Co-Existence of LMPP-Like and GMP-Like Leukemia Stem Cells In Acute Myeloid Leukemia

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 91-91
Author(s):  
Nicolas Goardon ◽  
Emmanuele Marchi ◽  
Lynn Quek ◽  
Anna Schuh ◽  
Petter Woll ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Acute Myeloid Leukemia ◽  
Stem Cell ◽  
Myeloid Leukemia ◽  
Expression Profiles ◽  
Leukemic Stem Cell ◽  
Self Renewal ◽  
Two Populations ◽  
Acute Myeloid

Abstract Abstract 91 In normal and leukemic hemopoiesis, stem cells differentiate through intermediate progenitors into terminal cells. In human Acute Myeloid Leukemia (AML), there is uncertainty about: (i) whether there is more than one leukemic stem cell (LSC) population in any one individual patient; (ii) how homogeneous AML LSCs populations are at a molecular and cellular level and (iii) the relationship between AML LSCs and normal stem/progenitor populations. Answers to these questions will clarify the molecular pathways important in the stepwise transformation of normal HSCs/progenitors. We have studied 82 primary human CD34+ AML samples (spanning a range of FAB subtypes, cytogenetic categories and FLT3 and NPM1 mutation states) and 8 age-matched control marrow samples. In ∼80% of AML cases, two expanded populations with hemopoietic progenitor immunophenotype coexist in most patients. One population is CD34+CD38-CD90-CD45RA+ (CD38-CD45RA+) and the other CD34+CD38+CD110-CD45RA+ (GMP-like). Both populations from 7/8 patients have leukemic stem cell (LSC) activity in primary and secondary xenograft assays with no LSC activity in CD34- compartment. The two CD34+ LSC populations are hierarchically ordered, with CD38-CD45RA+ LSC giving rise to CD38+CD45RA+ LSC in vivo and in vitro. Limit dilution analysis shows that CD38-CD45RA+LSCs are more potent by 8–10 fold. From 18 patients, we isolated both CD38-CD45RA+ and GMP-like LSC populations. Global mRNA expression profiles of FACS-sorted CD38-CD45RA+ and GMP-like populations from the same patient allowed comparison of the two populations within each patient (negating the effect of genetic/epigenetic changes between patients). Using a paired t-test, 748 genes were differentially expressed between CD38-CD45RA+ and GMP-like LSCs and separated the two populations in most patients in 3D PCA. This was confirmed by independent quantitative measures of difference in gene expression using a non-parametric rank product analysis with a false discovery rate of 0.01. Thus, the two AML LSC populations are molecularly distinct. We then compared LSC profiles with those from 4 different adult marrow normal stem/progenitor cells to identify the normal stem/progenitor cell populations which the two AML LSC populations are most similar to at a molecular level. We first obtained a 2626 gene set by ANOVA, that maximally distinguished normal stem and progenitor populations. Next, the expression profiles of 22 CD38-CD45RA+ and 21 GMP-like AML LSC populations were distributed by 3D PCA using this ANOVA gene set. This showed that AML LSCs were most closely related to their normal counterpart progenitor population and not normal HSC. This data was confirmed quantitatively by a classifier analysis and hierarchical clustering. Taken together, the two LSC populations are hierarchically ordered, molecularly distinct and their gene expression profiles do not map most closely to normal HSCs but rather to their counterpart normal progenitor populations. Finally, as global expression profiles of CD38-CD45RA+ AML LSC resemble normal CD38-CD45RA+ cells, we defined the functional potential of these normal cells. This had not been previously determined. Using colony and limiting dilution liquid culture assays, we showed that single normal CD38-CD45RA+ cells have granulocyte and macrophage (GM), lymphoid (T and B cell) but not megakaryocyte-erythroid (MK-E) potential. Furthermore, gene expression studies on 10 cells showed that CD38-CD45RA+ cells express lymphoid and GM but not Mk-E genes. Taken together, normal CD38-CD45RA+ cells are most similar to mouse lymphoid primed multi-potential progenitor cells (LMPP) cells and distinct from the recently identified human Macrophage Lymphoid progenitor (MLP) population. In summary, for the first time, we show the co-existence of LMPP-like and GMP-like LSCs in CD34+ AML. Thus, CD34+ AML is a progenitor disease where LSCs have acquired abnormal self-renewal potential (Figure 1). Going forward, this work provides a platform for determining pathological LSCs self-renewal and tracking LSCs post treatment, both of which will impact on leukemia biology and therapy. Disclosures: No relevant conflicts of interest to declare.

