| 1. |
- Woll, Petter S, et al.
(författare)
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Myelodysplastic Syndromes Are Propagated by Rare and Distinct Human Cancer Stem Cells In Vivo.
- 2014
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Ingår i: Cancer Cell. - : Elsevier BV. - 1878-3686 .- 1535-6108. ; 25:6, s. 794-808
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Tidskriftsartikel (refereegranskat)abstract
- Evidence for distinct human cancer stem cells (CSCs) remains contentious and the degree to which different cancer cells contribute to propagating malignancies in patients remains unexplored. In low- to intermediate-risk myelodysplastic syndromes (MDS), we establish the existence of rare multipotent MDS stem cells (MDS-SCs), and their hierarchical relationship to lineage-restricted MDS progenitors. All identified somatically acquired genetic lesions were backtracked to distinct MDS-SCs, establishing their distinct MDS-propagating function in vivo. In isolated del(5q)-MDS, acquisition of del(5q) preceded diverse recurrent driver mutations. Sequential analysis in del(5q)-MDS revealed genetic evolution in MDS-SCs and MDS-progenitors prior to leukemic transformation. These findings provide definitive evidence for rare human MDS-SCs in vivo, with extensive implications for the targeting of the cells required and sufficient for MDS-propagation.
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| 2. |
- Adolfsson, Jörgen, et al.
(författare)
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Identification of Flt3(+) lympho-myeloid stem cells lacking erythro-megakaryocytic potential: A revised road map for adult blood lineage commitment
- 2005
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Ingår i: Cell. - : Elsevier (Cell Press). - 0092-8674 .- 1097-4172. ; 121:2, s. 295-306
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Tidskriftsartikel (refereegranskat)abstract
- All blood cell lineages derive from a common hematopoietic stem cell (HSC). The current model implicates that the first lineage commitment step of adult pluripotent HSCs results in a strict separation into common lymphoid and common myeloid precursors. We present evidence for a population of cells which, although sustaining a high proliferative and combined lympho-myeloid differentiation potential, have lost the ability to adopt erythroid and megakaryocyte lineage fates. Cells in the Lin-Sca-1+c-kit+ HSC compartment coexpressing high levels of the tyrosine kinase receptor Flt3 sustain granulocyte, monocyte, and B and T cell potentials but in contrast to Lin-Sca-1(+)ckit(+)Flt3(-) HSCs fail to produce significant erythroid and megakaryocytic progeny. This distinct lineage restriction site is accompanied by downregulation of genes for regulators of erythroid and megakaryocyte development. In agreement with representing a lymphoid primed progenitor, Lin(-)Sca-l(+)c-kit(+)CD34(+)Flt3(+) cells display upregulated IL-7 receptor gene expression. Based on these observations, we propose a revised road map for adult blood lineage development.
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| 3. |
- Anderson, Kristina, et al.
(författare)
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Ectopic expression of PAX5 promotes maintenance of biphenotypic myeloid progenitors coexpressing myeloid and B-cell lineage-associated genes
- 2007
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 109:9, s. 3697-3705
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Tidskriftsartikel (refereegranskat)abstract
- The transcription factor PAX5 is a critical regulator of B-cell commitment and development. Although normally not expressed in myeloid progenitors, PAX5 has recently been shown to be frequently expressed in myeloid malignancies and to suppress expression of myeloid differentiation genes, compatible with an effect on the differentiation or maintenance of myeloid progenitors. However, previous studies in which PAX5 was ectopically expressed in normal myeloid progenitors in vivo and in vitro provided conflicting results as to the effect of PAX5 on myeloid development. Herein, we demonstrate that on ectopic expression of PAX5 in bone marrow multipotent stem/progenitor cells, cells with a biphenotypic B220+GR-1/MAC-1+ phenotype are produced. These remain cytokine-dependent, but unlike control-transduced cells they sustain long-term generation of myeloid progenitors in vitro and remain capable of myeloid differentiation. Notably, PAX5+B220+GR-1/MAC- 1+ myeloid progenitors coexpress, at the single-cell level, myeloid genes and otherwise B-cell-specific PAX5 target genes. These findings establish that ectopic expression of PAX5 introduces extensive self-renewal properties in otherwise short-lived myeloid progenitors. Along with the established ectopic expression of PAX5 in acute myeloid leukemia, this motivates a careful investigation of the potential involvement of ectopic PAX5 expression in myeloid and biphenotypic leukemias. © 2007 by The American Society of Hematology.
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| 4. |
- Anderson, Kristina, et al.
(författare)
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Ectopic expression of PAX5 promotes self renewal of bi-phenotypic myeloid progenitors co-expressing myeloid and B-cell lineage associated genes.
- 2007
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 109:Jan 11, s. 3697-3705
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Tidskriftsartikel (refereegranskat)abstract
- The transcription factor PAX5 is a critical regulator of B-cell commitment and development. Although normally not expressed in myeloid progenitors, PAX5 has recently been shown to be frequently expressed in myeloid malignancies and to suppress expression of myeloid differentiation genes, compatible with an effect on the differentiation or maintenance of myeloid progenitors. However, previous studies in which PAX5 was ectopically expressed in normal myeloid progenitors in vivo and in vitro provided conflicting results as to the effect of PAX5 on myeloid development. Herein, we demonstrate that on ectopic expression of PAX5 in bone marrow multipotent stem/progenitor cells, cells with a biphenotypic B220+GR-1/MAC-1+ phenotype are produced. These remain cytokine-dependent, but unlike control-transduced cells they sustain long-term generation of myeloid progenitors in vitro and remain capable of myeloid differentiation. Notably, PAX5+B220+GR-1/MAC-1+ myeloid progenitors coexpress, at the single-cell level, myeloid genes and otherwise B-cell–specific PAX5 target genes. These findings establish that ectopic expression of PAX5 introduces extensive self-renewal properties in otherwise short-lived myeloid progenitors. Along with the established ectopic expression of PAX5 in acute myeloid leukemia, this motivates a careful investigation of the potential involvement of ectopic PAX5 expression in myeloid and biphenotypic leukemias.
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| 5. |
- Buza-Vidas, Natalija, et al.
(författare)
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Cytokines regulate postnatal hematopoietic stem cell expansion : Opposing roles of thrombopoietin and LNK
- 2006
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Ingår i: Genes & Development. - Woodbury, NY, USA : Cold Spring Harbor Laboratory Press (CSHL). - 0890-9369 .- 1549-5477. ; 20:15, s. 2018-2023
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Tidskriftsartikel (refereegranskat)abstract
- The role of cytokines as regulators of hematopoietic stem cell (HSC) expansion remains elusive. Herein, we identify thrombopoietin (THPO) and the cytokine signaling inhibitor LNK, as opposing physiological regulators of HSC expansion. Lnk(-/-) HSCs continue to expand postnatally, up to 24-fold above normal by 6 mo of age. Within the stem cell compartment, this expansion is highly selective for self-renewing long-term HSCs (LT-HSCs), which show enhanced THPO responsiveness. Lnk(-/-) HSC expansion is dependent on THPO, and 12-wk-old Lnk(-/-)Thpo(-/-) mice have 65-fold fewer LT-HSCs than Lnk(-/-) mice. Expansions of multiple myeloid, but not lymphoid, progenitors in Lnk(-/-) mice also proved THPO-dependent.
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| 6. |
- Castor, Anders, et al.
(författare)
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Distinct patterns of hematopoietic stem cell involvement in acute lymphoblastic leukemia
- 2005
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 11:6, s. 630-637
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Tidskriftsartikel (refereegranskat)abstract
- The cellular targets of primary mutations and malignant transformation remain elusive in most cancers. Here, we show that clinically and genetically different subtypes of acute lymphoblastic leukemia (ALL) originate and transform at distinct stages of hematopoietic development. Primary ETV6-RUNX1 (also known as TEL-AML1) fusions and subsequent leukemic transformations were targeted to committed B-cell progenitors. Major breakpoint BCR-ABL1 fusions (encoding P210 BCR-ABL1) originated in hematopoietic stem cells (HSCs), whereas minor BCR-ABL1 fusions (encoding P190 BCR-ABL1) had a B-cell progenitor origin, suggesting that P190 and P210 BCR-ABL1 ALLs represent largely distinct tumor biological and clinical entities. The transformed leukemia-initiating stem cells in both P190 and P210 BCR-ABL1 ALLs had, as in ETV6-RUNX1 ALLs, a committed B progenitor phenotype. In all patients, normal and leukemic repopulating stem cells could successfully be separated prospectively, and notably, the size of the normal HSC compartment in ETV6-RUNX1 and P190 BCR-ABL1 ALLs was found to be unaffected by the expansive leukemic stem cell population.
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| 7. |
- Fujimoto, T., et al.
(författare)
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Cdk6 blocks myeloid differentiation by interfering with Runx1 DNA binding and Runx1-C/EBP alpha interaction
- 2007
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Ingår i: EMBO Journal. - : Wiley. - 1460-2075 .- 0261-4189. ; 26:9, s. 2361-2370
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Tidskriftsartikel (refereegranskat)abstract
- Interactions between the cell cycle machinery and transcription factors play a central role in coordinating terminal differentiation and proliferation arrest. We here show that cyclin-dependent kinase 6 (Cdk6) is specifically expressed in proliferating hematopoietic progenitor cells, and that Cdk6 inhibits transcriptional activation by Runx1, but not C/ EBP alpha or PU. 1. Cdk6 inhibits Runx1 activity by binding to the runt domain of Runx1, interfering with Runx1 DNA binding and Runx1-C/ EBPa interaction. Cdk6 expression increased myeloid progenitor proliferation, and inhibited myeloid lineage-specific gene expression and terminal differentiation in vitro and in vivo. These effects of Cdk6 did not require Cdk6 kinase activity. Cdk6-mediated inhibition of granulocytic differentiation could be reversed by excess Runx1, consistent with Runx1 being the major target for Cdk6. We propose that Cdk6 downregulation in myeloid progenitors releases Runx1 from Cdk6 inhibition, thereby allowing terminal differentiation. Since Runx transcription factors play central roles in hematopoietic, neuronal and osteogenic lineages, this novel, noncanonical Cdk6 function may control terminal differentiation in multiple tissues and cell types.
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| 8. |
- Giustacchini, Alice, et al.
(författare)
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Single-cell transcriptomics uncovers distinct molecular signatures of stem cells in chronic myeloid leukemia
- 2017
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Ingår i: Nature Medicine. - : NATURE PUBLISHING GROUP. - 1078-8956 .- 1546-170X. ; 23:6, s. 692-
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Tidskriftsartikel (refereegranskat)abstract
- Recent advances in single-cell transcriptomics are ideally placed to unravel intratumoral heterogeneity and selective resistance of cancer stem cell (SC) subpopulations to molecularly targeted cancer therapies. However, current single-cell RNA-sequencing approaches lack the sensitivity required to reliably detect somatic mutations. We developed a method that combines high-sensitivity mutation detection with whole-transcriptome analysis of the same single cell. We applied this technique to analyze more than 2,000 SCs from patients with chronic myeloid leukemia (CML) throughout the disease course, revealing heterogeneity of CML-SCs, including the identification of a subgroup of CML-SCs with a distinct molecular signature that selectively persisted during prolonged therapy. Analysis of nonleukemic SCs from patients with CML also provided new insights into cell-extrinsic disruption of hematopoiesis in CML associated with clinical outcome. Furthermore, we used this single-cell approach to identify a blast-crisis-specific SC population, which was also present in a subclone of CML-SCs during the chronic phase in a patient who subsequently developed blast crisis. This approach, which might be broadly applied to any malignancy, illustrates how single-cell analysis can identify subpopulations of therapy-resistant SCs that are not apparent through cell-population analysis.
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| 9. |
- Kirstetter, Peggy, et al.
(författare)
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Activation of the canonical Wnt pathway leads to loss of hematopoietic stem cell repopulation and multilineage differentiation block
- 2006
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Ingår i: Nature Immunology. - : Springer Science and Business Media LLC. - 1529-2908 .- 1529-2916. ; 7:10, s. 1048-1056
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Tidskriftsartikel (refereegranskat)abstract
- Wnt signaling increases hematopoietic stem cell self-renewal and is activated in both myeloid and lymphoid malignancies, indicating involvement in both normal and malignant hematopoiesis. We report here activated canonical Wnt signaling in the hematopoietic system through conditional expression of a stable form of beta-catenin. This enforced expression led to hematopoietic failure associated with loss of myeloid lineage commitment at the granulocyte-macrophage progenitor stage; blocked erythrocyte differentiation; disruption of lymphoid development; and loss of repopulating stem cell activity. Loss of hematopoietic stem cell function was associated with decreased expression of Cdkn1a ( encoding the cell cycle inhibitor p21(cdk)), Sfpi1, Hoxb4 and Bmi1 ( encoding the transcription factors PU.1, HoxB4 and Bmi-1, respectively) and altered integrin expression in Lin(-)Sca-1(+)c-Kit(+) cells, whereas PU.1 was upregulated in erythroid progenitors. Constitutive activation of canonical Wnt signaling therefore causes multilineage differentiation block and compromised hematopoietic stem cell maintenance.
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| 10. |
- Lee, Benjamin H., et al.
(författare)
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FLT3 mutations confer enhanced proliferation and survival properties to multipotent progenitors in a murine model of chronic myelomonocytic leukemia
- 2007
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Ingår i: Cancer Cell. - : Elsevier BV. - 1878-3686 .- 1535-6108. ; 12:4, s. 367-380
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Tidskriftsartikel (refereegranskat)abstract
- Despite their known transforming properties, the effects of leukemogenic FLT3-ITD mutations on hematopoietic stem and multipotent progenitor cells and on hematopoietic differentiation are not well understood. We report a mouse model harboring an ITD in the murine Flt3 locus that develops myeloproliferative disease resembling CMML and further identified FLT3-ITD mutations in a subset of human CMML. These findings correlated with an increase in number, cell cycling, and survival of multipotent stem and progenitor cells in an ITD dose-dependent manner in animals that exhibited alterations within their myeloid progenitor compartments and a block in normal B cell development. This model provides insights into the consequences of constitutive signaling by an oncogenic tyrosine kinase on hematopoietic progenitor quiescence, function, and cell fate.
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