1
|
Luo H, Zhai L, Qiu W, Liang H, Yu L, Li Y, Xiong M, Guo J, Tang H. p16 loss facilitate hydroquinone-induced malignant transformation of TK6 cells through promoting cell proliferation and accelerating the cell cycle progression. ENVIRONMENTAL TOXICOLOGY 2021; 36:1591-1599. [PMID: 33932074 DOI: 10.1002/tox.23155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/17/2021] [Indexed: 06/12/2023]
Abstract
The p16INK4A is a multifunction gene that includes regulation of the cell cycle, apoptosis, senescence and tumor development. However, the effects of p16 in hydroquinone-induced malignant transformation of TK6 cells remain unclear. The present study aimed to explore whether p16 loss facilitate malignant transformation in TK6 cells. The results demonstrated that p16/Rb signal pathway was suppressed in hydroquinone-induced malignant transformation of TK6 cells. We further confirmed that p16 loss stimulated cell proliferation, and accelerated cell cycle progression in vitro and in vivo. The immunoblotting analysis indicated that p16 regulated cell cycle progression via Rb and p53. Therefore, we conclude that p16 is involved in HQ-induced malignant transformation associated with suppressing Rb and p53 which resulting in accelerating the cell cycle progression.
Collapse
Affiliation(s)
- Hao Luo
- Department of Environmental and Occupational Health, Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, China
| | - Lu Zhai
- Department of Environmental and Occupational Health, Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, China
| | - Weifeng Qiu
- Department of Environmental and Occupational Health, Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, China
| | - Hairong Liang
- Department of Environmental and Occupational Health, Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, China
| | - Lei Yu
- Department of Environmental and Occupational Health, Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, China
| | - Yuan Li
- Department of Environmental and Occupational Health, Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, China
| | - Mengyun Xiong
- Department of Environmental and Occupational Health, Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, China
| | - Jiaying Guo
- Department of Environmental and Occupational Health, Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, China
| | - Huanwen Tang
- Department of Environmental and Occupational Health, Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, China
| |
Collapse
|
2
|
Zhang H, Yuan Q, Pan Z, Ling X, Tan Q, Wu M, Zheng D, Xie P, Xie D, Liu L. Up-regulation of DNMT3b contributes to HOTAIRM1 silencing via DNA hypermethylation in cells transformed by long-term exposure to hydroquinone and workers exposed to benzene. Toxicol Lett 2020; 322:12-19. [PMID: 31899212 DOI: 10.1016/j.toxlet.2019.12.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 11/14/2019] [Accepted: 12/22/2019] [Indexed: 12/31/2022]
Abstract
Benzene exposure is a risk factor of acute myeloid leukemia (AML), during such carcinogenesis long non-coding RNAs (lncRNAs) are important epigenetic regulators. HOTAIRM1 (HOXA transcript antisense RNA, myeloid-specific 1) plays an indispensable role in the development of AML. Hydroquinone (HQ) is one major metabolite of benzene and its ideal replacement in toxicology research. But the influence of benzene or HQ on HOTAIRM1 expression in AML associated pathway is still unclear. In the TK6 cells with short-term exposure to HQ (HQ-ST cells) or long term HQ exposure induced malignant transformed TK6 cells (HQ-MT cells), the relationship between DNMT3b and HOTAIRM1 was explored. Comparing to counterparts, HOTAIRM1 expression was increased firstly and then decreased in HQ-ST cells, and definitely decreased in HQ-MT cells; while the expression change tendency of DNMT3b was in contrast to that of HOTAIRM1. Moreover, the average HOTAIRM1 expression of 17 paired workers being exposed to benzene within 1.5 years was increased, but that of the remaining 92 paired workers with longer exposure time was decreased. Furthermore, in 5-AzaC (DNA methyltransferase inhibitor) or TSA (histone deacetylation inhibitor) treated HQ-MT cells, the expression of HOTAIRM1 was restored by reduced DNA promoter methylation levels. HQ-MT cells with DNMT3b knockout by CRISPR/Cas9 displayed the promoter hypomethylation and the increase of HOTAIRM1, also confirmed in benzene exposure workers. These suggest that long term exposure to HQ or benzene might induce the increase of DNMT3b expression and the promoter hypermethylation to silence the expression of HOTAIRM1, a possible tumor-suppressor in the AML associated carcinogenesis pathway.
