Project description:Meningiomas are the most common primary intracranial tumor. However, surgical resection and radiation frequently fail to eliminate high grade tumors, leading to significant morbidity and mortality. Predicting which tumors will recur rapidly is critical to effective treatment strategies. To address the prognostic challenges and dearth of therapeutic targets, we interrogated the enhancer landscape of a diverse cohort of meningiomas. Enhancers robustly stratified meningiomas into three biologically distinct groups and identified a subset of tumors with a poor prognosis, independent of histological grading. Integrating enhancer networks with transcriptional profiles revealed unique lineage transcriptional regulators associated with each subgroup. A strong hormonal epidemiologic association is well-characterized in meningiomas, but mechanistic insight remains lacking. We identified differential hormonal regulators that stratified between subgroups, and implicated progesterone receptor in maintaining the super enhancer network of a subset of tumors. Super enhancers marked critical and druggable dependencies across a panel of meningioma models.
Project description:Meningiomas are the most common primary intracranial tumor. However, surgical resection and radiation frequently fail to eliminate high grade tumors, leading to significant morbidity and mortality. Predicting which tumors will recur rapidly is critical to effective treatment strategies. To address the prognostic challenges and dearth of therapeutic targets, we interrogated the enhancer landscape of a diverse cohort of meningiomas. Enhancers robustly stratified meningiomas into three biologically distinct groups and identified a subset of tumors with a poor prognosis, independent of histological grading. Integrating enhancer networks with transcriptional profiles revealed unique lineage transcriptional regulators associated with each subgroup. A strong hormonal epidemiologic association is well-characterized in meningiomas, but mechanistic insight remains lacking. We identified differential hormonal regulators that stratified between subgroups, and implicated progesterone receptor in maintaining the super enhancer network of a subset of tumors. Super enhancers marked critical and druggable dependencies across a panel of meningioma models.
Project description:This SuperSeries is composed of the following subset Series: GSE40684: Foxp3 exploits a preexistent enhancer landscape for regulatory T cell lineage specification [ChIP-Seq] GSE40685: Foxp3 exploits a preexistent enhancer landscape for regulatory T cell lineage specification [Expression] Refer to individual Series
Project description:Regulatory T (Treg) cells, whose identity and function are defined by the transcription factor Foxp3, are indispensable for immune homeostasis. It is unclear whether Foxp3 exerts its Treg lineage specification function through active modification of the chromatin landscape and establishment of new enhancers or by exploiting a pre-existing enhancer landscape. Analysis of the chromatin accessibility of Foxp3-bound enhancers in Treg and Foxp3-negative T cells showed that Foxp3 was bound overwhelmingly to pre-accessible enhancers occupied by its cofactors in precursor cells or a structurally related predecessor. Furthermore, the bulk of Foxp3-bound Treg cell enhancers lacking in Foxp3- CD4+ cells became accessible upon T cell receptor activation prior to Foxp3 expression with only a small subset associated with several functionally important genes being exclusively Treg cell-specific. Thus, in a late cellular differentiation process Foxp3 defines Treg cell functionality in an “opportunistic” manner by largely exploiting the preformed enhancer network instead of establishing a new enhancer landscape. Four transcription factors (Foxp3, Ets1, Elf1, and Cbfb) were immunoprecipated while crosslinked to chromatin. These experiments were then combined with DNase-seq data (being uploaded separately as part of ENCODE project) to find that Foxp3 binds exclusively to open chromatin. Data was also leveraged from GSE40657 and GSE33653.
Project description:Unrestrained receptor tyrosine kinase (RTK) signaling and epigenetic deregulation are root causes of tumorigenesis. We establish linkage between these processes by demonstrating that aberrant RTK signaling unleashed by oncogenic HRasG12V or loss of negative feedback through Sprouty gene deletion remodels histone modifications associated with active typical and super-enhancers. However, while both lesions disrupt the Ras-Erk axis, the expression programs, enhancer signatures, and transcription factor networks modulated upon HRasG12V-transformation or Sprouty deletion are largely distinct. Oncogenic HRasG12V elevates histone 3 lysine 27 acetylation (H3K27ac) levels at enhancers near the transcription factor Gata4 and the kinase Prkcb, as well as their expression levels. We show that Gata4 is necessary for the aberrant gene expression and H3K27ac marking at enhancers, and Prkcb is required for the oncogenic effects of HRasG12V-driven cells. Taken together, our findings demonstrate that dynamic reprogramming of the cellular enhancer landscape is a major effect of oncogenic RTK signaling. We performed ChIP-seq to assess the global changes in the histone modifications H3K27ac (AC), H3K4me1 (me1), and H3K4me3 (me3) upon loss of feedback regulation through Sprouty (Spry) deletion, and upon unrestrained signaling driven by oncogenic HRasG12V. ChIP-seq was performed in biological duplicate; replicate2 is indicated in the sample name. Spry124fl/fl (VEC) and Spry124-/- (CRE) MEFs were profiled in three conditions: unsynchronized (U), serum starved (S), and serum starved and FGF treated (F). Spry124fl/fl (VEC) MEFs transduced with empty vector (EV) control or HRasG12V (HRas) were profiled in the unsynchronized state.