Project description:Clinical sequencing efforts are rapidly identifying sarcoma gene fusions that lack functional validation. An example is the new fusion of transcriptional coactivators, VGLL2-NCOA2, found in infantile rhabdomyosarcoma. To delineate VGLL2-NCOA2 tumorigenic mechanisms and identify therapeutic vulnerabilities, we implemented a cross-species comparative oncology approach with zebrafish, mouse allograft, and patient samples. We found that VGLL2-NCOA2 is sufficient to generate mesenchymal tumors that display features of immature skeletal muscle and recapitulate the human disease. A subset of VGLL2-NCOA2 zebrafish tumors transcriptionally cluster with embryonic somitogenesis and identify VGLL2-NCOA2 developmental targets, including a RAS family GTPase, arf6/ARF6. In VGLL2-NCOA2 zebrafish, mouse allograft, and patient tumors, arf6/ARF6 is highly expressed and is absent from mature skeletal muscle. Moreover, ARF6 is overexpressed in adult and pediatric sarcoma subtypes. Our data indicate that VGLL2-NCOA2 is an oncogene which leverages developmental programs for tumorigenesis, and that the reactivation or persistence of arf6/ARF6 could represent a therapeutic opportunity.
Project description:Clinical sequencing efforts are rapidly identifying sarcoma gene fusions that lack functional validation. An example is the fusion of transcriptional coactivators, VGLL2-NCOA2, found in infantile rhabdomyosarcoma. To delineate VGLL2-NCOA2 tumorigenic mechanisms and identify therapeutic vulnerabilities, we implement a cross-species comparative oncology approach with zebrafish, mouse allograft, and patient samples. We find that VGLL2-NCOA2 is sufficient to generate mesenchymal tumors that display features of immature skeletal muscle and recapitulate the human disease. A subset of VGLL2-NCOA2 zebrafish tumors transcriptionally cluster with embryonic somitogenesis and identify VGLL2-NCOA2 developmental programs, including a RAS family GTPase, ARF6. In VGLL2-NCOA2 zebrafish, mouse, and patient tumors, ARF6 is highly expressed. ARF6 knockout suppresses VGLL2-NCOA2 oncogenic activity in cell culture, and, more broadly, ARF6 is overexpressed in adult and pediatric sarcomas. Our data indicate that VGLL2-NCOA2 is an oncogene that leverages developmental programs for tumorigenesis and that reactivation or persistence of ARF6 could represent a therapeutic opportunity.
Project description:The vestigial like family proteins (VGLL) are thought to regulate transcription by interacting with the TEA domain transcription factors (TEAD), the primary mediators of the Hippo pathway. However, the functional regulation of VGLL proteins remains poorly characterized. Here, we explored the molecular mechanism of two VGLL2 and TEAD1 fusion proteins generated by recurrent translocations in spindle cell rhabdomyosarcoma. We demonstrated that, compared to VGLL2 and TEAD1 alone, VGLL2-NCOA2 and TEAD1-NCOA2 act as strong transcriptional activators of TEAD-mediated transcription. Although VGLL2-NCOA2 and Yes1 associated transcriptional regulator (YAP) control overlapping transcriptional programs and chromatin landscapes, the downstream transcription induced by the fusion proteins does not require YAP and WW domain containing transcription regulator 1 (TAZ). Furthermore, VGLL2-NCOA2 and TEAD1-NCOA2 fusions engage distinct epigenetic regulation by recruiting E1A binding protein p300 (p300) to drive TEAD-dependent transcription. We showed that small molecule p300 inhibition can suppress VGLL2-NCOA2 and TEAD1-NCOA2-induced oncogenic transformation both in vitro and in vivo. Overall, our data reveal a tumorigenic mechanism of VGLL and TEAD fusion proteins that is related to the Hippo pathway but independent of YAP/TAZ, suggesting potential therapeutic strategies for tumors carrying VGLL, TEAD, or nuclear receptor coactivator (NCOA) gene rearrangements.
Project description:The vestigial like family proteins (VGLL) are thought to regulate transcription by interacting with the TEA domain transcription factors (TEAD), the primary mediators of the Hippo pathway. However, the functional regulation of VGLL proteins remains poorly characterized. Here, we explored the molecular mechanism of two VGLL2 and TEAD1 fusion proteins generated by recurrent translocations in spindle cell rhabdomyosarcoma. We demonstrated that, compared to VGLL2 and TEAD1 alone, VGLL2-NCOA2 and TEAD1-NCOA2 act as strong transcriptional activators of TEAD-mediated transcription. Although VGLL2-NCOA2 and Yes1 associated transcriptional regulator (YAP) control overlapping transcriptional programs and chromatin landscapes, the downstream transcription induced by the fusion proteins does not require YAP and WW domain containing transcription regulator 1 (TAZ). Furthermore, VGLL2-NCOA2 and TEAD1-NCOA2 fusions engage distinct epigenetic regulation by recruiting E1A binding protein p300 (p300) to drive TEAD-dependent transcription. We showed that small molecule p300 inhibition can suppress VGLL2-NCOA2 and TEAD1-NCOA2-induced oncogenic transformation both in vitro and in vivo. Overall, our data reveal a tumorigenic mechanism of VGLL and TEAD fusion proteins that is related to the Hippo pathway but independent of YAP/TAZ, suggesting potential therapeutic strategies for tumors carrying VGLL, TEAD, or nuclear receptor coactivator (NCOA) gene rearrangements.