439 Dual modes of action for anti-TIM-3 antibody MBG453 in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML): preclinical evidence for immune-mediated and anti-leukemic activity

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A465-A465
Author(s):  
Catherine Sabatos-Peyton ◽  
Tyler Longmire ◽  
Lisa Baker ◽  
Nidhi Patel ◽  
Anne-Sophie Wavreille ◽  
...  
Keyword(s):  
Stem Cells ◽  
Acute Myeloid Leukemia ◽  
Stem Cell ◽  
High Risk ◽  
Myeloid Leukemia ◽  
Leukemic Stem Cells ◽  
Self Renewal ◽  
Immune Mediated ◽  
Acute Myeloid ◽  
Cell Stem Cell

BackgroundTIM-3 is expressed on leukemic stem cells (LSCs) and blasts in AML,1 2 and TIM-3 expression on MDS blasts correlates with disease progression.3 Functional evidence for TIM-3 in AML was established with an anti-TIM-3 antibody which inhibited engraftment and development of human AML in immuno-deficient murine hosts.1 TIM-3 promotes an autocrine stimulatory loop via the TIM-3/Galectin-9 interaction, supporting LSC self-renewal.4 In addition to its cell-autonomous role on LSCs/blasts, TIM-3 also has a critical role in immune system regulation, in adaptive (CD4+ and CD8+ T effector cells, regulatory T cells) and innate (macrophages, dendritic cells, NK cells) immune responses.5 MBG453 is a high-affinity, humanized anti-TIM-3 IgG4 antibody (Ab) (stabilized hinge, S228P), which blocks the binding of TIM-3 to phosphatidylserine (PtdSer). Recent results from a multi-center, open label phase Ib dose-escalation study (NCT03066648) in patients with high-risk MDS and no prior hypomethylating agent therapy evaluating MBG453 in combination with decitabine demonstrated encouraging preliminary efficacy with an overall response rate of 58%,6 and MBG453 combined with azacitidine also showed encouraging response rates.7 Preclinical experiments were undertaken to define the mechanism of action of the hypomethylating agent and anti-TIM-3 combination.MethodsTHP-1 cells (a human monocytic AML cell line) were pre-treated with decitabine and co-cultured with anti-CD3 activated healthy human donor peripheral blood mononuclear cells (PBMCs) in an Incucyte-based assay to measure cell killing. The ability of MBG453 to mediate antibody-dependent cellular phagocytosis (ADCP) was measured by determining the phagocytic uptake of an engineered TIM-3-overexpressing Raji cell line in the presence of MBG453 by phorbol 12-myristate 13-acetate (PMA)-activated THP-1 cells. Patient-derived AML xenograft studies were undertaken in immune-deficient murine hosts to evaluate the combination of decitabine and MBG453.ResultsMBG453 was determined to partially block the TIM-3/Galectin-9 interaction in a plate-based MSD (Meso Scale Discovery) assay, supported by a crystal structure of human TIM-3.8 Pre-treatment of THP-1 cells with decitabine enhanced sensitivity to immune-mediated killing in the presence of MBG453. MBG453 was determined to mediate modest ADCP, relative to controls. MBG453 did not enhance the anti-leukemic activity of decitabine in patient-derived xenograft studies in immuno-deficient hosts.ConclusionsTaken together, these results support both direct anti-leukemic effects and immune-mediated modulation by MBG453. Further studies are ongoing to determine: (1) whether MBG453 can mediate physiologically relevant ADCP of TIM-3-expressing leukemic cells; and (2) the potential of MBG453 to impact the autocrine feedback loop of TIM-3/Galectin-9.Ethics ApprovalThe human tissue used in these studies was under the Novartis Institutes of BioMedical Research Ethics Board IRB, Approval Number 201252867.ReferencesKikushige Y, Shima T, Takayanagi S, et al. TIM-3 is a promising target to selectively kill acute myeloid leukemia stem cells. Cell Stem Cell 2010;7(6):708–717.Jan M, Chao MP, Cha AC, et al. Prospective separation of normal and leukemic stem cells based on differential expression of TIM3, a human acute myeloid leukemia stem cell marker. Proc Natl Acad Sci USA 2011; 108(12): 5009–5014.Asayama T, Tamura H, Ishibashi M, et al. Functional expression of Tim-3 on blasts and clinical impact of its ligand galectin-9 in myelodysplastic syndromes. Oncotarget 2017;8(51): 88904–88917.Kikushige Y, Miyamoto T, Yuda J, et al. A TIM-3/Gal-9 autocrine stimulatory loop drives self-renewal of human myeloid leukemia stem cells and leukemic progression. Cell Stem Cell 2015; 17(3):341–352.Acharya N, Sabatos-Peyton C, Anderson AC. Tim-3 finds its place in the cancer immunotherapy landscape. J Immunother Cancer 2020; 8(1):e000911.Borate U, Esteve J, Porkka K, et al. Phase Ib Study of the Anti-TIM-3 Antibody MBG453 in combination with decitabine in patients with high-risk myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Blood 2019;134 (Supplement_1):570.Borate U, Esteve J, Porkka K, et al. Abstract S185: Anti-TIM-3 antibody MBG453 in combination with hypomethylating agents (HMAs) in patients (pts) with high-risk myelodysplastic syndrome (HR-MDS) and acute myeloid leukemia (AML): a Phase 1 study. EHA 2020.Sabatos-Peyton C. MBG453: A high affinity, ligand-blocking anti-TIM-3 monoclonal Ab. AACR 2016.

