The aberrant landscape of DNA methylation and gene expression during arsenic-induced cell transformation
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ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Francisco Barajas-Olmos
PROVIDER: E-MTAB-7972 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:We describe the alterations in DNA methylation around the promoter region and the impact on gene expression in HaCaT cells during the transformation process caused by chronic exposure to arsenic. Nucleic acids were extracted at the beginning of treatment and at weeks 0, 5, 15, and 25. Cell cultures with the same passage (week 25) and no arsenic treatment served as controls.
2019-11-02 | E-MTAB-7973 | biostudies-arrayexpress
Project description:The purpose of this study is to search for aberrant genes in HaCaT keratinocytes after chronic exposure to arsenic trioxide. The objective of the investigation was to discover the mechanism of arsenic carcinogenicity in human epidermal keratinocytes. We hypothesize that a combined strategy of DNA microarray, qRT-PCR and gene function annotation will identify aberrantly expressed genes in HaCaT keratinocyte cell line after chronic treatment with arsenic trioxide. HaCaT cells were chronically exposed to 0.5M-BM-5g/mL arsenic trioxide (As2O3) up to 22 passages and RNA was extracted. Microarray data analysis identified 14 up-regulated genes and 21 down-regulated genes in response to arsenic trioxide Two experimental groups: 1. The treatment group was sub-cultured up to passage 22 to establish a chronic exposure state. 2. The passage control group was also sub-cultured up to 22 passages but with no exposure to arsenic trioxide. 4 technical replicates with 3 replicates making a total of 8X3 =24 samples HaCat Cell untreated (passage control): 1. H1_H001, H1_H002, H1_H003 2. H2_ H004, H2_H005, H2_H006 3. H3_ H007, H3_H008, H3_H009 4. H4_ H010, H4_H011, H4_H012 HaCat Cell treated with 0.5M-BM-5g/ml of arsenic trioxide: 5. A1_H013, A1_H014, A1_H015 6. A2_H016, A2_H017, A2_H018 7. A3_H019, A3_H020, A3_H021 8. A4_H022, A4_H023, A4_H024 Cell Type: Human Skin Keratinocyte: 1.5 M-CM-^W105 HaCaT cells were cultured in 7.5 ml of complete DMEM containing 10% Fetal Bovine Serum (FBS) and 1% penicillin, streptomycin in T-25 culture plate. Cells were incubated in a humidified atmosphere with 5% CO2 at 37 M-BM-:C. The treatment groups were exposed to 0.5M-BM-5g/mL As2O3 (equivalent to LC 0.5), and passaged at 90% confluent. Total RNA was extracted from 4 technical replicates of unexposed HaCaT cells and HaCaT cells chronically exposed to arsenic trioxide up to passage 22 using RNA STAT-60 (TEL-TEST, INC, Friendswood, TX, USA).
2012-04-11 | E-GEOD-37192 | biostudies-arrayexpress
Project description:Human pluripotent stem cells can be derived from somatic cells by forced expression of defined factors, and more recently by nuclear-transfer into human oocytes, revitalizing a debate on whether one reprogramming approach might be advantageous over the other. Here we compared the genetic and epigenetic stability of human nuclear-transfer embryonic stem cell (NT-ESC) lines and isogenic induced pluripotent stem cell (iPSC) lines, derived from the same somatic cell cultures of fetal, neonatal and adult origin. Both cell types shared similar genome-wide gene expression and DNA methylation profiles. Importantly, NT-ESCs and iPSCs have comparable numbers of de novo coding mutations but significantly higher than parthenogenetic ESCs. Similar to iPSCs NT-ESCs displayed clone- and gene-specific aberrations in DNA methylation and allele-specific expression of imprinted genes, similarly to iPSCs. The occurrence of these genetic and epigenetic defects in both NT-ESCs and iPSCs suggests that they are inherent to reprogramming, regardless of the underlying technique. Genome-wide DNA methylation profiling by Illumina Infinium HumanMethylation 450K Beadchip was performed on a total of 21 human cell lines, including: an isogenic set of 3 nuclear-transfer embryonic stem cell (NT-ESC) lines, 2 RNA-reprogrammed induced pluripotent stem cell (iPSC) lines and their parental neonatal fibroblast cell line; an isogenic set of 1 NT-ESC line, 6 iPSC lines and their parental adult fibroblast cell line (derived from a type 1 diabetic subject); as well as 7 control embryonic stem cell (ESC) lines.
2014-11-06 | E-GEOD-61461 | biostudies-arrayexpress
Project description:Chronic exposure to arsenic is associated with dermatological and non-dermatological disorders. Consumption of arsenic contaminated drinking water results in accumulation of arsenic in liver, spleen, kidneys, lungs and gastrointestinal tract. Although, arsenic is cleared from these sites, a substantial amount of residual arsenic is left in keratin-rich tissues such as skin. Epidemiological studies on arsenic suggest the association of skin cancer upon arsenic exposure, however, the exact mechanism of arsenic induced carcinogenesis is not completely understood. We have developed a cell line-based model to understand the molecular mechanisms involved in arsenic mediated toxicity and carcinogenicity. Human skin keratinocyte cell line, HaCaT was exposed to 100nM sodium arsenite for six months. We observed an increase in the basal ROS levels in arsenic exposed cells along with the increase in anti-apoptotic proteins. SILAC-based quantitative proteomics approach resulted in the identification and quantitation of 2,181 proteins of which 39 proteins were found to be overexpressed (≥2-fold) and 56 downregulated (≤2-fold) upon chronic arsenic exposure. Our study provides comprehensive insights into the molecular basis of chronic arsenic exposure on skin.
