Project description:Transcriptional profiling of the effect of shRNA silencing of Runx1 in human AMkL Meg-01 cells. RNA samples obtained from two independent colonies were compared to RNAs from negative control transductions in a two-color design. A total of four microarrays were completed, with a dye-swapped pair performed for each colony. Two-condition experiment, Runx1 knockdown vs. negative transduction controls. Biological replicates: 2 knockdown replicates, 2 control replicates.
Project description:Transcriptional profiling of the effect of shRNA silencing of Runx1 in human AMkL Meg-01 cells. RNA samples obtained from two independent colonies were compared to RNAs from negative control transductions in a two-color design. A total of four microarrays were completed, with a dye-swapped pair performed for each colony.
Project description:GAS2DN could suppress the growth of chronic myeloid leukemia cells, including K562, MEG-01 and CD34+ cells from patients. In addition, GAS2DN inhibited the tumorigenic ability of MEG-01 cells in nude mice. To understand the molecular insight of this inhibitory effect of GAS2DN, global gene expression were performed. The control and GAS2DN-transduced MEG-01 cells were used for microarray analysis.
Project description:GAS2DN could suppress the growth of chronic myeloid leukemia cells, including K562, MEG-01 and CD34+ cells from patients. In addition, GAS2DN inhibited the tumorigenic ability of MEG-01 cells in nude mice. To understand the molecular insight of this inhibitory effect of GAS2DN, global gene expression were performed. The control and GAS2DN-transduced MEG-01 cells were used for microarray analysis. Three biological independent extracts of control and GAS2DN-transduced cells were pooled together with equal amount, and then the pooled samples were compared with Affymetrix chips.
Project description:Cancer cells maintain a sensitive balance between growth-promoting oncogenes and apoptosis inhibitors. We show that WT RUNX1 is required for survival of t(8;21)-Kasumi-1 and inv(16)-ME-1 AML cell lines. The malignant AML phenotype is sustained by a delicate AML1-ETO/RUNX1 balance that involves competition for common DNA binding sites regulating a subset of AML1-ETO/RUNX1 targets. Genome expression was profiled after performing knockdown of RUNX1 and AML1-ETO in Kasumi-1 cells using specific siRNA-oligo nucleotides, and analyzed using Affymetrix Gene 1.0 ST arrays.
Project description:A high incidence of acute megakaryoblastic leukemia (AMKL) in Down syndrome patients implies that chromosome 21 genes have a pivotal role in AMKL development, but the functional contribution of individual genes remains elusive. Here, we report that SON, a chromosome 21-encoded DNA- and RNA-binding protein, inhibits megakaryocytic differentiation by suppressing RUNX1 and the megakaryocytic gene expression program. As megakaryocytic progenitors differentiate, SON expression is drastically reduced, with mature megakaryocytes having the lowest levels. In contrast, AMKL cells express an aberrantly high level of SON, and knockdown of SON induced the onset of megakaryocytic differentiation in AMKL cell lines. Genome-wide transcriptome analyses revealed that SON knockdown turns on the expression of pro-megakaryocytic genes while reducing erythroid gene expression. Mechanistically, SON represses RUNX1 expression by directly binding to the proximal promoter and two enhancer regions, the known +23 kb enhancer and the novel +139 kb enhancer, at the RUNX1 locus to suppress H3K4 methylation. In addition, SON represses the expression of the AP-1 complex subunits JUN, JUNB and FOSB which are required for late megakaryocytic gene expression. Our findings define SON as a negative regulator of RUNX1 and megakaryocytic differentiation, implicating SON overexpression in impaired differentiation during AMKL development.
