1
|
Lu PCW, Shahbaz S, Winn LM. Benzene and its effects on cell signaling pathways related to hematopoiesis and leukemia. J Appl Toxicol 2020; 40:1018-1032. [PMID: 32112456 DOI: 10.1002/jat.3961] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 01/30/2020] [Accepted: 02/09/2020] [Indexed: 12/14/2022]
Abstract
Benzene is an environmental toxicant found in many consumer products. It is an established human carcinogen and is known to cause acute myeloid leukemia in adults. Epidemiological evidence has since shown that benzene can cross the placenta and affect the fetal liver. Animal studies have shown that in utero exposure to benzene can increase tumor incidence in offspring. Although there have been risk factors established for acute myeloid leukemia, they still do not account for many of the cases. Clearly then, current efforts to elucidate the mechanism by which benzene exerts its carcinogenic properties have been superficial. Owing to the critical role of cell signaling pathways in the development of an organism and its various organ systems, it seems plausible to suspect that these pathways may have a role in leukemogenesis. This review article assesses current evidence of the effects of benzene on critical hematopoietic signaling pathways. Pathways discussed included Hedgehog, Notch/Delta, Wingless/Integrated, nuclear factor-kappaB and others. Following a review of the literature, it seems that current evidence about the effects of benzene on these critical signaling pathways remains limited. Given the important role of these pathways in hematopoiesis, more attention should be given to them.
Collapse
Affiliation(s)
- Peter C W Lu
- Department of Biomedical & Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Sara Shahbaz
- Department of Biomedical & Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Louise M Winn
- Department of Biomedical & Molecular Sciences, Queen's University, Kingston, Ontario, Canada.,School of Environmental Sciences, Queen's University, Kingston, Ontario, Canada
| |
Collapse
|
2
|
Zhang T, Hu C, Wu Y, Wang S, Liu X, Zhang D, Huang F, Gao H, Wang Z. Carbon Disulfide Induces Embryo Implantation Disorder by Disturbing the Polarization of Macrophages in Mice Uteri. Chem Res Toxicol 2019; 32:1989-1996. [PMID: 31468960 DOI: 10.1021/acs.chemrestox.9b00119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Carbon disulfide (CS2) induces embryo implantation disorders. Macrophages participate in the process of pregnancy. Therefore, we want to explore the effects of CS2 exposure on polarization and immune function of macrophages in pregnant mice uteri. The exposure times were gestation days 3 (GD3), 4 (GD4), and 5 (GD5), and the observation end points were arranged in a time series after CS2 exposure. The uterine tissues were collected to detect the expression levels of macrophages cytokines (IL-6, IL-12, TGF-β1, and Vegf-a) and downstream regulatory cytokines of Th1-type (IL-2 and IFN-γ) and Th2-type (IL-10 and IL-4) by flow cytometry, ELISA, and q-PCR. The results showed that, compared with the controls, the ratios of M1/M2 macrophages in the endometrium significantly increased by 96%, 110%, and 177% at the GD4, GD6, and GD7 observation end points after GD3 exposure and increased about 3.88-fold and 2.37-fold at the GD6 and GD7 observation end points after GD4 exposure, respectively. In contrast, the ratio of M1 and M2 macrophages significantly reduced by 53% at the GD5 observation end point after GD3 exposure. Meanwhile, the expression levels of IL-6 were significantly increased about 2.00-fold for mRNA and 1.60-fold for protein at GD4 observation end points after GD3 exposure, and the mRNA levels of IL-12 increased about 3.61-fold at the GD6 observation end points after GD4 exposure. The mRNA levels of TGF-β1 were significantly decreased by 41%, 25%, and 20% at the GD7 observation end points after exposure at GD3, GD4, and GD5, and the expression levels of Vegf-a mRNA and protein were decreased. Furthermore, the ratio of IL-2/IL4, IL-2/IL-10, IFN-γ/IL-4, and IFN-γ/IL-10 in the uterine tissue was significantly increased at the exposure groups. These findings suggest that the imbalanced polarization of macrophages is the key regulator in the progress of CS2-induced embryo loss.
