Project description:The comparative characterization of hematopoietic stem cells from healthy stem cell donors and patients with acute myeloid leukemia on a proteome level has the potential to reveal differentially regulated proteins which might be candidates for specific immunotherapy target molecules. Exemplarily, we analyzed the proteome of the cytosolic and the membrane fraction of CD34 and CD123 co-expressing FACS-sorted leukemic progenitors from five patients with acute myeloid leukemia employing mass spectrometry. As a reference, CD34+CD123+ normal hematopoietic progenitor cells from five healthy stem cell donors were analyzed. In this TMT 10-plex labeling based approach 2068 proteins were identified with 256 proteins differentially regulated in one or both cellular compartments. This study demonstrates the feasibility of a mass spectrometry based proteomic approach to detect differentially expressed proteins in two compartment fractions of leukemic stem cells as compared to their healthy stem cell counterparts.
Project description:This is a mathematical model describing the hematopoietic lineages with leukemia lineages, as controlled by end-product negative feedback inhibition. Variables include hematopoietic stem cells, progenitor cells, terminally differentiated HSCs, leukemia stem cells, and terminally differentiated leukemia stem cells.
Project description:The hematopoietic system is maintained throughout life by hematopoietic stem cells that are capable of differentiation to all hematopoietic lineages. An intimate balance between self-renewal, differentiation, and quiescence is required to maintain hematopoiesis. Disruption of this balance can result in hematopoietic malignancy, including acute myeloid leukemia (AML). FBXO9, from the F-box ubiquitin E3 ligases, is down-regulated in patients with AML compared to normal bone marrow. FBXO9 is a substrate recognition component of the Skp1-Cullin-F-box (SCF)-type E3 ligase complex. FBXO9 is highly expressed in hematopoietic stem and progenitor populations, which contain the tumor-initiating population in AML. In AML patients, decrease in FBXO9 expression is most pronounced in patients with the inversion of chromosome 16 (Inv(16)), a rearrangement that generates the transcription factor fusion gene, CBFB-MYH11. To study FBXO9 in malignant hematopoiesis, we generated a conditional knockout mouse model using a novel CRISPR/Cas9 strategy. Our data shows that deletion of Fbxo9 in mice expressing Cbfb-MYH11 leads to markedly accelerated and aggressive leukemia development. In addition, we find loss of FBXO9 leads to increased proteasome expression and tumors are more sensitive to bortezomib suggesting that FBXO9 expression may predict patient response to bortezomib treatment.
Project description:Data for the manuscript Casirati et al. "Epitope Editing of Hematopoietic Stem Cells Enables Adoptive Immunotherapies for Acute Myeloid Leukemia"
Project description:We applied a novel approach of parallel transcriptional analysis of multiple, highly fractionated stem and progenitor populations from patients with acute myeloid leukemia (AML) and a normal karyotype. We isolated phenotypic long-term HSC (LT-HSC), short-term HSC (ST-HSC), and committed granulocyte-monocyte progenitors (GMP) from individual patients, and measured gene expression profiles of each population, and in comparison to their phenotypic counterparts from age-matched healthy controls. Bone marrow samples from AML patients with normal karyotype and age-matched healthy controls were used in this study. Hematopoietic stem and progenitor compartments were purified by multiparameter-high speed fluorescence-activated cell sorting (FACS) from CD34+ enriched bone marrow to isolate LT-HSC (Lin-/CD34+/CD38-/CD90+), ST-HSC (Lin-/CD34+/CD38-/CD90-), and GMP (Lin-/CD34+/CD38+/CD123+/CD45R+).
