Genome-wide expression analysis of wide-type and PirBTM MLL-AF9 LSCs
Ontology highlight
ABSTRACT: How the stemness of adult stem cells and cancer stem cells is regulated by environmental cues through surface receptors is poorly understood. In this gene expression analysis, we found that, in the mouse MLL-AF9 acute myeloid leukemia (AML) model, a deficiency in intracellular signaling of inhibitory receptor PIR-B resulted in increased differentiation and decreased stemness of leukemia stem cells, revealing that PIR-B supports leukemia development. Our study indicates unexpected functional significance of a classical immune inhibitory receptor in the maintenance of stemness of cancer stem cells. Total RNA obtained from wild-type MLL-AF9 LSCs compared to PirBTM MLL-AF9 LSCs
Project description:How the stemness of adult stem cells and cancer stem cells is regulated by environmental cues through surface receptors is poorly understood. In this gene expression analysis, we found that, in the mouse MLL-AF9 acute myeloid leukemia (AML) model, a deficiency in intracellular signaling of inhibitory receptor PIR-B resulted in increased differentiation and decreased stemness of leukemia stem cells, revealing that PIR-B supports leukemia development. Our study indicates unexpected functional significance of a classical immune inhibitory receptor in the maintenance of stemness of cancer stem cells.
Project description:We performed a liquid chromatography-tandem mass spectrometry analysis of endogenous TWIST1 immunoprecipitates in the LSCs isolated from MLL-AF9-driven AML mice
Project description:Little is known about the roles of Rictor/mTORC2 in the leukemogenesis of AML. Here, we demonstrated that Rictor is essential for the maintenance of MLL-driven leukemia by preventing LSCs from exhaustion. Rictor depletion led to a reactive activation of mTORC1 signaling by facilitating the assembly of mTORC1. Hyperactivated mTORC1 signaling in turn drove LSCs into cycling, compromised the quiescence of LSCs and eventually exhausted their capacity to generate leukemia. At the same time, loss of Rictor had led to a reactive activation of FoxO3a in leukemia cells, which acts as negative feedback to restrain greater over-reactivation of mTORC1 activity and paradoxically protects leukemia cells from exhaustion. Simultaneous depletion of Rictor and FoxO3a enabled rapid exhaustion of MLL LSCs and a quick eradication of MLL leukemia. As such, our present findings highlighted a pivotal regulatory axis of Rictor-FoxO3a in maintaining quiescence and the stemness of LSCs. To understand the critical molecular events caused by Rictor loss in MLL-AF9-driven leukemia,the K+Gâ mice BM cells were sorted from the 1st BMT of RictorÎ/Î(MA9_R1,MA9_R2,MA9_R3) or control(MA9_C1,MA9_C2,MA9_C3), and subjected to microarray analysis on Affymetrix microarrays.Furthermore, the MLL-NRIP3-driven mice model was chosen for further examination.The K+Gâ mice BM cells were sorted from the 1st BMT of RictorÎ/Î(MN3_R1,MN3_R2,MN3_R3) or control(MN3_C1,MN3_C2,MN3_C3), and subjected to microarray analysis on Affymetrix microarrays.
Project description:By RNA-sequencing, we compared WT vs ST2 knockout leukemia stem cells (LSCs) from the bone marrow of ST2flox/flox and ST2flox/flox Mx1Cre MLL-AF9 LSCs, and found that ST2 deficiency in LSCs reprogramme the oncogenic, metabolic and cell cycle signatures which correlated with reduced leukemogenesis and maintenance.
Project description:Through targeted metabolomics analysis of bulk leukemia cells and leukemia stem cells (LSCs) derived from the MLL-AF9-driven acute myeloid leukemia (AML) model, in comparison with normal granulocyte-monocyte progenitor (GMP) cells and whole bone marrow (WBM) cells from normal mice, we identified enhanced purine metabolism in AML LSCs. Pharmacological targeting of the purine metabolism using mycophenolate mofetil (MMF) resulted in decreased levels of purine metabolites crucial for nucleolus rRNA synthesis. Importantly, inhibition of purine metabolism or disruption of the nucleolus rRNA synthesis, achieved by inhibiting pol I activity with CX-5461, triggered myeloid differentiation in the MLL-AF9-driven AML LSCs. These findings unveil a regulatory axis involving purine metabolism and nucleolar rRNA synthesis in maintaining AML LSC activity.