Collapse
Affiliation(s)
- Tongchao Zhang
- School of Public Health , Shandong University , 44 Wenhua Xi Road , Jinan , Shandong 250012 , P.R. China
| | - Chengxia Hu
- School of Public Health , Shandong University , 44 Wenhua Xi Road , Jinan , Shandong 250012 , P.R. China
| | - Yanling Wu
- School of Public Health , Shandong University , 44 Wenhua Xi Road , Jinan , Shandong 250012 , P.R. China
| | - Shuting Wang
- School of Public Health , Shandong University , 44 Wenhua Xi Road , Jinan , Shandong 250012 , P.R. China
| | - Xiaojing Liu
- School of Public Health , Shandong University , 44 Wenhua Xi Road , Jinan , Shandong 250012 , P.R. China
| | - Danhua Zhang
- School of Public Health , Shandong University , 44 Wenhua Xi Road , Jinan , Shandong 250012 , P.R. China
| | - Fengyan Huang
- School of Public Health , Shandong University , 44 Wenhua Xi Road , Jinan , Shandong 250012 , P.R. China
| | - Han Gao
- School of Public Health , Shandong University , 44 Wenhua Xi Road , Jinan , Shandong 250012 , P.R. China
| | - Zhiping Wang
- School of Public Health , Shandong University , 44 Wenhua Xi Road , Jinan , Shandong 250012 , P.R. China
| |
Collapse
|
3
|
Down-regulation of uterine LIF expression induced by the hormonal level disorder causes embryo implantation loss after mice exposed to carbon disulfide at peri-implantation. Biochem Biophys Res Commun 2015; 467:7-13. [DOI: 10.1016/j.bbrc.2015.09.141] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 09/26/2015] [Indexed: 11/23/2022]
|
4
|
Philbrook NA, Winn LM. Benzoquinone toxicity is not prevented by sulforaphane in CD-1 mouse fetal liver cells. J Appl Toxicol 2015; 36:1015-24. [DOI: 10.1002/jat.3251] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 09/06/2015] [Accepted: 09/06/2015] [Indexed: 01/07/2023]
Affiliation(s)
- Nicola A. Philbrook
- Department of Biomedical and Molecular Sciences, Graduate Program in Pharmacology and Toxicology; Queen's University; Kingston ON Canada K7L3N6
| | - Louise M. Winn
- School of Environmental Studies; Queen's University; Kingston ON Canada K7L3N6
| |
Collapse
|
5
|
Miller-Pinsler L, Wells PG. Embryonic catalase protects against ethanol embryopathies in acatalasemic mice and transgenic human catalase-expressing mice in embryo culture. Toxicol Appl Pharmacol 2015; 287:232-9. [DOI: 10.1016/j.taap.2015.06.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/02/2015] [Accepted: 06/10/2015] [Indexed: 11/30/2022]
|
6
|
Ali T, Saeed K, Abdullah M, Murtaza I. Antihematotoxic Role of Bunium persicum Seed Differential Extracts in Animal Model: Reactive Oxygen Species Might Be a Contributor. Osong Public Health Res Perspect 2015; 5:358-63. [PMID: 25562045 PMCID: PMC4281623 DOI: 10.1016/j.phrp.2014.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 09/15/2014] [Accepted: 10/01/2014] [Indexed: 11/29/2022] Open
Abstract
Objectives Humans have been using plants as natural medicines since prehistoric times. Bunium persicum is a rich source of oils with different biological activities such as antioxidative and antimicrobial activities. The aim of this study is to evaluate the antihematotoxic and antioxidative effects of the differential extracts of B. persicum against leukemic blood induced hematotoxicity in an animal model. Methods This study was performed on animals, which were divided into several groups: normal control, disease control, and groups that were administered with differential extracts of plants. We measured the concentration of free radical [reactive oxygen species (ROS)] and hematological parameters as blast cells from the tibia and femur in different groups. Results The ROS level and blast cells count were higher in disease control groups than in groups treated with varying amounts of B. persicum extract and the normal group. Moreover, there was an imbalance in hematological parameters in untreated and treated groups with a correlation between free radicals and plant extract administration. Conclusion These findings may indicate a possible link between free radicals and hematotoxicity and blast cells, while depicting a potential therapeutic role for B. persicum against ROS-induced hematotoxicity.
