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Project description:The mechanistic basis for the metastasis of Ewing sarcomas remains poorly understood, as these tumors harbor few mutations beyond the chromosomal translocation that initiates the disease. Instead, the epigenome of Ewing sarcoma cells reflects the regulatory state of genes associated with the DNA-binding activity of the fusion oncoproteins EWSR1::FLI1 or EWSR1::ERG. In this study, we examined the EWSR1::FLI1/ERG's repression of transcription factor genes, concentrating on those that exhibit a broader range of expression in tumors than in Ewing sarcoma cell lines. Focusing on one of these target genes, ETS1, we detected EWSR1::FLI1 binding and an H3K27me3-repressive mark at this locus. Depletion of EWSR1::FLI1 results in ETS1's binding of promoter regions, substantially altering the transcriptome of Ewing sarcoma cells, including the upregulation of the gene encoding TENSIN3 (TNS3), a focal adhesion protein. Ewing sarcoma cell lines expressing ETS1 (CRISPRa) exhibited increased TNS3 expression and enhanced movement compared with control cells. Visualization of control Ewing sarcoma cells showed a distributed vinculin signal and a network-like organization of F-actin; in contrast, ETS1-activated Ewing sarcoma cells showed an accumulation of vinculin and F-actin toward the plasma membrane. Interestingly, the phenotype of ETS1-activated Ewing sarcoma cell lines depleted of TNS3 resembled the phenotype of the control cells. Critically, these findings have clinical relevance as TNS3 expression in Ewing sarcoma tumors positively correlates with that of ETS1. Implications: ETS1's transcriptional regulation of the gene encoding the focal adhesion protein TENSIN3 in Ewing sarcoma cells promotes cell movement, a critical step in the evolution of metastasis.
| S-EPMC11219265 | biostudies-literature
Project description:The mechanistic basis for the metastasis of Ewing sarcomas remains poorly understood, as these tumors harbor few mutations beyond the chromosomal translocation that initiates the disease. Instead, the epigenome of Ewing sarcoma (EWS) cells reflects the regulatory state of genes associated with the DNA binding activity of the fusion oncoproteins EWSR1::FLI1 or EWSR1::ERG. In this study, we examined the EWSR1::FLI1/ERG's repression of transcription factor genes, concentrating on those that exhibit a broader range of expression in tumors than in EWS cell lines. Focusing on one of these target genes, ETS1, we detected EWSR1::FLI1 binding and an H3K27me3 repressive mark at this locus. Depletion of EWSR1::FLI1 results in ETS1's binding of promoter regions, substantially altering the transcriptome of EWS cells, including the upregulation of the gene encoding TENSIN3 (TNS3), a focal adhesion protein. EWS cell lines expressing ETS1 (CRISPRa) exhibited increased TNS3 expression and enhanced movement compared to control cells. The cytoskeleton of control cells and ETS1-activated EWS cell lines also differed. Specifically, control cells exhibited a distributed vinculin signal and a network-like organization of F-actin. In contrast, ETS1-activated EWS cells showed an accumulation of vinculin and F-actin towards the plasma membrane. Interestingly, the phenotype of ETS1-activated EWS cell lines depleted of TNS3 resembled the phenotype of the control cells. Critically, these findings have clinical relevance as TNS3 expression in EWS tumors positively correlates with that of ETS1.
| S-EPMC10769395 | biostudies-literature
Project description:ETS1, a target gene of the EWSR1::FLI1 fusion oncoprotein, regulates the expression of the focal adhesion protein TENSIN3
| PRJNA1017350 | ENA
Project description:Ewing sarcomas harbor few mutations beyond the chromosomal translocation that initiates disease and the mechanistic basis for the metastasis of these tumors remains poorly understood. The epigenome of Ewing sarcoma (EWS) cells reflects the regulatory state of genes associated with the DNA binding activity of the fusion oncoproteins EWSR1::FLI1 or EWSR1::ERG. In this study, we examined the repressive activities of the EWSR1::FLI1/ERG fusion oncoproteins. Focusing on one of the repressed EWSR1::FLI1/ERG target genes, ETS1, we detected EWSR1::FLI1 binding and a H3K27me3 repressive mark at this locus. Depletion of EWSR1::FLI1 results in ETS1’s binding of promoter regions, and we show ETS1 regulates the expression of multiple proteins that function in extracellular matrix organization including TENSIN3 (TSN3). Interestingly, TSN3 expression in EWS tumors significantly correlates with that of ETS1 (0.85, FDR <0.01). TNS3 is a focal adhesion protein that contributes to tumor cell migration by connecting the cytoplasmic tail of integrins to the actin cytoskeleton. EWS cell lines, in which we activated ETS1 expression (CRISPRa) exhibited increased TNS3 expression and a migratory phenotype. Critically, the activated ETS1 EWS cell lines show TNS3 accumulation at leading cell edges, with F-actin cytoskeletal reorganization, a phenotype associated with cell migration.
