Hypermethylation of tumor suppressor gene (TSG) promoters confers growth advantages to cancer cells, but how these changes arise is poorly understood. Here, we report that tumor hypoxia reduces the activity of oxygen-dependent TET enzymes, which catalyze DNA de-methylation through 5-methylcytosine oxidation. This occurs independently of hypoxia-associated alterations in TET gene expression, basal metabolism, HIF activity or nuclear reactive oxygen species, but directly depends on oxygen shortage. Hypoxia-induced loss of TET activity increases hypermethylation at gene promoters in vitro, while also in patients, gene promoters are markedly more methylated in hypoxic than normoxic tumors. Affected genes are frequently involved in DNA repair, cell cycle regulation, angiogenesis and metastasis, indicating cellular selection of hypermethylation events. Overall, up to 50% of the tumor-associated hypermethylation is ascribable to hypoxia across various cancer types. Accordingly, spontaneous murine breast tumors become hypermethylated when rendered hypoxic through vessel pruning, whereas vessel normalisation rescues this effect. Tumor hypoxia thus acts as a novel regulator underlying DNA methylation. Overall design: RNAseq of MCF7 cells grown under hypoxic and normoxic conditions. Submission includes data on 5 independent RNAseq experiments, each containing biological replicates grown under hypoxic conditions (0.5% oxygen), and under normoxic conditions.
Tumour hypoxia causes DNA hypermethylation by reducing TET activity.
Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Pax3 and Zic1 trigger the early neural crest gene regulatory network by the direct activation of multiple key neural crest specifiers.
Specimen part
View SamplesNeural crest development is orchestrated by a complex and still poorly understood gene regulatory network. Premigratory neural crest is induced at the lateral border of the neural plate by the combined action of signaling molecules and transcription factors such as AP2, Gbx2, Pax3 and Zic1. Among them, Pax3 and Zic1 are both necessary and sufficient to trigger a complete neural crest developmental program. However, their gene targets in the neural crest regulatory network remain unknown. Here, through a transcriptome analysis of frog microdissected neural border, we identified an extended gene signature for the premigratory neural crest, and we defined novel potential members of the regulatory network. This signature includes 34 novel genes, as well as 44 known genes expressed at the neural border. Using another microarray analysis which combined Pax3 and Zic1 gain-of-function and protein translation blockade, we uncovered 25 Pax3 and Zic1 direct targets within this signature. We demonstrated that the neural border specifiers Pax3 and Zic1 are direct upstream regulators of neural crest specifiers Snail1/2, Foxd3, Twist1, and Tfap2b. In addition, they may modulate the transcriptional output of multiple signaling pathways involved in neural crest development (Wnt, Retinoic Acid) through the induction of key pathway regulators (Axin2 and Cyp26c1). We also found that Pax3 could maintain its own expression through a positive autoregulatory feedback loop. These hierarchical inductions, feedback loops, and pathway modulation provide novel tools to understand the neural crest induction network.
Pax3 and Zic1 trigger the early neural crest gene regulatory network by the direct activation of multiple key neural crest specifiers.
Specimen part
View SamplesGlucocorticoids (GC) have a major impact on the biology of normal and malignant cells of the lymphoid lineage. This includes induction of apoptosis which is exploited in the therapy of acute lymphoblastic leukemia (ALL) and related lymphoid malignancies. MicroRNAs (miRNAs) and the related mirtrons are ~22 nucleotide RNA molecules implicated in the control of essential biological functions including proliferation, differentiation and apoptosis. They derive from polymerase-II transcripts but whether GCs regulate miRNA-encoding transcription units is not known. We investigated miRNA/mirtron expression and GC regulation in 8 ALL in vitro models and 13 ALL children undergoing systemic GC monotherapy using a combination of expression profiling techniques, real time RT-PCR and northern blotting to detect mature miRNAs and/or their precursors. We identified a number of GC-regulated miRNAs/mirtrons, including the myeloid-specific miR-223 and the apoptosis and cell cycle arrest-inducing mir15~16 cluster. Thus, the observed complex changes in miRNA/mirtron expression during GC treatment might contribute to the anti-leukemic GC effects in a cell context dependent manner.
