Project description:The drug efflux pump ABCB1 is a key driver of chemoresistance, and high expression predicts for treatment failure in acute myeloid leukemia (AML). We show that both acute and chronic exposure of leukemia cells to daunorubicin activates an integrated stress response-like transcriptional program to induce ABCB1 through remodeling and dynamic activation of an ATF4-bound, stress-responsive enhancer. In primary human AML, stress-responsive ABCB1 enhancers are accessible and acetylated, and exposure of fresh blast cells to daunorubicin induces ABCB1 in a dose-dependent manner. Dynamic induction of ABCB1 by diverse stressors, including chemotherapy, facilitates escape of leukemia cells from targeted third-generation ABCB1 inhibition. Stress-induced up regulation of ABCB1 is mitigated by combined use of pharmacologic inhibitors U0126 and ISRIB, which inhibit stress signaling.

2020-02-03 | GSE131824 | GEO

NSD3-short is an adaptor protein that couples BRD4 to the CHD8 chromatin remodeler (ChIP-Seq)

Project description:The bromodomain and extraterminal (BET) protein BRD4 is a therapeutic target in acute myeloid leukemia (AML). Here, we demonstrate that the AML maintenance function of BRD4 requires its interaction with NSD3, which belongs to a subfamily of H3K36 methyltransferases. Unexpectedly, AML cells were found to only require a short isoform of NSD3 that lacks the methyltransferase domain. We show that NSD3-short is an adaptor protein that sustains leukemia by linking BRD4 to the CHD8 chromatin remodeler, by using a PWWP chromatin reader module, and by employing an acidic transactivation domain. Genetic targeting of NSD3 or CHD8 mimics the phenotypic and transcriptional effects of BRD4 inhibition. Furthermore, BRD4, NSD3, and CHD8 colocalize across the AML genome, and each is released from super-enhancer regions upon chemical inhibition of BET bromodomains. These findings suggest that BET inhibitors exert therapeutic effects in leukemia by evicting BRD4-NSD3-CHD8 complexes from chromatin to suppress transcription. ChIP-Seq for regulatory factors of BRD4, NSD3, CHD8 and histone modification H3K36me2 in MLL-AF9 transformed acute myeloid leukemia cells (RN2)

2015-12-17 | E-GEOD-71183 | biostudies-arrayexpress

BRD9 regulates leukemic cell survival via STAT5 pathway inhibition

Project description:Leukemia is characterized by genetic and epigenetic mutations resulting in selection of cancer stem cells, which are unable to differentiate. While genetic alterations are difficult to target, the epigenome is intrinsically dynamic and readily offers new therapeutic strategies. Thus, identifying cancer-specific context-dependent targets and unraveling their biological function may open up new therapeutic perspectives. Here, we identify bromodomain-containing protein 9 (BRD9) as a critical target required in acute myeloid leukemia (AML). We show that BRD9 is overexpressed in AML cells including ex vivo primary blasts compared to CD34+. By targeting BRD9 expression in AML, we observed an alteration in proliferation and survival, ultimately resulting in the induction of apoptosis. Intriguingly, genome-wide profiling revealed that BRD9 binds enhancer regions in a cell type-specific manner, regulating cell type-related processes. We unveil a novel BRD9-sustained STAT5 pathway activation via regulation of SOC3 expression levels. Our findings identify a previously undescribed BRD9-STAT5 axis as critical for leukemia maintenance, suggesting BRD9 as a potential therapeutic target.

2019-11-11 | PXD013245 | Pride

Genome wide maps of ZFX binding in human leukemia cell lines

Project description:Acute myeloid leukemia (AML) and acute T-lymphoblastic leukemia (T-ALL) maintain the undifferentiated phenotype and proliferative capacity of their respective cells of origin, hematopoietic stem/progenitor cells and immature thymocytes. The mechanisms that maintain these progenitor-like characteristics are poorly understood. We report that transcription factor Zfx is required for the development and propagation of experimental AML caused by MLL-AF9 fusion, and of T-ALL caused by Notch1 activation. In both leukemia types, Zfx activated progenitor-associated gene expression programs and prevented differentiation. Key Zfx target genes included mitochondrial enzymes Ptpmt1 and Idh2, whose overexpression partially rescued the propagation of Zfx-deficient AML. These studies identify a common mechanism that controls the cell-of-origin characteristics of acute leukemias derived from disparate lineages and transformation mechanisms. Analysis of genomic ZFX binding in the AML cell line NOMO-1 and the T-ALL cell line RPMI-8402

2014-01-30 | E-GEOD-43147 | biostudies-arrayexpress

Homo sapiens

Project description:Acute myeloid leukemia study

| PRJNA84991 | ENA