2024-04-15 | GSE243183 | GEO
Project description:Ewing sarcomas harbor few mutations beyond the chromosomal translocation that initiates disease and the mechanistic basis for the metastasis of these tumors remains poorly understood. The epigenome of Ewing sarcoma (EWS) cells reflects the regulatory state of genes associated with the DNA binding activity of the fusion oncoproteins EWSR1::FLI1 or EWSR1::ERG. In this study, we examined the repressive activities of the EWSR1::FLI1/ERG fusion oncoproteins. Focusing on one of the repressed EWSR1::FLI1/ERG target genes, ETS1, we detected EWSR1::FLI1 binding and a H3K27me3 repressive mark at this locus. Depletion of EWSR1::FLI1 results in ETS1’s binding of promoter regions, and we show ETS1 regulates the expression of multiple proteins that function in extracellular matrix organization including TENSIN3 (TNS3). Interestingly, TNS3 expression in EWS tumors significantly correlates with that of ETS1 (0.85, FDR <0.01). TNS3 is a focal adhesion protein that contributes to tumor cell migration by connecting the cytoplasmic tail of integrins to the actin cytoskeleton. EWS cell lines, in which we activated ETS1 expression (CRISPRa) exhibited increased TNS3 expression and a migratory phenotype. Critically, the activated ETS1 EWS cell lines show TNS3 accumulation at leading cell edges, with F-actin cytoskeletal reorganization, a phenotype associated with cell migration.
2024-04-15 | GSE243171 | GEO
Project description:Ewing sarcomas harbor few mutations beyond the chromosomal translocation that initiates disease and the mechanistic basis for the metastasis of these tumors remains poorly understood. The epigenome of Ewing sarcoma (EWS) cells reflects the regulatory state of genes associated with the DNA binding activity of the fusion oncoproteins EWSR1::FLI1 or EWSR1::ERG. In this study, we examined the repressive activities of the EWSR1::FLI1/ERG fusion oncoproteins. Focusing on one of the repressed EWSR1::FLI1/ERG target genes, ETS1, we detected EWSR1::FLI1 binding and a H3K27me3 repressive mark at this locus. Depletion of EWSR1::FLI1 results in ETS1’s binding of promoter regions, and we show ETS1 regulates the expression of multiple proteins that function in extracellular matrix organization including TENSIN3 (TSN3). Interestingly, TSN3 expression in EWS tumors significantly correlates with that of ETS1 (0.85, FDR <0.01). TNS3 is a focal adhesion protein that contributes to tumor cell migration by connecting the cytoplasmic tail of integrins to the actin cytoskeleton. EWS cell lines, in which we activated ETS1 expression (CRISPRa) exhibited increased TNS3 expression and a migratory phenotype. Critically, the activated ETS1 EWS cell lines show TNS3 accumulation at leading cell edges, with F-actin cytoskeletal reorganization, a phenotype associated with cell migration.