Evi-1 is a transcriptional target of mixed-lineage leukemia oncoproteins in hematopoietic stem cells

Blood ◽  
2011 ◽  
Vol 117 (23) ◽  
pp. 6304-6314 ◽  
Author(s):  
Shunya Arai ◽  
Akihide Yoshimi ◽  
Munetake Shimabe ◽  
Motoshi Ichikawa ◽  
Masahiro Nakagawa ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Acute Myeloid Leukemia ◽  
Stem Cell ◽  
Hematopoietic Stem Cells ◽  
Myeloid Leukemia ◽  
Mixed Lineage Leukemia ◽  
Aberrant Expression ◽  
Hematopoietic Stem ◽  
Acute Myeloid

Abstract Ecotropic viral integration site-1 (Evi-1) is a nuclear transcription factor that plays an essential role in the regulation of hematopoietic stem cells. Aberrant expression of Evi-1 has been reported in up to 10% of patients with acute myeloid leukemia and is a diagnostic marker that predicts a poor outcome. Although chromosomal rearrangement involving the Evi-1 gene is one of the major causes of Evi-1 activation, overexpression of Evi-1 is detected in a subgroup of acute myeloid leukemia patients without any chromosomal abnormalities, which indicates the presence of other mechanisms for Evi-1 activation. In this study, we found that Evi-1 is frequently up-regulated in bone marrow cells transformed by the mixed-lineage leukemia (MLL) chimeric genes MLL-ENL or MLL-AF9. Analysis of the Evi-1 gene promoter region revealed that MLL-ENL activates transcription of Evi-1. MLL-ENL–mediated up-regulation of Evi-1 occurs exclusively in the undifferentiated hematopoietic population, in which Evi-1 particularly contributes to the propagation of MLL-ENL–immortalized cells. Furthermore, gene-expression analysis of human acute myeloid leukemia cases demonstrated the stem cell–like gene-expression signature of MLL-rearranged leukemia with high levels of Evi-1. Our findings indicate that Evi-1 is one of the targets of MLL oncoproteins and is selectively activated in hematopoietic stem cell–derived MLL leukemic cells.