Project description:The genetic programs that promote retention of self-renewing leukemia stem cells (LSCs) at the apex of cellular hierarchies in acute myeloid leukemia (AML) are not known. In a mouse model of human AML, LSCs exhibit variable frequencies that correlate with the initiating MLL oncogene and are maintained in a self-renewing state by a transcriptional sub-program more akin to that of embryonic stem cells (ESCs) than adult stem cells. The transcription/chromatin regulatory factors Myb, Hmgb3 and Cbx5 are critical components of the program and suffice for Hoxa/Meis-independent immortalization of myeloid progenitors when co-expressed, establishing the cooperative and essential role of an ESC-like LSC maintenance program ancillary to the leukemia initiating MLL/Hox/Meis program. Enriched expression of LSC maintenance and ESC-like program genes in normal myeloid progenitors and poor prognosis human malignancies links the frequency of aberrantly self-renewing progenitor-like cancer stem cells to prognosis in human cancer. Experiment Overall Design: Samples are from five separate cohorts of mice where leukemia was initiated using distinct MLL fusion oncogenes: MLL-AF1p (n=9), MLL-AF10 (n=8), MLL-GAS7 (n=5), MLL-AF9 (n=5) and MLL-ENL (n=7). Four normal BM samples were also used as controls.
Project description:Using BCR-ABL-induced chronic myeloid leukemia (CML) as a disease model for leukemia stem cells (LSCs), we showed that BCR-ABL down-regulates the B lymphoid kinase (Blk) gene in leukemia stem cells in CML mice and that Blk functions as a tumor suppressor in LSCs and suppresses LSC function. Inhibition of this Blk pathway accelerates CML development, whereas increased activity of the Blk pathway delays CML development. To identify the pathways in which Blk regulates function of LSCs, we performed a comparative DNA microarray analysis using total RNA isolated from non-BCR-ABL-expressing Lin-Sca-1+c-Kit+, BCR-ABL- and BCR-ABL-Blk expressing LSCs. This analysis revealed a large group of candidate genes that exhibited changes in the levels of transcription in the Blk expressing LSCs, and uncovered the molecular mechanisms by which Blk suppresses LSCs and CML development. Bone marrow cells were transduced with GFP, BCR-ABL-GFP or BCR-ABL-Blk-GFP, followed by transplantation into recipient mice. Fourteen days after transplantation, bone marrow cells were isolated and LSCs were sorted by FACS for isolation of total RNA for DNA microarray analysis.
Project description:Using a mouse model of chronic myelogenous leukemia (CML), here we report that HIF1M-NM-1 plays a crucial role in survival maintenance of leukemia stem cells (LSCs). Deletion of HIF1M-NM-1 impairs the propagation of CML through impairing cell cycle progression and inducing apoptosis of LSCs. Deletion of HIF1M-NM-1 results in elevated expression of p16Ink4a and p19Arf in LSCs, and knockdown of p16Ink4a and p19Arf rescues the defective colony-forming ability of HIF1M-NM-1-/- LSCs. To further identify the pathways in which Hif1a regulates function of LSCs, we performed a comparative DNA microarray analysis using total RNA isolated from BCR-ABL-expressing wild type LSCs and BCR-ABL-expressing Hif1a-/- LSCs. The result was validated by quantitative real-time PCR analysis of non-BCR-ABL-expressing Lin-Sca-1+c-Kit+ cells, BCR-ABL-expressing wild type LSCs, and BCR-ABL-expressing Hif1a-/- LSCs. To identify genes that are regulated by BCR-ABL in LSCs and LSCs without the Hif1a gene, we compared the gene profile between wild type (WT) LSCs and Hif1a-/- LSCs.
Project description:Acute myeloid leukemia (AML) is initiated and propagated by leukemia stem cells (LSCs), a self-renewing population of leukemia cells. Here we performed an in vivo CRISPR screen and identified the facilitated glucose transporter type 1 (GLUT1) as a critical metabolic dependency for murine MLL::AF9 LSCs. GLUT1 disruption by genetic ablation or by pharmacological inhibition with BAY-876 led to suppression of leukemia progression and improved survival in an MLL::AF9 mouse model of AML. Glut1 inhibition further resulted in glycolytic suppression, decreased levels of tricarboxylic cycle intermediates, and elevated levels of amino acids. These changes in metabolic profile coincided with increased autophagic activity and differentiation of AML cells. Notably, dual inhibition of GLUT1 and oxidative phosphorylation exhibited synergistic anti-leukemic effects in human AML cells. Collectively, these findings increase our understanding of how murine LSCs are metabolically regulated and highlight GLUT1 inhibition as a promising therapeutic adjuvant approach in AML.
Project description:Using BCR-ABL-induced chronic myeloid leukemia (CML) as a disease model for leukemia stem cells (LSCs), we showed that BCR-ABL down-regulates the B lymphoid kinase (Blk) gene in leukemia stem cells in CML mice and that Blk functions as a tumor suppressor in LSCs and suppresses LSC function. Inhibition of this Blk pathway accelerates CML development, whereas increased activity of the Blk pathway delays CML development. To identify the pathways in which Blk regulates function of LSCs, we performed a comparative DNA microarray analysis using total RNA isolated from non-BCR-ABL-expressing Lin-Sca-1+c-Kit+, BCR-ABL- and BCR-ABL-Blk expressing LSCs. This analysis revealed a large group of candidate genes that exhibited changes in the levels of transcription in the Blk expressing LSCs, and uncovered the molecular mechanisms by which Blk suppresses LSCs and CML development.