Collapse
MESH Headings
- Benzene/adverse effects
- Case-Control Studies
- Cell Line, Transformed
- Cell Line, Tumor
- DNA (Cytosine-5-)-Methyltransferases/biosynthesis
- DNA (Cytosine-5-)-Methyltransferases/genetics
- DNA Methylation/drug effects
- Enzyme Induction
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Neoplastic
- Gene Silencing/drug effects
- Humans
- Hydroquinones/toxicity
- Leukemia, Myeloid, Acute/chemically induced
- Leukemia, Myeloid, Acute/enzymology
- Leukemia, Myeloid, Acute/genetics
- MicroRNAs/genetics
- MicroRNAs/metabolism
- Occupational Diseases/chemically induced
- Occupational Diseases/enzymology
- Occupational Diseases/genetics
- Occupational Exposure/adverse effects
- Promoter Regions, Genetic
- Risk Assessment
- DNA Methyltransferase 3B
Collapse
Affiliation(s)
- Haiqiao Zhang
- Department of Environmental and Occupational Health, School of Public Health, Guangdong Medical University, Dongguan, 523808, PR China; Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, PR China
| | - Qian Yuan
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, PR China
| | - Zhijie Pan
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, PR China
| | - Xiaoxuan Ling
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, PR China
| | - Qiang Tan
- Foshan Institute of Occupational Disease Prevention and Control, Foshan, Guangdong, 528000, PR China
| | - Minhua Wu
- Department of Histology and Embryology, Guangdong Medical University, Zhanjiang, PR China
| | - Dongyan Zheng
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, PR China
| | - Peien Xie
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, PR China
| | - Daxiao Xie
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, PR China
| | - Linhua Liu
- Department of Environmental and Occupational Health, School of Public Health, Guangdong Medical University, Dongguan, 523808, PR China; Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, PR China.
| |
Collapse
|
3
|
Nitiss KC, Nitiss JL, Hanakahi LA. DNA Damage by an essential enzyme: A delicate balance act on the tightrope. DNA Repair (Amst) 2019; 82:102639. [PMID: 31437813 DOI: 10.1016/j.dnarep.2019.102639] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 06/18/2019] [Accepted: 07/01/2019] [Indexed: 01/07/2023]
Abstract
DNA topoisomerases are essential for DNA metabolic processes such as replication and transcription. Since DNA is double stranded, the unwinding needed for these processes results in DNA supercoiling and catenation of replicated molecules. Changing the topology of DNA molecules to relieve supercoiling or resolve catenanes requires that DNA be transiently cut. While topoisomerases carry out these processes in ways that minimize the likelihood of genome instability, there are several ways that topoisomerases may fail. Topoisomerases can be induced to fail by therapeutic small molecules such as by fluoroquinolones that target bacterial topoisomerases, or a variety of anti-cancer agents that target the eukaryotic enzymes. Increasingly, there have been a large number of agents and processes, including natural products and their metabolites, DNA damage, and the intrinsic properties of the enzymes that can lead to long-lasting DNA breaks that subsequently lead to genome instability, cancer, and other diseases. Understanding the processes that can interfere with topoisomerases and how cells respond when topoisomerases fail will be important in minimizing the consequences when enzymes need to transiently interfere with DNA integrity.
Collapse
Affiliation(s)
- Karin C Nitiss
- University of Illinois College of Medicine, Department of Biomedical Sciences, Rockford, IL, 61107, United States; University of Illinois College of Pharmacy, Biopharmaceutical Sciences Department, Rockford IL, 61107, United States
| | - John L Nitiss
- University of Illinois College of Pharmacy, Biopharmaceutical Sciences Department, Rockford IL, 61107, United States.
| | - Leslyn A Hanakahi
- University of Illinois College of Pharmacy, Biopharmaceutical Sciences Department, Rockford IL, 61107, United States.