Collapse
|
7
|
DNA damage and apoptosis of endometrial cells cause loss of the early embryo in mice exposed to carbon disulfide. Toxicol Appl Pharmacol 2013; 273:381-9. [DOI: 10.1016/j.taap.2013.09.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 09/06/2013] [Accepted: 09/18/2013] [Indexed: 11/19/2022]
|
8
|
Stokes SE, Winn LM. NF-κB Signaling Is Increased in HD3 Cells Following Exposure to 1,4-Benzoquinone: Role of Reactive Oxygen Species and p38-MAPK a. Toxicol Sci 2013; 137:303-10. [DOI: 10.1093/toxsci/kft256] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
|
9
|
Carbon disulfide exposure at peri-implantation disrupts embryo implantation by decreasing integrin β3 expression in the uterine tissue of pregnant mice. Chem Biol Interact 2013; 206:126-33. [DOI: 10.1016/j.cbi.2013.08.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 08/10/2013] [Accepted: 08/30/2013] [Indexed: 01/07/2023]
|
10
|
Tung EWY, Philbrook NA, Macdonald KDD, Winn LM. DNA double-strand breaks and DNA recombination in benzene metabolite-induced genotoxicity. Toxicol Sci 2012; 126:569-77. [PMID: 22247006 DOI: 10.1093/toxsci/kfs001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In utero exposure to environmental carcinogens, including the ubiquitous pollutant benzene, may cause DNA damage in the fetus, leading to an increased risk for the development of childhood cancer. Benzene metabolite-induced DNA double-strand breaks (DSBs) may undergo erroneous repair, leading to chromosomal aberrations including chromosomal inversions and translocations. In this study, fetal murine hematopoietic cells from pZK1 transgenic mice were exposed to p-benzoquinone (BQ), a toxic metabolite of benzene, and assessed for DNA recombination, DNA damage including DNA DSBs as measured by γ-H2A.X foci and oxidative DNA damage, and reactive oxygen species (ROS) production. The pZK1 transgenic mouse model contains a DNA construct allowing for the detection of intrachromosomal recombination events. Using this model, a significant increase in recombination was observed following exposure to BQ (25 and 50μM) at various time points. Additionally, increased γ-H2A.X foci were observed following exposure to 25μM BQ for 30 min, 45 min, and 1 h, whereas this exposure did not significantly increase oxidative DNA damage. Pretreatment with 400 U/ml polyethylene glycol-conjugated-catalase attenuated increases in DNA recombination as compared with treatment with BQ alone. An increase in ROS production (30 min and 1 h), as measured by dichlorodihydrofluorescein diacetate fluorescence, was also observed following exposure to 25μM BQ. These studies indicate that BQ is able to induce DNA damage and recombination in fetal liver cells and that ROS may be important in the mechanism of toxicity.
Collapse
Affiliation(s)
- Emily W Y Tung
- Department of Biomedical and Molecular Sciences, Queen's University, Room 557, Botterell Hall, Kingston, Ontario K7L 3N6, Canada
| | | | | | | |
Collapse
|
11
|
Wu XR, Xue M, Li XF, Wang Y, Wang J, Han QL, Yi ZC. Phenolic metabolites of benzene inhibited the erythroid differentiation of K562 cells. Toxicol Lett 2011; 203:190-9. [PMID: 21414390 DOI: 10.1016/j.toxlet.2011.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 03/06/2011] [Accepted: 03/07/2011] [Indexed: 01/27/2023]
Abstract
Benzene is a common occupational hazard and a ubiquitous environmental pollutant. Benzene exposure at the levels even below 1ppm still showed hematotoxicity. It is widely accepted that the metabolites of benzene play important roles in the benzene toxicity to the hematopoietic system, but little is known about the effects of benzene metabolites on erythropoiesis. In present study, erythroid progenitor-like K562 cells were used to determine the effects of phenolic metabolites of benzene, including phenol, hydroquinone and 1,2,4-benzenetriol, on the erythroid differentiation. After the treatment with these benzene metabolites at the concentrations with no obvious cytotoxicity, the hemin-induced hemoglobin synthesis in K562 cells decreased in a concentration- and time-dependent manner, and the expression of CD71 and GPA protein on the surface of K562 cells was also inhibited. The reverse transcription-PCR was used to determine the mRNA level of the erythroid related genes in the K562 cells that were treated with benzene metabolites. The hemin-induced expression of globin genes, including α-, β- and γ-globin genes, and the gene encoding the heme synthesis enzyme porphobilinogen deaminase was inhibited by benzene metabolites. When the K562 cells were pretreated with benzene metabolites, the hemin-induced expression of two transcription factor genes GATA-1 and NF-E2 was distinctly reduced, and the pre-treatment with benzene metabolites promoted the decrease of the mRNA level of transcription factor gene GATA-2 by hemin. These results indicated that benzene metabolites inhibited the hemin-induced erythroid differentiation through affecting the transcription of the erythroid related genes.