Glucocorticoid-regulated microRNAs and mirtrons in acute lymphoblastic leukemia.
No sample metadata fields
View SamplesNeural crest development is orchestrated by a complex and still poorly understood gene regulatory network. Premigratory neural crest is induced at the lateral border of the neural plate by the combined action of signaling molecules and transcription factors such as AP2, Gbx2, Pax3 and Zic1. Among them, Pax3 and Zic1 are both necessary and sufficient to trigger a complete neural crest developmental program. However, their gene targets in the neural crest regulatory network remain unknown. Here, through a transcriptome analysis of frog microdissected neural border, we identified an extended gene signature for the premigratory neural crest, and we defined novel potential members of the regulatory network. This signature includes 34 novel genes, as well as 44 known genes expressed at the neural border. Using another microarray analysis which combined Pax3 and Zic1 gain-of-function and protein translation blockade, we uncovered 25 Pax3 and Zic1 direct targets within this signature. We demonstrated that the neural border specifiers Pax3 and Zic1 are direct upstream regulators of neural crest specifiers Snail1/2, Foxd3, Twist1, and Tfap2b. In addition, they may modulate the transcriptional output of multiple signaling pathways involved in neural crest development (Wnt, Retinoic Acid) through the induction of key pathway regulators (Axin2 and Cyp26c1). We also found that Pax3 could maintain its own expression through a positive autoregulatory feedback loop. These hierarchical inductions, feedback loops, and pathway modulation provide novel tools to understand the neural crest induction network.
Pax3 and Zic1 trigger the early neural crest gene regulatory network by the direct activation of multiple key neural crest specifiers.
Specimen part
View SamplesCD8+ T cells and NK cells protect from viral infections by killing virally-infected cells and secreting interferon-g. Several inhibitory receptors limit the magnitude and duration of these anti-viral responses.
The Inhibitory Receptor NKG2A Sustains Virus-Specific CD8⁺ T Cells in Response to a Lethal Poxvirus Infection.
No sample metadata fields
View SamplesETS1 and RAS/ERK regulate a common gene expression program in establishing enviroment suitable for prostate cancer cell migration. Overall design: mRNA profiles of luciferase knockdown (WT), ETS1 knockdown, and U0126 treated DU145 cells were generated using deep sequencing, in triplicate, using Illumina HiSeq. Knockdowns were stable shRNA expression from a lentiviral construct selected with puromycin.
Interaction with ZMYND11 mediates opposing roles of Ras-responsive transcription factors ETS1 and ETS2.
No sample metadata fields
View SamplesWe used microarrays to detail the global programme of gene expression underlying palate development by persistent expression in R26Pax3 mice and identified distinct classes of up-regulated and down-regulated genes during this process.
Persistent expression of Pax3 in the neural crest causes cleft palate and defective osteogenesis in mice.
No sample metadata fields
View SamplesStudying the causes and correlates of natural variation in gene expression in healthy populations assumes that individual differences in gene expression can be reliably and stably assessed across time. However, this is yet to be established.
Assessing individual differences in genome-wide gene expression in human whole blood: reliability over four hours and stability over 10 months.
Sex, Age, Specimen part
View SamplesKnockdowns of c-JUN and JUND had opposite effects on PC3 prostate cell migration. We predicted that c-JUN and JUND control the same set of cell migration genes, but in opposite directions. To test this hypothesis, mRNA with expression changes in c-JUN and JUND knockdown PC3 cell lines were compared to mRNA levels in control (luciferase knockdown) PC3 cells by RNA-seq. Overall design: mRNA profiles of luciferase knockdown (WT), c-Jun knockdown, and Jun-D knockdown in PC3 cells were generated using deep sequencing, in triplicate, using Illumina HiSeq. Knockdowns were stable shRNA expression from a lentiviral construct selected with puromycin.
Extracellular signal-regulated kinase signaling regulates the opposing roles of JUN family transcription factors at ETS/AP-1 sites and in cell migration.
No sample metadata fields
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