCC was 4-A2,6-DCP>4-A2CP>4-AP>4-A3CP. The cytotoxicity induced by 4-A2CP was reduced by pretreatment with the peroxidase inhibitor mercaptosuccinic acid, and some antioxidants (ascorbate, glutathione, N-acetyl-l-cysteine) but not by others (α-tocopherol, DPPD). In addition, pretreatment with the iron chelator deferoxamine, several CYP inhibitors (except for the general CYP inhibitor piperonyl butoxide), FMO inhibitors or indomethacin (a cyclooxygenase inhibitor) failed to attenuate 4-A2CP cytotoxicity. These results demonstrate that the number and ring position of chloro groups can influence the nephrotoxic potential of 4-aminochlorophenols. In addition, 4-A2CP may be bioactivated by cyclooxygenase and peroxidases, and free radicals appear to play a role in 4-A2CP cytotoxicity.
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Affiliation(s)
- Gary O Rankin
- Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, United States.
| | - Adam Sweeney
- Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, United States
| | - Christopher Racine
- Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, United States
| | - Travis Ferguson
- Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, United States
| | - Deborah Preston
- Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, United States
| | - Dianne K Anestis
- Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, United States
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Qin X, Lehmler HJ, Teesch LM, Robertson LW, Duffel MW. Chlorinated biphenyl quinones and phenyl-2,5-benzoquinone differentially modify the catalytic activity of human hydroxysteroid sulfotransferase hSULT2A1. Chem Res Toxicol 2013; 26:1474-85. [PMID: 24059442 DOI: 10.1021/tx400207q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Human hydroxysteroid sulfotransferase (hSULT2A1) catalyzes the sulfation of a broad range of environmental chemicals, drugs, and other xenobiotics in addition to endogenous compounds that include hydroxysteroids and bile acids. Polychlorinated biphenyls (PCBs) are persistent environmental contaminants, and oxidized metabolites of PCBs may play significant roles in the etiology of their adverse health effects. Quinones derived from the oxidative metabolism of PCBs (PCB-quinones) react with nucleophilic sites in proteins and also undergo redox cycling to generate reactive oxygen species. This, along with the sensitivity of hSULT2A1 to oxidative modification at cysteine residues, led us to hypothesize that electrophilic PCB-quinones react with hSULT2A1 to alter its catalytic function. Thus, we examined the effects of four phenylbenzoquinones on the ability of hSULT2A1 to catalyze the sulfation of the endogenous substrate, dehydroepiandrosterone (DHEA). The quinones studied were 2'-chlorophenyl-2,5-benzoquinone (2'-Cl-BQ), 4'-chlorophenyl-2,5-benzoquinone (4'-Cl-BQ), 4'-chlorophenyl-3,6-dichloro-2,5-benzoquinone (3,6,4'-triCl-BQ), and phenyl-2,5-benzoquinone (PBQ). At all concentrations examined, pretreatment of hSULT2A1 with the PCB-quinones decreased the catalytic activity of hSULT2A1. Pretreatment with low concentrations of PBQ, however, increased the catalytic activity of the enzyme, while higher concentrations inhibited catalysis. A decrease in substrate inhibition with DHEA was seen following preincubation of hSULT2A1 with all of the quinones. Proteolytic digestion of the enzyme followed by LC/MS analysis indicated PCB-quinone- and PBQ-adducts at Cys55 and Cys199, as well as oxidation products at methionines in the protein. Equilibrium binding experiments and molecular modeling suggested that changes due to these modifications may affect the nucleotide binding site and the entrance to the sulfuryl acceptor binding site of hSULT2A1.
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Affiliation(s)
- Xiaoyan Qin
- Interdisciplinary Graduate Program in Human Toxicology, University of Iowa , Iowa City, Iowa 52242, United States
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10
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Genotoxicity of hydroquinone in A549 cells. Cell Biol Toxicol 2013; 29:213-27. [DOI: 10.1007/s10565-013-9247-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 05/20/2013] [Indexed: 11/25/2022]
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Leukemia and benzene. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2012; 9:2875-93. [PMID: 23066403 PMCID: PMC3447593 DOI: 10.3390/ijerph9082875] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 07/05/2012] [Accepted: 08/07/2012] [Indexed: 01/21/2023]
Abstract
Excessive exposure to benzene has been known for more than a century to damage the bone marrow resulting in decreases in the numbers of circulating blood cells, and ultimately, aplastic anemia. Of more recent vintage has been the appreciation that an alternative outcome of benzene exposure has been the development of one or more types of leukemia. While many investigators agree that the array of toxic metabolites, generated in the liver or in the bone marrow, can lead to traumatic bone marrow injury, the more subtle mechanisms leading to leukemia have yet to be critically dissected. This problem appears to have more general interest because of the recognition that so-called "second cancer" that results from prior treatment with alkylating agents to yield tumor remissions, often results in a type of leukemia reminiscent of benzene-induced leukemia. Furthermore, there is a growing literature attempting to characterize the fine structure of the marrow and the identification of so called "niches" that house a variety of stem cells and other types of cells. Some of these "niches" may harbor cells capable of initiating leukemias. The control of stem cell differentiation and proliferation via both inter- and intra-cellular signaling will ultimately determine the fate of these transformed stem cells. The ability of these cells to avoid checkpoints that would prevent them from contributing to the leukemogenic response is an additional area for study. Much of the study of benzene-induced bone marrow damage has concentrated on determining which of the benzene metabolites lead to leukemogenesis. The emphasis now should be directed to understanding how benzene metabolites alter bone marrow cell biology.
