Project description:The treatment landscape of AML is evolving with promising therapies entering clinical translation, yet patient responses remain heterogeneous and biomarkers for tailoring treatment are lacking. To understand how disease heterogeneity links with therapy response, we determined the leukemia cell hierarchy make-up from bulk transcriptomes of over 1000 patients through deconvolution using single-cell reference profiles of leukemia stem, progenitor, and mature cell types. Leukemia hierarchy composition was associated with functional, genomic, and clinical properties and converged into four overall classes, spanning Primitive, Mature, GMP, and Intermediate. Critically, variation in hierarchy composition along the Primitive vs GMP or Primitive vs Mature axes were associated with response to chemotherapy or drug sensitivity profiles of targeted therapies, respectively. A 7-gene biomarker derived from the Primitive vs Mature axis was predictive of patient response to 105 investigational drugs. Thus, hierarchy composition constitutes a novel framework for understanding disease biology and advancing precision medicine in AML.
Project description:Experiments using xenografts show that some solid tumours and leukemias are organized as cellular hierarchies sustained by cancer stem cells (CSC). Despite promise, the relevance of the CSC model to human disease remains uncertain. Here we show that acute myeloid leukemia (AML) follows a CSC model based on sorting multiple populations from each of 16 primary human AML samples and identifying which contain leukemia stem cells (LSC) using a sensitive xenograft assay. Analysis of gene expression from all functionally validated populations yielded an LSC-specific signature. Similarly, a hematopoietic stem cell (HSC) gene signature was established. Bioinformatic analysis identified a core transcriptional program shared by LSC and HSC, revealing the molecular machinery underlying stemness properties. Both stem cell programs were highly significant independent predictors of patient survival and also found in existing prognostic signatures. Thus, determinants of stemness influence clinical outcome of AML establishing that LSC are clinically relevant and not mere artifacts of xenotransplantation. Analysis of gene expression in FACS sorted AML fractions that were functionally determined to be enriched for LSC or not (25 and 29 respectively).
Project description:The leukemia stem cell (LSC) populations of acute myeloid leukemia (AML) exhibit phenotypic, genetic and functional heterogeneity that contribute to therapy failure and relapse. Progress towards understanding the mechanistic basis for therapy resistance in LSCs has been hampered by difficulties in isolating cell fractions that enrich for the entire heterogeneous population of LSCs within individual AML samples. We previously reported that CD200 gene expression is upregulated in LSC-containing AML fractions. We demonstrate that CD200 is present on a greater proportion of CD45dim blasts compared to more differentiated CD45high cells in AML patient samples. In 75% of AML cases examined, CD200 was expressed on 10% of CD45dim blasts; of these, CD200 identified LSCs within the blast population in 90% of samples tested in xenotransplantation assays. Notably, CD200 expression captured both CD34- and CD34- LSCs within individual AML samples. Highly purified CD45dimCD200+ LSC-containing blasts were enriched in primitive HSC/progenitor-like signatures, while CD45dimCD200- nonengrafting blasts were enriched in myeloid-like signature. Moreover, analysis of CD45dimCD200+ blasts from NPM1-mutated AMLs also demonstrated an enrichment of primitive gene expression signatures compared to unfractionated (bulk) cells.
Project description:The leukemia stem cell (LSC) populations of acute myeloid leukemia (AML) exhibit phenotypic, genetic and functional heterogeneity that contribute to therapy failure and relapse. Progress towards understanding the mechanistic basis for therapy resistance in LSCs has been hampered by difficulties in isolating cell fractions that enrich for the entire heterogeneous population of LSCs within individual AML samples. We previously reported that CD200 gene expression is upregulated in LSC-containing AML fractions. We demonstrate that CD200 is present on a greater proportion of CD45dim blasts compared to more differentiated CD45high cells in AML patient samples. In 75% of AML cases examined, CD200 was expressed on 10% of CD45dim blasts; of these, CD200 identified LSCs within the blast population in 90% of samples tested in xenotransplantation assays. Notably, CD200 expression captured both CD34- and CD34- LSCs within individual AML samples. Highly purified CD45dimCD200+ LSC-containing blasts were enriched in primitive HSC/progenitor-like signatures, while CD45dimCD200- nonengrafting blasts were enriched in myeloid-like signature. Moreover, analysis of CD45dimCD200+ blasts from NPM1-mutated AMLs also demonstrated an enrichment of primitive gene expression signatures compared to unfractionated (bulk) cells.