| |
Collapse
|
4
|
Yang X, Lu Y, He F, Hou F, Xing C, Xu P, Wang QF. Benzene metabolite hydroquinone promotes DNA homologous recombination repair via the NF-κB pathway. Carcinogenesis 2019; 40:1021-1030. [PMID: 30770924 DOI: 10.1093/carcin/bgy157] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 10/11/2018] [Indexed: 12/29/2022] Open
Abstract
Abstract
Benzene, a widespread environmental pollutant, induces DNA double-strand breaks (DSBs) and DNA repair, which may further lead to oncogenic mutations, chromosomal rearrangements and leukemogenesis. However, the molecular mechanisms underlying benzene-induced DNA repair and carcinogenesis remain unclear. The human osteosarcoma cell line (U2OS/DR-GFP), which carries a GFP-based homologous recombination (HR) repair reporter, was treated with hydroquinone, one of the major benzene metabolites, to identify the potential effects of benzene on DSB HR repair. RNA-sequencing was further employed to identify the potential key pathway that contributed to benzene-initiated HR repair. We found that treatment with hydroquinone induced a significant increase in HR. NF-κB pathway, which plays a critical role in carcinogenesis in multiple tumors, was significantly activated in cells recovered from hydroquinone treatment. Furthermore, the upregulation of NF-κB by hydroquinone was also found in human hematopoietic stem and progenitor cells. Notably, the inhibition of NF-κB activity by small molecule inhibitors (QNZ and JSH-23) significantly reduced the frequency of hydroquinone-initiated HR (−1.36- and −1.77-fold, respectively, P < 0.01). Our results demonstrate an important role of NF-κB activity in promoting HR repair induced by hydroquinone. This finding sheds light on the underlying mechanisms involved in benzene-induced genomic instability and leukemogenesis and may contribute to the larger exploration of the influence of other environmental pollutants on carcinogenesis.
Collapse
Affiliation(s)
- Xuejing Yang
- CAS Key Laboratory of Genomic and Precision Medicine, Collaborative Innovation Center of Genetics and Development, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Chemical Safety and Health, National Institute for Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yedan Lu
- Key Laboratory of Chemical Safety and Health, National Institute for Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing, China
- Department of Nutrition, Food Safety and Toxicology, West China School of Public Health, Sichuan University, Chengdu, Sichuan, China
| | - Fuhong He
- CAS Key Laboratory of Genomic and Precision Medicine, Collaborative Innovation Center of Genetics and Development, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Fenxia Hou
- Key Laboratory of Chemical Safety and Health, National Institute for Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Caihong Xing
- Key Laboratory of Chemical Safety and Health, National Institute for Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Peiyu Xu
- Department of Nutrition, Food Safety and Toxicology, West China School of Public Health, Sichuan University, Chengdu, Sichuan, China
| | - Qian-Fei Wang
- CAS Key Laboratory of Genomic and Precision Medicine, Collaborative Innovation Center of Genetics and Development, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
5
|
Liu X, Wu J, Shi W, Shi W, Liu H, Wu X. Lead Induces Genotoxicity via Oxidative Stress and Promoter Methylation of DNA Repair Genes in Human Lymphoblastoid TK6 Cells. Med Sci Monit 2018; 24:4295-4304. [PMID: 29933360 PMCID: PMC6045917 DOI: 10.12659/msm.908425] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Background Lead (Pb) is a widely used metal in modern industry and is regarded as a health hazard. Although lead-induced genotoxicity has been confirmed, the direct evidence that lead induces genotoxicity in human cells and its related mechanisms has not been fully elucidated. In this study, for the first time, we evaluated the genotoxicity induced by lead in human lymphoblastoid TK6 cells. Material/Methods The TK6 cells were incubated with various concentrations of Pb(Ac)2 for 6 h, 12 h, or 24 h. Cell viability was detected by CCK8 assay. Various biochemical markers were assessed by specific kits. Immunofluorescence assay was used to detect γ-H2AX foci formation. The promoter methylation was assessed by methylation-specific PCR. The protein levels were determined by Western blot assay. Results The results showed that after exposure to lead, cell viability was obviously decreased and γ-H2AX foci formation was significantly enhanced in TK6 cells. Moreover, the levels of 8-OHdG, ROS, MDA, and GSSG were increased, while the GSH level and SOD activity were decreased in lead-treated TK6 cells. The activation of the Nrf2-ARE signaling pathway was involved in lead-induced oxidative stress in TK6 cells. Finally, the expressions of DNA repair genes XRCC1, hOGG-1, BRCA1, and XPD were inhibited via enhancing their promoter methylation in TK6 cells after exposure to lead. Conclusions Taken together, our study provides the first published evidence that lead exposure results in DNA damage via promoting oxidative stress and the promoter methylation of DNA repair genes in human lymphoblastoid TK6 cells.