Project description:Despite the advanced understanding of disease mechanisms, the current therapeutic regimens fail to cure most patients with acute myeloid leukemia (AML). In the present study, we address the role of protein synthesis control in AML leukemia stem cell (LSC) function and leukemia propagation. We apply a murine model of mixed-lineage leukemia-rearranged AML to demonstrate that LSCs synthesize more proteins per hour compared with the bulk of leukemia. Using a genetic model that permits inducible and graded regulation of ribosomal subunit joining, we show that defective ribosome assembly leads to a significant survival advantage by selectively eradicating LSCs but not normal hematopoietic stem and progenitor cells. Finally, transcriptomic and proteomic analyses identify a rare subset of LSCs with immature stem cell signature and high ribosome content that underlies the resistance to defective ribosome assembly. Collectively, our study unveils a critical requirement of high protein synthesis rate for LSC function, highlighting ribosome assembly as a therapeutic target in AML.
Project description:In an effort to identify novel drugs targeting fusion-oncogene induced acute myeloid leukemia (AML), we performed high-resolution proteomic analysis. In AML1-ETO (AE) driven AML we uncovered a deregulation of phospholipase C (PLC) signaling. We identified PLCgamma 1 (PLCG1) as a specific target of the AE fusion protein which is induced after AE binding to intergenic regulatory DNA elements. Genetic inactivation of PLCG1 in murine and human AML inhibited AML1-ETO dependent self-renewal programs, leukemic proliferation, and leukemia maintenance in vivo. In contrast, PLCG1 was dispensable for normal hematopoietic stem- and progenitor cell function. These findings are extended to and confirmed by pharmacologic perturbation of Ca++-signaling in AML1-ETO AML cells, indicating that the PLCG1 pathway poses an important therapeutic target for AML1-ETO positive leukemic stem cells.
Project description:Hierarchical maintenance of MLL myeloid leukemia stem cells employs a transcriptional program shared with embryonic rather than adult stem cells; 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: Refer to individual Series Experiment Overall Design: This SuperSeries is composed of the following subset Series: Experiment Overall Design: GSE13690: Gene expression profiling of murine MLL leukemias (whole BM) Experiment Overall Design: GSE13692: Expression profiling of MLL-AF10 myeloid leukemia cellular subsets Experiment Overall Design: GSE13693: Gene expression profiling of normal mouse myeloid cell populations
Project description:Acute myeloid leukemia (AML) with rearrangement of the mixed-lineage leukemia (MLL) gene are the most aggressive hematopoietic malignancies. Previous studies demonstrated the distribution of several epigenetic modifications including H3K9me3, H3K79me2, H3K36me3, H3K4me3 and H3K27me3, in MLL-AF9 transformed murine cells. Here, we examined the H3K9me3 distribution in c-Kit+ cells (enriched with stem/progenitor cells) from both MLL-AF9 transformed murine cells in parallel with control wild-type cells, and found an overall lower distribution of H3K9me3 in leukemia stem cells than normal hematopoietic stem/progenitor cells.
Project description:A single hematopoietic stem cell can give rise to all blood cells with remarkable fidelity. Here, we define the chromatin accessibility and transcriptional landscape controlling this process in thirteen primary cell types that traverse the hematopoietic hierarchy. Exploiting the finding that enhancer landscapes better reflect cell identity than mRNA levels, we enable "enhancer cytometry" for accurate enumeration of pure cell types from complex populations. We further reveal the lineage ontogeny of genetic elements linked to diverse human diseases. In acute myeloid leukemia, chromatin accessibility reveals distinctive regulatory evolution in pre-leukemic HSCs (pHSCs), leukemia stem cells, and leukemic blasts. These leukemic cells demonstrate unique lineage infidelity, confirmed by single cell regulomes. We further show that pHSCs have a competitive advantage that is conferred by reduced chromatin accessibility at HOXA9 targets and is associated with adverse patient outcomes. Thus, regulome dynamics can provide diverse insights into human hematopoietic development and disease. Transcription profiles of hematopoietic and leukemic cell types, assayed using unstranded RNA-seq, across 13 normal hematopoietic cell types and 3 acute myeloid leukemia cell types. The complete data set contains a total of 81 samples.