A runaway PRH/HHEX-Notch3 feedback loop drives cholangiocarcinoma (RNA-Seq)
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ABSTRACT:
PROVIDER: PRJNA512000 | ENA |
REPOSITORIES: ENA
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Project description:PRH/HHEX-Notch3 feedback loop drives cholangiocarcinoma
2018-12-28 | GSE124430 | GEO
Project description:PRH/HHEX-Notch3 feedback loop drives cholangiocarcinoma
2018-12-28 | GSE124429 | GEO
Project description:A runaway PRH/HHEX-Notch3 feedback loop drives cholangiocarcinoma (ChIP-seq)
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Project description:Analyses of RNAi-heterochromatin positive feedback loop in Tetrahymena
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Project description:Keratinocyte skin cancer, comprising cutaneous squamous (cSCC) and basal cell carcinoma, is the most common malignancy in the UK. P53 is frequently mutated in cSCC. iASPP is a key inhibitor of p53 and NF-kB signalling pathways and has been documented as highly expressed in several types of human cancer. We have previously identified an autoregulatory feedback loop between iASPP and p63, which is critical in epidermal homeostasis. We hypothesised a potential role for dysregulation of this axis in the pathogenesis of keratinocyte malignancies. Immunostaining of 116 cSCC clinical samples revealed increased iASPP and ΔNp63 expression but also highlighted a significant alteration of iASPP cellular localisation, with consequent deregulation of its function. Expression patterns, functionality, gene and microRNA expression analysis were further investigated in 10 cSCC cell lines. Our data suggest that whilst direct effects of iASPP and p63 upon each other’s expression are maintained in cSCC, epigenetic dysregulation of the feedback loop occurs at the microRNA level by a novel mechanism controlling p63 expression. We demonstrate that this autoregulatory feedback loop controls cell migration in cSCC by blocking EMT and promoting proliferation, and provides future directions for clinical biomarker and therapeutic target discovery in cutaneous SCC.
2019-11-20 | GSE123189 | GEO
Project description:An autoregulatory feedback loop converging on H2AK119ub1 drives synovial sarcoma
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Project description:The Hematopoietically-expressed homeobox (Hhex) transcription factor is overexpressed in human myeloid leukemias. Conditional knockout models of murine acute myeloid leukemia (AML) indicate that Hhex maintains leukemia stem cell self-renewal by enabling Polycomb-mediated epigenetic repression of the Cdkn2a tumor suppressor locus, encoding p16Ink4a and p19Arf. However, whether Hhex overexpression also affects hematopoietic differentiation is unknown. To study this, we retrovirally overexpressed Hhex in hematopoietic progenitors. This enabled serial replating of myeloid progenitors, leading to the rapid establishment of IL-3-dependent promyelocytic cell lines. Use of a Hhex-ERT2 fusion protein demonstrated that continuous nuclear Hhex is required for transformation, and structure function analysis demonstrated a requirement of the DNA binding and N-terminal repressive domains of Hhex for promyelocytic transformation. This included the N-terminal Pml interaction domain, although deletion of Pml failed to prevent Hhex-induced promyelocyte transformation, implying other critical partners. Furthermore, deletion of p16Ink4a or p19Arf did not promote promyelocyte transformation, indicating that repression of distinct Hhex target genes is required for this process. Indeed, transcriptome analysis showed that Hhex overexpression resulted in repression of several myeloid developmental genes. To test potential for Hhex overexpression to contribute to leukemic transformation, Hhex-transformed promyelocyte lines were rendered growth factor-independent using a constitutively active IL-3 receptor common b subunit (bcV449E). The resultant cell lines resulted in a rapid promyelocytic leukemia in vivo. Thus Hhex overexpression can contribute to myeloid leukemia via multiple mechanisms including differentiation blockade and enabling epigenetic repression of the Cdkn2a locus.
2018-01-30 | GSE109793 | GEO
Project description:Background & Aims: Perturbations in pancreatic ductal bicarbonate secretion often result in chronic pancreatitis. Although the physiological mechanism of ductal secretion is known, its transcriptional control is not well characterized. Here, we investigate the role of the transcription factor Hematopoietically-expressed homeobox protein (Hhex) in pancreatic secretion and pancreatitis. Methods: We derived mice with pancreas-specific, Cre-mediated Hhex gene ablation to determine the requirement of Hhex in the pancreatic duct in early life and in adult stages. Histological and immunostaining analyses were used to detect the presence of pathology. Pancreatic primary ductal cells (PDCs) were isolated to discover differentially expressed transcripts upon acute Hhex ablation. Results: Hhex protein was detected throughout the embryonic and adult ductal trees. Ablation of Hhex in pancreatic progenitors resulted in postnatal ductal ectasia associated with acinar-to-ductal metaplasia, a progressive phenotype that ultimately resulted in chronic pancreatitis. Hhex ablation in adult mice, however, did not cause any detectable pathology. Ductal ectasia did not result from perturbations in primary cilia, but was consistent with the effects of primary ductal hypertension. RNA-seq analysis of Hhex-ablated PDCs indicated the G-protein coupled receptor Natriuretic peptide receptor 3, implicated in paracrine signaling, was upregulated 4.70-fold. Conclusions: Although Hhex is dispensable for adult pancreatic function, ablation of Hhex in pancreatic progenitors results in profound pancreatitis that is consistent with primary ductal hypertension. Our data highlight the critical role of paracrine signaling in maintaining ductal homeostasis, especially in early life, and support ductal hypersecretion as a novel etiology of pediatric chronic pancreatitis. Pancreatic primary ductal cells (PDCs) were isolated from uninduced adult HhexL/L;Sox9CreERT2 (n=2) and littermate control HhexL/L (n=2) mice. PDCs were treated with 500nM 4-hydroxytamoxifen in vitro for 4 days, and then RNA was collected for transcriptome analysis.
2015-11-20 | E-GEOD-63526 | biostudies-arrayexpress
Project description:In the ciliated protozoan Tetrahymena, an RNAi-mediated feedback loop is important for assembling heterochromatin on the sequences that are removed from the somatic genome by programmed DNA elimination. Because heterochromatin is formed exclusively on the eliminated sequences, some mechanism must inhibit this feedback loop at the boundaries of the eliminated sequences. In this study, we show that the HP1-like protein Coi6p, its interaction partners Coi7p and Lia5p, and the histone demethylase Jmj1p are crucial for confining the production of small RNAs to the eliminated sequences.
2017-03-06 | GSE87011 | GEO