Project description:The EwingM-bM-^@M-^Ys sarcoma protein EWS belongs to the TET family (FUS/TLS, EWS, TAF15) of RNA and DNA binding proteins, implicated in DNA transcription, pre-mRNA splicing and maintenance of genomic integrity. Translocations of these genes are characteristic of particular neoplasias, including EwingM-bM-^@M-^Ys sarcoma. To identify physiological RNA targets of EWS, we performed in vivo cross-linking and immunoprecipitation followed by high-throughput RNA sequencing (HITS-CLIP/CLIP-Seq) in HeLa cells. Sequencing identified EWS binding sites characterized by guanosine-rich motifs in nearly 9000 genes, with particular enrichment in exonic regions near 5M-bM-^@M-^Y splice sites. Exon 6 of the Fas/CD95 receptor, which is alternatively spliced to generate isoforms with opposing activities in programmed cell death, was found as a prominent EWS CLIP target, as well as by chromatin-immunoprecipitation (ChIP) and functional analysis. Manipulation of EWS levels and mutation of EWS binding sites led to changes in alternative splicing consistent with EWS promoting exon 6 inclusion and leading to the synthesis of the pro-apoptotic Fas/CD95 isoform. Biochemical characterization of factors associated with FAS exon 6 are consistent with the notion that EWS binds to exonic sequences near the 5M-bM-^@M-^Y splice site and promotes the recruitment of U1snRNP, favoring also recognition of the upstream 3' splice site by U2AF and thus exon definition. Consistent with a role for EWS in the regulation of programmed cell death, cells depleted of EWS show decreased sensitivity to Fas-induced apoptosis. We discuss the potential implications of this novel function of EWS in EwingM-bM-^@M-^Ys sarcoma. CLIP-Seq analysis of EWS, with 2 biological replicates of EWS and one non-specific control
Project description:The Ewing’s sarcoma protein EWS belongs to the TET family (FUS/TLS, EWS, TAF15) of RNA and DNA binding proteins, implicated in DNA transcription, pre-mRNA splicing and maintenance of genomic integrity. Translocations of these genes are characteristic of particular neoplasias, including Ewing’s sarcoma. To identify physiological RNA targets of EWS, we performed in vivo cross-linking and immunoprecipitation followed by high-throughput RNA sequencing (HITS-CLIP/CLIP-Seq) in HeLa cells. Sequencing identified EWS binding sites characterized by guanosine-rich motifs in nearly 9000 genes, with particular enrichment in exonic regions near 5’ splice sites. Exon 6 of the Fas/CD95 receptor, which is alternatively spliced to generate isoforms with opposing activities in programmed cell death, was found as a prominent EWS CLIP target, as well as by chromatin-immunoprecipitation (ChIP) and functional analysis. Manipulation of EWS levels and mutation of EWS binding sites led to changes in alternative splicing consistent with EWS promoting exon 6 inclusion and leading to the synthesis of the pro-apoptotic Fas/CD95 isoform. Biochemical characterization of factors associated with FAS exon 6 are consistent with the notion that EWS binds to exonic sequences near the 5’ splice site and promotes the recruitment of U1snRNP, favoring also recognition of the upstream 3' splice site by U2AF and thus exon definition. Consistent with a role for EWS in the regulation of programmed cell death, cells depleted of EWS show decreased sensitivity to Fas-induced apoptosis. We discuss the potential implications of this novel function of EWS in Ewing’s sarcoma.
Project description:In this study, we characterize the fusion protein produced by the EPC1-PHF1 translocation in Low Grade Endometrial Stromal Sarcoma (LG-ESS) and Ossifying FibroMyxoid Tumors (OFMT). We express the fusion protein and necessary controls in K562 Cells. The fusion protein assembles a mega-complex harboring both NuA4/TIP60 and PRC2 subunits and enzymatic activities and leads to mislocalization of chromatin marks in the genome, linked to aberrant gene expression.
Project description:In this study, we characterize the fusion protein produced by the EPC1-PHF1 translocation in Low Grade Endometrial Stromal Sarcoma (LG-ESS) and Ossifying FibroMyxoid Tumors (OFMT). We express the fusion protein and necessary controls in K562 Cells. The fusion protein assembles a mega-complex harboring both NuA4/TIP60 and PRC2 subunits and enzymatic activities and leads to mislocalization of chromatin marks in the genome, linked to aberrant gene expression.
Project description:In this study, we characterize the fusion protein produced by the EPC1-PHF1 translocation in Low Grade Endometrial Stromal Sarcoma (LG-ESS) and Ossifying FibroMyxoid Tumors (OFMT). We express the fusion protein and necessary controls in K562 Cells. The fusion protein assembles a mega-complex harboring both NuA4/TIP60 and PRC2 subunits and enzymatic activities and leads to mislocalization of chromatin marks in the genome, linked to aberrant gene expression.
Project description:Identification of druggable targets is a prerequisite for developing targeted therapies against Ewing sarcoma. We report the identification of Protein Kinase C Beta (PRKCB) as a protein specifically and highly expressed in Ewing sarcoma as compared to other pediatric cancers. Its transcriptional activation is directly regulated by the EWSR1-FLI1 oncogene. Getting insights in PRKCB activity we show that, together with PRKCA, it is responsible for the phosphorylation of histone H3T6, allowing global maintenance of H3K4 trimethylation on a variety of gene promoters. In the long term, PRKCB RNA interference induces apoptosis in vitro. More importantly, in xenograft mice models, complete impairment of tumor engraftment and even tumor regression were observed upon PRKCB inhibition, highlighting PRKCB as a most valuable therapeutic target. Deciphering PRKCB roles in Ewing sarcoma using expression profiling, we found a strong overlap with genes modulated by EWSR1-FLI1 and an involvement of RPKCB in regulating crucial signaling pathways. Altogether, we show that PRKCB may have two important independent functions and should be considered as highly valuable for understanding Ewing sarcoma biology and as a promising target for new therapeutic approaches in Ewing sarcoma. A673 Ewing cell line was treated for 72 hours by either control siRNA or siRNA directed against PRKCB or EWSR1-FLI1. Total RNAs were extracted and hybridized on HuGene1.1STv1 Affymetrix Arrays. Normalisation was performed using specific Brainarray Enrtez gene CDF file (v14.1).