Project description:Ewing Sarcoma is the second most common solid pediatric malignant neoplasm of the bone and soft tissue. Driven by EWS/Ets, or rarely variant, oncogenic fusions, Ewing Sarcoma is a biologically and clinically aggressive disease with a high propensity for metastasis. Our laboratory has previously identified the Jumonji-domain H3K9 me 1/2 histone demethylase KDM3A as a novel oncogene downstream of EWS/Fli1, the most common oncofusion in Ewing Sarcoma. Herein, we uncover a role for KDM3A in the promotion of Ewing Sarcoma metastasis. Using global gene expression profiling, we show that some of the most strongly regulated genes by KDM3A are those implicated in cell migration and metastasis, and demonstrate, using functional assays, that KDM3A promotes migration in vitro and metastasis in vivo. We further provide evidence that MCAM, one of the most strongly and consistently regulated genes by KDM3A, is an important effector of KDM3A pro-metastatic action. Our studies also show that KDM3A regulates MCAM expression both through a direct mechanism, involving modulation of H3K9 methylation at the MCAM promoter, and an indirect mechanism, via the Ets1 transcription factor.
Project description:Pediatric patients with recurrent metastatic Ewing sarcoma (ES) have a dismal 5-year survival of < 30% largely secondary to treatment resistance in the tumor microenvironment (TME). Novel therapeutic approaches are desperately needed and represent an unmet need. Here, we developed a chimeric antigen receptor (CAR) expressing natural killer (NK) cell targeting melanoma cell adhesion molecule (MCAM) by electroporation of CAR mRNA into ex-vivo expanded NK cells. Expression of anti-MCAM CAR significantly and specifically enhanced NK cytotoxic activity compared to mock NK cells against MCAMhigh ES cells in vitro, and significantly reduced lung metastasis and extended animal survival in an orthotopic xenograft mouse model of ES. However, anti-MCAM CAR NK cells had minimal effects on decreasing primary tumor growth in vivo. We performed transcriptome profiling in patient-derived xenografts to identify the underlying mechanisms of NK cell resistance in ES TME.
Project description:Analysis of miR-130b regulated genes in TC71 Ewing Sarcoma cells. The hypothesis tested being that overexpression of miR-130b increases metastasis in Ewing Sarcoma.
Project description:Tumor: tumor microenvironment (TME) interactions are critical for tumor progression and the composition and structure of the local extracellular matrix (ECM) are key determinants of tumor metastasis. We recently reported that activation of Wnt/beta- catenin signaling in Ewing sarcoma cells induces widespread transcriptional changes that are associated with acquisition of a metastatic tumor phenotype. Significantly, ECM protein-encoding genes were found to be enriched among Wnt/beta-catenin induced transcripts, leading us to hypothesize that activation of canonical Wnt signaling might induce changes in the Ewing sarcoma secretome. To address this hypothesis, conditioned media from Ewing sarcoma cell lines cultured in the presence or absence of Wnt3a was collected for proteomic analysis. Label-free mass spectrometry was used to identify and quantify differentially secreted proteins. We then used in silico databases to identify only proteins annotated as secreted. Comparison of the secretomes of two Ewing sarcoma cell lines revealed numerous shared proteins, as well as a degree of heterogeneity, in both basal and Wnt-stimulated conditions. Gene set enrichment analysis of secreted proteins revealed that Wnt stimulation reproducibly resulted in increased secretion of proteins involved in ECM organization, ECM receptor interactions, and collagen formation. In particular, Wnt-stimulated Ewing sarcoma cells upregulated secretion of structural collagens, as well as matricellular proteins, such as the metastasis-associated protein, tenascin C (TNC). Interrogation of published databases confirmed reproducible correlations between Wnt/beta-catenin activation and TNC and COL1A1 expression in patient tumors. In summary, this first study of the Ewing sarcoma secretome reveals that Wnt/beta-catenin activated tumor cells upregulate secretion of ECM proteins. Such Wnt/beta-catenin mediated changes are likely to impact on tumor: TME interactions that contribute to metastatic progression.
Project description:Ewing sarcoma, a rare and aggressive pediatric cancer, is characterized by chromosomal translocations that give rise to chimeric transcription factors. The most frequent of these chromosomal translocations is the t(11;22) that produces the fusion of the EWSR1 and FLI1 genes to generate the chimeric transcription factor EWSR1::FLI1. EWSR1::FLI1 is the main oncogenic event in Ewing's sarcoma. Recently, it has been proposed that EWSR1::FLI1 levels may fluctuate in Ewing sarcoma cells, giving rise to two cell populations: cells expressing low levels of EWSR1::FLI1 are characterized by a more migratory and invasive phenotype, while cells expressing high levels of EWSR1::FLI1 are more proliferative. The identification and functional characterization of EWSR1::FLI1 gene targets is therefore relevant to understanding the pathobiology of Ewing sarcoma, which in turn could contribute to the identification of new therapeutic targets. Using this approach, we have observed that CD44, a transmembrane protein involved in cell adhesion and migration and associated with metastasis in various cancer types, is overexpressed in the EWSR1::FLI1-low phenotype. Our results suggest that CD44 may play a role in regulating cell migration in Ewing sarcoma cells and thus contribute to the spread of tumor cells.
