MLL-AF9 lates transcriptional initiation in mixed lineage leukemic cells
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ABSTRACT:
PROVIDER: PRJNA967726 | ENA |
REPOSITORIES: ENA
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Project description:MLL-fusion proteins (MLL-FPs) are believed to maintain gene activation and induce mixed lineage leukemia (MLL) through aberrantly stimulating transcriptional elongation, but the underlying mechanisms are incompletely understood. Here we show that both MLL1 and AF9, one of the major fusion partners of MLL1, mainly occupy promoters and distal intergenic regions, exhibiting chromatin occupancy patterns resembling that of RNA polymerase II (Pol II) in HEL, a human cell line without MLL1 arrangement (MLLr). MLL1 and AF9 only co-regulate over a dozen genes despite of their co-occupancy on thousands of genes. They do not interact with each other, and their chromatin occupancy is also independent of each other. Moreover, AF9 deficiency in HEL cells decreases global TBP occupancy while decreases CDK9 occupancy on a small number of genes, suggesting an accessory role of AF9 in CDK9 recruitment and a possible major role in transcriptional initiation via initiation factor recruitment. Importantly, MLL1 and MLL-AF9 occupy promoters and distal intergenic regions, exhibiting identical chromatin occupancy patterns in MLL cells, and MLL-AF9 deficiency decreased occupancy of TBP and TFIIE on major target genes of MLL-AF9 in iMA9, a murine acute myeloid leukemia (AML) cell line inducibly expressing MLL-AF9, suggesting that it can also regulate initiation. These results suggest that there is no difference between MLL1 and MLL-AF9 with respect to location and size of occupancy sites, contrary to what people have believed, and that MLL-AF9 may also regulate transcriptional initiation in addition to widely-believed elongation.
2024-07-15 | GSE231814 | GEO
Project description:Chromatin immunoprecipitation (ChIP) for H3K27me3 followed by Solexa sequencing in WT and Ezh2-null leukemic cells from primary and secondary recipients. Leukemic cells from primary and secondary recipients of MLL-AF9-transduced WT and Ezh2-null cells were sorted for GFP and YFP expression and analyzed by Chip-Seq.
2012-02-22 | E-GEOD-34962 | biostudies-arrayexpress
Project description:Using an acute myeloid leukemia (AML) mouse model driven by tet-regulated MLL-AF9 (fusion between the gene MLL1 (KMT2A/MLL) and MLLT3 (AF9)) co-expressed with oncogenic NRASG12D (Tet-off MLL-AF9), we investigated the effect of modulating the expression of the MLL-AF9 fusion oncogene on the transcriptome and proteome of established murine AML. Treatment in vitro or in vivo of these Tet-off MLL-AF9 AMLs with doxycycline (DOX) results in the efficient down-regulation of the expression of the driver oncogene MLL-AF9. RNA sequencing analysis was performed on primary Tet-Off MLL-AF9 AML cells obtained from the spleen of leukemic animals and cultured in vitro for either 2 or 4 days in the presence of doxycycline (1μg/ml) (DOX= down-regulation of MLL-AF9) or left untreated (UT).
2021-12-31 | GSE108326 | GEO
Project description:This study report that miR-150, a key hematopoietic regulatory microRNA (miRNA) and one of the most downregulated miRNAs in MLL-associated leukemias, acts as a tumor suppressor to block the leukemogenic potency of leukemic stem cells. When expression of miR-150 was restored, a significantly suppressed leukemic stem cell potency of MLL-AF9 cells was observed both in vivo and in vitro. To investigate the tumor suppressive function of miR-150 in MLL-AF9 cells, we isolated three batches of MLL-AF9 cells infected with MDH empty vector or MDH-miR-150 expression retrovirus. Total RNA were extracted and applied for Agilent array analysis. Gene profiling analysis demonstrated that elevated miR-150 altered various aspects of gene expression patterns in MLL-AF9 cells, including stem cell signatures, cancer pathways, and cell survival. miR-150-MLL-AF9 and MDH-MLL-AF9 isolated cells were compared for gene expression patterns. Triplicates using three batches of FACS sorted cells were compared in pairs on the array. MDH-MLL-AF9 samples were labeld with Cy3 and miR-150-MLL-AF9 samples were labled with Cy5.
2011-07-19 | E-GEOD-30771 | biostudies-arrayexpress
Project description:A t(9;11)(p22;q23) translocation produces the MLL-AF9 fusion protein, which is found in up to 25% of de novo AML cases in children. Despite major advances, obtaining a comprehensive under-standing of context-dependent MLL-AF9-mediated gene programs during early hematopoiesis is challenging. Here, we generated a human inducible pluripotent stem cell (hiPSC) model with a doxycycline dose-dependent MLL-AF9 expression. We exploited MLL-AF9 expression as an onco-genic hit to uncover epigenetic and transcriptomic effects on iPSC-derived hematopoietic develop-ment and the transformation into (pre-)leukemic states. In doing so, we observed a disruption in early myelomonocytic development. Accordingly, we identified gene profiles that were consistent with primary MLL-AF9 AML and uncovered high-confidence MLL-AF9-associated core genes that are faithfully represented in primary MLL-AF9 AML, including known and presently unknown factors. Using single-cell RNA-sequencing, we identified an increase of CD34 expressing early hematopoietic progenitor-like cell states as well as granulocyte-monocyte progenitor-like cells upon MLL-AF9 activation. Our system allows for careful chemically controlled and stepwise in vitro hiPSC-derived differentiation under serum-free and feeder-free conditions. For a disease that cur-rently lacks effective precision medicine, our system provides a novel entry-point into exploring po-tential novel targets for personalized therapeutic strategies.
