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Zhang X, Wallace AD, Du P, Lin S, Baccarelli AA, Jiang H, Jafari N, Zheng Y, Xie H, Soares MB, Kibbe WA, Hou L. Genome-wide study of DNA methylation alterations in response to diazinon exposure in vitro. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2012; 34:959-68. [PMID: 22964155 PMCID: PMC3514648 DOI: 10.1016/j.etap.2012.07.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 07/20/2012] [Accepted: 07/25/2012] [Indexed: 05/21/2023]
Abstract
Pesticide exposure has repeatedly been associated with cancers. However, molecular mechanisms are largely undetermined. In this study, we examined whether exposure to diazinon, a common organophosphate that has been associated with cancers, could induce DNA methylation alterations. We conducted genome-wide DNA methylation analyses on DNA samples obtained from human hematopoietic K562 cell exposed to diazinon and ethanol using the Illumina Infinium HumanMethylation27 BeadChip. Bayesian-adjusted t-tests were used to identify differentially methylated gene promoter CpG sites. We identified 1069 CpG sites in 984 genes with significant methylation changes in diazinon-treated cells. Gene ontology analysis demonstrated that some genes are tumor suppressor genes, such as TP53INP1 (3.0-fold, q-value <0.001) and PTEN (2.6-fold, q-value <0.001), some genes are in cancer-related pathways, such as HDAC3 (2.2-fold, q-value=0.002), and some remain functionally unknown. Our results provided direct experimental evidence that diazinon may modify gene promoter DNA methylation levels, which may play a pathological role in cancer development.
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Affiliation(s)
- Xiao Zhang
- Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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Zhang X, Wallace AD, Du P, Kibbe WA, Jafari N, Xie H, Lin S, Baccarelli A, Soares MB, Hou L. DNA methylation alterations in response to pesticide exposure in vitro. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2012; 53:542-9. [PMID: 22847954 PMCID: PMC3753688 DOI: 10.1002/em.21718] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 06/13/2012] [Accepted: 06/21/2012] [Indexed: 05/20/2023]
Abstract
Although pesticides are subject to extensive carcinogenicity testing before regulatory approval, pesticide exposure has repeatedly been associated with various cancers. This suggests that pesticides may cause cancer via nonmutagenicity mechanisms. The present study provides evidence to support the hypothesis that pesticide-induced cancer may be mediated in part by epigenetic mechanisms. We examined whether exposure to seven commonly used pesticides (i.e., fonofos, parathion, terbufos, chlorpyrifos, diazinon, malathion, and phorate) induces DNA methylation alterations in vitro. We conducted genome-wide DNA methylation analyses on DNA samples obtained from the human hematopoietic K562 cell line exposed to ethanol (control) and several organophosphate pesticides (OPs) using the Illumina Infinium HumanMethylation27 BeadChip. Bayesian-adjusted t-tests were used to identify differentially methylated gene promoter CpG sites. In this report, we present our results on three pesticides (fonofos, parathion, and terbufos) that clustered together based on principle component analysis and hierarchical clustering. These three pesticides induced similar methylation changes in the promoter regions of 712 genes, while also exhibiting their own OP-specific methylation alterations. Functional analysis of methylation changes specific to each OP, or common to all three OPs, revealed that differential methylation was associated with numerous genes that are involved in carcinogenesis-related processes. Our results provide experimental evidence that pesticides may modify gene promoter DNA methylation levels, suggesting that epigenetic mechanisms may contribute to pesticide-induced carcinogenesis. Further studies in other cell types and human samples are required, as well as determining the impact of these methylation changes on gene expression.
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Affiliation(s)
- Xiao Zhang
- Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Andrew D. Wallace
- Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, North Carolina, USA
| | - Pan Du
- Department of Bioinformatics and Computational Biology, Genentech Inc., South San Francisco, California, USA
| | - Warren A. Kibbe
- Northwestern University Biomedical Informatics Center (NUBIC), Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Nadereh Jafari
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Hehuang Xie
- Falk Brain Tumor Center, Cancer Biology and Epigenomics Program, Children’s Memorial Research Center, Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Simon Lin
- Biomedical Informatics Research Center, Marshfield Clinic Research Foundation, Marshfield, Wisconsin, USA
| | - Andrea Baccarelli
- Exposure, Epidemiology and Risk Program, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA
| | - Marcelo Bento Soares
- Falk Brain Tumor Center, Cancer Biology and Epigenomics Program, Children’s Memorial Research Center, Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Lifang Hou
- Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- The Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- For reprints and all correspondence: Lifang Hou Department of Preventive Medicine Feinberg School of Medicine, Northwestern University 680 North Lake Shore Drive, Chicago, Illinois 60611 Phone: (312) 503-4798; Fax: (312) 908-9588
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Martin-Kleiner I, Svoboda-Beusan I, Gabrilovac J. PMA and doxorubicin decrease viability, MTT activity and expression of CD10 marker on NALM-1 leukemic cells. Immunopharmacol Immunotoxicol 2007; 28:411-20. [PMID: 16997790 DOI: 10.1080/08923970600927520] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PMA (10, 20 ng/ml) and doxorubicin (5-20 ng/ml) decreased the viability and MTT-activity of NALM-1 pre-B leukemic cells (3 days' treatment). Further, CD10 was downregulated, suggesting that PMA and doxorubicin induced differentiation of NALM-1 cells. However, PMA did not alter expression of B cell markers CD20 and of mIgM. In contrast to PMA, another differentiation agent ATRA did not alter CD10 expression on NALM-1 cells but affected viability after 6 days (5, 10 ng/ml). The data in this study are the first evidence that PMA and doxorubicin inhibited viability and MTT activity and induced partial differentiation, by decreasing CD10 on NALM-1 cells.