The Novel Leukemia Stem Cell Marker GPR56 Discriminates Leukemic Subclones with Divergent Stem Cell Properties in Human Acute Myeloid Leukemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1859-1859
Author(s):  
Caroline Pabst ◽  
Anne Bergeron ◽  
Vincent-Philippe Lavallée ◽  
Jonathan Yeh ◽  
Patrick Gendron ◽  
...  
Keyword(s):  
Stem Cells ◽  
Acute Myeloid Leukemia ◽  
Stem Cell ◽  
Myeloid Leukemia ◽  
Expression Profiles ◽  
Stem Cell Marker ◽  
Mouse Bone Marrow ◽  
Rna Seq ◽  
Hematopoietic Stem ◽  
Acute Myeloid

Abstract Insights into the complex clonal architecture of acute myeloid leukemia (AML) unravelled by deep sequencing technologies have challenged the concept of AML as a hierarchically organised disease initiated and driven by rare self-renewing leukemic stem cells (LSCs). In contrast to normal human hematopoietic stem cells (HSCs), which are highly enriched in the CD34+ CD38- population, LSCs have also been found in the CD34- and the CD38+ fractions questioning the existence of a consistent LSC surface marker profile for AML. Besides, low LSC frequencies in primary samples, rapid onset of differentiation upon ex vivo culture, and genetic inter-specimen heterogeneity hamper the dissection of the molecular machinery that drives LSC self-renewal. We performed RNA-Sequencing of primary human AML samples and assessed LSC frequencies by limiting dilution analyses for 56 of these in NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice. By comparing gene expression profiles between high vs low LSC frequency leukemias, we identified the G-protein coupled receptor 56 (GPR56) has significantly more expressed in high LSC frequency leukemias. We validated the RNA-seq data with protein expression by FACS and found an excellent correlation. To determine whether GPR56 positive cells overlapped with the known LSC-associated phenotype CD34+ CD38-, we stained 45 AML samples with CD34, CD38, GPR56, and antibodies against other described LSC markers. Although CD34+ GPR56+ and CD34+ CD38- compartments identified the same population in some samples, we found in the majority of samples that GPR56 further subdivided the CD34+ CD38- compartment. Accordingly, not only the proportions of total GPR56+ and CD34+ GPR56+ cells were significantly higher in LSChigh versus LSClow samples, but also the proportion of GPR56+ cells within the CD34+ CD38- compartment was significantly different between the groups indicating that GPR56 might be of additional value to what is currently considered the best described LSC phenotype. The percentage of total CD34 positive cells did not correlate with LSC frequency clearly distinguishing GPR56 from CD34 or CD38, which are only suitable LSC markers when used in combination. We analysed other potential LSC markers (TIM3, CD96, CD44, CD123, CLL1 and CD47) in our RNA-Seq dataset and by FACS analysis in combination with CD34 as we did for GPR56 and none of them correlated with LSC frequency in our sample collection. To determine whether GPR56 discriminates engrafting LSCs from non-LSCs, we sorted GPR56+ and GPR56- cells within the CD34-positive and -negative compartments from selected specimens with known engraftment potential. We found that GPR56 identified the engrafting fraction in CD34positive AML samples, with a >50 fold enrichment in LSC in the CD34+GRP56+ fraction vs the CD34+GPR56- fraction within the same sample, demonstrating that GPR56 is a good LSC marker. Specimens with high molecular or cytogenetic risk such as chromosome 5 or 7 anomalies and EVI1- rearrangementexpressed high levels of both, GPR56 and CD34, while samples with coexistent FLT3 -ITD, DNMT3A, and NPM1 mutations displayed a unique CD34low GPR56high profile. Moreover, we found a divergent distribution of variant allele frequencies in GPR56+ versus GPR56- fractions identifying GPR56 as a discriminator of leukemic sub-clones with high and low NSG engrafting capacity. Analysis of engrafted cells re-sorted based on GPR56 after being harvested from mouse bone marrow revealed reduced complexity of the clonal composition. Most importantly, GPR56 positive cells differentiated to GPR56 negative cells in mice, which did not happen in the human niche, in which GPR56 positive and negative fractions represented two independently evolved subclones. In summary our work identifies GPR56 as a novel LSC marker in AML and also shows that GPR56 readily identifies a functionally distinct LSC-rich subclone in the majority of human AML patients and reveals hitherto unforeseen complexity in the interaction between human LSCs and the NSG mouse environment. Disclosures No relevant conflicts of interest to declare.

