Gene expression profiling of P53/R26 +/+ (n=2) versus P53/R26-Zeb2tg/tg (n=3) thymic tumors
Ontology highlight
ABSTRACT: Early T-cell precursor leukemia (ETP-ALL) is a high-risk subtype of human leukemia that is poorly understood at the molecular level. Here, we report translocations targeting the zinc finger E-box binding transcription factor ZEB2 as a new and recurrent genetic lesion in immature/ETP-ALL. Using a conditional gain-of-function mouse model, we demonstrate that sustained Zeb2 expression perturbs normal T-cell differentiation and initiates T-cell leukemia. Moreover, Zeb2 driven mouse leukemia exhibit some features of the human immature/ETPALL gene expression signature, as well as an enhanced leukemia-initiation potential and activated JAK/STAT signaling through transcriptional activation of IL7R. This study reveals ZEB2 as a novel oncogene in the biology of immature/ETP-ALL and paves the way towards pre-clinical studies of novel compounds for the treatment of this aggressive subtype of human T-ALL using our Zeb2 driven mouse model. Conditional Zeb2 knockin mouse model was developed and crossed into p53 null background. Murine T-cell leukemia/lymphoma tumors developed both in the p53 null control and the p53 null Zeb2 transgenic group. In this experiment, gene expression profiling was performed on these murine leukemias to determine the transcriptional program associated with sustained Zeb2 expression in the context of P53 null driven murine T cell leukemogenesis.
Project description:Early T-cell precursor leukemia (ETP-ALL) is a high-risk subtype of human leukemia that is poorly understood at the molecular level. Here, we report translocations targeting the zinc finger E-box binding transcription factor ZEB2 as a new and recurrent genetic lesion in immature/ETP-ALL. Using a conditional gain-of-function mouse model, we demonstrate that sustained Zeb2 expression perturbs normal T-cell differentiation and initiates T-cell leukemia. Moreover, Zeb2 driven mouse leukemia exhibit some features of the human immature/ETPALL gene expression signature, as well as an enhanced leukemia-initiation potential and activated JAK/STAT signaling through transcriptional activation of IL7R. This study reveals ZEB2 as a novel oncogene in the biology of immature/ETP-ALL and paves the way towards pre-clinical studies of novel compounds for the treatment of this aggressive subtype of human T-ALL using our Zeb2 driven mouse model.
Project description:RNA sequencing was performed on biological triplicates of p53 null T-ALL cells with ZEB2 overexpression (P53/R26-Zeb2tg/tg) versus p53 null T-ALL cells without Zeb2 overexpression (P53/R26+/+) treated with 100nM GSK2879552 for 24h versus their corresponding DMSO treatment controls. P53/R26+/+ and P53/R26-Zeb2tg/tg tumor lines displayed a very distinct gene expression signature under baseline (DMSO) conditions in line with our previous observations that Zeb2 driven thymomas reflect a more immature T-ALL subtype. GSK2879552 is a potent, selective and orally bioavailable inhibitor of the lysine-specific histone demethylase 1 (LSD1). LSD1i treatment in control P53/R26+/+ cell lines only caused limited effects on overall transcription. In contrast, gene transcription was more severely affected by LSD1 perturbations in the P53/R26-Zeb2tg/tg lines with significant changes in the expression transcripts enriched for signalling pathways essential for embryonic development (like TGFbeta and Wnt signalling), genes involved in transcriptional repression/regulation, apoptosis and DNA replication/repair. All together, these results demonstrate that Zeb2 overexpression modulates murine T-ALL responsiveness to LSD1 inhibitors.
