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:Genome wide DNA methylation profiling of leukemia stem, blast cells obtained from 15 AML patients and of normal hematopoietic stem/progenitor cells from 5 normal bone marrow. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across approximately 450,000 CpGs in the samples. Samples included 20 leukemia stem cells, 24 blast cells and 30 normal hematopoietic stem and progenitor cells (6 different types from 5 normal bone marrows).
Project description:The formation of hematopoietic cells relies on the chromatin remodeling activities of ISWI ATPase SMARCA5 (SNF2H) and its complexes. The Smarca5 null and conditional alleles have been used to study its functions in embryonic and organ development in mice. These mouse model phenotypes vary from embryonic lethality of constitutive knockout to less severe phenotypes observed in tissue-specific Smarca5 deletions, e.g., in the hematopoietic system. Here we show that, in a gene dosage-dependent manner, the hypomorphic allele of SMARCA5 (S5tg) can rescue not only the developmental arrest in hematopoiesis in the hCD2iCre model but also the lethal phenotypes associated with constitutive Smarca5 deletion or Vav1iCre-driven conditional knockout in hematopoietic progenitor cells. Interestingly, the latter model also provided evidence for the role of SMARCA5 expression level in hematopoietic stem cells, as the Vav1iCre S5tg animals accumulate stem and progenitor cells. Furthermore, their hematopoietic stem cells exhibited impaired lymphoid lineage entry and differentiation. This observation contrasts with the myeloid lineage which is developing without significant disturbances. Our findings indicate that animals with low expression of SMARCA5 exhibit normal embryonic development with altered lymphoid entry within the hematopoietic stem cell compartment.
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:RNA-Sequencing of 27 functionally validated LSC and blast fractions from 9 AML patients. Three healthy hematopoietic stem and progenitor cells from age-matched controls.
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:Acute myeloid leukemia (AML) is an aggressive hematological disorder comprised of a hierarchy of quiescent leukemic stem cells and fast proliferating blasts with limited self-renewal ability. Significant plasticity in the AML epigenome and metabolome results in a high rate of drug resistance and relapse, with extremely low 2-year survival rates in the poorest cytogenetic risk patients. The current backbone of clinical induction chemotherapy reduces total disease burden, but does not deplete leukemic stem cells which reconstitute the disease in vivo, and also suffers from severe toxicity of healthy hematopoietic cells. Whilst much work has been done to identify epigenetic vulnerabilities in AML, little is known about protein dynamics, and here we explored the therapeutic inhibition of highly specific CKS1-dependent protein degradation. We report a dual role for CKS1-depdent protein degradation in specifically targeting AML, whilst protecting normal hematopoietic cells from chemotherapeutic toxicity.