H19 Noncoding RNA, an independent prognostic factor, regulates essential Rb-E2F and CDK8/ß-catenin signaling in colorectal cancer
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ABSTRACT:
PROVIDER: PRJNA344744 | ENA |
REPOSITORIES: ENA
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Project description:Mutations in cancer are due in part to DNA cytosine deamination by APOBEC3B (A3B). While low in healthy tissues, A3B expression and activity are elevated in tumors and further increase in metastases. However, molecular mechanisms responsible for A3B transcriptional regulation are poorly understood. Here, we address whether the RB/E2F pathway, which is often dysregulated in breast cancer, is a molecular trigger of A3B overexpression. First, an A3B promoter-driven luciferase reporter was used to demonstrate reporter activation by disruption of only one out of five predicted E2F binding sites. Second, A3B-luciferase reporter activation was also triggered by expressing the BK polyomavirus T-antigen, which inactivates RB and thereby alleviates repression of E2F regulated genes. Importantly, A3B-luciferase reporter induction by BK polyomavirus T-antigen could not be further increased by mutating the functional E2F binding site. Third, both CRISPR disruption and targeted base substitutions in the endogenous E2F binding site caused strong A3B upregulation and confirmed importance of this regulatory element. Fourth, proteomics experiments showed that members of the DREAM and PRC1.6-complexes including multiple E2F family members are able to bind to wild-type but not E2F mutant promoter sequences. Finally, a combination of genetic and biochemical studies implicated E2F4 and E2F6 in endogenous A3B gene repression. Altogether, our studies demonstrate that A3B expression is suppressed in normal cells by the RB/E2F axis and that viral or mutational disruption of this pathway causes overexpression of this DNA deaminase in cancer and contributes mutational fuel to tumor evolution.
2020-10-19 | PXD020473 | Pride
Project description:The Rb/E2F tumor suppressor regulates gene expression to control the onset and timing of differentiation in many different cell types during development. This critical function makes Rb/E2F a frequent target for inactivation in tumors of diverse tissue origin. However, the mechanisms by which Rb/E2F governs tissue-specific gene regulation in vivo are poorly understood. We have determined the genome-wide binding profiles for components of the C. elegans Rb/E2F transcriptional regulatory pathway in the germ line, the intestine, and broadly in somatic tissues. Rb/E2F exhibits highly tissue-specific regulation, with unique sets of target genes that are activated or repressed depending on whether cells are in a progenitor (germ line) or terminally differentiated (somatic) state. In particular, LIN-35 binding is impaired in the germ line relative to the soma. Moreover, in the intestine, LIN-35 binds independently of EFL-1/DPL-1 at broad intergenic sites at which the heterochromatin protein HPL-2 also binds. Finally, recently defined âHOTâ sites, which are non-specifically bound by many unrelated factors, appear to be restricted primarily to somatic tissues, suggesting that germ line chromatin is in a state that globally restricts promiscuous association of regulatory factors. In sum, these tissue-specific binding profiles led to significant mechanistic insights into tissue-specific properties of Rb/E2F function in C. elegans that are likely relevant to other organisms.
