scholarly journals Metabolism and the leukemic stem cell

2010 ◽  
Vol 207 (4) ◽  
pp. 677-680 ◽  
Author(s):  
Omar Abdel-Wahab ◽  
Ross L. Levine
Keyword(s):  
Stem Cell ◽  
Metabolic Pathways ◽  
Myeloid Leukemia ◽  
Leukemic Cells ◽  
Oxygen Species ◽  
Leukemic Stem Cell ◽  
Hematopoietic Differentiation ◽  
Acute Leukemias ◽  
Self Renewal ◽  
Leukemic Clone

Acute leukemias are clonal disorders of hematopoiesis wherein a leukemic stem cell (LSC) acquires mutations that confer the capacity for unlimited self-renewal, impaired hematopoietic differentiation, and enhanced proliferation to the leukemic clone. Many recent advances in understanding the biology of leukemia have come from studies defining specific genetic and epigenetic abnormalities in leukemic cells. Three recent articles, however, further our understanding of leukemia biology by elucidating specific abnormalities in metabolic pathways in leukemic hematopoiesis. These studies potentially converge on the concept that modulation of reactive oxygen species (ROS) abundance may influence the pathogenesis and treatment of acute myeloid leukemia (AML).

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.

PRMT1 Activates Leukemic Stem Cell Program in MLL-Rearranged Leukemia

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3493-3493
Author(s):  
Wing Chi Lui ◽  
Yuen Fan Chan ◽  
Ray Ng
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Fusion Protein ◽  
Fusion Proteins ◽  
Leukemic Cells ◽  
Leukemic Stem Cell ◽  
Self Renewal ◽  
Mll Gene ◽  
Acute Myeloid

Abstract In MLL-rearranged leukemia, the Mixed Lineage Leukemia (MLL) gene undergoes chromosomal translocation that results in the loss of C-terminal histone methyltransferase SET domain, whereas the N-terminal of MLL gene fuses in-frame with one of the 60 identified partner genes. The resultant MLL fusion proteins lead to a characteristic aberrant gene expression pattern in human acute myeloid and lymphoblastic leukemia. Epigenetic dysregulation mediated by MLL fusion proteins has been suggested to be a key event in MLL-rearranged leukemia. It has been demonstrated that MLL-EEN/PRMT1 oncogenic complex induces transformation of primary myeloid progenitors via introduction of aberrant H4R3me2 at target Hoxloci. PRMT1 is the predominant protein arginine methyltransferase in mammals and is responsible for over 85% of arginine methylation activity in mammalian cells. Dysregulation of PRMT1 has been implicated in different cancers such as leukemia, suggesting the expression of PRMT1 is positively correlated with cancer progression and clinical parameters. Nevertheless, the leukemogenic role of PRMT1 in the establishment of leukemic stem cell (LSC) remains unclear. Previously we have demonstrated that a MLL fusion protein, MLL-EEN, can strongly enhance the self-renewal ability of murine primary hematopoietic cells through multiple rounds of replating assays. We have created a conditional Mll-Een invertor mouse model (MllEen/+) in which the expression of fusion protein is restricted to hematopoietic progenitors. Immunophenotypic analysis demonstrated a significant increase in the immature myeloid cell population (c-kit+Mac-1+) in bone marrow of MllEen/+ mice, suggesting that the expression of Mll-Een induces the development of acute myeloid leukemia. We have also established an Mll-Een expressing cell line from the bone marrow of MllEen/+ mouse. These leukemic cells can persistently form colonies and they also demonstrated deregulation of Hox genes, which is frequently observed in human leukemia cases. The leukemogenicity of Mll-Een is closely associated with Prmt1, which was demonstrated through knockdown of Prmt1. Strikingly, we discovered a subpopulation of CD41+Mll-Een expressing cells, which showed enhanced self-renewal ability in the serial colony forming assays. The percentage of CD41+ leukemic cells is reduced once Prmt1 was knocked down, suggesting that Prmt1 is crucial in the maintenance of this subpopulation of cells. In addition, the CD41+ cells showed enhanced expression of genes associated with hematopoietic stem cell (HSC) activities (Bmi-1, Runx1, Tal-1 and Lmo2), implying that part of the HSC transcriptional program has been re-activated in these cells. We therefore speculate that the CD41+ cells may represent a group of MLL leukemic cells that harbors strong stem cell features, and presumably functions as LSCs. The CD41+ leukemic cells will be further characterized by their LSC functions and CD41 can potentially serve as a novel LSC marker in MLL-rearranged leukemia. Taken together, studies on the role of PRMT1 can provide novel insights on the establishment of LSC and the development of effective clinical treatment for MLL-rearranged leukemia. Disclosures No relevant conflicts of interest to declare.

