For assessing the cancer-causing potential for humans of a chemical compound, the conventional approach is the use of the 2-year rodent carcinogenicity bioassay, thus alternatives such as in vitro toxicogenomics are highly desired. In the present study, the transcriptomics responses following exposure to genotoxic (GTX) and non-genotoxic (NGTX) hepatocarcinogens and non-carcinogens (NC) in five liver-based in vitro models, namely conventional and epigenetically-stabilized cultures of primary rat hepatocytes, the human hepatoma-derived HepaRG and HepG2 cell lines and the human embryonic stem cell-derived hepatocyte-like cells hES-Heps are examined and compared.
Transcriptomic responses generated by hepatocarcinogens in a battery of liver-based in vitro models.
Specimen part, Cell line, Treatment
View SamplesX-chromosome aneuploidies have long been associated with human cancers, but causality has not been established. In mammals, X-chromosome inactivation (XCI) is triggered by Xist RNA to equalize gene expression between the sexes. Here we delete Xist in the blood compartment of mice and demonstrate that mutant females develop a highly aggressive myeloproliferative neoplasm and myelodysplastic syndrome (mixed MPN/MDS) with 100% penetrance. Significant disease components include primary myelofibrosis, leukemia, histiocytic sarcoma, and vasculitis. Xist-deficient hematopoietic stem cells (HSC) show aberrant maturation and age-dependent loss. Reconstitution experiments indicate that MPN/MDS and myelofibrosis are of hematopoietic rather than stromal origin. We propose that Xist loss results in X-reactivation and consequent genome-wide changes that lead to cancer, thereby causally linking the X-chromosome to cancer in mice. Thus, Xist RNA is not only required to maintain XCI but also suppresses cancer in vivo.
Xist RNA is a potent suppressor of hematologic cancer in mice.
Sex, Age, Specimen part
View SamplesThe earliest stages of Huntington’s disease are marked by changes in gene expression that are caused in an indirect and poorly understood manner by polyglutamine expansions in the huntingtin protein (HTT). To explore the hypothesis DNA methylation may be altered in cells expressing mutated HTT, we use reduced-representation bisulfite sequencing (RRBS) to map sites of DNA methylation in cells carrying either wild-type or mutant HTT. We find that a large fraction of the genes that change in expression in the presence of mutant huntingtin demonstrate significant changes in DNA methylation. Regions with low CpG content, which have previously been shown to undergo methylation changes in response to neuronal activity, are disproportionately affected. Based on the sequence of regions that change in methylation, we identify AP-1 and SOX2 as transcriptional regulators associated with DNA methylation changes, and we confirm these hypotheses using genome-wide chromatin immunoprecipitation (ChIP-Seq). Our findings suggest new mechanisms for the effects of polyglutamine-expanded HTT. These results also raise important questions about the potential effects of changes in DNA methylation on neurogenesis and at later stages, cognitive decline in Huntington’s patients. Overall design: mRNA-seq in STHdhQ7/Q7 and STHdhQ111/Q111 cells
Extensive changes in DNA methylation are associated with expression of mutant huntingtin.
Specimen part, Cell line, Subject
View SamplesRNA-seqs followed by miRNA transfections (miR-124 and miR-155) into four different cell lines( HeLa, HEK293, Huh7, and IMR90). Overall design: There are two biological replicates of RNA-seqs per each miRNA transfection per each sample and there are corresponding mock transfections.
Global analyses of the effect of different cellular contexts on microRNA targeting.
No sample metadata fields
View SamplesGene expression in larval, early third instar eye-antenna discs was assessed to reveal an ATF4 contribution to target gene induction following COX7a knockdown. As hypothesised, these COX7a-RNAi induced target genes require the transcription factor ATF4 for induction, irrespective of concomitant Notch pathway activation through Delta over-expression.
ATF4-Induced Warburg Metabolism Drives Over-Proliferation in Drosophila.
No sample metadata fields
View SamplesGene expression in larval, early third instar eye-antenna discs was assesed in genotypes with Notch Gain-of-Function (UAS-Delta or UAS-Notch[intra2]) over-expression or mitochondrial COX7a Loss-of-function (UAS-COX7a-RNAi) or a combination of both (UAS-Delta, UAS-COX7a-RNAi). The analysis revealed that, despite a strong genetic interaction between Notch pathway activation and knockdown of COX7a, no transcriptional cooperation or synergy was detectable in early L3 eye-antenna discs. Rather, COX7a knockdown induced a unique transcriptional signature, which further experiments revealed to be mediated by the transcription factor ATF4.
ATF4-Induced Warburg Metabolism Drives Over-Proliferation in Drosophila.
No sample metadata fields
View SamplesWe used microarrays to investigate the global changes of gene expression in B cells of mir-155 Knockout mice.
Global analyses of the effect of different cellular contexts on microRNA targeting.
Specimen part
View SamplesTranscriptional dysregulation is an early feature of Huntington''s disease (HD). We observed gene-specific changes in H3K4me3 at transcriptionally repressed promoters in R6/2 mouse and human HD brain. Genome-wide analysis showed a novel chromatin signature for this mark. Reducing the levels of the H3K4 demethylase SMCX/Jarid1c in primary neurons reversed down-regulation of key neuronal genes caused by mutant Huntingtin (Htt) expression. Finally, reduction of SMCX/Jarid1c in primary neurons from BACHD mice or the single Jarid1 in a Drosophila HD model was protective. Therefore, targeting this epigenetic signature may be an effective strategy to ameliorate the consequences of HD. Overall design: mRNA-seq in wild type and R6/2 cortex and striatum at 8 and 12 weeks.
Targeting H3K4 trimethylation in Huntington disease.
Age, Specimen part, Subject
View SamplesTo attain deeper insight into metabolic alterations in Trpm6 gene deficient mice we used microarrays for profiling of hepatic transcripts of Trpm6 ko and control mice.
Epithelial magnesium transport by TRPM6 is essential for prenatal development and adult survival.
Sex, Age
View SamplesChildhood T-ALL samples were compared with thymocyte subsets
Deregulated WNT signaling in childhood T-cell acute lymphoblastic leukemia.
Specimen part
View Samples