Project description:Cohesin complexes carrying STAG1 or STAG2 organize the genome into chromatin loops. STAG2 loss-of-function mutations promote metastasis in Ewing sarcoma, a pediatric cancer that is driven by the fusion transcription factor EWS-FLI1. We have integrated transcriptomic data from patients and cellular models to identify a STAG2-dependent gene signature associated with worse prognosis. Subsequent genomic profiling and high-resolution chromatin interaction data from Capture Hi-C indicate that cohesin-STAG2 facilitates the communication between EWS-FLI1-bound long GGAA repeats acting as neoenhancers and their target promoters. Changes in CTCF-dependent chromatin contacts, unrelated to EWS-FLI1 binding, also contribute to the aggressive phenotype. STAG1 is unable to compensate for STAG2 loss and chromatin-bound cohesin is severely decreased, while levels of the processivity factor NIPBL remain unchanged, resulting in altered DNA looping dynamics. These results illuminate how STAG2 loss rewires the Ewing sarcoma chromatin interactome to promote metastasis and provide a list of potential biomarkers and therapeutic targets.
Project description:Cohesin complexes carrying STAG1 or STAG2 organize the genome into chromatin loops. STAG2 loss-of-function mutations promote metastasis in Ewing sarcoma, a pediatric cancer that is driven by the fusion transcription factor EWS-FLI1. We have integrated transcriptomic data from patients and cellular models to identify a STAG2-dependent gene signature associated with worse prognosis. Subsequent genomic profiling and high-resolution chromatin interaction data from Capture Hi-C indicate that cohesin-STAG2 facilitates the communication between EWS-FLI1-bound long GGAA repeats acting as neoenhancers and their target promoters. Changes in CTCF-dependent chromatin contacts, unrelated to EWS-FLI1 binding, also contribute to the aggressive phenotype. STAG1 is unable to compensate for STAG2 loss and chromatin-bound cohesin is severely decreased, while levels of the processivity factor NIPBL remain unchanged, resulting in altered DNA looping dynamics. These results illuminate how STAG2 loss rewires the Ewing sarcoma chromatin interactome to promote metastasis and provide a list of potential biomarkers and therapeutic targets.
Project description:Cohesin complexes carrying STAG1 or STAG2 organize the genome into chromatin loops. STAG2 loss-of-function mutations promote metastasis in Ewing sarcoma, a pediatric cancer that is driven by the fusion transcription factor EWS-FLI1. We have integrated transcriptomic data from patients and cellular models to identify a STAG2-dependent gene signature associated with worse prognosis. Subsequent genomic profiling and high-resolution chromatin interaction data from Capture Hi-C indicate that cohesin-STAG2 facilitates the communication between EWS-FLI1-bound long GGAA repeats acting as neoenhancers and their target promoters. Changes in CTCF-dependent chromatin contacts, unrelated to EWS-FLI1 binding, also contribute to the aggressive phenotype. STAG1 is unable to compensate for STAG2 loss and chromatin-bound cohesin is severely decreased, while levels of the processivity factor NIPBL remain unchanged, resulting in altered DNA looping dynamics. These results illuminate how STAG2 loss rewires the Ewing sarcoma chromatin interactome to promote metastasis and provide a list of potential biomarkers and therapeutic targets.
Project description:Ewing Sarcoma is caused by a pathognomonic genomic translocation that places an N-terminal EWSR1 gene in approximation with one of several ETS genes (typically FLI1). This aberration, in turn, alters the transcriptional regulation of more than five hundred genes and perturbs a number of critical pathways that promote oncogenesis, cell growth, invasion, and metastasis. Among them, translocation-mediated up-regulation of the insulin-like growth factor receptor 1 (IGF-1R) and mammalian target of rapamycin (mTOR) are of particular importance since they work in concert to facilitate IGF-1R expression and ligand-induced activation, respectively, of proven importance in ES transformation. When used as a single agent in Ewing sarcoma therapy, IGF-1R or mTOR inhibition leads to rapid counter-regulatory effects that blunt the intended therapeutic purpose. Therefore, identify new mechanisms of resistance that are used by Ewing sarcoma to evade cell death to single-agent IGF-1R inhibition might suggest a number of therapeutic combinations that could improve its clinical activity.
Project description:Ewing Sarcoma is caused by a pathognomonic genomic translocation that places an N-terminal EWSR1 gene in approximation with one of several ETS genes (typically FLI1). This aberration, in turn, alters the transcriptional regulation of more than five hundred genes and perturbs a number of critical pathways that promote oncogenesis, cell growth, invasion, and metastasis. Among them, translocation-mediated up-regulation of the insulin-like growth factor receptor 1 (IGF-1R) and mammalian target of rapamycin (mTOR) are of particular importance since they work in concert to facilitate IGF-1R expression and ligand-induced activation, respectively, of proven importance in ES transformation. When used as a single agent in Ewing sarcoma therapy, IGF-1R or mTOR inhibition leads to rapid counter-regulatory effects that blunt the intended therapeutic purpose. Therefore, identify new mechanisms of resistance that are used by Ewing sarcoma to evade cell death to single-agent IGF-1R or mTOR inhibition might suggest a number of therapeutic combinations that could improve their clinical activity.