Drug Induced MLL Fusion Degradation Via Hsp90 Inhibition

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4850-4850
Author(s):  
Sandra Cantilena ◽  
Nicholas Goulden ◽  
Owen Williams ◽  
Jasper de Boer
Keyword(s):  
Stem Cell ◽  
Fusion Protein ◽  
Target Genes ◽  
Fusion Gene ◽  
Leukemic Stem Cell ◽  
Down Regulation ◽  
Drug Induced ◽  
Acute Leukemias ◽  
Self Renewal

Abstract The survival rate for infants is less than 50%. The fast majority of infant acute leukemias are characterized cytogenetically by balanced chromosomal translocations involving the mixed lineage leukemia (MLL) gene. Leukemic therapies that degrade the driver oncogene are associated with loss of cancer cell self-renewal and excellent cure rates. Therefore, therapy that degrades the MLL fusion gene would offer new hope to these patients. Recently it was shown that the Drosophila Trithorax gene, an analogue of the human MLL, is degraded by Radicicol. Radicicol is a natural compound and a well-known Hsp90 inhibitor. Here, we show that Radicicol is able to induce a dose dependent degradation of the MLL-fusion protein in a panel of human MLL rearranged cell lines and in human cord blood-derived MLL-AF9 immortalised myeloid cells. This drug induced degradation of the MLL-fusion gene results in down-regulation of the expression of MLL target genes, including HOXA9, MEIS1 and c-MYB. Functionally, this results in a loss of self-renewal of the leukemic stem cells, as shown by methylcellulose colony forming assays. Radicicol proved ineffective and too toxic for in vivo use. One of the best tolerated Hsp90 inhibitors is Ganetespib. It is currently in phase II/III clinical trials. We extended our Radicicol data to Ganetespib. Like Radicicol, Ganetespib induces MLL-fusion protein degradation and downregulation of MLL target genes. Treatment of MLL rearranged leukemia with Ganetespib results in a loss of leukemic stem cell activity. In conclusion, we show how the inactivation of the MLL-fusion and down-regulation of MLL target genes results in a block of leukemic stem cell self- renewal. We will validate these findings in a pre-clinical in vivo model in the near future. Disclosures No relevant conflicts of interest to declare.

scholarly journals KLF4 Controls Leukemic Stem Cell Self-Renewal in MLL-AF9-Induced Acute Myeloid Leukemia

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1231-1231
Author(s):  
Andrew Lewis ◽  
Chun Shik Park ◽  
Monica Puppi ◽  
H. Daniel Lacorazza
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Myeloid Leukemia ◽  
Leukemic Cells ◽  
Epigenetic Mechanisms ◽  
Leukemic Stem Cells ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Limiting Dilution

