We show that EWS-FLI1, an aberrant transcription factor responsible for the pathogenesis of Ewing sarcoma, reprograms gene regulatory circuits by directly inducing or directly repressing enhancers. At GGAA repeats, which lack regulatory potential in other cell types and are not evolutionarily conserved, EWS- FLI1 multimers potently induce chromatin opening, recruit p300 and WDR5, and create de novo enhancers. GGAA repeat enhancers can loop to physically interact with target promoters, as demonstrated by chromosome conformation capture assays. Conversely, EWS-FLI1 inactivates conserved enhancers containing canonical ETS motifs by displacing wild-type ETS transcription factors and abrogating p300 recruitment. Overall design: Ewing sarcoma cell lines (A673 and SKNMC) were analyzed by RNA-seq. EWS-FLI1 was depleted by infection with lentiviral shRNAs (shFLI1 and shGFP control).
EWS-FLI1 utilizes divergent chromatin remodeling mechanisms to directly activate or repress enhancer elements in Ewing sarcoma.
No sample metadata fields
View SamplesNext generation sequencing was used to identify Notch mutations in a large collection of diverse solid tumors. NOTCH1 and NOTCH2 rearrangements leading to constitutive receptor activation were confined to triple negative breast cancers (TNBC, 6 of 66 tumors). TNBC cell lines with NOTCH1 rearrangements associated with high levels of activated NOTCH1 (N1-ICD) were sensitive to the gamma-secretase inhibitor (GSI) MRK-003, both alone and in combination with pacitaxel, in vitro and in vivo, whereas cell lines with NOTCH2 rearrangements were resistant to GSI. Immunohistochemical staining of N1-ICD in TNBC xenografts correlated with responsiveness, and expression levels of the direct Notch target gene HES4 correlated with outcome in TNBC patients. Activating NOTCH1 point mutations were also identified in other solid tumors, including adenoid cystic carcinoma (ACC). Notably, ACC primary tumor xenografts with activating NOTCH1 mutations and high N1-ICD levels were sensitive to GSI, whereas N1-ICD low tumors without NOTCH1 mutations were resistant. Overall design: Gene expression profiling for Notch-sensitive cancer cell lines using RNA-seq, each sample with triplicates
Discovery of biomarkers predictive of GSI response in triple-negative breast cancer and adenoid cystic carcinoma.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
An epigenetic mechanism of resistance to targeted therapy in T cell acute lymphoblastic leukemia.
Specimen part, Cell line
View SamplesHere we modeled T-ALL resistance to Notch inhibition, identifying persister cells that readily expand in the presence of gamma secretase inhibitor (GSI) and the absence of Notch signaling. Rare persister cells are already present in nave T-ALL populations, and the reversibility of the phenotype is suggestive of an epigenetic mechanism. Relative to GSI-sensitive cells, persisters activate distinct signaling and gene expression programs, and exhibit global chromatin compaction. A shRNA screen identified chromatin regulators whose depletion preferentially impairs persister cell viability, including BRD4, an acetyl-histone reader. BRD4 is up-regulated in the persisters and binds enhancers near genes with critical functions in T-ALL, including MYC and BCL2. Treatment of persisters with the BRD4 inhibitor JQ1 down-regulates these targets and induces growth arrest and apoptosis, at doses well tolerated by GSI-sensitive cells. Prompted by these findings, we examined and established the efficacy of GSI JQ1 combination therapy against primary human leukemias in vivo. Our findings establish a role for epigenetic heterogeneity in leukemia drug resistance and suggest the potential of combination therapies that include epigenetic modulators to prevent and treat resistant disease.
An epigenetic mechanism of resistance to targeted therapy in T cell acute lymphoblastic leukemia.
Specimen part, Cell line
View SamplesThe data was used to study mechanisms of apoptosis resistance induced by loss of PRC2. Overall design: CCRF-CEM cells infected with shLuciferase, shGFP, shEZH2.1, shEZH2.4, shEED2, shEED5, shSUZ12.2, shSUZ12.3 were harvested, RNA isolated, and RNAsequencing performed on HiSeq 2000.
PRC2 loss induces chemoresistance by repressing apoptosis in T cell acute lymphoblastic leukemia.
Cell line, Subject
View SamplesTotal gene expression analysis was performed on RNA from testes extracted from two litters of constitutive homozygous and heterozygous H3f3b knockout mice compared to WT littermates.
Histone H3.3 regulates dynamic chromatin states during spermatogenesis.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Endogenous mammalian histone H3.3 exhibits chromatin-related functions during development.
Specimen part
View SamplesTotal gene expression analysis was performed on CRE induced conditional knockout E12.5 MEFs relative to GFP infected control MEFs. Intent was to analyze the role of H3f3b in overall gene expression.
Endogenous mammalian histone H3.3 exhibits chromatin-related functions during development.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Hematopoietic stem cell function and survival depend on c-Myc and N-Myc activity.
Age, Specimen part
View SamplesAnalysis of HSCs from control and c-myc N-myc deficient long-term hematopoietic stem cells. HSCs lacking both c-myc and N-myc display increased apoptosis rates. Data provide insight into the molecular changes occuring upon complete loss of Myc activity, clarifying the resulting apoptotic mechanism and the role of Myc family proteins in HSCs.
Hematopoietic stem cell function and survival depend on c-Myc and N-Myc activity.
Age, Specimen part
View Samples