ABSTRACT: Next Generation Sequencing Facilitates Quantitative Analysis of Bone Marrow Macrophages and Splenic Macrophages Transcriptomes in Mouse MLL-AF9 AML Leukemia
Project description:We investigated the role of the transcriptional regulator Id2 in the context of MLL-rearranged acute myeloid leukemia (AML). Using an Id2/GFP-reporter mouse model of MLL-AF9-driven AML, we showed that Id2 is expressed heterogeneously across the leukemic population. Moreover, differential expression of Id2 and the stemness marker Kit defines subsets of AML cells with different leukemogenic properties with lower levels of Id2 associated with enrichment in leukemia stem cell potential. To define gene expression patterns associated with distinct endogenous levels of Id2 and higher LSC potential, RNA sequencing analysis was performed on FACS-sorted KitHIâId2HI (BM_Kplus-Iplus), KitHIâId2LOW(BM_Kplus-Iminus), KitLOWâId2HI (BM_Kminus-Iplus) and KitLOWâId2LOW (BM_Kminus-Iminus) MLL-AF9-cherry+ AML cells obtained from bone marrow of terminally sick mice. Primary MLL-AF9+ AMLs were generated by reconstituting lethally irradiated congenic mice with foetal liver cells obtained from Id2-GFP reporter mice and transduced with a retroviral vector co-expressing MLL-AF9 and the cherry reporter protein. KitHighâId2High, KitHighâId2Low, KitLowâId2High and KitLowâId2Low MLL-AF9/cherry+ AML cells obtained from bone marrow of terminally sick primary recipients were FACS-sorted and used for RNA sequencing analysis (3 samples/subset).
Project description:The Wnt/beta-catenin pathway is required for the development of leukemia stem cells in MLL-AF9 AML. We evaluated the dependance on beta-catenin for KrasG12DMLL-AF9 leukemia. Lin-Kit+ bone marrow cells obtained from mice transplanted with primary MLL-AF9 leukemia cells and KRasG12DMLL-AF9 leukemia cells were assessed for gene expression in the presence or absence of beta-catenin
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.
Project description:To identify such targets of leukemia-related miRNAs such as miR-196b, we conducted Affymetrix gene arrays of leukemic BM samples from 24 mice including 9 primary (including 3 each of negative control, MLL-AF9, and miR-196b+MLL-AF9) and 15 secondary (including 3 negative control, 6 MLL-AF9, and 6 miR-196b+MLL-AF9) recipient mice A total of 24 mouse bone marrow samples including 9 primary (including 3 each of negative control, MLL-AF9, and miR-196b+MLL-AF9) and 15 secondary (including 3 negative control, 6 MLL-AF9, and 6 miR-196b+MLL-AF9) obtained from the in vivo mouse bone marrow reconstitution assays were analyzed by use of Affymetrix GeneChip Mouse Gene 1.0 ST Array (Affymetirx, Santa Clara, CA)
Project description:To determine role of Notch signaling in AML leukemia initiating cells we used a conditional mouse knock-in model of Notch1-IC to induce Notch1-IC expression in MLL-AF9 transformed LGMP. WT and Notch1-IC+ LGMP were analyzed to determined genes controlled by Notch signaling. 12 weeks old wt lethaly irradiated mice were transplanted with 50000 cKit+ MLL-AF9-IRES-YFP infected cells from MLL-AF9 EF1 wt/wt ROSAwt/CreERT2 or MLL-AF9 EF1 wt/lsl-N1-IC ROSAwt/CreERT2 mice + 250000 support wt total bone marrow cells. 4 weeks after transplant mice were injected 2 times with tamoxifen (0.2mg/g body weight) every other day. Mice were sacrificed and analyzed 6 days after last injection. LGMP were flow purified for RNA extraction and hybridization on Affymetrix microarrays.