Collapse
Affiliation(s)
- Xiao-Rong Wu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | | | | | | | | | | | | |
Collapse
|
12
|
Borillo GA, Mason M, Quijada P, Völkers M, Cottage C, McGregor M, Din S, Fischer K, Gude N, Avitable D, Barlow S, Gustafsson AB, Glembotski C, Gottlieb RA, Brown JH, Sussman MA. Pim-1 kinase protects mitochondrial integrity in cardiomyocytes. Circ Res 2010; 106:1265-74. [PMID: 20203306 PMCID: PMC2864233 DOI: 10.1161/circresaha.109.212035] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
RATIONALE Cardioprotective signaling mediates antiapoptotic actions through multiple mechanisms including maintenance of mitochondrial integrity. Pim-1 kinase is an essential downstream effector of AKT-mediated cardioprotection but the mechanistic basis for maintenance of mitochondrial integrity by Pim-1 remains unexplored. This study details antiapoptotic actions responsible for enhanced cell survival in cardiomyocytes with elevated Pim-1 activity. OBJECTIVE The purpose of this study is to demonstrate that the cardioprotective kinase Pim-1 acts to inhibit cell death by preserving mitochondrial integrity in cardiomyocytes. METHODS AND RESULTS A combination of biochemical, molecular, and microscopic analyses demonstrate beneficial effects of Pim-1 on mitochondrial integrity. Pim-1 protein level increases in the mitochondrial fraction with a corresponding decrease in the cytosolic fraction of myocardial lysates from hearts subjected to 30 minutes of ischemia followed by 30 minutes of reperfusion. Cardiac-specific overexpression of Pim-1 results in higher levels of antiapoptotic Bcl-X(L) and Bcl-2 compared to samples from normal hearts. In response to oxidative stress challenge, Pim-1 preserves the inner mitochondrial membrane potential. Ultrastructure of the mitochondria is maintained by Pim-1 activity, which prevents swelling induced by calcium overload. Finally, mitochondria isolated from hearts created with cardiac-specific overexpression of Pim-1 show inhibition of cytochrome c release triggered by a truncated form of proapoptotic Bid. CONCLUSION Cardioprotective action of Pim-1 kinase includes preservation of mitochondrial integrity during cardiomyopathic challenge conditions, thereby raising the potential for Pim-1 kinase activation as a therapeutic interventional approach to inhibit cell death by antagonizing proapoptotic Bcl-2 family members that regulate the intrinsic apoptotic pathway.
