Project description:DBX1 is a transcriptional repressor whose role in human cancer is poorly understood. DBX1 is highly expressed in FN-RMS. Here, we depleted DBX1 expression with 2 shRNAs targeting DBX1 in a human FN-RMS cell line we derived from a PDX - SJRHB015721_X1. We determined the transcriptional changes using a Clariom S human microarray.
Project description:Sarcomas are derailed in pathways that specify mesenchymal lineages during embryogenesis, causing tumor cells to stall at early stages of differentiation. Among them, rhabdomyosarcoma (RMS) is a pediatric soft tissue sarcoma of skeletal muscle origin. A key feature of RMS is their inability to terminally differentiate despite the high expression of master myogenic regulator MYOD. The bHLH transcription factor TWIST2, which governs mesenchymal stem cell identity and restricts myogenesis, is overexpressed in patient fusion-negative RMS (FN-RMS) tumors. We show that knockdown of TWIST2 enables FN-RMS cells to exit the cell cycle and undergo myogenic differentiation, thereby reducing the growth of FN-RMS xenograft tumors. ChIP-seq analysis revealed that most TWIST2-mediated gene regulation occurs independent of changes in MYOD binding in FN-RMS cells. Instead, TWIST2 controls the deposition of H3K27 acetylation at distal enhancers by interacting with the chromatin remodelers, SMARCA4 and CHD3, to activate growth-related and repress myogenesis-related TWIST2 target genes. Our findings provide new insights into the role of TWIST2 in maintaining an undifferentiated and tumorigenic state of FN-RMS and highlight the clinical potential of reversing the TWIST2-regulated phenotype.
Project description:Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. Prognosis for patients with high grade and metastatic disease is still very poor, and survivors are burdened with long-lasting side effects. Therefore, more effective and less toxic therapies are needed. Surface proteins are ideal targets for antibody-based therapies, like bispecific antibodies, antibody drug conjugates, or chimeric antigen receptor (CAR) T cell. Specific surface targets for RMS are scarce. Here, we performed a surfaceome profiling based on differential centrifugation enrichment of surface/membrane proteins and detection by LC-MS on six fusion-positive (FP) RMS cell lines, five fusion-negative (FN) RMS cell lines, and three RMS patient-derived xenografts (PDXs). 699 proteins were detected in the three RMS groups. Ranking based on expression levels and comparison to expression in normal MRC-5 fibroblasts and myoblasts, followed by statistical analysis, highlighted known RMS targets such as FGFR4, NCAM1, and CD276/B7-H3, and revealed AGRL2, JAM3, MEGF10, GPC4, CADM2, as potential targets for immunotherapies of RMS. L1CAM expression was investigated in RMS tissues and strong L1CAM expression was observed in more than 80% of alveolar RMS tumors, making it a practicable target for antibody-based therapies of alveolar RMS.
Project description:We report the transcriptomic differences between ASPcKO and ASPcKOP7cKO flow cytometry-sorted FN-RMSs by RNA sequencing. The goal of this study is to determine what role Pax7 loss has on Pten-deficient, Hedgehog-activated murine FN-RMS tumors. These results provide implications for the transcriptomic program driven by Pax7 in dictating FN-RMS tumor fate.
Project description:To investigate the role of TGF-β1-regulated miRNAs in the progression of RMS,we performed comprehensive miRMA microarray analysis on RNA derived from typical RMS cell lines and TGF-β1 knock-down cell lines. We identified a novel set of TGF-β1-related miRNAs.