Expression of meningioma 1 (MN1) has been proposed to be a negative prognostic molecular marker in adult AML with normal cytogenetics, however its role in pediatric leukemia is unknown. We found elevated MN1 expression in 53 of 88 pediatric leukemia cases: significant amounts of MN1 were found in immature B-cell ALL and most cases of infant leukemia but no MN1 expression was detected in T-cell acute lymphoblastic leukemia (T-ALL). Interestingly 17 of 19 cases harboring MLL-X fusions showed also elevated MN1 expression. Lentiviral siRNA mediated MN1 knock-down resulted in cell cycle arrest and impaired clonogenic growth of 3 MLL-X-positive human leukemia cell lines overexpressing MN1 (THP-1, RS4;11, MOLM13). In a mouse MLL/ENL-induced leukemia MN1 overexpression resulted from retroviral provirus insertion. Strikingly co-expression of MN1 with MLL/ENL resulted in significantly reduced latency for induction of an AML phenotype in mice suggesting functional cooperation. MN1 overexpression in MLL/ENL-carrying cells resulted in expansion of the L-GMP population and facilitated disease induction in secondary recipients. Gene expression profiling allowed to define a number of potential MN1 hematopoietic targets. Up-regulation of CD34, FLT3, HLF, or DLK1 was validated in bone marrow transiently overexpressing MN1, in MN1-induced mouse leukemias, as well as in some cases of pediatric leukemias overexpressing MN1. Taken together, our work suggests that MN1 overexpression is essential for growth of leukemic cells, and that MN1 can act as a cooperating oncogene with MLL-X fusion genes most probably through modification of a distinct gene expression program that leads to expansion of a leukemia initiating cell population.
Functional characterization of high levels of meningioma 1 as collaborating oncogene in acute leukemia.
No sample metadata fields
View SamplesEstrogens are potential regulators of the hematopoietic stem cell (HSC) niche and have effects on mature hematopoietic cells; however, whether estrogen signaling directly regulates normal and malignant HSC remains unclear. We demonstrate differential expression and specific roles of estrogen receptors (ER) in hematopoietic progenitors. ERa activation in short-term HSC and multipotent progenitors induced apoptosis. In contrast, the selective ER modulator (SERM) tamoxifen induced proliferation of quiescent long-term HSC, altered their self-renewal signature and compromised hematopoietic reconstitution following myelotoxic stress. Treatment with tamoxifen alone abolished hematopoietic progenitor expansion induced by JAK2V617F by restoring normal levels of apoptosis, blocked JAK2V617F-induced myeloproliferative neoplasm in vivo, and sensitized MLL-AF9+ leukemias to chemotherapy. Tamoxifen showed selective effects on mutant cells compared to normal ones, and had only a minor impact on steady-state hematopoiesis in disease-free animals. These results uncover specific regulation of hematopoietic progenitors by estrogens and potential anti-leukemic properties of SERM Overall design: LT-HSCs, ST-HSCs and MPPs sorted from the bone marrow of mice treated with tamoxifen or vehicle (3 biological replicates per group)
Estrogen signaling selectively induces apoptosis of hematopoietic progenitors and myeloid neoplasms without harming steady-state hematopoiesis.
No sample metadata fields
View SamplesWe have cloned and characterized a fusion gene NUP98/HHEX1 resulting from t(7;10) from a patient with acute myeloid leukemia (AML). As NUP98/HHEX acts as an aberrant transcriptional activator, putative targets were searched upon transient expression of the fusion in primary murine bone marrow cells.
Leukemogenic mechanisms and targets of a NUP98/HHEX fusion in acute myeloid leukemia.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Neuropathy of haematopoietic stem cell niche is essential for myeloproliferative neoplasms.
Specimen part
View SamplesMyeloproliferative neoplasms (MPNs) are diseases caused by mutations in the haematopoietic stem cell (HSC) compartment. Most MPN patients have a common acquired mutation of Janus kinase 2 (JAK2) gene in HSCs that renders this kinase constitutively active, leading to uncontrolled cell expansion. The bone marrow (BM) microenvironment might contribute to the clinical outcomes of this common event. We previously showed that BM nestin+ mesenchymal stem cells (MSCs) innervated by sympathetic nerve fibres regulate normal HSCs. Here we demonstrate that abrogation of this regulatory circuit is essential for MPN pathogenesis. Sympathetic nerve fibres, supporting Schwann cells and nestin+ MSCs are consistently reduced in the BM of MPN patients and mice expressing the human JAK2V617F mutation in HSCs. Unexpectedly, MSC reduction is not due to differentiation but is caused by BM neural damage and Schwann cell death triggered by interleukin-1b produced by mutant HSCs. In turn, in vivo depletion of nestin+ cells or their production of CXCL12 expanded mutant HSCs and accelerated MPN progression. In contrast, administration of neuroprotective or sympathomimetic drugs prevented mutant HSC expansion. Treatment with b3-adrenergic agonists that restored the sympathetic regulation of nestin+ MSCs prevented the loss of these cells and blocked MPN progression by indirectly reducing leukaemic stem cells. Our results demonstrate that mutant HSC-driven niche damage critically contributes to disease manifestation in MPN and identify niche-forming MSCs and their neural regulation as promising therapeutic targets.