Project description:The vestigial like family proteins (VGLL) are thought to regulate transcription by interacting with the TEA domain transcription factors (TEAD), the primary mediators of the Hippo pathway. However, the functional regulation of VGLL proteins remains poorly characterized. Here, we explored the molecular mechanism of two VGLL2 and TEAD1 fusion proteins generated by recurrent translocations in spindle cell rhabdomyosarcoma. We demonstrated that, compared to VGLL2 and TEAD1 alone, VGLL2-NCOA2 and TEAD1-NCOA2 act as strong transcriptional activators of TEAD-mediated transcription. Although VGLL2-NCOA2 and Yes1 associated transcriptional regulator (YAP) control overlapping transcriptional programs and chromatin landscapes, the downstream transcription induced by the fusion proteins does not require YAP and WW domain containing transcription regulator 1 (TAZ). Furthermore, VGLL2-NCOA2 and TEAD1-NCOA2 fusions engage distinct epigenetic regulation by recruiting E1A binding protein p300 (p300) to drive TEAD-dependent transcription. We showed that small molecule p300 inhibition can suppress VGLL2-NCOA2 and TEAD1-NCOA2-induced oncogenic transformation both in vitro and in vivo. Overall, our data reveal a tumorigenic mechanism of VGLL and TEAD fusion proteins that is related to the Hippo pathway but independent of YAP/TAZ, suggesting potential therapeutic strategies for tumors carrying VGLL, TEAD, or nuclear receptor coactivator (NCOA) gene rearrangements.
Project description:Exparession profiling of ETV6-NCOA2 at different stages of disease dEmpty vectorelopment: CD34 cord blood cells transduced with ETV6-NCOA2-GFP or with empty vector-GFP, CD34 cord blood cells transduced with ETV6-NCOA2-NGFR or ETV6-NCOA2-NGFR + NOTCH1-L1601PdP-GFP and transplanted in NSGS mice, and ETV6-NCOA2 patient derived xenografts.
Project description:Mesenchymal chondrosarcoma is a high-grade malignant neoplasm characterized by biphasic growth of poorly differentiated small round cells and well differentiated cartilage. Mesenchymal chondrosarcoma affects adolescents and young adults, and the HEY1-NCOA2 fusion gene is causally associated with most cases. Here we generate a mouse model for mesenchymal chondrosarcoma by introducing HEY1-NCOA2 into mouse embryonic chondrogenic progenitors followed by subcutaneous transplantation into nude mice. HEY1-NCOA2 expression successfully induced subcutaneous tumors in 68.9% of recipients, showing biphasic morphologies and expression of Sox9, a master regulator of chondrogenic differentiation, typical to human mesenchymal chondrosarcoma. Chromatin immunoprecipitation sequencing (ChIP-seq) analyses indicated frequent inclusion of the RUNX DNA consensus sequences within HEY1-NCOA2-binding peaks. Runx2 that is important for differentiation and proliferation of the chondrocytic lineage is invariably expressed in mouse mesenchymal chondrosarcoma, and interaction between HEY1-NCOA2 and Runx2 is observed using NCOA2 C-terminal domains. This interaction promotes repression of Runx2 target genes such as Adamts4 and Mmp13 to suppress chondrocytic differentiation and cell growth of tumors, and treatment with the HDAC inhibitor Panobinostat abrogates the repression activity of HEY1-NCOA2 and Runx2 to inhibit tumor growth both in vitro and in vivo. These results demonstrate that HEY1-NCOA2 expression induces malignant transformation of chondrogenic progenitors by modulating the RUNX2-regulated transcriptional program. We used microarrays to detail the global program of gene expression in mouse mesenchymal chondrosarcoma
Project description:Mesenchymal chondrosarcoma is a high-grade malignant neoplasm characterized by biphasic growth of poorly differentiated small round cells and well differentiated cartilage. Mesenchymal chondrosarcoma affects adolescents and young adults, and the HEY1-NCOA2 fusion gene is causally associated with most cases. Here we generate a mouse model for mesenchymal chondrosarcoma by introducing HEY1-NCOA2 into mouse embryonic chondrogenic progenitors followed by subcutaneous transplantation into nude mice. HEY1-NCOA2 expression successfully induced subcutaneous tumors in 68.9% of recipients, showing biphasic morphologies and expression of Sox9, a master regulator of chondrogenic differentiation, typical to human mesenchymal chondrosarcoma. Chromatin immunoprecipitation sequencing (ChIP-seq) analyses indicated frequent inclusion of the RUNX DNA consensus sequences within HEY1-NCOA2-binding peaks. Runx2 that is important for differentiation and proliferation of the chondrocytic lineage is invariably expressed in mouse mesenchymal chondrosarcoma, and interaction between HEY1-NCOA2 and Runx2 is observed using NCOA2 C-terminal domains. This interaction promotes repression of Runx2 target genes such as Adamts4 and Mmp13 to suppress chondrocytic differentiation and cell growth of tumors, and treatment with the HDAC inhibitor Panobinostat abrogates the repression activity of HEY1-NCOA2 and Runx2 to inhibit tumor growth both in vitro and in vivo. These results demonstrate that HEY1-NCOA2 expression induces malignant transformation of chondrogenic progenitors by modulating the RUNX2-regulated transcriptional program.