scholarly journals Identification of Existing Bioactive Compounds That Target Acute Myeloid Leukemia Stem Cells

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3681-3681
Author(s):  
Isabelle Laverdiere ◽  
Andrea L. Neumann ◽  
Meaghan Boileau ◽  
Heather Duncan ◽  
Sara Chisling ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Acute Myeloid Leukemia ◽  
Stem Cell ◽  
Cord Blood ◽  
Myeloid Leukemia ◽  
Day Treatment ◽  
Blood Samples ◽  
Stem And Progenitor Cells ◽  
Acute Myeloid

Abstract Current therapies for acute myeloid leukemia (AML) are able to achieve complete remission in 80-85% of patients; however large portions of these cases relapse. The 5-year survival rate is estimated at 30%. Thus, the development of more efficient approaches to treat AML is absolutely needed. Similarly to normal hematopoiesis, leukemias are organized as cellular hierarchies supported by leukemic stem cells (LSCs). LSCs are relatively resistant to chemotherapy and may act as a cancer cell reservoir that leads to relapse. The discovery of therapeutics that can eradicate these cells is essential to achieve complete patient recovery. We hypothesize that by using an in silico strategy and stem cell gene expression data we can identify bioactive compounds that target LSCs with minimal impact on normal hematopoietic stem cell (HSC) function. We had previously generated human LSC and HSC expression signatures from 16 primary AML and 4 independent pooled cord blood samples that were prognostic for patient survival (Eppert et al Nat Med 2011). By interrogating existing gene expression profiles of drug response with our LSC and HSC signatures, as well as additional novel signatures, we identified 92 molecules predicted to inhibit human LSC properties without harming HSCs. Nearly 60% of the positive hits were anti-infectives, psychotropics, hormones and steroids, anticancer or cardiovascular therapies. In support of the efficacy of this bioinformatic approach, we identified known chemotherapeutic agents such as azacitidine, daunorubicin and doxorubicin, although these were predicted to harm HSCs. We assessed the anti-LSC activity of one sub-group known to target a class of G-protein-coupled receptors (GPCR) to further validate the list of candidate compounds. Using a primary human AML sample (8227) with known LSC phenotype (CD34+), we tested 2 candidate anti-GPCR compounds (hits A and B) and observed that they were highly effective in targeting both bulk cells and LSCs. The IC50 for bulk cells was 3.4 µM and 4.2 µM for compounds A and B, respectively (A - 6 day treatment, B - 2 day treatment). The IC50 of the CD34+ cell fraction, which included stem and progenitor cells, was 5.9 µM and 4.1 µM, respectively. Thus, these compounds are effective at targeting both bulk and LSC-enriched AML cell populations. The efficacy of these predicted compounds against the primitive cells within the CD34+ population was assessed using colony formation assays on human AML. 8227 cells treated with compound B resulted in significantly fewer colonies compared to the DMSO control (3.8 ± 3.0 vs 13.3 ± 2.8; at 4.5 µM). To test whether our candidate compounds target leukemic cells and not normal blood cells, we examined 3 additional primary human AML samples and a cord blood sample. There was only a minor effect on normal cells, including stem and progenitor cells, but significant cell death in all leukemia samples (70% and more at ≥ 3 µM). Next, we will determine the effectiveness of our compounds in vivo using established xenografts of primary human AML samples and cord blood samples. In conclusion, using our in silico approach we successfully identified novel anti-LSC compounds that have efficacy in vitro with minimal toxicity on primary HSCs. Furthermore, as each predicted compound is associated with specific molecular pathways, our approach has improved our understanding of LSC biology by acting as a screen for LSC-related pathways. In the near future, we will continue investigating the 92 candidate compounds to identify, develop, and transition a novel anti-LSC compound into clinical use. Disclosures No relevant conflicts of interest to declare.

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