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:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
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>