Collapse
Affiliation(s)
- Xiangquan Liu
- Department of Nutrition and Food Safety, School of Public Health, Fujian Medical University, Fuzhou, Fujian, China (mainland)
| | - Jingying Wu
- Department of Preventive Medicine, Fuzhou Center for Disease Control and Prevention, Fuzhou, Fujian, China (mainland)
| | - Wenyan Shi
- Department of Clinical Nutrition, Shenzhen Third People's Hospital, Shenzhen, Guangdong, China (mainland)
| | - Wenhua Shi
- Department of Occupational Health, Fuzhou Center for Disease Control and Prevention, Fuzhou, Fujian, China (mainland)
| | - Hekun Liu
- Department of Cell Biology and Genetics, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, China (mainland)
| | - Xiaonan Wu
- Department of Nutrition and Food Safety, School of Public Health, Fujian Medical University, Fuzhou, Fujian, China (mainland)
| |
Collapse
|
6
|
Ji Z, McHale CM, Bersonda J, Tung J, Smith MT, Zhang L. Induction of centrosome amplification by formaldehyde, but not hydroquinone, in human lymphoblastoid TK6 cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2015; 56:535-44. [PMID: 25821186 PMCID: PMC6529207 DOI: 10.1002/em.21947] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 02/20/2015] [Indexed: 05/08/2023]
Abstract
Benzene and formaldehyde (FA) are important industrial chemicals and environmental pollutants that cause leukemia by inducing DNA damage and chromosome aberrations in hematopoietic stem cells (HSC), the target cells for leukemia. Our previous studies showed that workers exposed to benzene and FA exhibit increased levels of aneuploidy in their blood cells. As centrosome amplification is a common phenomenon in human cancers, including leukemia, and is associated with aneuploidy in carcinogenesis, we hypothesized that benzene and FA would induce centrosome amplification in vitro. We treated human lymphoblastoid TK6 cells with a range of concentrations of hydroquinone (HQ, a benzene metabolite) or FA for 24 h, allowed the cells to recover in fresh medium for 24 h, and examined centrosome amplification; chromosomal gain, loss, and breakage; and cytotoxicity. We included melphalan and etoposide, chemotherapeutic drugs that cause therapy-related acute myeloid leukemia and that have been shown to induce centrosome amplification as well as chromosomal aneuploidy and breakage, as positive controls. Melphalan and etoposide induced centrosome amplification and chromosome gain and breakage in a dose-dependent manner, at cytotoxic concentrations. HQ, though cytotoxic, did not induce centrosome amplification or any chromosomal aberration. FA-induced centrosome amplification and cytotoxicity, but did not induce chromosomal aberrations. Our data suggest, for the first time, that centrosome amplification is a potential mechanism underlying FA-induced leukemogenesis, but not benzene-induced leukemogenesis, as mediated through HQ. Future studies are needed to delineate the mechanisms of centrosome amplification and its association with DNA damage, chromosomal aneuploidy and carcinogenesis, following exposure to FA.
Collapse
Affiliation(s)
- Zhiying Ji
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, California
| | - Cliona M. McHale
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, California
| | - Jessica Bersonda
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, California
| | - Judy Tung
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, California
| | - Martyn T. Smith
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, California
| | - Luoping Zhang
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, California
| |
Collapse
|
7
|
Moeller BC, Recio L, Green A, Sun W, Wright FA, Bodnar WM, Swenberg JA. Biomarkers of exposure and effect in human lymphoblastoid TK6 cells following [13C2]-acetaldehyde exposure. Toxicol Sci 2013; 133:1-12. [PMID: 23425604 PMCID: PMC3627555 DOI: 10.1093/toxsci/kft029] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 02/11/2013] [Indexed: 01/13/2023] Open
Abstract
The dose-response relationship for biomarkers of exposure (N(2)-ethylidene-dG adducts) and effect (cell survival and micronucleus formation) was determined across 4.5 orders of magnitude (50nM-2mM) using [(13)C2]-acetaldehyde exposures to human lymphoblastoid TK6 cells for 12h. There was a clear increase in exogenous N (2)-ethylidene-dG formation at exposure concentrations ≥ 1µM, whereas the endogenous adducts remained nearly constant across all exposure concentrations, with an average of 3.0 adducts/10(7) dG. Exogenous adducts were lower than endogenous adducts at concentrations ≤ 10µM and were greater than endogenous adducts at concentrations ≥ 250µM. When the endogenous and exogenous adducts were summed together, statistically significant increases in total adduct formation over the endogenous background occurred at 50µM. Cell survival and micronucleus formation were monitored across the exposure range and statistically significant decreases in cell survival and increases in micronucleus formation occurred at ≥ 1000µM. This research supports the hypothesis that endogenously produced reactive species, including acetaldehyde, are always present and constitute the majority of the observed biological effects following very low exposures to exogenous acetaldehyde. These data can replace default assumptions of linear extrapolation to very low doses of exogenous acetaldehyde for risk prediction.
