ABSTRACT: The AML1-ETO fusion protein, a transcription factor generated by the t(8;21) translocation in acute myeloid leukaemia (AML), dictates a leukemic program by increasing self-renewal and inhibiting differentiation. Here we demonstrate that the histone demethylase JMJD1C functions as a co-activator for AML1-ETO and is required for its transcriptional program. JMJD1C is directly recruited by AML1-ETO to its target genes and regulates their expression by maintaining low H3K9me2 levels. Analyses in JMJD1C knockout mice also establish a JMJD1C requirement for AML1-ETO’s ability to increase proliferation. We also show a critical role for JMJD1C in the survival of multiple human AML cell lines, suggesting that it is required for leukemic programs in different AML cell types through its association with key transcription factors.
Project description:The AML1-ETO fusion protein, a transcription factor generated by the t(8;21) translocation in acute myeloid leukaemia (AML), dictates a leukemic program by increasing self-renewal and inhibiting differentiation. Here we demonstrate that the histone demethylase JMJD1C functions as a co-activator for AML1-ETO and is required for its transcriptional program. JMJD1C is directly recruited by AML1-ETO to its target genes and regulates their expression by maintaining low H3K9me2 levels. Analyses in JMJD1C knockout mice also establish a JMJD1C requirement for AML1-ETOâs ability to increase proliferation. We also show a critical role for JMJD1C in the survival of multiple human AML cell lines, suggesting that it is required for leukemic programs in different AML cell types through its association with key transcription factors. Examination of JMJD1C and LYL1 chromatin binding in Kasumi-1 cells, HL-60 cells, NB-4 cells and THP-1 cells, including ChIP-seqs of JMJD1C and LYL1, and input DNAs for Kasumi-1, HL-60, NB4.
Project description:The AML1-ETO fusion protein, a transcription factor generated by the t(8;21) translocation in acute myeloid leukaemia (AML), dictates a leukemic program by increasing self-renewal and inhibiting differentiation. Here we demonstrate that the histone demethylase JMJD1C functions as a co-activator for AML1-ETO and is required for its transcriptional program. JMJD1C is directly recruited by AML1-ETO to its target genes and regulates their expression by maintaining low H3K9me2 levels. Analyses in JMJD1C knockout mice also establish a JMJD1C requirement for AML1-ETOâs ability to increase proliferation. We also show a critical role for JMJD1C in the survival of multiple human AML cell lines, suggesting that it is required for leukemic programs in different AML cell types through its association with key transcription factors. Examination of RNA expression when Kasumi-1 cells are treated with control shRNA or two different JMJD1C shRNAs; in duplicate. Please note that the 'shAML1_ETO_vs_shControl.all_gene_exp.tb.txtl' was generated comparing control and shRNA treated RNA abundance-using previously published data [GSE43834; GSM1071857 and GSM1071852].
Project description:The AML1-ETO fusion protein, a transcription factor generated by the t(8;21) translocation in acute myeloid leukaemia (AML), dictates a leukemic program by increasing self-renewal and inhibiting differentiation. Here we demonstrate that the histone demethylase JMJD1C functions as a co-activator for AML1-ETO and is required for its transcriptional program. JMJD1C is directly recruited by AML1-ETO to its target genes and regulates their expression by maintaining low H3K9me2 levels. Analyses in JMJD1C knockout mice also establish a JMJD1C requirement for AML1-ETO’s ability to increase proliferation. We also show a critical role for JMJD1C in the survival of multiple human AML cell lines, suggesting that it is required for leukemic programs in different AML cell types through its association with key transcription factors.
Project description:Gene expression profiling and proteome analysis of normal and malignant hematopoietic stem cells have firmly established the existence of shared core stemness properties. However, the discordance between mRNA and protein signatures underscores an important role for post-transcriptional regulation by miRNAs in governing this critical nexus. Here, we identify miR-130a as a regulator of hematopoietic stem cell (HSC) self-renewal and lineage differentiation. Integration of mass spectrometry and chimeric AGO2 eCLIP-seq identify TBL1XR1 as a primary miR-130a target. TBL1XR1 loss of function impairs lymphoid differentiation and expands long-term (LT)-HSC. This post-transcriptional regulation by miR-130a is usurped in t(8;21) acute myeloid leukemia (AML). Reduction of miR-130a levels in t(8;21) AML cells results in altered chromatin binding and composition of the AML1-ETO complex, demonstrating that miR-130a is critical for maintaining the oncogenic molecular program mediated by AML1-ETO. Our study establishes that comprehensive identification of the miRNA targetome within primary tissue enables the discovery of novel genes and molecular networks underpinning stemness properties of normal and leukemic cells.
