Project description:We report the genome-wide maps of PAX3-FKHR binding sites. Chromatin immunoprecipitation was performed against PAX3-FKHR positive (Rh4) and PAX3-FKHR negative (RD) rhabdomyosarcoma cells with a monoclonal antibody (pFM2) specific for the fusion region of PAX3-FKHR. We obtained 4 million sequence tags for both input and ChIP DNA that aligned to the human genome. We identified 1,463 binding sites from ChIP-seq of Rh4 cells, none of which appeared from ChIP-seq of fusion negative RD cells. The PAX3-FKHR binding sites were found to associate with 1,072 genes in RMS cells. The data shows that PAX3-FKHR binds to the same sites as PAX3, at the enhancers for MYF5, FGFR4, and the MYOD core enhancer previously shown to be regulated by PAX3. Moreover, our dataset has the precision for rapid identification and validation of novel and specific sequences required for the enhancer activity of MYOD and FGFR4. The genome wide analysis reveals that the PAX3-FKHR sites are: 1) mostly distal to transcription start sites; 2) conserved; 3) enriched for PAX3 motifs; and 4) strongly associated with genes over-expressed in PAX3-FKHR positive RMS cells and tumors. There is little evidence in our dataset for PAX3-FKHR binding at the promoters. In one instance, we show two intronic enhancer elements for MET, rather than at the previously described promoter. The genome-wide analysis further illustrates a strong association between PAX3 and E-box motifs in these binding sites, suggestive of a common co-regulation for many target genes. The map of PAX3-FKHR binding sites provides new links for PAX3 and PAX3-FKHR functions and new targets for RMS therapy. Examination of PAX3-FKHR binding sites in translocation-positive rhabdomyosarcoma cells via ChIP-seq with an antibody specific for the fusion protein.
Project description:Bullous pemphigoid (BP) is a rare, life-threatening autoimmune blistering disease with pruritus and tension blisters/bullous as the main clinical manifestations. Glucocorticosteroids are the main therapeutic agents for it, but their efficacy is poor in some patients. Tofacitinib, a small molecule agent that inhibits JAK1/3, has shown incredible efficacy in a wide range of autoimmune diseases and maybe a new valuable treatment option for refractory BP. To report a case of refractory BP successfully treated with tofacitinib, then explore the underlying mechanism behind the treatment, and finally review similarities to other cases reported in the literature. Case report and literature review of published cases of successful BP treatment with JAK inhibitors. The case report describes a 73-year-old male with refractory BP that was successfully managed with the combination therapy of tofacitinib and low-dose glucocorticoids for 28 weeks. Immunohistochemistry and RNA sequencing were performed to analyze the underlying mechanism of tofacitinib therapy. A systematic literature search was conducted to identify other cases of treatment with JAK inhibitors. Throughout the 28-week treatment period, the patient experienced clinical, autoantibody and histologic resolution. Immunohistochemical analysis showed tofacitinib significantly decreased the pSTAT3 and pSTAT6 levels in the skin lesions of this patient. RNA sequencing and immunohistochemical testing of lesion samples from other BP patients identified activation of the JAK-STAT signaling pathway. Literature review revealed 17 previously reported cases of BP treated with four kinds of JAK inhibitors successfully, including tofacitinib (10), baricitinib (1), upadacitinib (3) and abrocitinib (3). Our findings support the potential of tofacitinib as a safe and effective treatment option for BP. Larger studies are underway to better understand this efficacy and safety.
Project description:We report the genome-wide maps of PAX3-FKHR binding sites. Chromatin immunoprecipitation was performed against PAX3-FKHR positive (Rh4) and PAX3-FKHR negative (RD) rhabdomyosarcoma cells with a monoclonal antibody (pFM2) specific for the fusion region of PAX3-FKHR. We obtained 4 million sequence tags for both input and ChIP DNA that aligned to the human genome. We identified 1,463 binding sites from ChIP-seq of Rh4 cells, none of which appeared from ChIP-seq of fusion negative RD cells. The PAX3-FKHR binding sites were found to associate with 1,072 genes in RMS cells. The data shows that PAX3-FKHR binds to the same sites as PAX3, at the enhancers for MYF5, FGFR4, and the MYOD core enhancer previously shown to be regulated by PAX3. Moreover, our dataset has the precision for rapid identification and validation of novel and specific sequences required for the enhancer activity of MYOD and FGFR4. The genome wide analysis reveals that the PAX3-FKHR sites are: 1) mostly distal to transcription start sites; 2) conserved; 3) enriched for PAX3 motifs; and 4) strongly associated with genes over-expressed in PAX3-FKHR positive RMS cells and tumors. There is little evidence in our dataset for PAX3-FKHR binding at the promoters. In one instance, we show two intronic enhancer elements for MET, rather than at the previously described promoter. The genome-wide analysis further illustrates a strong association between PAX3 and E-box motifs in these binding sites, suggestive of a common co-regulation for many target genes. The map of PAX3-FKHR binding sites provides new links for PAX3 and PAX3-FKHR functions and new targets for RMS therapy.
Project description:PAX3-FOXO1 is a fusion transcription factor that is the main driver of tumorigenesis leading to the development of alveolar rhabdomyosarcoma (aRMS). Since aRMS cells are addicted to PAX3-FOXO1 activity, the fusion protein also represents a major target for therapeutic interference, which is however challenging as transcription factors usually cannot be inhibited directly by small molecules. Hence, characterization of the biology of PAX3-FOXO1 might lead to the discovery of new possibilities for an indirect inhibition of its activity. Here, our goal was to characterize the proteomic neighborhood of PAX3-FOXO1 and to find candidates potentially affecting its activity and tumor cell viability. Towards this aim, we expressed BirA fused versions of PAX3-FOXO1 (N- and C-terminal) in HEK293T cells under presence of biotin. In the control setup, we expressed the BirA enzyme alone. After Streptavidin purification of biotinylated proteins, we performed mass spectrometry and quantified relative abundances compared to control conditions. This enabled us to determine PAX3-FOXO1 proximal proteins, which we investigated further in orthogonal endogenous systems.