Tumorigenic carryover effects of early life exposure to dichloroacetic acid in male B6C3F1 mice
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE58585 | GEO | 2015/02/26
SECONDARY ACCESSION(S): PRJNA252943
REPOSITORIES: GEO
Similar Datasets
Project description:Here we investigated the longterm carryover effects of dichloroacetic acid (DCA), a common by-product of drinking water chlorination, on hepatic tumorigenesis in mice. Our findings demonstrate that postnatal exposure to a common drinking water contaminant results in longterm carryover effects on tumorigenesis, potentially via epigenetic events altering cellular respiration and metabolism. The gene expression study followed a stop-promotion design in which 7d male B6C3F1 mice received the following treatments: deionized water alone (dH2O, control); 0.06% phenobarbital (PB), a rodent liver mitogen and tumor promoter; or DCA (3.5g/L) for 10 weeks followed by dH2O for 90 weeks.
2015-02-26 | E-GEOD-58585 | biostudies-arrayexpress
Project description:Mechanistic understanding of transient exposures that lead to adverse health outcomes will enhance our ability to recognize biological signatures of disease. Here, we measured the transcriptomic and epigenomic alterations due to exposure to the metabolic reprogramming agent, dichloroacetic acid (DCA). Previously, we showed that exposure to DCA increased liver cancer in B6C3F1 mice after continuous or early life exposures similarly over background level. Measures from these studies did not support direct cytotoxic, mitogenic, or genotoxic modes-of-action of tumorigenesis. Using archived formalin-fixed liver samples, we utilized modern methodologies to measure gene expression and DNA methylation levels to link to previously generated phenotypic measures. Gene expression was measured by targeted RNA sequencing (TempO-seq 1500+ toxicity panel: 2754 total genes) in liver samples collected from 10-, 32-, 57-, and 78-week old mice exposed to deionized water (controls), DCA continuously at 3.5g/L in drinking water (“Direct” group), or DCA at 3.5g/L for 10-, 32-, or 57-weeks followed by control water (“Stop” groups). Genome-scaled alterations in DNA methylation were measured by Reduced Representation Bisulfite Sequencing (RRBS) at 78-weeks. Transcriptomic changes were most robust with concurrent or adjacent timepoints after exposure stoppage. DNA methylation alterations followed a similar pattern, measuring 2720 and 567 differentially methylated regions (DMRs) in 78-week Direct and 10-week “Stop” DCA exposure groups, respectively. Gene pathway analysis indicated cellular effects linked to increased oxidative metabolism, a primary mechanism of action for DCA, closer to exposure windows especially early in life. Conversely, many gene signatures and pathways reversed patterns later in life and reflected more pro-tumorigenic patterns for both current and prior DCA exposures. DNA methylation patterns linked to early gene pathway perturbations, suggesting persistence in the epigenome and possible regulatory effects. In total, results suggested that liver metabolic reprogramming effects of DCA interact with normal age mechanisms to increase tumor burden with both continuous and prior DCA exposure in the B6C3F1 rodent model.
2024-05-30 | GSE242664 | GEO
Project description:Mechanistic understanding of transient exposures that lead to adverse health outcomes will enhance our ability to recognize biological signatures of disease. Here, we measured the transcriptomic and epigenomic alterations due to exposure to the metabolic reprogramming agent, dichloroacetic acid (DCA). Previously, we showed that exposure to DCA increased liver cancer in B6C3F1 mice after continuous or early life exposures similarly over background level. Measures from these studies did not support direct cytotoxic, mitogenic, or genotoxic modes-of-action of tumorigenesis. Using archived formalin-fixed liver samples, we utilized modern methodologies to measure gene expression and DNA methylation levels to link to previously generated phenotypic measures. Gene expression was measured by targeted RNA sequencing (TempO-seq 1500+ toxicity panel: 2754 total genes) in liver samples collected from 10-, 32-, 57-, and 78-week old mice exposed to deionized water (controls), DCA continuously at 3.5g/L in drinking water (“Direct” group), or DCA at 3.5g/L for 10-, 32-, or 57-weeks followed by control water (“Stop” groups). Genome-scaled alterations in DNA methylation were measured by Reduced Representation Bisulfite Sequencing (RRBS) at 78-weeks. Transcriptomic changes were most robust with concurrent or adjacent timepoints after exposure stoppage. DNA methylation alterations followed a similar pattern, measuring 2720 and 567 differentially methylated regions (DMRs) in 78-week Direct and 10-week “Stop” DCA exposure groups, respectively. Gene pathway analysis indicated cellular effects linked to increased oxidative metabolism, a primary mechanism of action for DCA, closer to exposure windows especially early in life. Conversely, many gene signatures and pathways reversed patterns later in life and reflected more pro-tumorigenic patterns for both current and prior DCA exposures. DNA methylation patterns linked to early gene pathway perturbations, suggesting persistence in the epigenome and possible regulatory effects. In total, results suggested that liver metabolic reprogramming effects of DCA interact with normal age mechanisms to increase tumor burden with both continuous and prior DCA exposure in the B6C3F1 rodent model.