Collapse
MESH Headings
- Animals
- Animals, Newborn
- Apoptosis
- BH3 Interacting Domain Death Agonist Protein/metabolism
- Cell Survival
- Cells, Cultured
- Cytochromes c/metabolism
- Disease Models, Animal
- Humans
- Membrane Potential, Mitochondrial
- Mice
- Mice, Transgenic
- Mitochondria, Heart/enzymology
- Mitochondria, Heart/ultrastructure
- Mitochondrial Swelling
- Myocardial Reperfusion Injury/enzymology
- Myocardial Reperfusion Injury/genetics
- Myocardial Reperfusion Injury/pathology
- Myocardial Reperfusion Injury/prevention & control
- Myocytes, Cardiac/enzymology
- Myocytes, Cardiac/ultrastructure
- Oxidative Stress
- Protein Transport
- Proto-Oncogene Proteins c-bcl-2/metabolism
- Proto-Oncogene Proteins c-pim-1/genetics
- Proto-Oncogene Proteins c-pim-1/metabolism
- Rats
- Rats, Sprague-Dawley
- Recombinant Fusion Proteins/metabolism
- Time Factors
- Transfection
- bcl-X Protein/metabolism
Collapse
Affiliation(s)
- Gwynngelle A. Borillo
- San Diego State Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | - Matt Mason
- San Diego State Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | - Pearl Quijada
- San Diego State Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | - Mirko Völkers
- San Diego State Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | - Christopher Cottage
- San Diego State Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | - Michael McGregor
- San Diego State Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | - Shabana Din
- San Diego State Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | - Kimberlee Fischer
- San Diego State Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | - Natalie Gude
- San Diego State Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | - Daniele Avitable
- San Diego State Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | - Steven Barlow
- San Diego State Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | - Asa B. Gustafsson
- San Diego State Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | | | - Roberta A. Gottlieb
- San Diego State Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | - Joan Heller Brown
- Department of Pharmacology, University of California, San Diego, CA 92093-0636, USA
| | - Mark A. Sussman
- San Diego State Heart Institute, San Diego State University, San Diego, CA 92182, USA
| |
Collapse
|
13
|
Benzene-initiated oxidative stress: Effects on embryonic signaling pathways. Chem Biol Interact 2009; 184:218-21. [PMID: 19913523 DOI: 10.1016/j.cbi.2009.11.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 11/04/2009] [Accepted: 11/05/2009] [Indexed: 12/19/2022]
Abstract
Approximately 90% of childhood cancers are of unknown etiology; however, it is hypothesized that in utero carcinogen exposure may contribute. Epidemiological studies have correlated parental exposure to benzene with an increased incidence of childhood leukemias. However, mechanisms of benzene-induced carcinogenesis following in utero exposure remain unknown. We hypothesize that in utero exposure to benzene causes alterations in the redox-sensitive signaling pathways involving c-Myb, Pim-1, AKT, ERK-MAPK, p38-MAPK, and NF-kappaB via the production of reactive oxygen species (ROS) as a possible mechanism of in utero-initiated carcinogenesis. Using a CD-1 mouse model we have shown increased oxidative stress in fetal tissue from embryos exposed in utero to benzene by measuring reduced to oxidized glutathione ratios, and increased levels of ROS in male fetuses using flow cytometry and the ROS sensitive fluorescent probe dichlorofluoroscein diacetate (DCFDA). In addition, using Western blotting techniques we observed increased expression of fetal Pim-1, Pim-1 phosphorylation, c-Myb, and phosphorylated p38-MAPK (activated form) and lower protein levels of IkappaBalpha, while phosphorylated ERK-MAPK and AKT protein levels did not change. Interestingly, we found male fetuses more susceptible to benzene-induced oxidative stress, which is in agreement with the literature suggesting that males are more susceptible to benzene toxicity. Further studies evaluating the reason for this gender difference are ongoing.
Collapse
|
14
|
Badham HJ, Winn LM. In utero exposure to benzene disrupts fetal hematopoietic progenitor cell growth via reactive oxygen species. Toxicol Sci 2009; 113:207-15. [PMID: 19812361 DOI: 10.1093/toxsci/kfp242] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
It is hypothesized that the increasing incidence of childhood leukemia may be due to in utero exposure to environmental pollutants, such as benzene, but the mechanisms involved remain unknown. We hypothesize that reactive oxygen species (ROS) contribute to the deregulation of fetal hematopoiesis caused by in utero benzene exposure. To evaluate this hypothesis, pregnant C57Bl/6N mice were exposed to benzene or polyethylene glycol-conjugated catalase (PEG-catalase) (antioxidative enzyme) and benzene. Colony formation assays on fetal liver cells were performed to measure erythroid and myeloid progenitor cell growth potential. The presence of ROS in CD117(+) fetal liver cells was measured by flow cytometric analysis. Oxidative cellular damage was assessed by Western blot analysis of 4-hydroxynonenol (4-HNE) and nitrotyrosine products, as well as reduced to oxidized glutathione ratios. Alterations in the redox-sensitive signaling pathway nuclear factor-kappa-light-chain-enhancer of activated B cells (NF-kappaB) were measured by Western blot analysis of Inhibitor of NF-kB-alpha (IkappaB-alpha) protein levels in fetal liver tissue. In utero exposure to benzene caused a significant increase in ROS production and significantly altered fetal liver erythroid and myeloid colony numbers but did not increase the levels of 4-HNE or nitrotyrosine products or alter reduced to oxidized glutathione ratios. However, in utero exposure to benzene did cause a significant decrease in fetal liver IkappaB-alpha protein levels, suggesting activation of the NF-kappaB pathway. Benzene-induced ROS formation, abnormal colony growth, and decreased IkappaB-alpha levels were all abrogated by pretreatment with PEG-catalase. These results suggest that ROS play a key role in the development of in utero-initiated benzene toxicity potentially through disruption of hematopoietic cell signaling pathways.
