EWS-Fli and LNC regulated genes in comparison to GFP samples
Ontology highlight
ABSTRACT: RNA from A673 cells with shRNA-mediated knockdown of GFP (4 libraries), EWS-FLI1 (4 libraries), or lnc277 (7 libraries) was isolated with TRIzol (Invitrogen). Each sample was DNase treated and further purified on an RNeasy Mini column (Qiagen) before quality analysis on an Agilent 2100 Bioanalyzer. For each sample, 100-150ng of RNA was synthesized into cDNA, sheared on a Covaris ultrasonicator, and amplified using the NuGen Encore Complete kit (NuGen) to produce strand-specific and rRNA-depleted libraries. Samples were multiplexed (4/lane) for 2x100bp paired-end sequencing on an Illumina HiSeq 2000 RNA from A673 cells with shRNA-mediated knockdown of GFP (4 libraries), EWS-FLI1 (4 libraries), or lnc277 (7 libraries) was isolated with TRIzol (Invitrogen).
Project description:RNA from A673 cells with shRNA-mediated knockdown of GFP (4 libraries), EWS-FLI1 (4 libraries), or lnc277 (7 libraries) was isolated with TRIzol (Invitrogen). Each sample was DNase treated and further purified on an RNeasy Mini column (Qiagen) before quality analysis on an Agilent 2100 Bioanalyzer. For each sample, 100-150ng of RNA was synthesized into cDNA, sheared on a Covaris ultrasonicator, and amplified using the NuGen Encore Complete kit (NuGen) to produce strand-specific and rRNA-depleted libraries. Samples were multiplexed (4/lane) for 2x100bp paired-end sequencing on an Illumina HiSeq 2000
Project description:Fusion of the EWS gene to FLI1 produces a fusion oncoprotein that drives an aberrant gene expression program responsible for the development of Ewing sarcoma. We used a homogenous proximity assay to screen for compounds that disrupt the binding of EWS-FLI1 to its cognate DNA targets. A number of DNA-binding chemotherapeutic agents were found to non-specifically disrupt protein binding to DNA. In contrast, actinomycin D was found to preferentially disrupt EWS-FLI1 binding by comparison to p53 binding to their respective cognate DNA targets in vitro. In cell-based assays, low concentrations of actinomycin preferentially blocked EWS-FLI1 binding to chromatin, and disrupted EWS-FLI1-mediated gene expression. Higher concentrations of actinomycin globally repressed transcription. These results demonstrate that actinomycin preferentially disrupts EWS-FLI1 binding to DNA at selected concentrations. Although the window between this preferential effect and global suppression is too narrow to exploit in a therapeutic manner, these results suggest that base-preferences may be exploited to find DNA-binding compounds that preferentially disrupt subclasses of transcription factors. Using proximity assays in A673 Ewing Sarcoma cells, we screened 7 bioactive-enriched small molecule libraries, totaling 5,200 compounds to identify compounds that could disrupt the binding of EWS-FLI1 to its cognate DNA binding sequence. We defined a set of EWS-FLI1-regulated genes by shRNA depletion of EWS-FLI1in the same cell line. Duplicate knock down experiments were carried out and compared to duplicate scrambled shRNA controls. This signature was used to interrogate the effects in duplicate experiments of low- and high-dose actinomycin D treatment in A673 cells as compared to DMSO and untreated controls (2 each).
Project description:We generated A673 Ewing Sarcoma cell lines which stably express shRNA targeting the EWS-FLI1 fuison protein or Luciferase as a control to study the effect of EWS-FLI1 on the transcriptome. The vectors used to generate the cell lines were a gift from Stephen Lessnick and were first published in PMID 16697960
Project description:Ewing’s sarcoma (EWS) is a cancer of the bones or soft tissues in children and adolescents. EWS-FLI1 is a transcriptional factor and the key driver of EWS. To characterize the changes of downstream transcriptional profiles of EWS-FLI1 in A673 cells upon knockdown of EWS-FLI1 and deubiquitinase USP9X, RNA-seq was performed in A673 cells transfected with EWS-FLI1 esiRNA, USP9X esiRNA or GFP esiRNA as control. The data indicates that USP9X regulates transcriptional profiles of EWS through mediating EWS-FLI1.
Project description:We have performed a high-throughput RNA interference screen to identify targets inhibiting EWS-FLI1 driven cell proliferation in Ewing sarcoma cells. EWS-FLI1 expressing A673 Ewing sarcoma cells were screened both in presence and absence of EWS-FLI1 shRNA induction with druggable siRNA library. Leucine rich repeats and WD repeat Domain containing 1 (LRWD1) targeting siRNA pool was the strongest anti-proliferative hit identified only in presence of EWS-FLI1. Validation experiments confirmed the anti-proliferative effect of LRWD1 depletion especially in EWS-FLI1 expressing cells. Functional analysis of differentially expressed genes in LRWD1 depleted Ewing sarcoma cells showed over-representation of connective tissue development, cell projection morphogenesis and neuronal processes.