2024-04-29 | GSE242661 | GEO
Project description:Early-life environmental factors can increase later-life susceptibility to cancer. Short-term exposure to dichloroacetic acid (DCA), a trace drinking water contaminant with distinctive metabolic effects, increased liver cancer in mice 84 weeks after exposure was stopped. Here we evaluated time course dynamics for key events related to this latent effect. This study followed a stop-exposure design in which 28-day-old male B6C3F1 mice were given the following treatments in drinking water for up to 93 weeks: deionized water (dH20, control); 3.5 g/l DCA continuously; or 3.5 g/l DCA for 4, 10, 26, or 52 weeks followed by dH20. Effects were evaluated at eight interim time points. A short-term biomarker study was used to evaluate DCA effects at 6, 15, and 30 days. Liver tumor incidence was higher in all DCA treatment groups, including carcinomas in 82% of mice previously treated with DCA for only 4 weeks. Direct effects of DCA in the short-term study included decreased liver cell proliferation and marked mRNA changes related to mitochrondrial dysfunction and altered cell metabolism. All observed short-term effects of DCA were reversible. Prior DCA treatment did not alter liver cell proliferation, apoptosis, necrosis, or DNA sequence variants with age. Key intermediate events resulting from early-life DCA exposure do not fit classical cytotoxic, mitogenic, or genotoxic modes of action for carcinogenesis, suggesting a novel epigenetic mechanism related to metabolic disruption.
2017-12-21 | GSE86065 | GEO
Project description:Dichloroacetyl chloride (DCAC) is a metabolic intermediate of trichloroethene (TCE), an industrial chemical and ubiquitous environmental contaminant. TCE and its metabolites have been implicated in the induction of organ-specific and systemic autoimmunity, in the acceleration of autoimmune responses, and in the development of liver toxicity. In humans, effects of environmental toxicants are often multifactorial and detected only after long-term exposure. Therefore, we developed a small-animal model to determine mechanisms by which DCAC and related acylating agents affect liver disease. Autoimmune-prone female MRL +/+ mice were injected i.p. with 0.2 mmole/kg of DCAC or the acylating agent dichloroacetic anhydride (DCAA) in corn oil twice weekly for six weeks. We then determined changes in the liver transcriptome using microarray gene expression analysis. After exposure to DCAC or DCAA, we observed changes in liver gene expression consistent with inflammatory processes. Both toxicants up-regulated expression of acute phase response and inflammatory genes. Further, metallothionein genes were strongly up-regulated, indicating effects of the toxicants on zinc ion homeostasis and stress responses. In addition, DCAC and DCAA induced up-regulation of several genes indicative of tumorogenesis. Microarray gene expression analysis using a restricted set of genes could be a valuable tool to screen for early changes in liver function following suspected exposure to environmental toxicants. Experiment Overall Design: Animals: Four-week-old female MRL +/+ mice were purchased from Jackson Laboratory (Bar Harbor, ME) and housed in an animal room maintained at ~22°C and 50-60% relative humidity with a 12-h light/dark cycle. Lab chow and drinking water was provided ad libitum, and mice were acclimatized for one week before starting the treatment. Mice were injected intraperitoneally with 0.2 mmol/kg of DCAC or DCAA in 100 µl of corn oil twice weekly for six weeks. Control animals received only corn oil. Mice were sacrificed 24 h after the last treatment. Experiment Overall Design: Samples: Livers from three mice per group were independently processed. The integrity of the RNA samples was tested using an Agilent 2100 Bioanalyzer and RNA 6000 LabChip® kit (Agilent Technologies, Palo Alto, CA). Only RNA samples without signs of degradation were used. Comprehensive gene expression profiles were analyzed.
2008-06-13 | E-GEOD-5241 | biostudies-arrayexpress
Project description:Formalin-fixed paraffin-embedded (FFPE) samples are the only remaining biological archive for many toxicological and clinical studies, yet their use in genomics has been limited due to variability in RNA quality from formalin fixation. Older FFPE samples, which often have highly degraded RNA, pose a particularly difficult technical challenge. Recent developments in probe-based targeted sequencing technologies show promise in addressing this issue, while also being more cost effective than traditional RNA-sequencing (RNA-seq) methods. In the current study, we evaluated dose-dependent transcriptional changes from paired frozen and archival FFPE liver samples stored for over 20 years using targeted resequencing (TempO-Seq) and whole-genome RNA-seq methods. Samples were originally collected from male mice exposed to a reference chemical (dichloroacetic acid, DCA) at 0, 198, 313 and 427 mg/kg-day, (n=6/dose) by drinking water for 6 days. TempO-Seq showed high overlap in differentially expressed genes (DEGs) between matched FFPE and flash-frozen (FROZ) samples and concordance in fold-changes across the highest two dose levels of DCA vs. control (R2 ≥ 0.94). Similarly, high concordance in fold-changes was observed between TempO-Seq FFPE and RNA-seq FROZ results (R2 ≥ 0.92). Only 28 DEGs or fewer were identified in RNA-seq FFPE samples. Modeling of DCA-dependent changes in gene sets identified benchmark doses from TempO-Seq FROZ and FFPE samples that were within 1.4-fold of RNA-seq FROZ samples (93.9 mg/kg-d), whereas RNA-seq FFPE samples were 3.3-fold higher (310.3 mg/kg-d). This work demonstrates that targeted sequencing may provide a more robust method for quantifying gene expression profiles from aged archival FFPE samples.
