Project description:Solitary fibrous tumor (SFT) is a rare and aggressive sarcoma driven by NAB2::STAT6 gene fusions, yet effective targeted therapies remain unavailable. Here, we report that the NAB2ex4::STAT6ex2 fusion variant forms nuclear condensates via liquid-liquid phase separation (LLPS) in engineered fibroblast models and primary SFT cells. These condensates co-localize with BRD4S and EGR1, key transcriptional regulators, and are functionally active, driving widespread transcriptional reprogramming. Treatment with Mithramycin A, a compound that disrupts EGR1-DNA interactions, dissolves NAB2::STAT6 condensates and reverses their aberrant gene expression and chromatin binding signatures. Our findings uncover a previously unrecognized role for NAB2::STAT6 in condensate-mediated oncogenic signaling and provide a mechanistic rationale for condensate-targeted therapy in SFT.
Project description:The pathogenesis of many rare tumor types is poorly understood, preventing the design of effective treatments. Solitary Fibrous Tumors (SFTs) are neoplasms of mesenchymal origin that affect 1/1,000,000 individuals every year and are clinically assimilated to sarcomas. SFTs are commonly found throughout the body and can be surgically removed upon diagnosis. However, 30-40% of tumors become aggressive and can locally relapse or metastasize. There are no effective treatments for malignant SFTs to date. The molecular hallmark of SFTs is a gene fusion between the NAB2 and STAT6 loci on chromosome 12, resulting in a chimeric protein of poorly characterized function called NAB2-STAT6. We use primary samples and an inducible cell model to discover that NAB2-STAT6 operates as a transcriptional coactivator for a specific set of enhancers and promoters that are normally targeted by the EGR1 transcription factor. In physiological conditions, NAB2 is primarily localized to the cytoplasm and only a small nuclear fraction is available to operate as a co-activator of EGR1 targets. NAB2-STAT6 redirects NAB1, NAB2, and additional EGR1 to the nucleus and bolster the expression of neuronal EGR1 targets. The STAT6 moiety of the fusion protein is a major driver of its nuclear localization and further contributes to NAB2’s co-activating abilities. In primary tumors, NAB2-STAT6 activates a neuroendocrine gene signature that sets it apart from most sarcomas. These discoveries provide new insight into the pathogenesis of SFTs and reveal new targets with therapeutic potential.
Project description:The pathogenesis of many rare tumor types is poorly understood, preventing the design of effective treatments. Solitary Fibrous Tumors (SFTs) are neoplasms of mesenchymal origin that affect 1/1,000,000 individuals every year and are clinically assimilated to sarcomas. SFTs are commonly found throughout the body and can be surgically removed upon diagnosis. However, 30-40% of tumors become aggressive and can locally relapse or metastasize. There are no effective treatments for malignant SFTs to date. The molecular hallmark of SFTs is a gene fusion between the NAB2 and STAT6 loci on chromosome 12, resulting in a chimeric protein of poorly characterized function called NAB2-STAT6. We use primary samples and an inducible cell model to discover that NAB2-STAT6 operates as a transcriptional coactivator for a specific set of enhancers and promoters that are normally targeted by the EGR1 transcription factor. In physiological conditions, NAB2 is primarily localized to the cytoplasm and only a small nuclear fraction is available to operate as a co-activator of EGR1 targets. NAB2-STAT6 redirects NAB1, NAB2, and additional EGR1 to the nucleus and bolster the expression of neuronal EGR1 targets. The STAT6 moiety of the fusion protein is a major driver of its nuclear localization and further contributes to NAB2’s co-activating abilities. In primary tumors, NAB2-STAT6 activates a neuroendocrine gene signature that sets it apart from most sarcomas. These discoveries provide new insight into the pathogenesis of SFTs and reveal new targets with therapeutic potential.
Project description:<p>Transcriptome sequencing of solitary fibrous tumors / hemangiopericytomas from a variety of anatomic sites revealed recurrent gene fusions between two genes, NAB2 and STAT6. All SFTs examined exhibited an in-frame fusion transcript encoding a fusion protein containing the EGR1 interaction domain of NAB2 with the transcriptional activation domain of STAT6. Functional testing of the fusion alleles confirmed the conversion of the wt NAB2 repressor into a transcriptional activator. A range of individual fusion junctions can be detected by next-generation sequencing acro the sample set, highlighting the suitability of this method in the diagnostic characterization of SFTs. This study indentified the pathognomonic alteration in solitary fibrous tumors and illuminates a pathway towards targeted therapeutics for this cancer.</p>
Project description:The pathogenesis of many rare tumor types is poorly understood, preventing the design of effective treatments. Solitary Fibrous Tumors (SFTs) are neoplasms of mesenchymal origin that affect 1/1,000,000 individuals every year and are clinically assimilated to sarcomas. SFTs are commonly found throughout the body and can be surgically removed upon diagnosis. However, 30-40% of tumors become aggressive and can locally relapse or metastasize. There are no effective treatments for malignant SFTs to date. The molecular hallmark of SFTs is a gene fusion between the NAB2 and STAT6 loci on chromosome 12, resulting in a chimeric protein of poorly characterized function called NAB2-STAT6. We use primary samples and an inducible cell model to discover that NAB2-STAT6 operates as a transcriptional coactivator for a specific set of enhancers and promoters that are normally targeted by the EGR1 transcription factor. In physiological conditions, NAB2 is primarily localized to the cytoplasm and only a small nuclear fraction is available to operate as a co-activator of EGR1 targets. NAB2-STAT6 redirects NAB1, NAB2, and additional EGR1 to the nucleus and bolster the expression of neuronal EGR1 targets. The STAT6 moiety of the fusion protein is a major driver of its nuclear localization and further contributes to NAB2’s co-activating abilities. In primary tumors, NAB2-STAT6 activates a neuroendocrine gene signature that sets it apart from most sarcomas. These discoveries provide new insight into the pathogenesis of SFTs and reveal new targets with therapeutic potential.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:The generation of pancreatic organoids from human pluripotent stem cells represents a major breakthrough for regenerative medicine and the modeling of diseases such as diabetes. However, current approaches remain inefficient due to lengthy multi-step differentiation protocols and limited functional maturity in the organoids. In this study, we overcome these challenges using multi-phase optimization screens to achieve rapid generation of functionally mature pancreatic organoids from a stable endocrine progenitor culture. We conducted stepwise culture condition screens that enabled the stable culture of multiple pancreatic progenitor cell states, including the unprecedented stable propagation of NEUROD1-expressing endocrine progenitor-like cells (EpSCs). Further transcriptomic profiling of EpSC confirmed similarity of that to previously reported endocrine progenitor populations. Using EpSCs, we significantly reduced the number of steps and timing required to generate pancreatic organoids, enabling rapid testing of conditions for organoid maturation. Utilizing this optimized protocol, we further tested conditions to promote pancreatic organoid maturation. We identified that exosome-delivered WNT5B, in combination with RSPO1 (exoW/R), could strongly induce non-canonical WNT/JNK signaling, promoting pancreatic organoid maturation. This combinatorial exosome treatment enhances epithelial organization, reduces immature cell states, and significantly improves glucose responsiveness and insulin secretion. Collectively, our work establishes a robust pancreatic differentiation platform that integrates long-term progenitor expansion with optimized organoid maturation. This system provides a reproducible experimental framework for studying pancreatic development, investigating disease mechanisms, and facilitating future translational applications involving pancreatic organoids.