Project description:Investigation of the transcriptional profile of MLL-rearranged AML in response to DHODH inhibition by AG636. Chemo-refractory syngeneic murine AML model driven by doxycycline-inducible expression of MLL-AF9 and constitutive expression of oncogenic Nras (MN) was transplanted into Ptprca recipients. Mice bearing MN tumors were treated with doxycycline or AG636 for one or four days. Leukemic stem cells (cKit high; CD11b low) from bone marrow and spleen were isolated and RNA sequencing performed.
Project description:We investigated the role of the transcriptional regulator Id2 in the context of MLL-rearranged acute myeloid leukemia (AML). Using an Id2/GFP-reporter mouse model of MLL-AF9-driven AML, we showed that Id2 is expressed heterogeneously across the leukemic population. Moreover, differential expression of Id2 and the stemness marker Kit defines subsets of AML cells with different leukemogenic properties with lower levels of Id2 associated with enrichment in leukemia stem cell potential. To define gene expression patterns associated with distinct endogenous levels of Id2 and higher LSC potential, RNA sequencing analysis was performed on FACS-sorted KitHI–Id2HI (BM_Kplus-Iplus), KitHI–Id2LOW(BM_Kplus-Iminus), KitLOW–Id2HI (BM_Kminus-Iplus) and KitLOW–Id2LOW (BM_Kminus-Iminus) MLL-AF9-cherry+ AML cells obtained from bone marrow of terminally sick mice.
Project description:In acute myeloid leukemia (AML), malignant cells surviving chemotherapy rely on high mRNA translation and their microenvironmental metabolic support to drive relapse. However, the role of translational reprogramming in the niche is unclear. Here we found that relapsing AML cells increase translation in their bone marrow (BM) niches, where BM mesenchymal stromal cells (BMSCs) become a source of eIF4A-cap-dependent translation machinery that is transferred to AML cells via extracellular vesicles (EVs), to meet their translational demands. In two independent models of highly chemo-resistant AML driven by MLL-AF9 or FLT3-ITD;NPMc mutations, protein synthesis levels increase in refractory AML dependently on nestin+ BMSCs. Inhibiting cap-dependent translation in BMSCs abolishes their chemoprotective ability, while EVs from BMSCs carrying eIF4A boost AML cell translation and survival. Consequently, eIF4A inhibition synergizes with conventional chemotherapy. Together, these results suggest that AML cells rely on BMSCs to maintain an oncogenic translational program required for relapse.
Project description:In acute myeloid leukemia (AML), malignant cells surviving chemotherapy rely on high mRNA translation and their microenvironmental metabolic support to drive relapse. However, the role of translational reprogramming in the niche is unclear. Here we found that relapsing AML cells increase translation in their bone marrow (BM) niches, where BM mesenchymal stromal cells (BMSCs) become a source of eIF4A-cap-dependent translation machinery that is transferred to AML cells via extracellular vesicles (EVs), to meet their translational demands. In two independent models of highly chemo-resistant AML driven by MLL-AF9 or FLT3-ITD;NPMc mutations, protein synthesis levels increase in refractory AML dependently on nestin+ BMSCs. Inhibiting cap-dependent translation in BMSCs abolishes their chemoprotective ability, while EVs from BMSCs carrying eIF4A boost AML cell translation and survival. Consequently, eIF4A inhibition synergizes with conventional chemotherapy. Together, these results suggest that AML cells rely on BMSCs to maintain an oncogenic translational program required for relapse
Project description:The purpose of this study is to investigate the transcriptional programs as it relates to disease latency initiated by different MLL fusion proteins, including: MLL-AF1p, MLL-AF6, MLL-Gas7, MLL-AF9 and MLL-ENL. Leukemia cell lines were established by transforming kit+ mouse bone marrow cells with retroviruses coding MLL-AF1p, MLL-AF6, MLL-Gas7, MLL-AF9 or MLL-ENL. At early phase after the cell lines were established, cells growing at exponential phase (cell density at 0.5~1x106/ml) were harvested for RNA extraction and sequencing purpose. Sequencing is performed on total RNA isolated from mouse leukemia cell lines generated from kit+ mouse bone marrow cells transduced with various MLL fusion proteins and is compared to control total RNA isolated from kit+ mouse bone marrow cells.