2023-05-03 | GSE217014 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE34959: Expression profiling of primary wild type (WT), Ezh2-null and Eed-null murine MLL-AF9 AML GSE34961: Expression profiling of secondary wild type (WT) and Ezh2-null murine MLL-AF9 AML GSE34962: Epigenetic profiling of WT and Ezh2-null MLL-AF9 murine leukemic cells Refer to individual Series
2012-02-22 | E-GEOD-34963 | biostudies-arrayexpress
Project description:ASH1L and MLL1 are two histone methyltransferases that facilitate transcriptional activation during normal development. However, the roles of ASH1L and its enzymatic activity in the development of MLL-rearranged leukemias are not fully elucidated in Ash1L gene knockout animal models. In this study, we used an Ash1L conditional knockout mouse model to show that loss of ASH1L in hematopoietic progenitor cells impaired the initiation of MLL-AF9-induced leukemic transformation in vitro. Furthermore, genetic deletion of ASH1L in the MLL-AF9-transformed cells impaired the maintenance of leukemic cells in vitro and largely blocked the leukemia progression in vivo. Importantly, the loss of ASH1L function in the Ash1L-deleted cells could be rescued by wild-type but not the catalytic-dead mutant ASH1L, suggesting the enzymatic activity of ASH1L was required for its function in promoting MLL-AF9-induced leukemic transformation. At the molecular level, ASH1L enhanced the MLL-AF9 target gene expression by directly binding to the gene promoters and modifying the local histone H3K36me2 levels. Thus, our study revealed the critical functions of ASH1L in promoting the MLL-AF9-induced leukemogenesis, which provides a molecular basis for targeting ASH1L and its enzymatic activity to treat MLL-arranged leukemias.
2021-09-07 | GSE183413 | GEO
Project description:This study report that miR-150, a key hematopoietic regulatory microRNA (miRNA) and one of the most downregulated miRNAs in MLL-associated leukemias, acts as a tumor suppressor to block the leukemogenic potency of leukemic stem cells. When expression of miR-150 was restored, a significantly suppressed leukemic stem cell potency of MLL-AF9 cells was observed both in vivo and in vitro. To investigate the tumor suppressive function of miR-150 in MLL-AF9 cells, we isolated three batches of MLL-AF9 cells infected with MDH empty vector or MDH-miR-150 expression retrovirus. Total RNA were extracted and applied for Agilent array analysis. Gene profiling analysis demonstrated that elevated miR-150 altered various aspects of gene expression patterns in MLL-AF9 cells, including stem cell signatures, cancer pathways, and cell survival.
2011-07-20 | GSE30771 | GEO
Project description:MIR139 is a critical tumor suppressor and commonly silenced in human cancer, including acute myeloid leukemia (AML). Here, we found that depletion of identified MIR139 targets affects AML outgrowth. We unraveled the mechanism of MIR139 gene inactivation in AML expressing the Mixed-Lineage Leukemia (MLL)-AF9 oncogene. Epigenetic analyses revealed two well-conserved putative enhancer regions in close proximity of transcriptional start sites (TSS) of MIR139. These regions were silenced by the Polycomb-Repressive Complex-2 (PRC2) downstream of MLL-AF9. Genomic deletion of these regions abolished MIR139 transcriptional regulation in normal and oncogenic conditions. Genome-wide knockout screens revealed the transcriptional pausing factor of RNA Polymerase-II, POLR2M, as a critical MIR139-silencing factor. Furthermore, direct POLR2M binding to the MIR139 TSS induced paused transcription, which was abrogated upon PRC2 inhibition. We present evidence for an oncogenic POLR2M-mediated MIR139 silencing mechanism, downstream of MLL-AF9 and PRC2. Together, our findings highlight the importance of POLR2M-mediated paused transcription in AML.
2021-11-11 | PXD022488 | Pride
Project description:Leukemias derived from the MLL-AF9 rearrangement rely on deranged transcriptional networks. ZNF521, a transcription co-factor implicated in the control of hematopoiesis, has been proposed to sustain leukemic transformation in collaboration with other oncogenes. We demonstrate here that ZNF521 mRNA levels correlate with specific genetic aberrations: in particular, the highest expression is observed in AMLs bearing MLL rearrangements, while the lowest is detected in AMLs with FLT3-ITD, NPM1 or CEBPα double mutations. In cord blood-derived CD34+ cells, enforced expression of ZNF521 provides a significant proliferative advantage, and acts synergistically when co-expressed with MLL-AF9 throughout the proliferation and expansion of leukemic progenitor cells. Transcriptome analysis of primary CD34+ cultures displayed subsets of genes upregulated by MLL-AF9 or ZNF521 single transgene overexpression as well as in MLL-AF9/ZNF521 combinations, either at early or late time points of an in vitro model of leukemogenesis. Silencing of ZNF521 in MLL-AF9+ THP-1 cell line coherently results in an impairment of growth and clonogenicity, recapitulating effects observed in primary cells. Taken together, these results underscore a role for ZNF521 in sustaining self-renewal of the AML immature compartment, most likely through the perturbation of the gene expression landscape which ultimately favors the expansion of MLL-AF9 transformed leukemic clones.
2022-03-24 | GSE181006 | GEO