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Affiliation(s)
- I Martin-Kleiner
- Division of Molecular Medicine, Ruder Bosković Institute, Zagreb, Croatia.
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Zimmermann SY, Esser R, Rohrbach E, Klingebiel T, Koehl U. A novel four-colour flow cytometric assay to determine natural killer cell or T-cell-mediated cellular cytotoxicity against leukaemic cells in peripheral or bone marrow specimens containing greater than 20% of normal cells. J Immunol Methods 2005; 296:63-76. [PMID: 15680151 DOI: 10.1016/j.jim.2004.10.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2004] [Revised: 09/15/2004] [Accepted: 10/25/2004] [Indexed: 11/25/2022]
Abstract
To be able to determine the cytotoxic activity of NK cells or T cells against leukaemic cells in patient samples containing >20% of normal peripheral blood cells, we have developed a four-colour flow cytometric cytotoxicity assay. The assay is based on differential immunostaining of both leukaemic cells and effector cells in combination with propidium iodide (PI). The cytometer is set for measuring the fluorescence of the monoclonal antibody (mAb) bound fluorochromes, with moderate overcompensation of the third and fourth fluorescence signals. PI-positive events were excluded from analysis by their characteristic uncompensated signal on these two detectors. Thus, all four fluorescence ranges can be used for detection of mAb-derived signals and this allows discrimination between various populations contained in effector and target cell samples. The cytotoxic activity in our assay is calculated by the absolute loss of vital leukaemic cells. For this purpose, fluorescent beads are included as an internal standard. When calculating the effector concentrations after coculture, characteristic changes can be seen which yield additional information about the presence of cytotoxic activity and the active effector cell subset. With this assay, we present a versatile tool that combines minimum cell manipulation before coculture with maximum information from a sample. The assay is suitable for the analysis of complex samples with regard to different cell subsets, their decrease or increase, and conjugate formation.
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Affiliation(s)
- Stefanie-Yvonne Zimmermann
- Laboratory for Stem Cell Transplantation and Immunotherapy, Paediatric Haematology, Oncology and Haemostaseology, Johann Wolfgang Goethe-Universität, Theodor-Stern-Kai 7, Frankfurt am Main, Germany.
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Doggett KL, Briggs JA, Linton MF, Fazio S, Head DR, Xie J, Hashimoto Y, Laborda J, Briggs RC. Retroviral mediated expression of the human myeloid nuclear antigen in a null cell line upregulates Dlk1 expression. J Cell Biochem 2002; 86:56-66. [PMID: 12112016 DOI: 10.1002/jcb.10190] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The human myeloid nuclear differentiation antigen (MNDA) is a hematopoietic cell specific nuclear protein. MNDA and other related gene products interact with and alter the activity of a large number of proteins involved in regulating specific gene transcription. MNDA and related genes exhibit expression characteristics, which suggest functions unique to specific lineages of cells, in addition to mediating the effects of interferons. Cells of the human K562 myeloid line do not express MNDA and are relatively immature compared to lines that express MNDA (HL-60, U937, and THP1). The hypothesis that MNDA influences the expression of specific genes was tested by creating MNDA expressing K562 cells using stable retroviral mediated gene transfer followed by evaluation of transcription profiles. Two macroarrays containing a total of 2,350 cDNAs of known genes showed a specific up-regulation of Dlk1 expression in MNDA expressing K562 cell clones. Real time quantitative RT-PCR analysis confirmed an average of over 3- and 7-fold upregulation of Dlk1 in two clones of MNDA expressing K562 cells. The effects on Dlk1 were also confirmed by Northern blotting. Dlk1 is essential for normal hematopoiesis and abnormal expression is a proposed marker of myelodysplastic syndrome. Additional screening of transcription profiles after induced erythroid and megakaryoblastic differentiation showed no additional gene transcripts altered by the presence of MNDA. These results indicate that MNDA alters expression of a gene essential for normal hematopoiesis.
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Affiliation(s)
- Kevin L Doggett
- Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-5310, USA
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