Project description:Synovial sarcoma-like tumors were generated in mice by conditionally expressing the human t(X;18) translocation-derived SYT-SSX2 fusion protein. Using a Tamoxifen-inducible CreER system, we show here that sporadic expression of SYT-SSX2 across multiple tissue types leads to exclusive formation of synovial sarcoma-like tumors while its widespread expression is lethal. CreER-based sporadic expression both avoids the severe early developmental phenotypes associated with widespread SYT-SSX2 expression and better models natural pathogenesis of cancers where transformed cells usually arise within an environment of largely normal cells. Experiment Overall Design: Genetically engineered mice capable of conditionally expressing the human synovial sarcoma-associated SYT-SSX2 fusion oncogene were mated with genetically engineered mice expressing the CreER fusion protein from ROSA locus. The progenies harboring both CreER and SYT-SSX2 were followed up with or without tamoxifen injection. Tumors were generated in these mice that were dissected out, RNA extracted, and subjected to expression profiling by microarray analysis.
Project description:Transcriptome comparisons by RNAseq of genetically engineered mouse models of synovial sarcoma, expressing SS18-SSX1 or SS18-SSX2 and having homozygous conditional genetic silencing of Pten or wildtype Pten.
Project description:SS18-SSX fusion proteins play a central role in synovial sarcoma development, however, genetic network and mechanisms of synovial sarcomagenesis remain largely unknown. To clarify such unknown mechanisms, we have established a new ex vivo mouse model for synovial sarcoma, using retrovirus-mediated gene transfer of SS18-SSX1 to mouse embryonic mesenchymal cells followed by subcutaneous transplantation into nude mice. This approach successfully induced subcutaneous tumors in 100% of recipients, showing invasive proliferation of short spindle tumor cells with occasional biphasic appearance. Cytokeratin expression was observed in epithelial components in tumors and expression of TLE1 and BCL2 was also shown. Gene expression profiling indicates modulation of the SWI/SNF pathway by introduction of SS18-SSX1 into mesenchymal cells, and upregulation of Tle1 and Atf2 in tumors. Collectively, these findings indicate the model exhibits typical phenotypes of human synovial sarcoma. Retroviral tagging of the tumor identified 15 common retroviral integration sites with the Dnm3 locus as the most frequent in 30 mouse synovial sarcomas. Up-regulation of micro RNAs miR-199a2 and miR-214 within the Dnm3 locus was observed. Co-introduction of SS18-SSX1 and miR-214 indeed accelerated sarcoma onset, indicating that miR-214 is a cooperative onco-miR in synovial sarcomagenesis. miR-214 functions in the cell non-autonomous manner, promoting cytokine gene expression such as Cxcl15/IL8. We have succeeded to generate a novel mouse model for human synovial sarcoma. As miR-214 overexpression in human synovial sarcoma was reported, our results underscore the important role of miR-214 in tumor development and disease progression. We used microarrays to detail the global program of gene expression in mouse synovial sarcoma and embryonic mesenchymal cells
Project description:Epithelioid hemangioendothelioma (EHE) is a rare vascular sarcoma that is associated with a WWTR1-CAMTA1 fusion gene in greater than 90% of cases. Using an adaptation of the FLEx system, we generated a genetically engineered mouse model of EHE whereby the endogenous Wwtr1 Locus is replaced with an Wwtr1-Camta1 locus. Tumors generated from this mouse model were dissociated and a 10X genomics library preparation was performed. The barcoded library was then deep sequenced.