Project description:P2X7 was significantly up-regulated in leukemia patients, especially in AML (MLL-AF9) and often related to poor prognosis.We compared the transcriptomic changes in MLL-AF9 induced mouse AML and overexpressed wP2X7 in MLL-AF9 induced AML. Engaged to explore the mechanism of P2X7 in leukemia progression. Mouse AML was induced by expressing MLL-AF9 in mouse HSPCs. Leukemia cells were divided into two groups, c-kit+ and c-kit-. Due to leukemia cells were nearly 95% c-kit+ in P2X7-overexpressed AML cells, we set up four groups of leukemia cells, namely leukemia total cells (V total), leukemia c-kit positive cells (V c-kit+), leukemia c-kit negative cells (V c-kit-), overexpressed wide type P2X7 leukemia cells (wP2X7).
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.
Project description:This SuperSeries is composed of the following subset Series: GSE30745: Expression data from murine acute myeloid leukemia (AML) cells following shRNA-mediated suppression of Myb GSE30746: Expression data from murine Tet-off MLL-AF9/Ras acute myeloid leukemia cell lines following withdrawal of MLL-AF9 Refer to individual Series
Project description:We investigated the role of the transcriptional regulator Id2 in the context of MLL-rearranged acute myeloid leukemia (AML). Using an AML mouse model driven by tet-regulated MLL-AF9 co-expressed with oncogenic NRASG12D (Tet-off MLL-AF9), we demonstrated that MLL-AF9 regulates the E protein pathway by suppressing Id2, while activating the expression of its target E2-2. Moreover, we found that Id2 over-expression in Tet-Off MLL-AF9 AML cells in vitro partially phenocopies MLL-AF9 depletion and results inhibition of leukemia growth, loss of leukemia stem cell-associated gene expression pattern and induction of differentiation. To compare gene expression changes associated with enforced Id2 expression and MLL-AF9 withdrawal, RNA sequencing analysis was performed on Tet-off MLL-AF9 cells transduced with an Id2 over-expressing or a control vector, or upon MLL-AF9 dox-inducible knock-down.
Project description:We investigated the role of the transcriptional regulators Id2 and E2-2 (encoded by Tcf4) in the context of MLL-rearranged acute myeloid leukemia (AML). Using an AML mouse model driven by a Tet-off inducible MLL-AF9 allele co-expressed with oncogenic NRASG12D, we demonstrated that MLL-AF9 regulates the E protein pathway by suppressing Id2, while activating the expression of its target E2-2. Moreover, we found that Id2 over-expression in MLL-AF9 AML cells results inhibition of leukemia growth, loss of leukemia stem cell-associated gene expression pattern and induction of differentiation. E2-2 silencing phenocopies Id2 overexpression in MLL-AF9-AML cells. To study the gene expression changes associated with E2-2 depletion in the context of MLL-rearranged AML, RNA sequencing analysis was performed on MLL-AF9;NRAS AML cells transduced with vectors expressing hairpins against E2-2 (shTcf4#654 and shTcf4#3646) or a control hairpin against Renilla luciferase (shRen).
Project description:To explore oncogene addiction programs in a genetically defined leukemia context we developed an AML mouse model driven by a conditional MLL-AF9 allele together with oncogenic Ras, which enabled us to examine the consequences of MLL-AF9 inhibition in established disease. In order to produce a tightly regulated system that was easy to monitor, we constructed two retroviral vectors containing dsRed-linked MLL-AF9 under control of a tetracycline response element promoter, and KrasG12D or NrasG12D linked to the “Tet-off” tet-transactivator, which activates TRE expression in a doxycycline repressible manner. Leukemias were generated by retroviral cotransduction of both vectors into hematopoietic stem and progenitor cells, which were transplanted into syngeneic mice. Cells harboring both constructs induced aggressive myelomonocytic leukemia. Five independent primary leukemia cell lines were established from bone marrow of terminal mice. Treatment of these lines with doxycycline rapidly turned off MLL-AF9 expression, and induced terminal myeloid differentiation and complete disease remission in vivo. To identify molecular mechanisms underlying addiction to MLL-AF9, we analyzed global gene expression changes following doxycycline-induced suppression of MLL-AF9. Independent primary acute myeloid leukemia lines induced by cotransduction of Tet-off MLL-AF9 together with either KrasG12D or NrasG12D were grown in culture and treated with doxycycline for 6 days to inactivate MLL-AF9 expression. In addition, primary acute myeloid leukemia lines with constitutive MLL-AF9 and KrasG12D were included to control for the effects of doxycycline. Untreated and treated cells were harvested for RNA extraction and hybridization to Affymetrix arrays.