2024-04-15 | GSE243279 | GEO
Project description:Ewing sarcomas harbor few mutations beyond the chromosomal translocation that initiates disease and the mechanistic basis for the metastasis of these tumors remains poorly understood. The epigenome of Ewing sarcoma (EWS) cells reflects the regulatory state of genes associated with the DNA binding activity of the fusion oncoproteins EWSR1::FLI1 or EWSR1::ERG. In this study, we examined the repressive activities of the EWSR1::FLI1/ERG fusion oncoproteins. Focusing on one of the repressed EWSR1::FLI1/ERG target genes, ETS1, we detected EWSR1::FLI1 binding and a H3K27me3 repressive mark at this locus. Depletion of EWSR1::FLI1 results in ETS1’s binding of promoter regions, and we show ETS1 regulates the expression of multiple proteins that function in extracellular matrix organization including TENSIN3 (TSN3). Interestingly, TSN3 expression in EWS tumors significantly correlates with that of ETS1 (0.85, FDR <0.01). TNS3 is a focal adhesion protein that contributes to tumor cell migration by connecting the cytoplasmic tail of integrins to the actin cytoskeleton. EWS cell lines, in which we activated ETS1 expression (CRISPRa) exhibited increased TNS3 expression and a migratory phenotype. Critically, the activated ETS1 EWS cell lines show TNS3 accumulation at leading cell edges, with F-actin cytoskeletal reorganization, a phenotype associated with cell migration.
2024-04-15 | GSE243277 | GEO
Project description:Pediatric malignancies frequently harbor chromosomal translocations that induce expression of fusion oncoproteins. The EWSR1-FLI1 fusion oncoprotein acts as a neomorphic transcription factor and is the dominant genetic driver of Ewing's sarcoma. Interrogation of the mechanisms by which EWSR1-FLI1 drives tumorigenesis has been limited by a lack of model systems to precisely and selectively control its expression in patient-derived cell lines and xenografts. Here, we report the generation of a panel of patient-derived EWS cell lines in which inducible protein degrons were engineered into the endogenous EWSR1-FLI1 locus. These alleles enabled rapid and efficient depletion of EWSR1-FLI1. Complete suppression of EWSR1-FLI1 induced a reversible cell cycle arrest at the G1-S checkpoint, and we identified a core set of transcripts downstream of EWSR1-FLI1 across multiple cell lines and degron systems. Additionally, depletion of EWSR1-FLI1 potently suppressed tumor growth in xenograft models validating efforts to directly target EWSR1-FLI1 in Ewing's sarcoma.
| S-EPMC11566046 | biostudies-literature
Project description:The mechanism whereby the fusion of EWSR1 with the ETS transcription factor FLI1 contributes to malignant transformation in Ewing sarcoma remains unclear. We show that injection of human or zebrafish EWSR1/FLI1 mRNA into developing zebrafish embryos leads to mitotic defects with multipolar and disorganized mitotic spindles. Expression of human EWSR1/FLI1 in HeLa cells also results in mitotic defects, along with mislocalization of Aurora kinase B, a key regulator of mitotic progression. Because these mitotic abnormalities mimic those observed with the knockdown of EWSR1 in zebrafish embryos and HeLa cells, we investigated whether EWSR1/FLI1 interacts with EWSR1 and interferes with its function. EWSR1 coimmunoprecipitates with EWSR1/FLI1, and overexpression of EWSR1 rescues the mitotic defects in EWSR1/FLI1-transfected HeLa cells. This interaction between EWSR1/FLI1 and EWSR1 in Ewing sarcoma may induce mitotic defects leading to genomic instability and subsequent malignant transformation.
| S-EPMC2766243 | biostudies-literature
Project description:Focal adhesions are macromolecular complexes that connect the actin cytoskeleton to the extracellular matrix. Dynamic turnover of focal adhesions is crucial for cell migration. Paxillin is a multi-adaptor protein that plays an important role in regulating focal adhesion dynamics. Here, we identify TRIM15, a member of the tripartite motif protein family, as a paxillin-interacting factor and a component of focal adhesions. TRIM15 localizes to focal contacts in a myosin-II-independent manner by an interaction between its coiled-coil domain and the LD2 motif of paxillin. Unlike other focal adhesion proteins, TRIM15 is a stable focal adhesion component with restricted mobility due to its ability to form oligomers. TRIM15-depleted cells display impaired cell migration and reduced focal adhesion disassembly rates, in addition to enlarged focal adhesions. Thus, our studies demonstrate a cellular function for TRIM15 as a regulatory component of focal adhesion turnover and cell migration.
| S-EPMC4163643 | biostudies-literature