2022-10-10 | GSE186113 | GEO
Project description:Dichloroacetyl chloride (DCAC) is a metabolic intermediate of trichloroethene (TCE), an industrial chemical and ubiquitous environmental contaminant. TCE and its metabolites have been implicated in the induction of organ-specific and systemic autoimmunity, in the acceleration of autoimmune responses, and in the development of liver toxicity. In humans, effects of environmental toxicants are often multifactorial and detected only after long-term exposure. Therefore, we developed a small-animal model to determine mechanisms by which DCAC and related acylating agents affect liver disease. Autoimmune-prone female MRL +/+ mice were injected i.p. with 0.2 mmole/kg of DCAC or the acylating agent dichloroacetic anhydride (DCAA) in corn oil twice weekly for six weeks. We then determined changes in the liver transcriptome using microarray gene expression analysis. After exposure to DCAC or DCAA, we observed changes in liver gene expression consistent with inflammatory processes. Both toxicants up-regulated expression of acute phase response and inflammatory genes. Further, metallothionein genes were strongly up-regulated, indicating effects of the toxicants on zinc ion homeostasis and stress responses. In addition, DCAC and DCAA induced up-regulation of several genes indicative of tumorogenesis. Microarray gene expression analysis using a restricted set of genes could be a valuable tool to screen for early changes in liver function following suspected exposure to environmental toxicants. Keywords: Response to acylating agents; inflammatory response; disease state analysis.
2008-01-31 | GSE5241 | GEO
Project description:Genetic analysis of women from the Andes Mountains that are exposed to arsenic in drinking water.
| EGAS00001001168 | EGA
Project description:We characterized the bacterial diversity of chlorinated drinking water from three surface water treatment plants supplying the city of Paris, France. For this purpose, we used serial analysis of V6 ribosomal sequence tag (SARST-V6) to produce concatemers of PCR-amplified ribosomal sequence tags (RSTs) from the V6 hypervariable region of the 16S rRNA gene for sequence analysis. Using SARST-V6, we obtained bacterial profiles for each drinking water sample, demonstrating a strikingly high degree of biodiversity dominated by a large collection of low-abundance phylotypes. In all water samples, between 57.2-77.4% of the sequences obtained indicated bacteria belonging to the Proteobacteria phylum. Full-length 16S rDNA sequences were also generated for each sample, and comparison of the RSTs with these sequences confirmed the accurate assignment for several abundant bacterial phyla identified by SARST-V6 analysis, including members of unclassified bacteria, which account for 6.3-36.5% of all V6 sequences. These results suggest that these bacteria may correspond to a common group adapted to drinking water systems. The V6 primers used were subsequently evaluated with a computer algorithm to assess their hybridization efficiency. Potential errors associated with primer-template mismatches and their impacts on taxonomic group detection were investigated. The biodiversity present in all three drinking water samples suggests that the bacterial load of the drinking water leaving treatment plants may play an important role in determining the downstream community dynamics of water distribution networks.
2009-01-08 | GSE14318 | GEO
Project description:Perfluoroalkyl acid carboxylates and sulfonates (PFAAs) have many consumer and industrial applications. The persistence and widespread distribution of these compounds in humans have brought them under intense scrutiny. Limited pharmacokinetic data is available in humans; however, human data exists for two communities with drinking water contaminated by PFAAs. Also, there is toxicological and pharmacokinetic data for monkeys, which can be quite useful for cross-species extrapolation to humans. The goal of this research was to develop a physiologically-based pharmacokinetic (PBPK) model for PFOA and PFOS for monkeys and then scale this model to humans in order to describe available human drinking water data. The monkey model simulations were consistent with available PK data for monkeys. The monkey model was then extrapolated to the human and then used to successfully simulate the data collected from residents of two communities exposed to PFOA in drinking water. Human PFOS data is minimal; however, using the half-life estimated from occupational exposure, our model exhibits reasonable agreement with the available human serum PFOS data. It is envisioned that our PBPK model will be useful in supporting human health risk assessments for PFOA and PFOS by aiding in understanding of human pharmacokinetics.
Model is encoded by Ruby and submitted to BioModels by Ahmad Zyoud
2020-03-20 | MODEL2003190002 | BioModels