2012-06-26 | GSE30246 | GEO
Project description:We demonstrate that the cell cycle regulators, E2f /Dp and Rb, control the transcription of ribosomal proteins (RP) in Drosophila embryos. Mutation of E2f1 or Dp and over expression of Rbf1 increase and reduce RP transcription, respectively. Although E2f/Dp/Rb might exert this effect through a repressor complex, the regulatory regions of RP genes do not show an enrichment of canonical E2f binding sites. In addition, E2f1, Dp and Rbf1 also regulate the expression of RACK1, a ribosomal component and a negative regulator of cell cycle progression. These findings strengthen the coupling of cell cycle regulation to protein biosynthesis. Keywords: genotype response
2008-04-27 | GSE7655 | GEO
Project description:The Rb/E2F tumor suppressor regulates gene expression to control the onset and timing of differentiation in many different cell types during development. This critical function makes Rb/E2F a frequent target for inactivation in tumors of diverse tissue origin. However, the mechanisms by which Rb/E2F governs tissue-specific gene regulation in vivo are poorly understood. We have determined the genome-wide binding profiles for components of the C. elegans Rb/E2F transcriptional regulatory pathway in the germ line, the intestine, and broadly in somatic tissues. Rb/E2F exhibits highly tissue-specific regulation, with unique sets of target genes that are activated or repressed depending on whether cells are in a progenitor (germ line) or terminally differentiated (somatic) state. In particular, LIN-35 binding is impaired in the germ line relative to the soma. Moreover, in the intestine, LIN-35 binds independently of EFL-1/DPL-1 at broad intergenic sites at which the heterochromatin protein HPL-2 also binds. Finally, recently defined âHOTâ sites, which are non-specifically bound by many unrelated factors, appear to be restricted primarily to somatic tissues, suggesting that germ line chromatin is in a state that globally restricts promiscuous association of regulatory factors. In sum, these tissue-specific binding profiles led to significant mechanistic insights into tissue-specific properties of Rb/E2F function in C. elegans that are likely relevant to other organisms. Staged C. elegans worms carrying different transgenes expressing GFP-transcription factors under different promoters were treated to ChIP-seq in biological replicate. A total of eleven different transgenic lines were analyzed. Three transcription factors (LIN-35, EFL-1 and DPL-1) were each tagged with GFP and expressed under the pie-1 promoter (germline), the ges-1 promoter (intestine), or their endogenous promoter (somatic expression), for a total of nine lines. In addition, LIN-35:GFP was expressed under the mex-5 promoter (germline), and HPL-2 was expressed under the ges-1 promoter, for an additional two lines. All strains with germline expression were analyzed as young adults, while the intestine or somatic expressed lines were analyzed as L1s. For each replicate of each transgenic line at the appropriate stage, anti-GFP was used to immunoprecipitate the tagged transcription factor, and the factor-enriched chromatin was subjected to Illumina sequencing. As a control, for every ChIP sample, the input (without immunoprecipitation) was also sequenced.
2012-06-26 | E-GEOD-30246 | biostudies-arrayexpress
Project description:We demonstrate that the cell cycle regulators, E2f /Dp and Rb, control the transcription of ribosomal proteins (RP) in Drosophila embryos. Mutation of E2f1 or Dp and over expression of Rbf1 increase and reduce RP transcription, respectively. Although E2f/Dp/Rb might exert this effect through a repressor complex, the regulatory regions of RP genes do not show an enrichment of canonical E2f binding sites. In addition, E2f1, Dp and Rbf1 also regulate the expression of RACK1, a ribosomal component and a negative regulator of cell cycle progression. These findings strengthen the coupling of cell cycle regulation to protein biosynthesis. Experiment Overall Design: Our study examines the genomic response of intact Drosophila embryos to the genetic manipulation of E2F/Rb pathway molecules. For over-expression experiments, Arm-Gal4 stocks were crossed to UAS-gene stocks for the following genes: E2f1/Dp, E2f2/Dp, Rbf1, and E2f1336-805 (a dominant negative form of E2f1 lacking the DNA binding domain) [16]. The E2f17172 and E2f191 null alleles were balanced by TM3[Kr-GFP]. Dpa2 and Dpa4 null alleles were balanced by CyO[Kr-GFP]. 14-16 hr E2f17172/E2f191 null mutant embryos were hand selected based on the absence of fluorescent Bolwigâs organs in Kr-GFP balanced stocks using a Zeiss stereomicroscope equipped with epifluorescence. E2f17172/E2f191 and Dpa2/Dpa4 null mutant embryos (8-10h) were selected using the COPASTM SELECT system for automated sorting of multi-cellular organisms. Eighteen RNA samples, two from each cross, were obtained from approximately 200 to 700 embryos per sample. For each cross, 2 h embryo collections were aged for 8 to 14 h at 25oC, quick frozen in an ethanol/dry ice mixture, and stored at -80 oC. The RNA was prepared for microarray analysis in accordance with Affymetrix instructions.
2008-06-15 | E-GEOD-7655 | biostudies-arrayexpress
Project description:The clinical significance of long noncoding RNAs (lncRNAs) in colorectal cancer (CRC) remains largely unexplored. Here, we analyzed a large panel of lncRNA candidates with The Cancer Genome Atlas (TCGA) CRC dataset, and identified H19 as the most significant lncRNA associated with CRC patient survival. We further validated such association in two independent CRC cohorts. H19 silencing blocked G1-S transition, reduced cell proliferation, and inhibited cell migration. We profiled gene expression changes to gain mechanism insight of H19 function. Transcriptome data analysis revealed not only previously identified mechanisms such as Let-7 regulation by H19, but also RB1-E2F1 function and β-catenin activity as essential upstream regulators mediating H19 function. Our experimental data showed that H19 affects phosphorylation of RB1 protein by regulating gene expression of CDK4 and CCND1. We further demonstrated that reduced CDK8 expression underlies changes of β-catenin activity, and identified that H19 interacts with macroH2A, an essential regulator of CDK8 gene transcription. However, the relevance of H19-macroH2A interaction in CDK8 regulation remains to be experimentally determined. We further explored the clinical relevance of above mechanisms in clinical samples, and showed that combined analysis of H19 with its targets improved prognostic value of H19 in CRC.
