Project description:ChIP-Seq detected global binding of NOTCH1 oncogene in a human T-Cell Leukemia Cell line. ChIP-Seq of NOTCH1 in HBALL cell lines and Whole Cell Extract (WCE) as control.
Project description:Missense FBXW7 mutations are prevalent in various tumors, including T-cell acute lymphoblastic leukemia (T-ALL). To study the effects of such lesions, we generated animals carrying regulatable Fbxw7 mutant alleles. We show here that these mutations specifically bolster cancer-initiating cell activity in collaboration with Notch1 oncogenes, but spare normal hematopoietic stem cell function. We were also able to show that FBXW7 mutations specifically affect the ubiquitylation and half-life of c-Myc protein, a key T-ALL oncogene. Using animals carrying c-Myc fusion alleles, we connected Fbxw7 function to c-Myc abundance and correlated c-Myc expression to leukemia-initiating activity. Three independent Notch1 T-ALL were derived on c-Myc-GFP background and sorted from the spleen of leukemic mice on the basis of GFP expression for RNA extraction and hybridization on Affymetrix microarrays
Project description:Senescence, a persistent form of cell cycle arrest, is often associated with a diverse secretome, which provides complex downstream functionality for senescent cells within the tissue microenvironment. We show that oncogene-induced senescence (OIS) is accompanied by a dynamic fluctuation of NOTCH1 activity, which drives a TGF-β-rich secretome, whilst suppressing the senescence-associated pro-inflammatory secretome through inhibition of C/EBPβ. NOTCH1 and NOTCH1-driven TGF-β contribute to ‘lateral induction of senescence’ through a juxtacrine NOTCH-JAG1 pathway. In addition, NOTCH1 inhibition during senescence facilitates upregulation of pro-inflammatory cytokines, promoting lymphocyte recruitment and senescence surveillance in vivo. Because enforced activation of NOTCH1 signalling confers a near mutually exclusive secretory profile compared to typical senescence, our data collectively indicate that the dynamic alteration of NOTCH1 activity during senescence dictates a functional balance between these two distinct secretomes: one representing TGF-β and the other pro-inflammatory cytokines, highlighting that NOTCH1 is a temporospatial controller of secretome composition.
Project description:The most recurrently mutated oncogene in T-cell acute lymphoblastic leukemia (T-ALL) is NOTCH1. The core Notch complex consists of an ICN protein, a Maml cofactor, and the DNA binding factor Rbpj. The known direct cofactors of Notch appear to act nonselectively, homogeneously driving Notch gene expression functions. It is unclear whether there are direct cofactors of Notch that act selectively and heterogeneously regulate ICN. We discovered that Zmiz1, a Protein Inhibitor of Activated STAT (PIAS)-like coactivator, directly bound ICN1. ChIP-Seq showed that Zmiz1 selectively co-bound only a subset of Notch-regulated enhancers. This led to hypothesize that Zmiz1 regulates only a subset of Notch1 target genes. To investigate this, we performed RNA-Seq on four 8946 cell linesin which L1601P (activated Notch1) or Zmiz1 were expressed alone or in combination. Zmiz1 induced ~10% of Notch target genes. The Notch target gene that was most strongly induced by Zmiz1 was Myc. Our data suggest that Zmiz1 selectively amplifies a subset of Notch target genes with strong amplification of Myc. RNA-Seq in a murine T-ALL cell line
Project description:Missense FBXW7 mutations are prevalent in various tumors, including T-cell acute lymphoblastic leukemia (T-ALL). To study the effects of such lesions, we generated animals carrying regulatable Fbxw7 mutant alleles. We show here that these mutations specifically bolster cancer-initiating cell activity in collaboration with Notch1 oncogenes, but spare normal hematopoietic stem cell function. We were also able to show that FBXW7 mutations specifically affect the ubiquitylation and half-life of c-Myc protein, a key T-ALL oncogene. Using animals carrying c-Myc fusion alleles, we connected Fbxw7 function to c-Myc abundance and correlated c-Myc expression to leukemia-initiating activity.
Project description:T-cell acute lymphoblastic leukemia (T-ALL) is an immature hematopoietic malignancy driven mainly by oncogenic activation of NOTCH1 signaling. In this study we used a mouse model of T-ALL through the overexpression of the intarcellular transcriptionally active part of Notch1 (N1-IC). This model faithfully recapitulates the major characteristics of the human disease. Comparison of the leukemic cells from peripheral tumors(thymoma) of this mouse model to normal thymic cells Double Positive (DP) for the markers CD4 and CD8 that express very low levels of Notch1 showed major expression changes (please see GSE34554) in pathways controlling the transition from physiology to disease. Further correlation of the data to ChIP-Seq data from the same cell populations led us to identify a hitherto unknown antagonism of the Notch1 oncogenic pathway and the polycomb complex (PRC2) in leukemia. Importantly exome sequencing in primary samples from human patients with T-ALL revealed that the PRC2 complex is frequently mutated and inactivated, further supporting the tumor suppressor role of the complex in this disease. Gene expression profiles from CD4+/8+ Double Positive (named DP) derived from normal thymus and Notch1-IC over-expressing tumors (named T-ALL) were analyzed for the genomewide enrichments of two major activating epigenetic marks (Histone 3 Lysine 9 acetylation (H3K9ac) and lysine 4 trimethylation (H3K4me3)), one reprressive mark (Histone 3 lysine 27 trimethylation, H3K27me3) and the major oncogene Notch1.