Collapse
Affiliation(s)
- Benjamin C. Moeller
- *Curriculum in Toxicology, University of North Carolina, Chapel Hill, North Carolina 27599
| | | | | | - Wei Sun
- ‡Biostatistics, Gillings School of Global Public Health
- §Department of Genetics, School of Medicine, and
| | | | - Wanda M. Bodnar
- ¶Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina 27599
| | - James A. Swenberg
- *Curriculum in Toxicology, University of North Carolina, Chapel Hill, North Carolina 27599
- ¶Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina 27599
| |
Collapse
|
8
|
Hu G, Huang H, Yang L, Zhong C, Xia B, Yang Y, Liu J, Wu D, Liu Q, Zhuang Z. Down-regulation of Polη expression leads to increased DNA damage, apoptosis and enhanced S phase arrest in L-02 cells exposed to hydroquinone. Toxicol Lett 2012; 214:209-17. [DOI: 10.1016/j.toxlet.2012.08.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 08/27/2012] [Accepted: 08/28/2012] [Indexed: 01/25/2023]
|
9
|
McHale CM, Zhang L, Smith MT. Current understanding of the mechanism of benzene-induced leukemia in humans: implications for risk assessment. Carcinogenesis 2012; 33:240-52. [PMID: 22166497 PMCID: PMC3271273 DOI: 10.1093/carcin/bgr297] [Citation(s) in RCA: 207] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 11/21/2011] [Accepted: 12/07/2011] [Indexed: 01/01/2023] Open
Abstract
Benzene causes acute myeloid leukemia and probably other hematological malignancies. As benzene also causes hematotoxicity even in workers exposed to levels below the US permissible occupational exposure limit of 1 part per million, further assessment of the health risks associated with its exposure, particularly at low levels, is needed. Here, we describe the probable mechanism by which benzene induces leukemia involving the targeting of critical genes and pathways through the induction of genetic, chromosomal or epigenetic abnormalities and genomic instability, in a hematopoietic stem cell (HSC); stromal cell dysregulation; apoptosis of HSCs and stromal cells and altered proliferation and differentiation of HSCs. These effects modulated by benzene-induced oxidative stress, aryl hydrocarbon receptor dysregulation and reduced immunosurveillance, lead to the generation of leukemic stem cells and subsequent clonal evolution to leukemia. A mode of action (MOA) approach to the risk assessment of benzene was recently proposed. This approach is limited, however, by the challenges of defining a simple stochastic MOA of benzene-induced leukemogenesis and of identifying relevant and quantifiable parameters associated with potential key events. An alternative risk assessment approach is the application of toxicogenomics and systems biology in human populations, animals and in vitro models of the HSC stem cell niche, exposed to a range of levels of benzene. These approaches will inform our understanding of the mechanisms of benzene toxicity and identify additional biomarkers of exposure, early effect and susceptibility useful for risk assessment.
Collapse
Affiliation(s)
| | | | - Martyn T. Smith
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, CA 94720-7356, USA
| |
Collapse
|
10
|
Peng D, Jiaxing W, Chunhui H, Weiyi P, Xiaomin W. Study on the cytogenetic changes induced by benzene and hydroquinone in human lymphocytes. Hum Exp Toxicol 2012; 31:322-35. [DOI: 10.1177/0960327111433900] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Benzene (BN) is a prototypical hematotoxicant, genotoxic carcinogen, and ubiquitous environmental pollutant. Although the molecular mechanisms of BN-induced cytotoxicity and genotoxic damage are poorly understood in humans, previous studies suggested that bioactivated BN metabolites are capable of oxidative stress, cell cycle arrest, apoptosis, and DNA damage. The objective of the current study was to investigate the BN-induced cytogenetic changes and underlying mechanisms based on these hypotheses. Peripheral blood lymphocytes (PBLs) might be the targets for BN-induced cytotoxicity and genotoxicity, and therefore DNA damage responses of PBLs after exposure to different concentrations of BN (0.25, 3.5, 50 μmol/L) or BN metabolite, hydroquinone (HQ; 50, 150, 450 μmol/L) were studied in vitro. Microculture tetrazolium assay, flow cytometry, 2′,7′-dichlorodihydrofluorescein-diacetate assay, comet assay, micronuclei assay, and attenuated total reflectance microspectroscope were chosen for this study. Based on the results, we reached the conclusion that different concentrations of BN or HQ significantly inhibited cell growth, induced the arrest of S phase and G2/M phase, and increased late apoptosis in a concentration-dependent manner. Furthermore, evidence was also provided to support the conclusion that BN and HQ induced DNA strand breaks and chromosomal mutations in PBL, which indicated the genotoxicity of BN and HQ. Current evidence has indicated that multiple mechanisms including dysfunction of cell cycle, programmed cell death, oxidative stress, and DNA lesions are likely to contribute to BN-induced cytogenetic changes.