Project description:We investigated the role of the transcriptional regulator Id2 in the context of MLL-rearranged acute myeloid leukemia (AML). Using an AML mouse model driven by tet-regulated MLL-AF9 co-expressed with oncogenic NRASG12D (Tet-off MLL-AF9), we demonstrated that MLL-AF9 regulates the E protein pathway by suppressing Id2, while activating the expression of its target E2-2. Moreover, we found that Id2 over-expression in Tet-Off MLL-AF9 AML cells in vitro partially phenocopies MLL-AF9 depletion and results inhibition of leukemia growth, loss of leukemia stem cell-associated gene expression pattern and induction of differentiation. To compare gene expression changes associated with enforced Id2 expression and MLL-AF9 withdrawal, RNA sequencing analysis was performed on Tet-off MLL-AF9 cells transduced with an Id2 over-expressing or a control vector, or upon MLL-AF9 dox-inducible knock-down. Primary AMLs driven by Tet-off inducible MLL/AF9 expression linked to dsRED reporter, in association with oncogenic NRASG12D (Tet-off MLL-AF9) were generated by reconstituting lethally irradiated congenic mice with foetal liver cells co-transduced with a Tet-Off-MLL-AF9-dRED retroviral vector and a second vector co-expressing NRASG12D together with the Tet-Off responsive transcriptional activator. RNA sequencing analysis sequencing analysis was performed on Tet-Off MLL-AF9/dsRED+ AML cells treated in vitro with doxycycline (DOX) for 4 days to inactivate MLL-AF9 expression or left untreated (UT). For the Id2 over-expression experiment, Tet-Off MLL-AF9/dsRED+ AML cells were transduced in vitro with an Id2-GFP or a control-GFP retroviral vector. Viable GFP-positive cells were FACS-sorted 2 days after transduction and used for RNA sequencing analysis.
Project description:We investigated the role of the transcriptional regulators Id2 and E2-2 (encoded by Tcf4) in the context of MLL-rearranged acute myeloid leukemia (AML). Using an AML mouse model driven by a Tet-off inducible MLL-AF9 allele co-expressed with oncogenic NRASG12D, we demonstrated that MLL-AF9 regulates the E protein pathway by suppressing Id2, while activating the expression of its target E2-2. Moreover, we found that Id2 over-expression in MLL-AF9 AML cells results inhibition of leukemia growth, loss of leukemia stem cell-associated gene expression pattern and induction of differentiation. E2-2 silencing phenocopies Id2 overexpression in MLL-AF9-AML cells. To study the gene expression changes associated with E2-2 depletion in the context of MLL-rearranged AML, RNA sequencing analysis was performed on MLL-AF9;NRAS AML cells transduced with vectors expressing hairpins against E2-2 (shTcf4#654 and shTcf4#3646) or a control hairpin against Renilla luciferase (shRen). Primary AMLs driven by MLL/AF9 expression linked to cherry reporter, in association with oncogenic NRASG12D (MLL/AF9;NRAS) were generated by reconstituting lethally irradiated congenic mice with fetal liver cells co-transduced with the MSCV-MLL/AF9-IRES-cherry retroviral vector and a second vector co-expressing NRASG12D together with luciferase (MSCV-luciferase-IRES-NRASG12D). RNA sequencing analysis sequencing analysis was performed on MLL-AF9;NRAS AML cells transduced in vitro with vectors expressing hairpins against E2-2 (shTcf4#654 and shTcf4#3646) or a control hairpin against Renilla luciferase (shRen) linked to the reporter GFP. Viable GFP-positive cells were FACS-sorted 2 days after transduction and used for RNA sequencing analysis. Two independent biological replicates of the experiment were used for the RNA sequencing (9-5-14 and 14-4-14).
Project description:Identification of histone acetylation targets of Kat2a activity in murine models of acute myeloid leukemia (AML) driven by the MLL-AF9 oncogenic fusion
Project description:In leukemogenesis Notch signaling can be up- and down-regulated in a context-dependent manner. Here we report that deletion of hairy and enhancer of split-1 (Hes1) promotes acute myeloid leukemia (AML) development induced by the MLL-AF9 fusion protein. Subsequently, the FMS-like tyrosine kinase 3 (FLT3) was up-regulated in mouse cells of a Hes1- or RBP-J-null background. MLL-AF9-expressing Hes1-null AML cells showed enhanced proliferation and ERK phosphorylation following FLT3 ligand stimulation. FLT3 inhibition efficiently abrogated proliferation of MLL-AF9-induced Hes1-null AML cells. Furthermore, an agonistic anti-Notch2 antibody induced apoptosis of MLL-AF9-induced AML cells in a Hes1-wild type but not a Hes1-null background. These observations demonstrate that Hes1 mediates tumor suppressive roles of Notch signaling in AML development by down-regulating FLT3 expression. 4 samples are analyzed, two pairs of MLL-AF9/Hes1-/- and MLL-AF9/Hes1+/+ leukemic bone marrows.