| S-EPMC5264449 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2016-09-29 | GSE87431 | GEO
Project description:Bladder cancer (BC) is a highly prevalent human disease in which Rb pathway inactivation and epigenetic alterations are common events. However, the connection between these two processes is still poorly understood. Here we show that the in vivo inactivation of all Rb family genes in the mouse urothelium is sufficient to initiate BC development. The characterization of the mouse tumors revealed multiple molecular features of human BC, including the activation of E2F transcription factor and subsequent Ezh2 expression, and the activation of several signaling pathways previously identified as highly relevant in urothelial tumors. Whole transcriptional characterizations of the mouse bladder tumors revealed a significant overlap with human BC samples, and a predominant role for Ezh2 in the downregulation of gene expression programs. Importantly, we determined that in human superficial BC patients, the increased tumor recurrence and progression in these recurrences is associated with increased E2F and Ezh2 expression and Ezh2-mediated gene expression repression. Collectively, our studies provide a genetically defined model for human high-grade superficial BC and demonstrate the existence of an Rb-E2F-Ezh2 axis in bladder whose disruption can promote tumor development. Gene expression was analyzed in normal bladder and bladder tumours, both in humans and in transgenic mice.
2014-10-02 | E-GEOD-38264 | biostudies-arrayexpress
Project description:Most E2F-binding sites repress transcription through the recruitment of Retinoblasoma (RB) family members until the end of the G1 cell-cycle phase. Although the MYB promoter contains an E2F-binding site, its transcription is activated shortly after the exit from quiescence, before RB family members inactivation, by unknown mechanisms. We had previously uncovered a nuclear factor distinct from E2F, Myb-sp, whose DNA-binding site overlapped the E2F element and had hypothesized that this factor might overcome the transcriptional repression of MYB by E2F-RB family members. We have purified Myb-sp and discovered that Myc-associated zinc finger proteins (MAZ) are major components. We show that various MAZ isoforms are present in Myb-sp and activate transcription via the MYB-E2F element. Moreover, while forced RB or p130 expression repressed the activity of a luciferase reporter driven by the MYB-E2F element, co-expression of MAZ proteins not only reverted repression, but also activated transcription. Finally, we show that MAZ binds the MYB promoter in vivo, that its binding site is critical for MYB transactivation, and that MAZ knockdown inhibits MYB expression during the exit from quiescence. Together, these data indicate that MAZ is essential to bypass MYB promoter repression by RB family members and to induce MYB expression.
2017-10-04 | PXD006857 | Pride
Project description:Protein tyrosine phosphatase 1B (PTP1B) plays a key role in developing different types of cancer. However, the molecular mechanism underlying this effect is unclear. To identify possible molecular targets of PTP1B that mediate its positive role in tumorigenesis, we undertook a SILAC-based phosphoproteomic approach, which allowed us to identify the Cyclin-dependent kinase 3 (Cdk3) as a novel PTP1B substrate. Molecular docking studies revealed stable interactions between the PTP1B catalytic domain and Cdk3. In addition, we observed that PTP1B dephosphorylates Cdk3 at Tyrosine residue 15 in vitro and interacts with it in the nucleus and cytoplasm of human glioblastoma (GB) cells. Finally, we found that the pharmacological inhibition of PTP1B or its depletion with siRNA leads to cell cycle arrest with the diminished activity of Cdk3, the consequent hypophosphorylation of Rb, and the down-regulation of E2F and its target genes Cdk1, Cyclin A, and Cyclin E1. These data delineate a novel signaling pathway from PTP1B to Cdk3 required for efficient cell cycle progression in an Rb-E2F dependent manner in human GB cells and suggest new therapeutic strategies for treating these tumors.
2023-12-05 | PXD046000 | Pride