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Djurhuus R, Nossum V, Øvrebø S, Skaug V. Proposal on limits for chemical exposure in saturation divers' working atmosphere: the case of benzene. Crit Rev Toxicol 2012; 42:211-29. [PMID: 22304480 DOI: 10.3109/10408444.2011.650791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Saturation diving is performed under extreme environmental conditions. The divers are confined to a limited space for several weeks under high environmental pressure and elevated oxygen partial pressure. At present, divers are protected against chemical exposure by standard exposure limits only adjusted for the increased exposure length, i.e. from 8 to 24 hours a day and from 5 to 7 days a week. The objective of the present study was to indicate a procedure for derivation of occupational exposure limits for saturation diving, termed hyperbaric exposure limits (HEL). Using benzene as an example, a procedure is described that includes identification of the latest key documents, extensive literature search with defined exclusion criteria for the literature retrieved. Hematotoxicity and leukemia were defined as the critical effects, and exposure limits based upon concentration and cumulative exposure data and corresponding risks of leukemia were calculated. Possible interactions of high pressure, elevated pO₂, and continuous exposure have been assessed, and incorporated in a final suggestion of a HEL for benzene. The procedure should be applicable for other relevant chemicals in the divers' breathing atmosphere. It is emphasized that the lack of interactions from pressure and oxygen indicated for benzene may be completely different for other chemicals.
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Affiliation(s)
- Rune Djurhuus
- Norwegian Underwater Intervention AS (NUI AS), Bergen, Norway.
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13
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Lee JS, Yang EJ, Kim IS. Hydroquinone-induced apoptosis of human lymphocytes through caspase 9/3 pathway. Mol Biol Rep 2012; 39:6737-43. [DOI: 10.1007/s11033-012-1498-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 01/24/2012] [Indexed: 12/31/2022]
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Bird MG, Wetmore BA, Letinski DJ, Nicolich M, Chen M, Schnatter AR, Whitman FT. Influence of toluene co-exposure on the metabolism and genotoxicity of benzene in mice using continuous and intermittent exposures. Chem Biol Interact 2010; 184:233-9. [PMID: 20079720 DOI: 10.1016/j.cbi.2010.01.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Revised: 01/05/2010] [Accepted: 01/06/2010] [Indexed: 11/19/2022]
Abstract
Benzene exposure in occupational settings often occurs with concurrent exposure to toluene, the methyl-substituted derivative of benzene. Toluene is also readily metabolized by CYP450 isozymes although oxidation primarily occurs in the methyl group. While earlier mouse studies addressing co-exposure to benzene and toluene at high concentrations demonstrated a reduction in benzene-induced genotoxicity, we have previously found, using an intermittent exposure regimen with lower concentrations of benzene (50 ppm) and toluene (100 ppm), that toluene enhances benzene-induced clastogenic or aneugenic bone marrow injury in male CD-1 mice with significantly increased CYP2E1, and depleted GSH and GSSG levels. The follow-up study reported here also used the same daily and total co-exposures but over consecutive days and compared the effects of co-exposure on genotoxicity and metabolism in CD-1 mice both with and without buthionine sulfoximine (BSO) treatment to deplete GSH. In this study the toluene co-exposure doubled the genotoxic response (as determined by the erythrocyte micronucleus test) to benzene alone. Further, GSH depletion caused a reduction in this genotoxicity in both benzene exposed and benzene/toluene co-exposed mice. The results are discussed in terms of the analyses of urinary metabolites from this consecutive day study and the intermittent exposure study as well as levels of CYP2E1, epoxide hydrolase, quinone reductase, alcohol dehydrogenase, and aldehyde dehydrogenase activities. The results suggest that the presence of glutathione is necessary for benzene genotoxicity either as a metabolite conjugate or through an indirect mechanism such as TNF-induced apoptosis.
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Affiliation(s)
- M G Bird
- ExxonMobil Biomedical Sciences Inc, Annandale, NJ 08801-0971, USA.
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