Collapse
Affiliation(s)
- D Peng
- Department of Public Health, School of Basic Medical, Hubei University of Medicine, Shiyan, Hubei, PR China
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, Guangxi, PR China
| | - W Jiaxing
- School of Chemical Project, Beijing University of Chemical Technology, Beijing, PR China
| | - H Chunhui
- Department of Clinical Laboratories, the Affiliated Taihe Hospital, Hubei University of Medicine, Hubei Shiyan, PR China
| | - P Weiyi
- Department of Health Statistics and Environmental Health, School of Public Health, Guangxi Medical University, Nanning, Guangxi, PR China
| | - W Xiaomin
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, Guangxi, PR China
| |
Collapse
|
11
|
Liu L, Ling X, Liang H, Gao Y, Yang H, Shao J, Tang H. Hypomethylation mediated by decreased DNMTs involves in the activation of proto-oncogene MPL in TK6 cells treated with hydroquinone. Toxicol Lett 2012; 209:239-45. [PMID: 22245671 DOI: 10.1016/j.toxlet.2011.12.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Revised: 12/28/2011] [Accepted: 12/29/2011] [Indexed: 12/15/2022]
Abstract
Hydroquinone (HQ), one of the most important metabolites derived from benzene, is known to be associated with acute myelogenous leukemia (AML) risk, however, its carcinogenic mechanism remains unclear. In this study, the epigenetic mechanism of HQ exposure was investigated. We characterized the epigenomic response of TK6 cells to HQ exposure, and examined the mRNA expression of DNA methyltransferases (DNMTs) including DNMT1, DNMT3a and DNMT3b, methyl-CpG-binding domain protein 2 (MBD2) and six proto-oncogenes (MPL, RAF1, MYB, MYC, ERBB2 and BRAF). Compared to the control cells, HQ exposure (2.5, 5.0, 10.0 and 20.0 μM for 48 h) resulted in the decrease of DNMTs and MBD2 expression, the global hypomethylation and increase of MPL at mRNA level. Meanwhile, most of these changes were in dose-dependent manner. Moreover, inhibition of DNMTs induced by 5-aza-2'-deoxycytidine (5-AZA), an identified DNMT inhibitor, caused more induction of MPL expression at mRNA level compared to the HQ (10.0 μM) pre-treated group. Furthermore, treatment of HQ potentially led to MPL itself hypomethylation (10.0 and 20.0 μM reduced by 47% and 44%, respectively), further revealing that the activation of proto-oncogene MPL was related to hypomethylation in its DNA sequences. In conclusion, hypomethylation, including global and specific hypomethylation, might be involved in the activation of MPL, and the hypomethylation could be induced by decreased DNMTs in TK6 cells exposed to HQ.
Collapse
Affiliation(s)
- Linhua Liu
- Department of Environmental and Occupational Health, School of Public Health, Guangdong Medical College, Dongguan 523808, PR China
| | | | | | | | | | | | | |
Collapse
|
12
|
In vivo hydroquinone exposure alters circulating neutrophil activities and impairs LPS-induced lung inflammation in mice. Toxicology 2011; 288:1-7. [DOI: 10.1016/j.tox.2011.05.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 05/10/2011] [Accepted: 05/16/2011] [Indexed: 02/07/2023]
|
13
|
Mazzeo DEC, Fernandes TCC, Marin-Morales MA. Cellular damages in the Allium cepa test system, caused by BTEX mixture prior and after biodegradation process. CHEMOSPHERE 2011; 85:13-18. [PMID: 21741065 DOI: 10.1016/j.chemosphere.2011.06.056] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 06/01/2011] [Accepted: 06/12/2011] [Indexed: 05/31/2023]
Abstract
Petroleum and derivatives have been considered one of the main environmental contaminants. Among petroleum derivatives, the volatile organic compounds benzene, toluene, ethylbenzene and xylene (BTEX) represent a major concern due to their toxicity and easy accumulation in groundwater. Biodegradation methods seem to be suitable tools for the clean-up of BTEX contaminants from groundwater. Genotoxic and mutagenic potential of BTEX prior and after biodegradation process was evaluated through analyses of chromosomal aberrations and MN test in meristematic and F(1) root cells using the Allium cepa test system. Seeds of A. cepa were germinated into five concentrations of BTEX, non-biodegraded and biodegraded, in ultra-pure water (negative control), in MMS 4×10(-4)M (positive control) and in culture medium used in the biodegradation (blank biodegradation control). Results showed a significant frequency of both chromosomal and nuclear aberrations. The micronucleus (MN) frequency in meristematic cells was significant for most of tested samples. However, MN was not present in significant levels in the F(1) cells, suggesting that there was no permanent damage for the meristematic cell. The BTEX effects were significantly reduced in the biodegraded samples when compared to the respective non-biodegraded concentrations. Therefore, in this study, the biodegradation process showed to be a reliable and effective alternative to treat BTEX-contaminated waters. Based on our results and available data, the BTEX toxicity could also be related to a synergistic effect of its compounds.