Project description:The most recurrently mutated oncogene in T-cell acute lymphoblastic leukemia (T-ALL) is NOTCH1. The core Notch complex consists of an ICN protein, a Maml cofactor, and the DNA binding factor Rbpj. The known direct cofactors of Notch appear to act nonselectively, homogeneously driving Notch gene expression functions. It is unclear whether there are direct cofactors of Notch that act selectively and heterogeneously regulate ICN. We discovered that Zmiz1, a Protein Inhibitor of Activated STAT (PIAS)-like coactivator, directly bound ICN1. In order to determine whether this interaction occured at chromatin, we performed ChIP-Seq. We identified significant overlap between ICN1, Rbpj, and Zmiz1 peaks. 75% of overlapping ICN1/Rbpj peaks overlapped with Zmiz1 (HA) peaks (273 peaks). The size of Zmiz1 (HA) peaks had moderate correlation with the size of Rbpj and ICN1 peaks. Like Rbpj and ICN1 peaks, Zmiz1 (HA) peaks were associated with activating H3K27ac, H3K4me1, and H3K4me3 chromatin marks and were devoid of repressive H3K27me3 marks. These data suggest that Zmiz1 is a selective Notch regulator. It co-binds only a subset of ICN1 and Rbpj-regulated sites. Zmiz1, ICN1, Rbpj, histone mehylation ChIP-Seq in murine T-ALL cell line
Project description:Runt-related transcription factor 1 (RUNX1) is oncogenic in diverse types of leukemia and epithelial cancers where its expression is associated with poor prognosis. Current models suggest that RUNX1 cooperates with other oncogenic factors (e.g., NOTCH1, TAL1) to drive the expression of proto-oncogenes in T cell acute lymphoblastic leukemia (T-ALL) but the molecular mechanisms controlled by RUNX1 and its cooperation with other factors remain unclear. Integrative chromatin and transcriptional analysis following inhibition of RUNX1 and NOTCH1 revealed a surprisingly widespread role of RUNX1 in the establishment of global H3K27ac levels and that RUNX1 is required by NOTCH1 for cooperative transcription activation of key NOTCH1 target genes including MYC, DTX1, HES4, IL7R, and NOTCH3. Super-enhancers were preferentially sensitive to RUNX1 knockdown and RUNX1-dependent super-enhancers were disrupted following the treatment of a pan-BET inhibitor, I-BET151.
Project description:Runt-related transcription factor 1 (RUNX1) is oncogenic in diverse types of leukemia and epithelial cancers where its expression is associated with poor prognosis. Current models suggest that RUNX1 cooperates with other oncogenic factors (e.g., NOTCH1, TAL1) to drive the expression of proto-oncogenes in T cell acute lymphoblastic leukemia (T-ALL) but the molecular mechanisms controlled by RUNX1 and its cooperation with other factors remain unclear. Integrative chromatin and transcriptional analysis following inhibition of RUNX1 and NOTCH1 revealed a surprisingly widespread role of RUNX1 in the establishment of global H3K27ac levels and that RUNX1 is required by NOTCH1 for cooperative transcription activation of key NOTCH1 target genes including MYC, DTX1, HES4, IL7R, and NOTCH3. Super-enhancers were preferentially sensitive to RUNX1 knockdown and RUNX1-dependent super-enhancers were disrupted following the treatment of a pan-BET inhibitor, I-BET151.
Project description:Runt-related transcription factor 1 (RUNX1) is oncogenic in diverse types of leukemia and epithelial cancers where its expression is associated with poor prognosis. Current models suggest that RUNX1 cooperates with other oncogenic factors (e.g., NOTCH1, TAL1) to drive the expression of proto-oncogenes in T cell acute lymphoblastic leukemia (T-ALL) but the molecular mechanisms controlled by RUNX1 and its cooperation with other factors remain unclear. Integrative chromatin and transcriptional analysis following inhibition of RUNX1 and NOTCH1 revealed a surprisingly widespread role of RUNX1 in the establishment of global H3K27ac levels and that RUNX1 is required by NOTCH1 for cooperative transcription activation of key NOTCH1 target genes including MYC, DTX1, HES4, IL7R, and NOTCH3. Super-enhancers were preferentially sensitive to RUNX1 knockdown and RUNX1-dependent super-enhancers were disrupted following the treatment of a pan-BET inhibitor, I-BET151.