Many regions of the tongues showed a loss of normal epithelial architecture including destruction of the lamina propria as well as extensive neutrophil infiltration

on capacity of FUS-DDIT3 cells further indicates that PPARc2 and C/EBPa were regulated directly by FUS-DDIT3. The adipogenesis defects in FUS-DDIT3 MEFs can be rescued by ectopic expression of PPARc2 Our data revealed that PPARc2 expression is modulated by FUS-DDIT3, suggesting an interesting link between this gene and FUS-DDIT3. In order to confirm this transcriptional regulation we Ridaforolimus re-introduced PPARc2 in both control and FUS-DDIT3 MEFs by retroviral transduction and evaluated the adipogenesis capacity and the expression level of PPARc2 by western-blot. The adipogenesis of MEFs by hormonal induction is a well established model system for the study of adipocyte differentiation. To further examine the contribution of PPARc2 to FUS-DDIT3-mediated adipogenesis, we isolated MEFs from days 13.5 of FUS-DDIT3 and control embryos. At day 8 after hormonal induction, there is lipid accumulation in control MEFs and this lipid accumulation is lacking in FUS-DDIT3 MEFs. However, retrovirus-mediated expression of PPARc2 in FUS-DDIT3-MEFS re-established the adipocyte differentiation capacity to wild-type levels as shown in Expression pattern of transcription factors governing adipogenesis in human liposarcoma cells Next, we wanted to confirm that the characteristic expression pattern of transcription factors governing adipogenesis detected in liposarcomas coming from FUS-DDIT3 transgenic mice was also present in human liposarcoma cells. In order to address this aim, we took advantage of two human liposarcoma cell lines harboring the chromosomal translocation t and expressing the FUS-DDIT3 chimeric gene. The analysis of the expression pattern of these transcription 17876302 factors in both human liposarcoma cell lines confirmed an expression pattern similar to that previously observed in liposarcomas derived from FUS-DDIT3 transgenic mice, although we detected variable, although low, levels of PPARc1 in the human liposarcoma cell lines. These results demonstrate that tumors arisen in the FUS-DDIT3 transgenic mouse mimic human liposarcomas both histologically and molecularly. Taken together, these findings suggest that FUS-DDIT3 could prevent the development of committed adipocytic precursors in liposarcoma through the interference with PPARc and C/EBPa expression, two transcription factors with a critical role in adipogenesis. FUS-DDIT3 represses the PPARc2 promoter Because the results so far suggest that FUS-DDIT3directly regulates PPARc2 expression, we examined whether FUS-DDIT3 might be directly involved in the control of PPARc2 transcription. A 1 kb proximal promoter region of human PPARc2 was previously shown to be sufficient to drive the PPARc29s expression in reporter assays and it is active in U2OS cells when cotransfected with C/EBPb expression vector. To directly assess the ability of FUS-DDIT3 to activate transcription from DNA sequences present in the PPARc2 promoter, an expression vector containing a FUS-DDIT3 cDNA was cotransfected into U2OS cells along with the reporter vector containing the PPARc2 promoter and with C/EBPb expression vector. Co-expression of FUSDDIT3 repressed luciferase activity. Previous results have provided evidence that both the FUS and the DDIT3 domains of FUS-DDIT3 play a specific and critical 25730130 role in the pathogenesis of liposarcoma. Thus, we next investigated which FUS-DDIT3 domain was responsible for the repression of the PPARc2 promoter. Using the same system, we showed that while the co-expression of the domain NH2-FU

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