Project description:The T-cell leukemia homeobox 1 (TLX1, HOX11) transcription factor is critically involved in the multistep pathogenesis of T-cell acute lymphoblastic leukemia (T-ALL) and often cooperates with NOTCH1 activation during malignant T-cell transformation. However, the exact molecular mechanisms by which these T-cell specific oncogenes cooperate during transformation remain to be established. Here, we used an integrative genomics approach to show that the oncogenic properties of TLX1 are mediated by genome-wide interference with the ETS1 and RUNX1 transcription factors. Partial disruption of ETS1 and RUNX1 activity by ectopic TLX1 expression in immature thymocytes drives repression of T-cell specific super-enhancers and mediates an unexpected transcriptional antagonism with NOTCH1 signaling. These phenomena coordinately trigger a TLX1 driven pre-leukemic phenotype in human thymic precursor cells, which corresponds with the in vivo thymic regression observed in murine TLX1 tumor models, and creates a strong genetic pressure for acquiring activating NOTCH1 mutations as a prerequisite for full leukemic transformation. In conclusion, our results uncover a functional antagonism between cooperative oncogenes during the earliest phases of tumor development and provide novel insights in the multistep pathogenesis of TLX1 driven human leukemia. Gene expression profiling of 64 T-ALL patient samples
Project description:The T-cell leukemia homeobox 1 (TLX1, HOX11) transcription factor is critically involved in the multistep pathogenesis of T-cell acute lymphoblastic leukemia (T-ALL) and often cooperates with NOTCH1 activation during malignant T-cell transformation. However, the exact molecular mechanisms by which these T-cell specific oncogenes cooperate during transformation remain to be established. Here, we used an integrative genomics approach to show that the oncogenic properties of TLX1 are mediated by genome-wide interference with the ETS1 and RUNX1 transcription factors. Partial disruption of ETS1 and RUNX1 activity by ectopic TLX1 expression in immature thymocytes drives repression of T-cell specific super-enhancers and mediates an unexpected transcriptional antagonism with NOTCH1 signaling. These phenomena coordinately trigger a TLX1 driven pre-leukemic phenotype in human thymic precursor cells, which corresponds with the in vivo thymic regression observed in murine TLX1 tumor models, and creates a strong genetic pressure for acquiring activating NOTCH1 mutations as a prerequisite for full leukemic transformation. In conclusion, our results uncover a functional antagonism between cooperative oncogenes during the earliest phases of tumor development and provide novel insights in the multistep pathogenesis of TLX1 driven human leukemia. Gene expression was measured in the ALL-SIL T-ALL cell line after electroporation with scrambled siRNA and 2 independent RUNX1 targetings siRNAs. Cells were collected 24h after treatment. This was performed for 3 replicates.
Project description:The T-cell leukemia homeobox 1 (TLX1, HOX11) transcription factor is critically involved in the multistep pathogenesis of T-cell acute lymphoblastic leukemia (T-ALL) and often cooperates with NOTCH1 activation during malignant T-cell transformation. However, the exact molecular mechanisms by which these T-cell specific oncogenes cooperate during transformation remain to be established. Here, we used an integrative genomics approach to show that the oncogenic properties of TLX1 are mediated by genome-wide interference with the ETS1 and RUNX1 transcription factors. Partial disruption of ETS1 and RUNX1 activity by ectopic TLX1 expression in immature thymocytes drives repression of T-cell specific super-enhancers and mediates an unexpected transcriptional antagonism with NOTCH1 signaling. These phenomena coordinately trigger a TLX1 driven pre-leukemic phenotype in human thymic precursor cells, which corresponds with the in vivo thymic regression observed in murine TLX1 tumor models, and creates a strong genetic pressure for acquiring activating NOTCH1 mutations as a prerequisite for full leukemic transformation. In conclusion, our results uncover a functional antagonism between cooperative oncogenes during the earliest phases of tumor development and provide novel insights in the multistep pathogenesis of TLX1 driven human leukemia. Gene expression was measured in the ALL-SIL T-ALL cell line after electroporation with scrambled siRNA and 2 independent ETS1 targetings siRNAs. Cells were collected 24h after treatment. This was performed for 3 replicates.
Project description:The T-cell leukemia homeobox 1 (TLX1, HOX11) transcription factor is critically involved in the multistep pathogenesis of T-cell acute lymphoblastic leukemia (T-ALL) and often cooperates with NOTCH1 activation during malignant T-cell transformation. However, the exact molecular mechanisms by which these T-cell specific oncogenes cooperate during transformation remain to be established. Here, we used an integrative genomics approach to show that the oncogenic properties of TLX1 are mediated by genome-wide interference with the ETS1 and RUNX1 transcription factors. Partial disruption of ETS1 and RUNX1 activity by ectopic TLX1 expression in immature thymocytes drives repression of T-cell specific super-enhancers and mediates an unexpected transcriptional antagonism with NOTCH1 signaling. These phenomena coordinately trigger a TLX1 driven pre-leukemic phenotype in human thymic precursor cells, which corresponds with the in vivo thymic regression observed in murine TLX1 tumor models, and creates a strong genetic pressure for acquiring activating NOTCH1 mutations as a prerequisite for full leukemic transformation. In conclusion, our results uncover a functional antagonism between cooperative oncogenes during the earliest phases of tumor development and provide novel insights in the multistep pathogenesis of TLX1 driven human leukemia. Gene expression was measured in the ALL-SIL T-ALL cell line after treatment with DMSO (solvent control) or JQ1. Cells were collected 12h after treatment. This was performed for 3 replicates.