Project description:Acute myeloid leukemia (AML) with the t(8;21)(q22;q22) chromosomal translocation is among the most common subtypes of AML and produces the AML1-ETO (AE) oncogenic fusion gene. AML1-ETO expression is critical to for t(8;21) AML leukemogenesis and maintenance. Post-transcriptional regulation of gene expression is often mediated through transcript 3'-untranslated regions (UTR). AML1-ETO uses the 3’UTR of the ETO gene, which is not normally expressed in hematopoietic cells. Therefore, the mechanisms regulating AML1-ETO via the 3’UTR are attractive therapeutic targets. In this study, we examine the regulation of AML1-ETO via the 3’UTR. We demonstrate that AML1-ETO primarily uses a 3.7kb isoform of the ETO 3’UTR in both t(8;21) patients and cell lines. Using a luciferase assay approach, we identify an AML1-ETO 3’UTR fragment between 2.8 and 3.4kb which is negatively regulated, increases expression upon inhibition of microRNA biogenesis, and contains a putative let-7 microRNA target site. We show that let-7b directly represses AML1-ETO through this site. An analysis of The Cancer Genome Atlas AML dataset shows that let-7b and let-7 family miRNA expression is significantly lower in t(8;21) AML than other AMLs. Finally, we demonstrate that let-7b-5p inhibits the proliferation of t(8;21) AML cell lines, rescues expression of AML1-ETO target genes, and promotes differentiation. Our findings establish AML1-ETO as a let-7b target gene and suggest that let-7 based therapeutics may be applied to t(8;21) AML.
Project description:The formation of the AML1-ETO fusion protein, resulting from the t(8;21) translocation, is considered to be among the t(8;21) acute myeloid leukemia (AML) initiating events. However, the mechanisms of the oncogenic activity of AML1-ETO remains unclear. In this study, we found that AML1-ETO triggers the heterochromatic silencing of UBXN8 by recognizing the AML1 binding sites and recruiting chromatin remodeling enzymes to the UBXN8 promoter region. Decitabine, a specific inhibitor of DNA methylation, upregulated the expression of UBXN8 in AML1-ETO+ AML cell lines. Overexpression of UBXN8 inhibited the proliferation and colony-forming ability and promoted cell cycle arrest in t(8;21) AML cell lines. Enhancement of UBXN8 level can significantly inhibit the tumor proliferation of AML1-ETO+ cells in vivo. Thus, our results indicated that epigenetic silencing of UBXN8 via its promoter region methylation mediated by the AML1-ETO fusion protein contributes to the leukemogenesis of t(8;21)AML. These results demonstrated the feasibility and effectiveness of the pharmacological disruption of AML1-ETO/HDACs/DNMTs complex and that the UBXN8 targeting maybe an potential therapeutic strategy for t(8;21)AML.
Project description:Here we describe the development and characterization of an induced pluripotent stem cell (iPSC) system that allows in vitro differentiation towards different mature myeloid cell types such as monocytes and granulocytes. During in vitro differentiation we inducible expressed the AML1-ETO fusion protein and examined the effects of the oncoprotein on differentiation and the underlying alterations in the gene program. Our analysis revealed that AML1-ETO as a single oncogenic hit in a presumable non-mutated background blocks granulocytic differentiation and deregulates the gene program via altering the acetylome of the differentiating granulocytic cells and inducing t(8;21) AML associated leukemic characteristics.
Project description:Nearly 10-15% of all acute myeloid leukemia (AML) cases are caused by a recurring chromosomal translocation between 8 and 21, t(8;21). The t(8;21) translocation generates the AML1-ETO leukemia fusion protein. AML1-ETO promotes leukemogenesis by transcriptionally dysregulating important cell-fate genes. Here, to better understand how AML1-ETO deregulates transcription, we performed paired ChIP-Seq analyses of sequence-specific transcription factors, coactivators, corepressors, HDACs, RNA Pol II and acetyl-histone marks in both control and AML1-ETO-depleted Kasumi-1 t(8;21) AML cells.
Project description:In an effort to identify novel drugs targeting fusion-oncogene induced acute myeloid leukemia (AML), we performed high-resolution proteomic analysis. In AML1-ETO (AE) driven AML we uncovered a deregulation of phospholipase C (PLC) signaling. We identified PLCgamma 1 (PLCG1) as a specific target of the AE fusion protein which is induced after AE binding to intergenic regulatory DNA elements. Genetic inactivation of PLCG1 in murine and human AML inhibited AML1-ETO dependent self-renewal programs, leukemic proliferation, and leukemia maintenance in vivo. In contrast, PLCG1 was dispensable for normal hematopoietic stem- and progenitor cell function. These findings are extended to and confirmed by pharmacologic perturbation of Ca++-signaling in AML1-ETO AML cells, indicating that the PLCG1 pathway poses an important therapeutic target for AML1-ETO positive leukemic stem cells.
Project description:JMJD1C, a Jumonji C (JmjC) domain-containing histone demethylase, has been reported as a direct cofactor of oncogenic transcription factor HOXA9. To identify JMJD1C downstream effectors, we performed a genome-wide gene expression profiling experiment. Our microarray analysis identified a new role for JMJD1C in regulating a cancer metabolic program in HOX-driven AML. GFP+ HOXA9/MEIS1-mediated pre-leukemic stem cells were transduced with retroviruses carrying JMJD1C or empty vector for the microarray experiment. Each group has 4 samples.