Project description:The molecular hallmark of the Ewing family of tumors is the presence of balanced chromosomal translocations leading to the formation of chimerical transcription factors (i.e. EWS/FLI1) that play a pivotal role in the pathogenesis of Ewing tumors by deregulating gene expression. We have recently demonstrated that DAX1 (NR0B1), an orphan nuclear receptor which was not previously implicated in cancer, is induced by the EWS/FLI1 oncoprotein and is highly expressed in Ewing tumors, suggesting that DAX1 is a biologically relevant target of EWS/FLI1-mediated oncogenesis. In this work we demonstrate that DAX1 is a direct transcriptional target of the EWS/FLI1 oncoprotein through its binding to a GGA-rich region in the DAX1 promoter and show that DAX1 is a key player of EWS/FLI1-mediated oncogenesis. DAX1 silencing using an inducible model of RNA interference induces growth arrest in the A673 Ewing cell line and severely impairs its capability to grow in semisolid medium and form tumors in immunodeficient mice. Gene expression profile analysis demonstrated that about ten percent of the genes regulated by EWS/FLI1 in Ewing cells are DAX1 targets, confirming the importance of DAX1 in Ewing oncogenesis. These findings indicate that DAX1 is an important player in the pathogenesis of the Ewing family of tumors, identify new functions for DAX1 as a cell cycle progression regulator and open the possibility to new therapeutic approaches based on DAX1 function interference. A673 cells derived from Ewing sarcoma were genetically enginereed to express specific shRNAs against GFP (control), EWS/FLI1 and DAX1 upon doxycycline stimulation. Three independent clones and a polyclonal population from each enginereed cell were analyzed. Cells were stimulated with doxycycline for 72 hours to induce the expression of the corresponding shRNA and whole gene expression profile performed. Gene expression profile in A673 cells in which EWS/FLI1 or DAX1 were silenced were compared to the control cells.
Project description:EWS-FLI-1 was silenced by an shRNA in A673 Ewing sarcoma cells and the resulting alterations in the secretome was analyzed by GeLC-MS/MS approach (six gel slices for each sample, luciferase shRNA-expressing cell secretome as control)
Project description:Ewing sarcoma is a highly aggressive tumor characterized by a translocation between members of the FET family of RNA binding proteins and one of several ETS transcription factors, with the most common translocation being EWS-FLI1. EWS-FLI1 leads to changes in gene expression through mechanisms that are not completely understood. We performed RNA sequencing analysis on primary pediatric human mesenchymal progenitor cells (pMPCs) expressing EWS-FLI1 in order to identify novel target genes. This analysis identified lnc277 as a previously uncharacterized long non-coding RNA upregulated by EWS-FLI1 in pMPCs. Inhibiting the expression of lnc277 diminished the ability of Ewing sarcoma cell lines to proliferate and form colonies in soft agar whereas inhibiting lnc277 had no effect on other cell types tested. By analyzing gene expression after shRNA knockdown, we found that both EWS-FLI1 and lnc277 repressed many more genes that they induced and that a significant fraction of EWS-FLI1 repressed targets were also repressed by lnc277. Analysis of primary human Ewing sarcoma RNA sequencing data further supports a role for lnc277 in mediating gene repression. We identified hnRNPK as an RNA binding protein that interacts directly with lnc277. We found a significant overlap in the genes repressed by hnRNPK and those repressed by both EWS-FLI1 and lnc277, suggesting that hnRNPK participates in lnc277 mediated gene repression. Thus, lnc277 is a previously uncharacterized long non-coding RNA downstream of EWS-FLI1 that facilitates the development of Ewing sarcoma via the repression of target genes. Our studies identify a novel mechanism of oncogenesis downstream of a chromosomal translocation and underscore the importance of lncRNA-mediated gene repression as a mechanism of EWS-FLI1 transcriptional regulation. A673 Ewing cells expressing an shRNA targeting hnRNPK or control were subjected to paired end RNA sequencing and compared to shGFP control.
Project description:Comparison of gene expression profile of Ewing sarcoma cells which have an exchange of the endogenous EWS/FLI1 to either wild-type or a turnover-deficient mutant EWS/FLI1. Most target genes are saturated as only a few target genes are soly driven by increasing protein amount. The effect of a stable EWS/FLI1 mutant on global gene expression was evaluated in A673 Ewing sarcoma cells.
Project description:We show that EWS-FLI1, an aberrant transcription factor responsible for the pathogenesis of Ewing sarcoma, reprograms gene regulatory circuits by directly inducing or directly repressing enhancers. At GGAA repeats, which lack regulatory potential in other cell types and are not evolutionarily conserved, EWS- FLI1 multimers potently induce chromatin opening, recruit p300 and WDR5, and create de novo enhancers. GGAA repeat enhancers can loop to physically interact with target promoters, as demonstrated by chromosome conformation capture assays. Conversely, EWS-FLI1 inactivates conserved enhancers containing canonical ETS motifs by displacing wild-type ETS transcription factors and abrogating p300 recruitment. Ewing sarcoma cell lines (A673 and SKNMC) were analyzed by RNA-seq. EWS-FLI1 was depleted by infection with lentiviral shRNAs (shFLI1 and shGFP control).