Project description:The leukemia stem cell (LSC) populations of acute myeloid leukemia (AML) exhibit phenotypic, genetic and functional heterogeneity that contribute to therapy failure and relapse. Progress towards understanding the mechanistic basis for therapy resistance in LSCs has been hampered by difficulties in isolating cell fractions that enrich for the entire heterogeneous population of LSCs within individual AML samples. We previously reported that CD200 gene expression is upregulated in LSC-containing AML fractions. We demonstrate that CD200 is present on a greater proportion of CD45dim blasts compared to more differentiated CD45high cells in AML patient samples. In 75% of AML cases examined, CD200 was expressed on 10% of CD45dim blasts; of these, CD200 identified LSCs within the blast population in 90% of samples tested in xenotransplantation assays. Notably, CD200 expression captured both CD34- and CD34- LSCs within individual AML samples. Highly purified CD45dimCD200+ LSC-containing blasts were enriched in primitive HSC/progenitor-like signatures, while CD45dimCD200- nonengrafting blasts were enriched in myeloid-like signature. Moreover, analysis of CD45dimCD200+ blasts from NPM1-mutated AMLs also demonstrated an enrichment of primitive gene expression signatures compared to unfractionated (bulk) cells.
Project description:Acute myeloid leukemia (AML) is a highly heterogeneous disease and reliable detection of leukemic stem cells (LSCs) across genetic subclasses has proven difficult. We aimed to transcriptionally characterize LSCs specifically in monocyte-like AML (Mono-AML) and and primitive-like AML (Prim-AML) samples using cell surface markers. We used CD64+CD11b+ to define Mature blasts and labelled the rest as Immature. To further enrich for LSC-like cells in the Immature blasts in both Mono- and Prim-AML samples, we included GPR56, a marker for LSCs. We performed RNA sequencing on the FACS-sorted LSC-like and Mature cells from 23 AML patients.
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:Experiments using xenografts show that some solid tumours and leukemias are organized as cellular hierarchies sustained by cancer stem cells (CSC). Despite promise, the relevance of the CSC model to human disease remains uncertain. Here we show that acute myeloid leukemia (AML) follows a CSC model based on sorting multiple populations from each of 16 primary human AML samples and identifying which contain leukemia stem cells (LSC) using a sensitive xenograft assay. Analysis of gene expression from all functionally validated populations yielded an LSC-specific signature. Similarly, a hematopoietic stem cell (HSC) gene signature was established. Bioinformatic analysis identified a core transcriptional program shared by LSC and HSC, revealing the molecular machinery underlying stemness properties. Both stem cell programs were highly significant independent predictors of patient survival and also found in existing prognostic signatures. Thus, determinants of stemness influence clinical outcome of AML establishing that LSC are clinically relevant and not mere artifacts of xenotransplantation. Analysis of gene expression in FACS sorted cord blood fractions that were functionally determined to be enriched for HSC or not (6 and 6 respectively). 12 samples were hybridized to Affymetrix HG_U133A microarray [HG_U133A] or Affymetrix HG_U133B microarray [HC_U133B]
Project description:Leukemic stem cells (LSC) might be the source for leukemic disease self-renewal and account for disease relapse after treatment, which makes them a critical target for further therapeutic options. Leukemia associated antigens (LAA) might be suitable structures to be attacked by immunotherapeutic agents. We performed primary AML sample enrichment and microarray studies to define LAA expression levels in AML. We compared the LAA expression in the enriched CD34+CD38- AML fraction to that of enriched HSC of healthy donors and AML bulk cells (CD34+CD38+, CD34-CD38+ and CD34-CD38). Furthermore, we investigated the expression patterns of co-stimulatory molecules in LSC, bulk AML cells and enriched HSC, Conclusion: We demonstrated the differential expression of several LAA in LSC, and their suitability as target structures. We enriched primary AML samples using CD34 and CD38 as markers to compare LAA expression levels of LSC, HSC and AML bulk. LAA expression profiles comparing LSC, HSC and leukemic bulk AML citation: Leukemic progenitor cells are susceptible to targeting by stimulated cytotoxic T cells against immunogenic leukemia-associated antigens Vanessa Schneider, Lu Zhang, Markus Rojewski, Natalie Fekete, Hubert Schrezenmeier, Alexander Erle, Lars Bullinger, Susanne Hofmann, Marlies Götz, Konstanze Döhner, Susann Ihme, Hartmut Döhner, Christian Buske, Michaela Feuring-Buske, Jochen Greiner
Project description:Leukemic stem cells (LSC) might be the source for leukemic disease self-renewal and account for disease relapse after treatment, which makes them a critical target for further therapeutic options. Leukemia associated antigens (LAA) might be suitable structures to be attacked by immunotherapeutic agents. We performed primary AML sample enrichment and microarray studies to define LAA expression levels in AML. We compared the LAA expression in the enriched CD34+CD38- AML fraction to that of enriched HSC of healthy donors and AML bulk cells (CD34+CD38+, CD34-CD38+ and CD34-CD38). Furthermore, we investigated the expression patterns of co-stimulatory molecules in LSC, bulk AML cells and enriched HSC, Conclusion: We demonstrated the differential expression of several LAA in LSC, and their suitability as target structures. We enriched primary AML samples using CD34 and CD38 as markers to compare LAA expression levels of LSC, HSC and AML bulk.