Collapse
|
14
|
Pacchierotti F, Eichenlaub-Ritter U. Environmental Hazard in the Aetiology of Somatic and Germ Cell Aneuploidy. Cytogenet Genome Res 2011; 133:254-68. [DOI: 10.1159/000323284] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
|
15
|
Ji Z, Zhang L, Peng V, Ren X, McHale CM, Smith MT. A comparison of the cytogenetic alterations and global DNA hypomethylation induced by the benzene metabolite, hydroquinone, with those induced by melphalan and etoposide. Leukemia 2010; 24:986-91. [PMID: 20339439 PMCID: PMC4353491 DOI: 10.1038/leu.2010.43] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Revised: 01/07/2010] [Accepted: 01/29/2010] [Indexed: 12/26/2022]
Abstract
Specific cytogenetic alterations and changes in DNA methylation are involved in leukemogenesis. Benzene, an established human leukemogen, is known to induce cytogenetic changes through its active metabolites including hydroquinone (HQ), but the specific alterations have not been fully characterized. Global DNA hypomethylation was reported in a population exposed to benzene, but has not been confirmed in vitro. In this study, we examined cytogenetic changes in chromosomes 5, 7, 8, 11 and 21, and global DNA methylation in human TK6 lymphoblastoid cells treated with HQ for 48 h, and compared the HQ-induced alterations with those induced by two well-known leukemogens, melphalan, an alkylating agent, and etoposide, a DNA topoisomerase II inhibitor. We found that rather than inducing cytogenetic alterations distinct from those induced by melphalan and etoposide, HQ induced alterations characteristic of each agent. HQ induced global DNA hypomethylation at a level intermediate to melphalan (no effect) and etoposide (potent effect). These results suggest that HQ may act similar to an alkylating agent and also similar to a DNA topoisomerase II inhibitor in living cells, both of which may be potential mechanisms of benzene toxicity. In addition to cytogenetic changes, global DNA hypomethylation may be another mechanism underlying the leukemogenicity of benzene.
Collapse
MESH Headings
- Antineoplastic Agents, Alkylating/pharmacology
- Antineoplastic Agents, Phytogenic/pharmacology
- Cells, Cultured
- Chromosomes, Human/drug effects
- Chromosomes, Human/genetics
- DNA Methylation/drug effects
- Etoposide/pharmacology
- Humans
- Hydroquinones/pharmacology
- In Situ Hybridization, Fluorescence
- Leukemia, Myeloid, Acute/drug therapy
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/pathology
- Lymphocytes/drug effects
- Melphalan/pharmacology
- Mutagens/pharmacology
Collapse
Affiliation(s)
- Z Ji
- Division of Environmental Health Sciences, School of Public Health, University of California at Berkeley, Berkeley, CA 94720-7360, USA
| | | | | | | | | | | |
Collapse
|
16
|
Zhang L, McHale CM, Rothman N, Li G, Ji Z, Vermeulen R, Hubbard AE, Ren X, Shen M, Rappaport SM, North M, Skibola CF, Yin S, Vulpe C, Chanock SJ, Smith MT, Lan Q. Systems biology of human benzene exposure. Chem Biol Interact 2010; 184:86-93. [PMID: 20026094 PMCID: PMC2846187 DOI: 10.1016/j.cbi.2009.12.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 12/09/2009] [Accepted: 12/10/2009] [Indexed: 01/09/2023]
Abstract
Toxicogenomic studies, including genome-wide analyses of susceptibility genes (genomics), gene expression (transcriptomics), protein expression (proteomics), and epigenetic modifications (epigenomics), of human populations exposed to benzene are crucial to understanding gene-environment interactions, providing the ability to develop biomarkers of exposure, early effect and susceptibility. Comprehensive analysis of these toxicogenomic and epigenomic profiles by bioinformatics in the context of phenotypic endpoints, comprises systems biology, which has the potential to comprehensively define the mechanisms by which benzene causes leukemia. We have applied this approach to a molecular epidemiology study