Project description:The chromatin regulator ATRX is inactivated in large subsets of adult and pediatric glioma. Whether and how ATRX deficiency promotes oncogenesis by epigenomic dysregulation remains unclear. We found that Atrx loss, especially when coupled with Tp53 inactivation, promoted cell motility and modulated differentiation state in primary murine neuroepithelial progenitors, recapitulating characteristic disease phenotypes and molecular features. Moreover, Atrx deficiency induced widespread shifts in chromatin accessibility, histone composition, and gene transcription at vacant Atrx binding sites distributed across the genome. Finally, target genes mediating Atrx-deficient phenotypes in vitro exhibited similarly selective misexpression in ATRX-mutant human glioma tissues and cell lines. These findings demonstrate that, in appropriate physiological contexts, ATRX deficiency and its epigenomic sequelae are sufficient to induce disease-defining oncogenic phenotypes.
Project description:The chromatin regulator ATRX is inactivated in large subsets of adult and pediatric glioma. Whether and how ATRX deficiency promotes oncogenesis by epigenomic dysregulation remains unclear. We found that Atrx loss, especially when coupled with Tp53 inactivation, promoted cell motility and modulated differentiation state in primary murine neuroepithelial progenitors, recapitulating characteristic disease phenotypes and molecular features. Moreover, Atrx deficiency induced widespread shifts in chromatin accessibility, histone composition, and gene transcription at vacant Atrx binding sites distributed across the genome. Finally, target genes mediating Atrx-deficient phenotypes in vitro exhibited similarly selective misexpression in ATRX-mutant human glioma tissues and cell lines. These findings demonstrate that, in appropriate physiological contexts, ATRX deficiency and its epigenomic sequelae are sufficient to induce disease-defining oncogenic phenotypes.
Project description:The chromatin regulator ATRX is inactivated in large subsets of adult and pediatric glioma. Whether and how ATRX deficiency promotes oncogenesis by epigenomic dysregulation remains unclear. We found that Atrx loss, especially when coupled with Tp53 inactivation, promoted cell motility and modulated differentiation state in primary murine neuroepithelial progenitors, recapitulating characteristic disease phenotypes and molecular features. Moreover, Atrx deficiency induced widespread shifts in chromatin accessibility, histone composition, and gene transcription at vacant Atrx binding sites distributed across the genome. Finally, target genes mediating Atrx-deficient phenotypes in vitro exhibited similarly selective misexpression in ATRX-mutant human glioma tissues and cell lines. These findings demonstrate that, in appropriate physiological contexts, ATRX deficiency and its epigenomic sequelae are sufficient to induce disease-defining oncogenic phenotypes.
Project description:The chromatin regulator ATRX is inactivated in large subsets of adult and pediatric glioma. Whether and how ATRX deficiency promotes oncogenesis by epigenomic dysregulation remains unclear. We found that Atrx loss, especially when coupled with Tp53 inactivation, promoted cell motility and modulated differentiation state in primary murine neuroepithelial progenitors, recapitulating characteristic disease phenotypes and molecular features. Moreover, Atrx deficiency induced widespread shifts in chromatin accessibility, histone composition, and gene transcription at vacant Atrx binding sites distributed across the genome. Finally, target genes mediating Atrx-deficient phenotypes in vitro exhibited similarly selective misexpression in ATRX-mutant human glioma tissues and cell lines. These findings demonstrate that, in appropriate physiological contexts, ATRX deficiency and its epigenomic sequelae are sufficient to induce disease-defining oncogenic phenotypes.
Project description:Mutational inactivation of α-thalassaemia/mental retardation X-linked (ATRX) represents a defining molecular feature in large subsets of adult and pediatric malignant glioma. ATRX deficiency gives rise to abnormal G-quadruplex (G4) DNA secondary structures at GC-rich regions of the genome, altering chromatin accessibility and enhancing DNA damage. Building on earlier work, we sought to assess the extent to which pharmacological G4 stabilization selectively enhances DNA damage and cell death in preclinical models of ATRX-deficient glioma. Deploying the G4 stabilizer CX-5461 in patient-derived glioma stem cells (GSCs) in vitro and in GSC murine flank and intracranial xenografts in vivo, we evaluated efficacy as both a single agent and in combination with ionizing radiation (IR), a central element of current treatment standards. CX-5461 promoted dose-sensitive lethality in ATRX-deficient GSCs relative to ATRX-intact controls. Mechanistic studies revealed that CX-5461 disrupted histone variant H3.3 deposition, enhanced replication stress and DNA damage pathways, activated p53-independent apoptosis, and induced G2/M arrest selectively in ATRX-deficient GSCs. These data were corroborated in vivo, where we notably demonstrated that combinational treatment leads to profound tumor growth delay and prolonged survival exclusively in ATRX-deficient flank tumors. In its totality, our work substantively demonstrates efficacy and defines mechanisms of action for a novel therapeutic strategy targeting ATRX-deficient malignant glioma, laying the groundwork for clinical translation.
Project description:The importance of unanchored Ub in innate immunity has been shown only for a limited number of unanchored Ub-interactors. We investigated what additional cellular factors interact with unanchored Ub and whether unanchored Ub plays a broader role in innate immunity. To identify unanchored Ub-interacting factors from murine lungs, we used His-tagged recombinant poly-Ub chains as bait. These chains were mixed with lung tissue lysates and protein complexes were isolated with Ni-NTA beads. Sample elutions were subjected to mass spectrometry (LC-MSMS) analysis.