2017-01-02 | PXD001645 | Pride
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2014-11-06 | E-GEOD-61657 | biostudies-arrayexpress
Project description:Germ cell tumours (GCTs) are a complex group of malignancies. They are unique in developing from a pluripotent progenitor cell. The initial lesion is believed to be the relatively benign precursor lesion (ICGNU), from which either highly chemosensitive seminomas or the more aggressive non-seminomas develop. Previous analyses of selected genes have suggested that non-seminomas exhibit much higher levels of DNA methylation than seminomas. However, the genomic targets that are methylated, the extent to which this results in gene silencing and the identity of the silenced genes most likely to play a role in the tumoursâ biology have not yet been established. Here genome-wide methylation and expression analysis of GCT cell lines was combined with gene expression data. This demonstrated that the seminoma cells exhibited very little aberrant DNA methylation while non-seminoma cells exhibited very high levels of DNA methylation. Large differences in the level of methylation of the CpG islands of individual genes between tumour cell lines correlated well with differential gene expression. Treatment of non-seminoma cells with 5-aza-2-deoxycytidine verified that methylation of all genes tested did indeed play a role in their silencing and many of these genes were also differentially expressed in primary tumours. Through this approach the genes silenced in the various GCT cell lines were identified. Conclusions: Several pluripotency-associated genes, never before implicated in this type of cancer, were identified as a major functional group of silenced genes. Silencing of these factors that normally suppress somatic differentiation might play an important role in the progression to non-seminoma formation. Genomic DNA and RNA was extracted from cell lines representing four subtypes of GCT. RNA was subjected to Affymetric expression array analysis while DNA was bisulfite treated and analysed using Illumina Infinium 450K arrays. Statistical approaches were used to correlate methylation and expression for each gene.
2016-01-15 | E-GEOD-65027 | biostudies-arrayexpress
Project description:Genome-wide profiling of placental DNA methylation in relation to arsenic exposure. The Illumina 450k methylation array was used to profile 343 samples for which 3 different measurements of arsenic exposure were available during gestation. These samples have been collected from the New Hampshire Birth Cohort Study (NHBCS). Bisulfite converted DNA was hybridized to the 450k platform and processed at the University of Minnesota Genomic Core
2016-07-01 | E-GEOD-71678 | biostudies-arrayexpress
Project description:We aim to improve anti-ageing drug discovery, currently achieved through laborious and lengthy longevity analysis. Recent studies demonstrated that the most accurate molecular method to measure human age is based on CpG methylation profiles, as exemplified by several epigenetics clocks that can accurately predict an individual’s age. Here, we developed CellAge, a new epigenetic clock that measures subtle ageing changes in primary human cells in vitro. As such it provides a unique tool to measure effects of relatively short pharmacological treatments on ageing. We validated our CellAge clock against known longevity drugs such as rapamycin and trametinib. Moreover, we uncovered novel anti-ageing drugs, torin2 and Dactolisib (BEZ-235), demonstrating the value of our approach as a screening and discovery platform for anti-ageing strategies. CellAge outperforms other epigenetic clocks in measuring subtle ageing changes in primary human cells in culture. The tested drug treatments reduced senescence and other ageing markers, further consolidating our approach as a screening platform. Finally, we showed that the novel anti-ageing drugs we uncovered in vitro, indeed increased longevity in vivo. Our method expands the scope of CpG methylation profiling from measuring human chronological and biological age from human samples in years, to accurately and rapidly detecting anti-ageing potential of drugs using human cells in vitro, providing a novel accelerated discovery platform to test sought after geroprotectors.
2021-10-01 | E-MTAB-8327 | biostudies-arrayexpress
Project description:Prenatal exposure to inorganic arsenic (iAs) is detrimental to the health of newborns and increases the risk of disease development later in life. Here we examined a subset of newborn cord blood leukocyte samples collected from mothers enrolled in the Biomarkers of Exposure to ARsenic (BEAR) pregnancy cohort in Gomez Palacio, Mexico who were exposed to a range of drinking water arsenic concentrations (0.456-236 µg/L). Changes in iAs-associated DNA 5-methyl cytosine methylation were assessed across 424,935 CpG sites representing 18,761 genes and were compared to corresponding expression levels and birth outcomes. In the context of arsenic exposure, a total of 2,705 genes were identified with iAs-associated differences in DNA methylation. Site-specific analyzes identified DNA methylation changes that were most predictive of gene expression levels. Specifically, CpG methylation within CpG islands positioned within the first exon and 200bp upstream of the transcription start site yielded the most significant association with gene expression levels. A set of 16 genes was identified with correlated iAs-associated changes in DNA methylation and mRNA expression and all were highly enriched for binding sites of the early growth response (EGR) and CCCTC-binding factor (CTCF) transcription factors. Furthermore, DNA methylation levels of seven of these genes were associated with differences in birth outcomes including gestational age, placental weight and head circumference. These data highlight the complex interplay between DNA methylation and functional changes in gene expression and health outcomes and underscore the need for functional analyzes coupled to epigenetic assessments. 48 DNA methylation profiles were obtained but only 38 samples corresponding to samples also analyzed for gene expression (see Rager 2014) were further normalized and used in the publication from the Biomarkers of Arsenic (BEAR) cohort were analyzed for DNA methylation profiles.
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