of workers exposed to benzene. Hematotoxicity, a significant decrease in almost all blood cell counts, was identified as a phenotypic effect of benzene that occurred even below 1 ppm benzene exposure. We found a significant decrease in the formation of progenitor colonies arising from bone marrow stem cells with increasing benzene exposure, showing that progenitor cells are more sensitive to the effects of benzene than mature blood cells, likely leading to the observed hematotoxicity. Analysis of transcriptomics by microarray in the peripheral blood mononuclear cells of exposed workers, identified genes and pathways (apoptosis, immune response, and inflammatory response) altered at high (>10 ppm) and low (<1 ppm) benzene levels. Serum proteomics by SELDI-TOF-MS revealed proteins consistently down-regulated in exposed workers. Preliminary epigenomics data showed effects of benzene on the DNA methylation of specific genes. Genomic screens for candidate genes involved in susceptibility to benzene toxicity are being undertaken in yeast, with subsequent confirmation by RNAi in human cells, to expand upon the findings from candidate gene analyses. Data on these and future biomarkers will be used to populate a large toxicogenomics database, to which we will apply bioinformatic approaches to understand the interactions among benzene toxicity, susceptibility genes, mRNA, and DNA methylation through a systems biology approach.
Collapse
Affiliation(s)
- Luoping Zhang
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA 94720-7356, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Golding BT, Barnes ML, Bleasdale C, Henderson AP, Jiang D, Li X, Mutlu E, Petty HJ, Sadeghi MM. Modeling the formation and reactions of benzene metabolites. Chem Biol Interact 2010; 184:196-200. [PMID: 20064493 DOI: 10.1016/j.cbi.2010.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2009] [Revised: 12/23/2009] [Accepted: 01/04/2010] [Indexed: 10/20/2022]
Abstract
One or more of the muconaldehyde isomers is a putative product of benzene metabolism. As muconaldehydes are highly reactive dienals and potentially mutagenic they might be relevant to the carcinogenicity of benzene. Muconaldehydes may be derived through the action of a cytochrome P450 mono-oxygenase on benzene oxide-oxepin, which are established metabolites of benzene. Oxidation of benzene oxide-oxepin either by the one-electron oxidant cerium(IV) ammonium nitrate (CAN) or by iron(III) tris(1,10-phenanthroline) hexafluorophosphate in acetone at -78 degrees C or acetonitrile at -40 degrees C gave (E,Z)-muconaldehyde, which was a single diastereoisomer according to analysis by (1)H NMR spectroscopy. Reaction of toluene-1,2-oxide/2-methyloxepin with CAN gave (2E,4Z)-6-oxo-hepta-2,4-dienal. Similarly, the action of CAN on 1,6-dimethylbenzene oxide-2,7-dimethyloxepin gave (3Z,5E)-octa-3,5-diene-2,7-dione. In vivo, benzene oxide-oxepin could suffer one-electron oxidation by cytochrome P450 mono-oxygenase giving (E,Z)-muconaldehyde. The observations presented may be relevant to the toxicology of benzene oxide-oxepin and other arene oxide-oxepins as we have previously shown that (E,Z)-muconaldehyde, analogously to (Z,Z)-muconaldehyde, affords pyrrole adducts with the exocyclic amino groups of the DNA bases adenine and guanine. Independent of their possible toxicological significance, the experiments described provide preparatively useful routes to (E,Z)-muconaldehyde and its congeners. Methods are also described for the trapping and analysis of reactive benzene metabolites, e.g. using the Diels-Alder reaction with the dienophile 4-phenyl-1,2,4-triazoline-3,5-dione to trap arene oxides and with the diene 1,3-diphenylisobenzofuran to trap enals.
Collapse
Affiliation(s)
- Bernard T Golding
- School of Chemistry, Bedson Building, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
| | | | | | | | | | | | | | | | | |
Collapse
|