This SuperSeries is composed of the SubSeries listed below.
Exploiting microRNA and mRNA profiles generated in vitro from carcinogen-exposed primary mouse hepatocytes for predicting in vivo genotoxicity and carcinogenicity.
Specimen part, Compound
View SamplesThe well-defined battery of in vitro systems applied within chemical cancer risk assessment is often characterised by a high false-positive rate, thus repeatedly failing to correctly predict the in vivo genotoxic and carcinogenic properties of test compounds. Toxicogenomics, i.e. mRNA-profiling, has been proven successful in improving the prediction of genotoxicity in vivo and the understanding of underlying mechanisms. Recently, microRNAs have been discovered as post-transcriptional regulators of mRNAs. It is thus hypothesised that using microRNA response-patterns may further improve current prediction methods. This study aimed at predicting genotoxicity and non-genotoxic carcinogenicity in vivo, by comparing microRNA- and mRNA-based profiles, using a frequently applied in vitro liver model and exposing this to a range of well-chosen prototypical carcinogens. Primary mouse hepatocytes (PMH) were treated for 24 and 48h with 21 chemical compounds [genotoxins (GTX) vs. non-genotoxins (NGTX) and non-genotoxic carcinogens (NGTX-C) versus non-carcinogens (NC)]. MicroRNA and mRNA expression changes were analysed by means of Exiqon and Affymetrix microarray-platforms, respectively. Classification was performed by using Prediction Analysis for Microarrays (PAM). Compounds were randomly assigned to training and validation sets (repeated 10 times). Before prediction analysis, pre-selection of microRNAs and mRNAs was performed by using a leave-one-out t-test. No microRNAs could be identified that accurately predicted genotoxicity or non-genotoxic carcinogenicity in vivo. However, mRNAs could be detected which appeared reliable in predicting genotoxicity in vivo after 24h (7 genes) and 48h (2 genes) of exposure (accuracy: 90% and 93%, sensitivity: 65% and 75%, specificity: 100% and 100%). Tributylinoxide and para-Cresidine were misclassified. Also, mRNAs were identified capable of classifying NGTX-C after 24h (5 genes) as well as after 48h (3 genes) of treatment (accuracy: 78% and 88%, sensitivity: 83% and 83%, specificity: 75% and 93%). Wy-14,643, phenobarbital and ampicillin trihydrate were misclassified. We conclude that genotoxicity and non-genotoxic carcinogenicity probably cannot be accurately predicted based on microRNA profiles. Overall, transcript-based prediction analyses appeared to clearly outperform microRNA-based analyses.
Exploiting microRNA and mRNA profiles generated in vitro from carcinogen-exposed primary mouse hepatocytes for predicting in vivo genotoxicity and carcinogenicity.
Specimen part, Compound
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Evaluating microRNA profiles reveals discriminative responses following genotoxic or non-genotoxic carcinogen exposure in primary mouse hepatocytes.
Specimen part, Compound
View SamplesThe study investigated differential gene expression in primary mouse hepatocyte mRNA following 24 and 48 hours of exposure to aflatoxin B1, cisplatin, benzo(a)pyrene, 2,3,7,8-tetrachloordibenzo-p-dioxine, cyclosporin A or Wy-14,643 or their responsive solvent. Three (four for Wy-14,643) biological replicates per compound/solvent.
Evaluating microRNA profiles reveals discriminative responses following genotoxic or non-genotoxic carcinogen exposure in primary mouse hepatocytes.
Specimen part, Compound
View SamplesTumor suppressor p53 promotes differentiation of human embryonic stem cells (hESCs), but an in-depth understanding of mechanism is lacking. Here, we define p53 functions in hESCs by genome wide profiling of p53 chromatin interactions and intersection with gene expression during early differentiation and in response to DNA damage. During differentiation, p53 targets and regulates a unique collection of genes, many of which encode transcription factors and developmental regulators with chromatin structure poised by OCT4 and NANOG and marked by repressive H3K27me3 in pluripotent hESCs. In contrast, genes associated with cell migration and motility are bound by p53 specifically after DNA damage. Surveillance functions of p53 in regulation of cell death and cell cycle genes are conserved during both DNA damage and differentiation. Our findings expand the registry of p53 -regulated genes in hESCs and define specific functions of p53 in opposing pluripotency, which are highly distinct from stress-induced p53 response in stem cells.
Genome-wide profiling reveals stimulus-specific functions of p53 during differentiation and DNA damage of human embryonic stem cells.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Extensive temporal transcriptome and microRNA analyses identify molecular mechanisms underlying mitochondrial dysfunction induced by multi-walled carbon nanotubes in human lung cells.
Specimen part, Treatment
View SamplesUnderstanding toxicity pathways of engineered nanomaterials (ENM) has recently been brought forward as a key step in 21st century ENM risk assessment. Molecular mechanisms linked to phenotypic end points is a step towards the development of toxicity tests based on key events, which may allow for grouping of ENM according to their mechanisms of action. This study identified molecular mechanisms underlying mitochondrial dysfunction in human bronchial epithelial BEAS 2B cells following exposure to one of the most studied multi-walled carbon nanotubes (MWCNTs; Mitsui-7). Asbestos was used as a positive control and a non-carcinogenic glass wool material was included as a negative fibre control. Decreased mitochondrial membrane potential (MMP) was observed for MWCNTs at a biologically relevant dose (0.25 g/cm2) and for asbestos at 2 g/cm2, but not for glass wool. Extensive temporal transcriptomic and microRNA expression analyses identified a 330-gene signature related to MWCNT- and asbestos-induced MMP. Fourty-nine of the MMP-associated genes showed highly similar expression patterns over time (six time points) and the majority was found to be regulated by two transcription factors strongly involved in mitochondrial homeostasis, APP and NRF1. In addition, four miRNAs were associated with MMP and one of them, miR-1275, was found to negatively correlate with a large part of the MMP-associated genes. Cellular processes such as gluconeogenesis, glucose metabolism, mitochondrial LC-fatty acid -oxidation and spindle microtubule function were enriched among the MMP-associated genes and miRNAs. These results are expected to be useful in the identification of key events in ENM-related toxicity pathways for the development of molecular screening techniques.
Extensive temporal transcriptome and microRNA analyses identify molecular mechanisms underlying mitochondrial dysfunction induced by multi-walled carbon nanotubes in human lung cells.
Specimen part, Treatment
View SamplesThe transcriptomics changes induced in the human liver cell line HepG2 by 17 hepatotoxic compounds, 5 non-hepatotoxic compounds and solvent controls after treatment for 24h
Classification of hepatotoxicants using HepG2 cells: A proof of principle study.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Integrative cross-omics analysis in primary mouse hepatocytes unravels mechanisms of cyclosporin A-induced hepatotoxicity.
Specimen part
View SamplesThe transcriptomics changes induced in Primary Mouse Hepatocytes by Cyclosporin A after treatment for 24h and 48h
Integrative cross-omics analysis in primary mouse hepatocytes unravels mechanisms of cyclosporin A-induced hepatotoxicity.
Specimen part
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