Neuropathy of haematopoietic stem cell niche is essential for myeloproliferative neoplasms.
Specimen part
View SamplesMyeloproliferative neoplasms (MPNs) are diseases caused by mutations in the haematopoietic stem cell (HSC) compartment. Most MPN patients have a common acquired mutation of Janus kinase 2 (JAK2) gene in HSCs that renders this kinase constitutively active, leading to uncontrolled cell expansion. The bone marrow (BM) microenvironment might contribute to the clinical outcomes of this common event. We previously showed that BM nestin+ mesenchymal stem cells (MSCs) innervated by sympathetic nerve fibres regulate normal HSCs. Here we demonstrate that abrogation of this regulatory circuit is essential for MPN pathogenesis. Sympathetic nerve fibres, supporting Schwann cells and nestin+ MSCs are consistently reduced in the BM of MPN patients and mice expressing the human JAK2V617F mutation in HSCs. Unexpectedly, MSC reduction is not due to differentiation but is caused by BM neural damage and Schwann cell death triggered by interleukin-1b produced by mutant HSCs. In turn, in vivo depletion of nestin+ cells or their production of CXCL12 expanded mutant HSCs and accelerated MPN progression. In contrast, administration of neuroprotective or sympathomimetic drugs prevented mutant HSC expansion. Treatment with b3-adrenergic agonists that restored the sympathetic regulation of nestin+ MSCs prevented the loss of these cells and blocked MPN progression by indirectly reducing leukaemic stem cells. Our results demonstrate that mutant HSC-driven niche damage critically contributes to disease manifestation in MPN and identify niche-forming MSCs and their neural regulation as promising therapeutic targets. Overall design: CD45- CD31- Ter119- GFP+ cells were sorted from the BM of Nes-gfp;Mx1-cre;JAK2-V617F mice and control littermates 6 weeks after pIpC treatment and were subjected to RNA sequencing. Each sample was pooled from 3 animals of the same genotype.
Neuropathy of haematopoietic stem cell niche is essential for myeloproliferative neoplasms.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
MLL-AF9 Expression in Hematopoietic Stem Cells Drives a Highly Invasive AML Expressing EMT-Related Genes Linked to Poor Outcome.
Specimen part
View SamplesTo address the impact of cellular origin on AML, we generated an inducible transgenic mouse model for MLL-AF9 driven leukemia. MLL-AF9 expression in long-term hematopoietic stem cells (LT-HSCs) in vitro resulted in unprecedented clonogenic growth and expression of genes involved in migration and invasion. In vivo, some LT-HSC-derived AMLs were particularly aggressive with extensive tissue infiltration, chemo-resistance and expression of genes related to epithelial-mesenchymal transition (EMT) in solid cancers. Knockdown of the EMT regulators Zeb1 and Tcf4 significantly reduced leukemic blast invasion. By classifying mouse and human leukemia according to Evi1/EVI1and Erg/ERG expression, reflecting aggressiveness and cell-of-origin and performing comparative transcriptomics we identified numerous EMT-related genes that were significantly associated with poor overall survival of AML patients. Overall design: RNA from FACS sorted bone marrow subpopulations was isolated, RNA-sequencing libraries were prepared and sequenced on an Illumina HiSeq 2000. Reads mapping to RefSeq transcripts were counted.
MLL-AF9 Expression in Hematopoietic Stem Cells Drives a Highly Invasive AML Expressing EMT-Related Genes Linked to Poor Outcome.
No sample metadata fields
View SamplesTo address the impact of cellular origin on AML, we generated an inducible transgenic mouse model for MLL-AF9 driven leukemia. MLL-AF9 expression in long-term hematopoietic stem cells (LT-HSCs) in vitro resulted in unprecedented clonogenic growth and expression of genes involved in migration and invasion. In vivo, some LT-HSC-derived AMLs were particularly aggressive with extensive tissue infiltration, chemo-resistance and expression of genes related to epithelial-mesenchymal transition (EMT) in solid cancers. Knockdown of the EMT regulators Zeb1 and Tcf4 significantly reduced leukemic blast invasion. By classifying mouse and human leukemia according to Evi1/EVI1and Erg/ERG expression, reflecting aggressiveness and cell-of-origin and performing comparative transcriptomics we identified numerous EMT-related genes that were significantly associated with poor overall survival of AML patients.
MLL-AF9 Expression in Hematopoietic Stem Cells Drives a Highly Invasive AML Expressing EMT-Related Genes Linked to Poor Outcome.
Specimen part
View SamplesGene expression upon DOT1L inhibition, or Menin inhibition, or a combination of DOT1L and Menin inhibiting agents, was assessed in several MLL-rearranged human cell lines and a mouse model of MLL-AF9 leukemia.
Complementary activities of DOT1L and Menin inhibitors in MLL-rearranged leukemia.
Cell line
View Samples