Homo sapiens
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PROVIDER: PRJNA261955 | ENA |
REPOSITORIES: ENA
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Project description:Hypoxia promotes stem cell phenotypes and poor prognosis through epigenetic regulation of DICER [MCF7]
| PRJNA261954 | ENA
Project description:MicroRNAs are small regulatory RNAs that post-transcriptionally control gene expression. Reduced expression of DICER, the enzyme involved in microRNA processing, is frequently observed in cancer and is associated with poor clinical outcome in various malignancies. Yet the underlying mechanisms are not well understood. Here, we identify tumor hypoxia as a regulator of DICER expression in large cohorts of breast cancer patients. We show that DICER expression is suppressed by hypoxia through an epigenetic mechanism that involves inhibition of oxygen-dependent H3K27me3 demethylases KDM6A/B and results in silencing of the DICER promoter. Subsequently, reduced miRNA processing leads to derepression of the miR-200 target ZEB1, stimulates the epithelial to mesenchymal transition and ultimately results in the acquisition of stem cell phenotypes in human mammary epithelial cells. Our study uncovers a previously unknown relationship between oxygen-sensitive epigenetic regulators, miRNA biogenesis and tumor stem cell phenotypes that may underlie poor outcome in breast cancer. miRNA profiling of MCF7 cells in normal or hypoxic conditions or after DICER knockdown in MCF7 cells.
2014-09-30 | E-GEOD-61720 | biostudies-arrayexpress
Project description:MicroRNAs are small regulatory RNAs that post-transcriptionally control gene expression. Reduced expression of DICER, the enzyme involved in microRNA processing, is frequently observed in cancer and is associated with poor clinical outcome in various malignancies. Yet the underlying mechanisms are not well understood. Here, we identify tumor hypoxia as a regulator of DICER expression in large cohorts of breast cancer patients. We show that DICER expression is suppressed by hypoxia through an epigenetic mechanism that involves inhibition of oxygen-dependent H3K27me3 demethylases KDM6A/B and results in silencing of the DICER promoter. Subsequently, reduced miRNA processing leads to derepression of the miR-200 target ZEB1, stimulates the epithelial to mesenchymal transition and ultimately results in the acquisition of stem cell phenotypes in human mammary epithelial cells. Our study uncovers a previously unknown relationship between oxygen-sensitive epigenetic regulators, miRNA biogenesis and tumor stem cell phenotypes that may underlie poor outcome in breast cancer. A total of 12 samples were analyzed. For each condition tested, 3 independent experiments were carried out (biological repicates).
2014-09-30 | E-GEOD-61721 | biostudies-arrayexpress
Project description:MicroRNAs are small regulatory RNAs that post-transcriptionally control gene expression. Reduced expression of DICER, the enzyme involved in microRNA processing, is frequently observed in cancer and is associated with poor clinical outcome in various malignancies. Yet the underlying mechanisms are not well understood. Here, we identify tumor hypoxia as a regulator of DICER expression in large cohorts of breast cancer patients. We show that DICER expression is suppressed by hypoxia through an epigenetic mechanism that involves inhibition of oxygen-dependent H3K27me3 demethylases KDM6A/B and results in silencing of the DICER promoter. Subsequently, reduced miRNA processing leads to derepression of the miR-200 target ZEB1, stimulates the epithelial to mesenchymal transition and ultimately results in the acquisition of stem cell phenotypes in human mammary epithelial cells. Our study uncovers a previously unknown relationship between oxygen-sensitive epigenetic regulators, miRNA biogenesis and tumor stem cell phenotypes that may underlie poor outcome in breast cancer.