Project description:The t(8;21) acute myeloid leukemia associated oncoprotein AML1-ETO is a transcription factor that aberrantly regulates the pathways that lead to myeloid differentiation. Here, we set out to investigate the effects of AML1-ETO on gene expression and the epigenome in patient blast cells. We identify two modules, one in which AML1-ETO binds promoter regions of active genes and one represented by non-promoter binding to accessible, yet inactive chromatin regions. Using genome-wide binding analysis and mass spectrometry interaction studies we identify ERG, FLI1, TAL1 and RUNX1 as common binding factors of all AML1-ETO occupied genomic regions, while LYL1 and LMO2 show preferential binding in the context of non promoter regions. Epigenetically, reduced histone acetylation levels at non-promoter regions seems HDAC dependent, as treatment with an HDACi increases acetylation and induces cell death. Both AML1-ETO modules are represented in most aberrantly regulated pathways, including many signaling pathways, self-renewal and apoptosis. For the latter, the expression of the wild type transcription factors RUNX1 and ERG is required, as alterations in expression are associated with the onset of an apoptosis program. Interestingly, upon RUNX1 or ERG knockdown this onset seems to be dependent on increased AML1-ETO expression as combinatorial knockdown of RUNX1/AML1-ETO or ERG/AML1-ETO results in rescue from apoptosis. Together our results show that the balanced interplay of the epigenetic environment and transcription factors retains an anti apoptotic phenotype in t(8;21) AML cells.
Project description:Human histone deacetylase 3 (HDAC3) plays an important role in gene transcription in diseased human cells, such as leukemia. The t(8;21) chromosomal translocation is one of the most commonly observed genetic abnormalities associated with acute myeloid leukemia. This translocation generates the AML1-ETO fusion protein between the wild-type RUNX1 transcription factor and wild-type ETO transcriptional corepressor. To better understand the role of HDAC3 in t(8;21) leukemogenesis, the human HDAC3-containing complexes were isolated from stably-transfected HeLa cells by using anti-FLAG immunoprecipitation. The resulting complexes were resolved in SDS-PAGE. The components of the complexes were identified using LC-MS/MS. We report here that the human RUNX1 transcription is a component of the HDAC3 complexes. We demonstrate that HDAC3 and RUNX1 collaboratively repress AML1-ETO-mediated transcription. These results reveal new insight into how AML1-ETO, RUNX1, and HDAC3 crosstalk to deregulate gene transcription in t(8;21) leukemia cells.
Project description:Disrupting mutations of the RUNX1 gene are found in 10% of patients with myelodysplasia (MDS) and 30% of patients with acute myeloid leukemia (AML). Previous studies have revealed an increase in hematopoietic stem cells (HSCs) and multipotent progenitor (MPP) cells in conditional Runx1-knockout (KO) mice, but the molecular mechanism is unresolved. We investigated the myeloid progenitor (MP) compartment in KO mice, arguing that disruptions at the HSC/MPP level may be amplified in downstream cells. We demonstrate that the MP compartment is increased more than fivefold in Runx1 KO mice, with a prominent skewing toward megakaryocyte (Meg) progenitors. Runx1- deficient granulocyte-macrophage progenitors are characterized by increased cloning capacity, impaired development into mature cells, and HSC and Meg transcription signatures. An HSC/MPP subpopulation expressing Meg markers was also increased in Runx1-deficient mice. Rescue experiments coupled with transcriptome analysis and Runx1 DNA-binding assays demonstrated that commitment is marked by Runx1 suppression of genes encoding adherence and motility proteins (Tek, Jam3, Plxnc1, Pcdh7, and Selp) that support HSCâMeg interactions with the BM niche. In vitro assays confirmed that enforced Tek expression in HSCs/MPPs increases Meg output. Interestingly, besides this key repressor function of Runx1 to control lineage decisions and cell numbers in progenitors, our study also revealed a critical activating function in erythroblast differentiation, in addition to its known importance in Meg and granulocyte/monocyte (G/M) maturation. Thus both repressor and activator functions of Runx1 at multiple hematopoietic stages and lineages likely contribute to the tumor suppressor activity in MDS and AML. GMP were isolated either from Runx1+/+-Tg(vav-Cre) and Runx1fl/fl-Tg(vav-Cre) mice or from mice transplanted with Runx1fl/fl-Tg(vav-Cre) progenitors engineered to express GFP with RUNX1-ERt2 or ERt2. RUNX1-ERt2 activity was induced by i.p. injection of tamoxifen on 3 consecutive days prior to GMP isolation.