Project description:The T-cell leukemia homeobox 1 (TLX1, HOX11) transcription factor is critically involved in the multistep pathogenesis of T-cell acute lymphoblastic leukemia (T-ALL) and often cooperates with NOTCH1 activation during malignant T-cell transformation. However, the exact molecular mechanisms by which these T-cell specific oncogenes cooperate during transformation remain to be established. Here, we used an integrative genomics approach to show that the oncogenic properties of TLX1 are mediated by genome-wide interference with the ETS1 and RUNX1 transcription factors. Partial disruption of ETS1 and RUNX1 activity by ectopic TLX1 expression in immature thymocytes drives repression of T-cell specific super-enhancers and mediates an unexpected transcriptional antagonism with NOTCH1 signaling. These phenomena coordinately trigger a TLX1 driven pre-leukemic phenotype in human thymic precursor cells, which corresponds with the in vivo thymic regression observed in murine TLX1 tumor models, and creates a strong genetic pressure for acquiring activating NOTCH1 mutations as a prerequisite for full leukemic transformation. In conclusion, our results uncover a functional antagonism between cooperative oncogenes during the earliest phases of tumor development and provide novel insights in the multistep pathogenesis of TLX1 driven human leukemia. Gene expression was measured in the ALL-SIL T-ALL cell line after electroporation with scrambled siRNA and 2 independent TLX1 targetings siRNAs. Cells were collected 24h after treatment. This was performed for 3 replicates.
Project description:The T-cell leukemia homeobox 1 (TLX1, HOX11) transcription factor is critically involved in the multistep pathogenesis of T-cell acute lymphoblastic leukemia (T-ALL) and often cooperates with NOTCH1 activation during malignant T-cell transformation. However, the exact molecular mechanisms by which these T-cell specific oncogenes cooperate during transformation remain to be established. Here, we used an integrative genomics approach to show that the oncogenic properties of TLX1 are mediated by genome-wide interference with the ETS1 and RUNX1 transcription factors. Partial disruption of ETS1 and RUNX1 activity by ectopic TLX1 expression in immature thymocytes drives repression of T-cell specific super-enhancers and mediates an unexpected transcriptional antagonism with NOTCH1 signaling. These phenomena coordinately trigger a TLX1 driven pre-leukemic phenotype in human thymic precursor cells, which corresponds with the in vivo thymic regression observed in murine TLX1 tumor models, and creates a strong genetic pressure for acquiring activating NOTCH1 mutations as a prerequisite for full leukemic transformation. In conclusion, our results uncover a functional antagonism between cooperative oncogenes during the earliest phases of tumor development and provide novel insights in the multistep pathogenesis of TLX1 driven human leukemia. Gene expression was measured in the ALL-SIL T-ALL cell line after treatment with DMSO (solvent control) or GSI (γ-Secretase Inhibitor). Cells were collected 48h after treatment. This was performed for 3 replicates.
Project description:The T-cell leukemia homeobox 1 (TLX1, HOX11) transcription factor is critically involved in the multistep pathogenesis of T-cell acute lymphoblastic leukemia (T-ALL) and often cooperates with NOTCH1 activation during malignant T-cell transformation. However, the exact molecular mechanisms by which these T-cell specific oncogenes cooperate during transformation remain to be established. Here, we used an integrative genomics approach to show that the oncogenic properties of TLX1 are mediated by genome-wide interference with the ETS1 and RUNX1 transcription factors. Partial disruption of ETS1 and RUNX1 activity by ectopic TLX1 expression in immature thymocytes drives repression of T-cell specific super-enhancers and mediates an unexpected transcriptional antagonism with NOTCH1 signaling. These phenomena coordinately trigger a TLX1 driven pre-leukemic phenotype in human thymic precursor cells, which corresponds with the in vivo thymic regression observed in murine TLX1 tumor models, and creates a strong genetic pressure for acquiring activating NOTCH1 mutations as a prerequisite for full leukemic transformation. In conclusion, our results uncover a functional antagonism between cooperative oncogenes during the earliest phases of tumor development and provide novel insights in the multistep pathogenesis of TLX1 driven human leukemia. Gene expression was measured after TLX1 overexpression in human CD34+ T-cell progenitors cultured on an OP9-DLL1 feeder layer. Cells were collected after 72h of co-culture. This was performed for 2 independent thymus CD34+ donors.
Project description:The most immature progenitors in the murine thymus are early T lineage progenitors (ETP). These cells are the precursors of more mature thymocytes that ultimately leave the thymus and colonize peripheral lymphoid tissues. As part of our efforts to define age-related changes in ETP, we harvested them from mice of different ages and performed whole transcriptome profiling. This analysis revealed major differences in patterns of gene expression between young and old ETP, and we were particularly struck by the significantly reduced expression of the gene encoding high mobility group A 2 protein (Hmga2).