Collapse
Affiliation(s)
- Helen J Badham
- Department of Pharmacology and Toxicology, Queen's University, Kingston, Ontario, Canada K7L 3N6
| | | |
Collapse
|
15
|
Abstract
The mouse embryo culture technique is a valuable tool for assessing embryotoxicity of exogenous compounds as it excludes any confounding maternal and placental effects, allows for the selection of embryos that are at similar stages of development, and permits the control of exposure concentrations of exogenous agents and modifiers of interest. This chapter will use the anticonvulsant drug valproic acid as a model teratogen to describe the mouse embryo culture in detail. Briefly, mice are bred and the presence of a vaginal plug in a female mouse indicates gestational day (GD) 1. On GD 9 embryos are explanted from pregnant dams and embryos that are at similar stages of development (4-6 somite pairs) are cultured in CO(2) saturated male rat serum for 24 h at 37 degrees C. After 24 h embryonic morphological and developmental parameters, including anterior neuropore closure, are evaluated using a dissecting microscope. Additional biochemical analysis, including molecular approaches to assess embryonic signal transduction, as well as some limitations of the technique will also be discussed.
Collapse
|
16
|
Induction of hsp70, hsp60, hsp83 and hsp26 and oxidative stress markers in benzene, toluene and xylene exposed Drosophila melanogaster: Role of ROS generation. Toxicol Appl Pharmacol 2009; 235:226-43. [DOI: 10.1016/j.taap.2008.12.002] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Revised: 11/14/2008] [Accepted: 12/02/2008] [Indexed: 11/24/2022]
|
17
|
Singh R, Winn LM. The effects of 1,4-benzoquinone on c-Myb and topoisomerase II in K-562 cells. Mutat Res 2008; 645:33-38. [PMID: 18778717 DOI: 10.1016/j.mrfmmm.2008.08.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Revised: 08/05/2008] [Accepted: 08/08/2008] [Indexed: 05/26/2023]
Abstract
Exposure to benzene, a ubiquitous environmental pollutant, has been linked to leukemia, although the mechanism of benzene-initiated leukemogenesis remains unclear. Benzene can be bioactivated to toxic metabolites such as 1,4 benzoquinone (BQ), which can alter signaling pathways and affect chromosomal integrity. BQ has been shown to increase the activity of c-Myb, which is an important transcription factor involved in hematopoiesis, cell proliferation, and cell differentiation. The c-Myb protein has also been shown to increase topoisomerase IIalpha (Topo IIalpha) promoter activity specifically in cell lines with hematopoietic origin. Topo IIalpha is a critical nuclear enzyme that removes torsional strain by cleaving, untangling and religating double-stranded DNA. Since Topo IIalpha mediates DNA strand breaks, aberrant Topo IIalpha activity or increased protein levels may increase the formation of DNA strand breaks, leaving the cell susceptible to mutational events. We hypothesized that BQ can increase c-Myb activity, which in turn increases Topo IIalpha promoter activity resulting in increased DNA strand breaks. Using luciferase reporter assays in K-562 cells we demonstrated that BQ (25 and 37microM) exposure caused an increase in c-Myb activity after 24h. Contradictory to previous findings, overexpression of exogenous c-Myb or a polypeptide consisting of c-Myb's DNA binding domain (DBD), which competitively inhibits the binding of endogenous c-Myb to DNA, did not affect Topo IIalpha promoter activity. However, BQ (37microM for 24h) exposure caused a significant increase in Topo IIalpha promoter activity, which could be blocked by the overexpression of the DBD polypeptide, suggesting that BQ exposure increases Topo IIalpha promoter activity through the c-Myb signaling pathway.
Collapse
Affiliation(s)
- Roopam Singh
- Department of Pharmacology and Toxicology, Queen's University, Kingston, Ontario, Canada
| | | |
Collapse
|