2014-09-30 | GSE61721 | GEO
Project description:MicroRNAs are small regulatory RNAs that post-transcriptionally control gene expression. Reduced expression of DICER, the enzyme involved in microRNA processing, is frequently observed in cancer and is associated with poor clinical outcome in various malignancies. Yet the underlying mechanisms are not well understood. Here, we identify tumor hypoxia as a regulator of DICER expression in large cohorts of breast cancer patients. We show that DICER expression is suppressed by hypoxia through an epigenetic mechanism that involves inhibition of oxygen-dependent H3K27me3 demethylases KDM6A/B and results in silencing of the DICER promoter. Subsequently, reduced miRNA processing leads to derepression of the miR-200 target ZEB1, stimulates the epithelial to mesenchymal transition and ultimately results in the acquisition of stem cell phenotypes in human mammary epithelial cells. Our study uncovers a previously unknown relationship between oxygen-sensitive epigenetic regulators, miRNA biogenesis and tumor stem cell phenotypes that may underlie poor outcome in breast cancer.
2014-09-30 | GSE61720 | GEO
Project description:Chronic Hypoxia predicts Poor Prognosis in Hepatocellular Carcinoma
| PRJNA117097 | ENA
Project description:HIF1α promotes glioblastoma cell proliferation and tumorigenesis under hypoxia conditions, leading to poor prognosis; however, none of the targeted therapies of HIF1α for glioblastoma is success nowadays. Therefore, we focused to look for the reason and wondered whether HIF2α contributed GBM growth. We did gene-chip and found that HIF2α contributed to the malignant progression of glioblastoma while blocking of HIF1α. Furthermore, our results revealed knock-out of HIF1α and HIF2α simultaneously improved the chemo-sensitization significantly. Moreover, miR-210-3p induced HIF1α expression but inhibited HIF2α, which meant the existence of regulation of cycle between HIF1α/HIF2α and miR-210-3p. Traditional studies have proved EGF as an upstream gene regulator of HIF1α in hypoxia conditions through EGFR-PI3K/AKT-mTOR signaling pathway. However, in this study, besides the signaling pathways mentioned above, we found the upstream regulators HIF1α and HIF2α also promoted EGF with the binding regions AGGCGTGG and GGGCGTGG. Briefly, in hypoxia microenvironment HIF1α/HIF2α-miR210-3p network promotes malignant progression of glioblastoma through EGFR-PI3K/AKT-mTOR signaling pathway with a positive feedback.
2020-11-24 | GSE142719 | GEO
Project description:Hypoxia, a hallmark of most solid tumors, leads to aberrations in epigenetic modifications promoting malignant tumor phenotypes, including metastatic features and stem cell-like characteristics. Aberrant DNA methylation has been considered to play an essential role during tumor progression and tightly associate with tumor malignancy. However, the mechanism by which hypoxia alters DNA methylation to promote tumor malignancy remains poorly understood. Ten-eleven translocation 1-3 (TET1-3) proteins, which catalyze the conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), play a critical role in the DNA demethylation that controls different biological processes. Here we demonstrate that the expression of TET1 and TET3 is closely associated with tumor hypoxia, tumor malignancy and poor prognosis of patients with breast cancer. Hypoxia results in deregulation of TET1 and TET3, leading to breast tumor initiating cell (BTIC) properties. Mechanically, hypoxia regulates expression of TET1 and TET3 via hypoxia-inducible factor-1a (HIF-1a), thereby resulting in 5hmC genome-wide changes, which in turn leads to the upregulation of TNFa expression and activation of its downstream p38-MAPK pathway. Importantly, signal transduction through the TET-TNFa-p38-MAPK signaling axis is required for the acquisition of BTIC characteristics and chemotherapy resistance, leading to more malignant tumor phenotypes. Inhibition of the hypoxia-TET-TNFα-p38-MAPK signaling pathway results in compromised BTIC properties and tumorigenicity in vitro and in vivo, suggesting a possible therapeutic strategy.
2015-10-05 | GSE60434 | GEO
Project description:Tumour hypoxia exhibits a highly dynamic spatial and temporal distribution and is associated with increased malignancy and poor prognosis. Assessment of time-dependent gene-expression changes in response to hypoxia may thus provide additional biological insights and help with patient prognosis.
2012-03-01 | GSE29641 | GEO