Development of gene expression signatures for TLX1 knockdown in the ALL-SIL cell line.

ABSTRACT: 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.

ORGANISM(S): Homo sapiens

SUBMITTER: Kaat Durinck 

PROVIDER: E-GEOD-62141 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress