Activation or maintenance of a leukemia stem cell self-renewal pathway in downstream myeloid cells
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ABSTRACT: Activation or maintenance of a leukemia stem cell self-renewal pathway in downstream myeloid cells is an important component of AML development We generated either MLL-AF9 mediated murine leukemias that originate from committed progenitor (GMP) cells or Hoxa9/Meis1a mediated murine leukemias that originate from hematopoietic stem cells (HSC). The leukemia stem cell fraction in these two type of leukemias shared a common self-renewal pathway with normal hematopoietic stem cells. Keywords: Cell type comparison Total RNA from HSC (KLS), CMP, and GMP, and from leukemia stem cells (LGMP) was isolated and hybridized to Affymetrix expresison microarrays.
Project description:We generated MLL-AF9 mediated murine leukemias that originate either from hematopoietic stem or committed progenitors cells. The luekemia stem cell fraction in these two type of leukemias shared exactly the same immunophenotype but their genetic programs differ. Total RNA from HSC(KLS), CMP, MEP, and GMP, and from leukemia stem cells (LGMP) was isolated and hybridized to Affymetrix expresison microarrays.
Project description:Activation or maintenance of a leukemia stem cell self-renewal pathway in downstream myeloid cells is an important component of AML development We generated either MLL-AF9 mediated murine leukemias that originate from committed progenitor (GMP) cells or Hoxa9/Meis1a mediated murine leukemias that originate from hematopoietic stem cells (HSC). The leukemia stem cell fraction in these two type of leukemias shared a common self-renewal pathway with normal hematopoietic stem cells. Keywords: Cell type comparison
Project description:Leukemias and other cancers possess a rare population of cells capable of self-renewal, and eradication of these cancer stem cells is likely necessary for long-term cancer-free survival. Given that both normal and cancer stem cells are capable of self-renewal the extent to which cancer stem cells resemble normal tissue stem cells is a critical issue if targeted therapies are to be developed. We introduced the MLL-AF9 fusion protein encoded by the t(9;11)(p22;q23) found in human acute myelogenous leukemia (AML) into murine committed granulocyte-macrophage progenitors (GMP). The resultant leukemias contained cells with an immunophenotype similar to normal GMP that were highly enriched for leukemia stem cells (LSC). Detailed gene expression comparisons between normal hematopoietic stem cells (HSC), committed progenitors, and the LSC population demonstrated the LSC were globally more similar to the normal GMP than any other population. However, a subset of genes highly expressed in normal stem cells was re-activated in the LSC. These data demonstrate LSC can be generated from committed progenitors without widespread reprogramming of gene expression, and a leukemia self-renewal associated signature is activated in the process. Our findings define progression from normal hematopoietic progenitor to leukemia stem cell, and suggest that targeting a self-renewal program expressed in an abnormal context may be possible. Experiment Overall Design: RNA from normal GMP, GMP-like cells isolated from leukemic bone marrow (LGMP) and cells derived from the in vitro propagation of LGMP were hybridized to affymetrix microarrays.
Project description:MLL-fusion proteins can induce acute myeloid leukemias (AML) from either hematopoietic stem cells (HSC) or granulocyte macrophage progenitors (GMP), but it remains unclear if the cell of origin influences the biology of the resultant leukemia. MLL-AF9 transduced single HSC or GMP could be continuously replated, but HSC-derived clones were more likely than GMP-derived clones to initiate AML in mice. Leukemia stem cells derived from either HSC or GMP had a similar immunophenotype consistent with a maturing myeloid cell (LGMP). Gene expression analyses demonstrated that LGMP inherited gene expression programs from the cell of origin including high-level Evi-1 expression in HSC derived LGMP. The gene expression signature of LGMP derived from HSC was enriched in poor prognosis human MLL-rearranged AML in three independent data sets. Moreover, global 5’-mC levels were elevated in HSC-derived leukemias as compared to GMP-derived leukemias. This mirrored a difference seen in 5-mC between MLL-rearranged human leukemias that are either EVI1-positive or EVI1-negative. Finally, HSC derived leukemias were more resistant to chemotherapy than GMP-derived leukemias. These data demonstrate that the cell of origin influences the gene expression profile, the epigenetic state, and the drug response in AML, and that these differences can account for clinical heterogeneity within a molecularly defined group of leukemias.
Project description:MLL-fusion proteins can induce acute myeloid leukemias (AML) from either hematopoietic stem cells (HSC) or granulocyte macrophage progenitors (GMP), but it remains unclear if the cell of origin influences the biology of the resultant leukemia. MLL-AF9 transduced single HSC or GMP could be continuously replated, but HSC-derived clones were more likely than GMP-derived clones to initiate AML in mice. Leukemia stem cells derived from either HSC or GMP had a similar immunophenotype consistent with a maturing myeloid cell (LGMP). Gene expression analyses demonstrated that LGMP inherited gene expression programs from the cell of origin including high-level Evi-1 expression in HSC derived LGMP. The gene expression signature of LGMP derived from HSC was enriched in poor prognosis human MLL-rearranged AML in three independent data sets. Moreover, global 5’-mC levels were elevated in HSC-derived leukemias as compared to GMP-derived leukemias. This mirrored a difference seen in 5-mC between MLL-rearranged human leukemias that are either EVI1-positive or EVI1-negative. Finally, HSC derived leukemias were more resistant to chemotherapy than GMP-derived leukemias. These data demonstrate that the cell of origin influences the gene expression profile, the epigenetic state, and the drug response in AML, and that these differences can account for clinical heterogeneity within a molecularly defined group of leukemias. Differential DNA methylation between of LSC isolated from murine HSC and GMP derived AMLs
Project description:Leukemias and other cancers possess a rare population of cells capable of self-renewal, and eradication of these cancer stem cells is likely necessary for long-term cancer-free survival. Given that both normal and cancer stem cells are capable of self-renewal the extent to which cancer stem cells resemble normal tissue stem cells is a critical issue if targeted therapies are to be developed. We introduced the MLL-AF9 fusion protein encoded by the t(9;11)(p22;q23) found in human acute myelogenous leukemia (AML) into murine committed granulocyte-macrophage progenitors (GMP). The resultant leukemias contained cells with an immunophenotype similar to normal GMP that were highly enriched for leukemia stem cells (LSC). Detailed gene expression comparisons between normal hematopoietic stem cells (HSC), committed progenitors, and the LSC population demonstrated the LSC were globally more similar to the normal GMP than any other population. However, a subset of genes highly expressed in normal stem cells was re-activated in the LSC. These data demonstrate LSC can be generated from committed progenitors without widespread reprogramming of gene expression, and a leukemia self-renewal associated signature is activated in the process. Our findings define progression from normal hematopoietic progenitor to leukemia stem cell, and suggest that targeting a self-renewal program expressed in an abnormal context may be possible. Experiment Overall Design: A normal HSC enriched population, common myeloid progenitors, granulocyte macrophage progenitors, megakaryocyte progenitors, and leukemia stem cells (leukemic-GMP) were isolated and labeled RNA was hybridzed to Affymetrix microarrays
Project description:Leukemias and other cancers possess a rare population of cells capable of self-renewal, and eradication of these cancer stem cells is likely necessary for long-term cancer-free survival. Given that both normal and cancer stem cells are capable of self-renewal the extent to which cancer stem cells resemble normal tissue stem cells is a critical issue if targeted therapies are to be developed. We introduced the MLL-AF9 fusion protein encoded by the t(9;11)(p22;q23) found in human acute myelogenous leukemia (AML) into murine committed granulocyte-macrophage progenitors (GMP). The resultant leukemias contained cells with an immunophenotype similar to normal GMP that were highly enriched for leukemia stem cells (LSC). Detailed gene expression comparisons between normal hematopoietic stem cells (HSC), committed progenitors, and the LSC population demonstrated the LSC were globally more similar to the normal GMP than any other population. However, a subset of genes highly expressed in normal stem cells was re-activated in the LSC. These data demonstrate LSC can be generated from committed progenitors without widespread reprogramming of gene expression, and a leukemia self-renewal associated signature is activated in the process. Our findings define progression from normal hematopoietic progenitor to leukemia stem cell, and suggest that targeting a self-renewal program expressed in an abnormal context may be possible. Experiment Overall Design: This reference series is composed of two noncomparable experiments (RNA was amplified on different days): Experiment Overall Design: GSE3721 Experiment Overall Design: GSE3722
Project description:Leukemias and other cancers possess a rare population of cells capable of self-renewal, and eradication of these cancer stem cells is likely necessary for long-term cancer-free survival. Given that both normal and cancer stem cells are capable of self-renewal the extent to which cancer stem cells resemble normal tissue stem cells is a critical issue if targeted therapies are to be developed. We introduced the MLL-AF9 fusion protein encoded by the t(9;11)(p22;q23) found in human acute myelogenous leukemia (AML) into murine committed granulocyte-macrophage progenitors (GMP). The resultant leukemias contained cells with an immunophenotype similar to normal GMP that were highly enriched for leukemia stem cells (LSC). Detailed gene expression comparisons between normal hematopoietic stem cells (HSC), committed progenitors, and the LSC population demonstrated the LSC were globally more similar to the normal GMP than any other population. However, a subset of genes highly expressed in normal stem cells was re-activated in the LSC. These data demonstrate LSC can be generated from committed progenitors without widespread reprogramming of gene expression, and a leukemia self-renewal associated signature is activated in the process. Our findings define progression from normal hematopoietic progenitor to leukemia stem cell, and suggest that targeting a self-renewal program expressed in an abnormal context may be possible. Experiment Overall Design: isolated granulocyte macrophage progenitors were incubated with a retrovirus that expressed either GFP or MLL-AF9 and GFP. Forty hours later, the GFP positive cells were isolated and RNA was hybrided to Affymetrix microarrays. The experiment was repeated three times.
Project description:Leukemias and other cancers possess a rare population of cells capable of self-renewal, and eradication of these cancer stem cells is likely necessary for long-term cancer-free survival. Given that both normal and cancer stem cells are capable of self-renewal the extent to which cancer stem cells resemble normal tissue stem cells is a critical issue if targeted therapies are to be developed. We introduced the MLL-AF9 fusion protein encoded by the t(9;11)(p22;q23) found in human acute myelogenous leukemia (AML) into murine committed granulocyte-macrophage progenitors (GMP). The resultant leukemias contained cells with an immunophenotype similar to normal GMP that were highly enriched for leukemia stem cells (LSC). Detailed gene expression comparisons between normal hematopoietic stem cells (HSC), committed progenitors, and the LSC population demonstrated the LSC were globally more similar to the normal GMP than any other population. However, a subset of genes highly expressed in normal stem cells was re-activated in the LSC. These data demonstrate LSC can be generated from committed progenitors without widespread reprogramming of gene expression, and a leukemia self-renewal associated signature is activated in the process. Our findings define progression from normal hematopoietic progenitor to leukemia stem cell, and suggest that targeting a self-renewal program expressed in an abnormal context may be possible. Keywords: MLL, stem cells, leukemia stem cells
Project description:Leukemias and other cancers possess a rare population of cells capable of self-renewal, and eradication of these cancer stem cells is likely necessary for long-term cancer-free survival. Given that both normal and cancer stem cells are capable of self-renewal the extent to which cancer stem cells resemble normal tissue stem cells is a critical issue if targeted therapies are to be developed. We introduced the MLL-AF9 fusion protein encoded by the t(9;11)(p22;q23) found in human acute myelogenous leukemia (AML) into murine committed granulocyte-macrophage progenitors (GMP). The resultant leukemias contained cells with an immunophenotype similar to normal GMP that were highly enriched for leukemia stem cells (LSC). Detailed gene expression comparisons between normal hematopoietic stem cells (HSC), committed progenitors, and the LSC population demonstrated the LSC were globally more similar to the normal GMP than any other population. However, a subset of genes highly expressed in normal stem cells was re-activated in the LSC. These data demonstrate LSC can be generated from committed progenitors without widespread reprogramming of gene expression, and a leukemia self-renewal associated signature is activated in the process. Our findings define progression from normal hematopoietic progenitor to leukemia stem cell, and suggest that targeting a self-renewal program expressed in an abnormal context may be possible. Keywords: MLL, stem cells, leukemia stem cells