Casirati et al. Epitope Editing of Hematopoietic Stem Cells
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ABSTRACT: Data for the manuscript Casirati et al. "Epitope Editing of Hematopoietic Stem Cells Enables Adoptive Immunotherapies for Acute Myeloid Leukemia"
Project description:A Scalable Epitope Tagging Approach for High Throughput ChIP-seq Analysis ChIP-seq comparison between CRISPR editing cells using epitope antibody and non-editing cells using endogeneous TF antibody
Project description:To analyze the prognostic relevance of transcriptional profiling in adult T-ALL, we analyzed a clinical series of 53 primary leukemia samples uniformly treated according to the ECOG E2993 protocol using gene expression oligonucleotide microarrays. Unsupervised analysis and consensus clustering of microarray gene expression data in this series revealed the presence of 2 stable gene expression clusters corresponding to early immature (n = 28) and cortical/mature (n = 25) adult T-ALLs respectively. Early immature T-ALLs show a gene expression signature related to hematopoietic stem cells and myeloid progenitors that was recently linked to a group of childhood T-ALLs with poor prognosis. Notably, univariate analysis in our patient series confirmed that early immature adult T-ALL is associated with poor prognosis and reduced overall survival compared with cortical/mature adult T-ALL (P = 0.0197) 53 adult T-ALL samples were analyzed
Project description:Chromatin organization is a highly orchestrated process that influences gene expression, in part by modulating access of regulatory factors to DNA and nucleosomes. We found that the chromatin accessibility regulator HMGN1, a target of recurrent DNA copy gains in leukemia, controls myeloid differentiation. HMGN1 amplification was associated with increased accessibility, expression, and histone H3K27 acetylation of loci important for hematopoietic stem cell (HSC) function and AML, such as HoxA cluster genes. In vivo, HMGN1 overexpression was linked to decreased quiescence and increased HSC activity in bone marrow transplantation. HMGN1 overexpression also cooperated with the AML-ETO9a fusion oncoprotein to impair myeloid differentiation and enhance leukemia stem cell (LSC) activity. Inhibition of histone acetyltransferases CBP/p300 relieved the HMGN1-associated differentiation block. These data nominate factors that modulate chromatin accessibility as regulators of HSCs and LSCs and suggest that targeting HMGN1 or its downstream effects on histone acetylation could be therapeutically active in AML.
Project description:To analyze the prognostic relevance of transcriptional profiling in adult T-ALL, we analyzed a clinical series of 53 primary leukemia samples uniformly treated according to the ECOG E2993 protocol using gene expression oligonucleotide microarrays. Unsupervised analysis and consensus clustering of microarray gene expression data in this series revealed the presence of 2 stable gene expression clusters corresponding to early immature (n = 28) and cortical/mature (n = 25) adult T-ALLs respectively. Early immature T-ALLs show a gene expression signature related to hematopoietic stem cells and myeloid progenitors that was recently linked to a group of childhood T-ALLs with poor prognosis. Notably, univariate analysis in our patient series confirmed that early immature adult T-ALL is associated with poor prognosis and reduced overall survival compared with cortical/mature adult T-ALL (P = 0.0197)
Project description:Leukemia initiating cells (LICs) of acute myeloid leukemia (AML) may arise from self-renewing hematopoietic stem cells (HSCs) and from committed progenitors. However, it remains unclear how leukemia-associated oncogenes instruct LIC formation from cells of different origins and if differentiation along the normal hematopoietic hierarchy is involved. Here, using murine models with the driver mutations MLL-AF9 or MOZ-TIF2, we found that regardless of the transformed cell types, myelomonocytic differentiation to the granulocyte macrophage progenitor (GMP) stage is critical for LIC generation. Blocking myeloid differentiation through disrupting the lineage-restricted transcription factor C/EBPa eliminates GMPs, blocks normal granulopoiesis, and prevents AML development. In contrast, restoring myeloid differentiation through inflammatory cytokines “rescues” AML transformation. Our findings identify myeloid differentiation as a critical step in LIC formation and AML development, thus guiding new therapeutic approaches. Examination of chromatin accessibility in Cebpa knock-out and control conditions.
Project description:Loss of immune function and an increased incidence of myeloid leukemia are two of the most clinically significant consequences of aging of the hematopoietic system. To better understand the mechanisms underlying hematopoietic aging, we evaluated the cell intrinsic functional and molecular properties of highly purified long-term hematopoietic stem cells (LT-HSCs) from young and old mice. We found that LT-HSC aging was accompanied by cell autonomous changes, including increased stem cell self-renewal, differential capacity to generate committed myeloid and lymphoid progenitors, and diminished lymphoid potential. Expression profiling revealed that LT-HSC aging was accompanied by the systemic down-regulation of genes mediating lymphoid specification and function and up-regulation of genes involved in specifying myeloid fate and function. Moreover, LT-HSCs from old mice expressed elevated levels of many genes involved in leukemic transformation. These data support a model in which age-dependent alterations in gene expression at the stem cell level presage downstream developmental potential and thereby contribute to age-dependent immune decline, and perhaps also to the increased incidence of leukemia in the elderly.
Project description:The defining characteristics of leukemia, such as lineage and genetics, are associated with a typical age of onset. Understanding mechanisms of leukemia age specificity could improve disease models to develop new therapies. We used heterochronic transplantation of murine leukemia driven by MLL-AF9 to investigate the relative contribution of the age of the cell-of-origin or the hematopoietic microenvironment to the lineage fate of leukemia initiating cells (LICs). We show that the neonatal hematopoietic niche supports the development of infant-like mixed lineage B-cell/myeloid leukemia, while a mature niche promotes adult-like pure acute myeloid leukemia (AML) from identical cells of origin. We attribute this to inhibition of B-lymphoid fate in multipotent progenitor-like LICs by Ccl5 from adult bone marrow (BM) stroma, and implicate glycogen synthase kinase-3 (GSK-3) signaling in the myeloid fate specification in mouse and human MLL-driven leukemia. These findings connect maturation and aging of the hematopoietic system to leukemia age specificity.