Acute myeloid leukemia (AML) develops from sequential mutations which transform hematopoietic stem and progenitor cells (HSPCs) in the bone marrow into leukemic stem cells (LSCs) which drive the progression of frank leukemia. Especially poor outcomes in elderly patients coupled with frequent relapse have led to a dismal 28.3% 5-year survival, warranting the need for innovative therapeutic approaches. Successful targeted therapy will selectively eliminate LSCs, which possess distinct characteristics enabling self-renewal and chemotherapeutic resistance, while sparing normal HSPCs. We theorized that KLF4, a zinc finger transcription factor, maintains key self-renewal pathways in LSCs due to its known importance in preserving stemness in embryonic and cancer stem cells. KLF4 alters gene transcription through its activating and repressing domains as well as remodeling chromatin through various epigenetic mechanisms, and work from our lab has demonstrated that loss of KLF4 in leukemia driven by the BCR-ABL fusion oncogene results in depletion of LSCs (Park et. al in revision) while enhancing self-renewal of hematopoietic stem cells. To address this hypothesis, mice featuring floxed Klf4 gene (Klf4fl/fl) were crossed with transgenic Vav-iCre mice to produce mice with hematopoietic-specific deletion of Klf4 (Klf4Δ/Δ). The murine t(9;11)(p21;q23) translocation (MLL-AF9 or MA9) transduction model has previously been shown to reflect clinical disease attributes, and represents the MLL-rearranged human patient subset with particularly poor prognosis and relatively higher levels of KLF4. Lin−Sca-1+c-Kit+ (LSK) cells from Klf4fl/fl and Klf4Δ/Δ mice were transduced with retrovirus containing MA9 and GFP reporter and transplanted into lethally-irradiated wild-type (WT) mice to generate trackable Klf4fl/fl and Klf4Δ/ΔAMLs. Recipients of both MA9Klf4fl/fl and Klf4Δ/Δ cells developed a rapid expansion of leukemic cells with myeloid immunophenotype by flow cytometric analysis (CD11b+Gr-1+; 68-91%), characterized as AML with latency of approximately 44.5 days. To quantify the defect induced by loss of KLF4 in the leukemic stem cell population, we performed secondary transplant of multiple limiting-dilution cell doses of primary transformed leukemic bone marrow from moribund mice. Klf4Δ/Δ AML mice exhibited significantly improved survival in all dose-cohorts, in some cases presenting no detectable leukemic cells at completion of monitoring (225 days). Limiting dilution analysis using the ELDA online software tool demonstrated a 7-fold reduction from 1 in 513 in Klf4fl/fl to 1 in 3836 in Klf4Δ/Δ AML bone marrow cells capable of leukemic initiation function (p<0.001), a hallmark of LSCs. Using the ERCre-tamoxifen inducible deletion system, Klf4 deletion 15 days post-transplant of AML significantly improved survival of Klf4Δ/Δ mice compared to controls, demonstrating KLF4 promotes maintenance of disease. Plating of leukemic bone marrow from Klf4Δ/Δ mice in methylcellulose medium revealed a reduction in serial colony-forming ability, further supporting a defect in self-renewal. To further determine the mechanisms connected to this reduction in functional LSCs, we isolated leukemic granulocyte-macrophage progenitors (L-GMPs), a population previously reported to be highly enriched for functional LSCs and representing a comparable cellular subset in human clinical samples, from Klf4fl/fl and Klf4Δ/Δ AMLs and conducted RNA-Seq to identify potential transcriptional targets of KLF4 with therapeutic promise. Taken together, these data suggest a novel function of the stemness transcription factor KLF4 in the preservation of leukemic stem cells in AML. Whereas prior models based on KLF4 expression in human cell lines and bulk AML samples have proposed a tumor suppressive role, our work suggests KLF4 supports expansion of leukemic cells with a stem cell phenotype and serial assays suggest an effect on LSC self-renewal. Further studies are being conducted to define the transcriptional and epigenetic mechanisms governing these findings. Understanding the molecular changes induced by loss of KLF4 presents promise for development of new therapies selectively targeting LSCs. Disclosures No relevant conflicts of interest to declare.

Isolation and Functional Characterization of a Novel “Oxidative State – low” Leukemic Population with Stem Cell Properties and Potential Resistance to Chemotherapy In Acute Myeloid Leukemia.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1580-1580
Author(s):  
Eleni D. Lagadinou ◽  
Dimitra Kokkinou ◽  
Elena Siapati ◽  
George Vassilopoulos ◽  
Craig T. Jordan ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Myeloid Leukemia ◽  
Redox State ◽  
Functional Characterization ◽  
Leukemic Cells ◽  
Self Renewal ◽  
Oxidative State ◽  
Resistance To Chemotherapy

Abstract Abstract 1580 Most adults with acute myeloid leukemia (AML) are not cured with current treatments due to primary chemo-resistance or relapse. Emerging evidence suggests that the pool of leukemic blasts is heterogeneous and disease persistence is due to a subset of leukemic (-stem) cells able to evade chemotherapy and sustain tumor growth. Cell surface marker expression has proven to be a valuable tool to isolate and study leukemic stem cells (LSC) which, similarly to normal hematopoiesis, are shown to reside in the CD34+/CD38- leukemic fraction. However, recent data indicate that the phenotype of LSC varies from patient to patient and it seems likely that no single phenotypic signature exists to uniformly identify LSC. Besides immunophenotype, isolating LSC on the basis of functional properties unique for these cells may enforce our understanding of AML biology and provide the basis to develop more effective therapies. Reactive oxygen species (ROS) regulate essential cellular functions such as self-renewal, proliferation and apoptosis. In normal neurogenesis and hematopoiesis, ROSlow states correlate with self-renewal and ROShigh is associated with differentiation. In malignant tissues, although cancer cells are commonly more oxidized than their normal counterparts, some cancer stem cells are shown to contain low ROS levels, a feature associated with increased resistance to therapy (Nature. 2009;458:780-783). We hypothesized that LSCs also reside in a less oxidized state than bulk leukemic cells, a condition which promotes self-renewal and confers resistance to chemotherapy. To validate this hypothesis, we evaluated the redox state of leukemic blasts isolated from bone marrow or peripheral blood from 21 AML and 2 high-risk MDS patients. Loading of cells with the fluorescent probe DCF-DA showed that primary AML specimens have a broad range of oxidative state, with cells clearly falling into ROShigh and ROSlow populations (ROSlow=11.5±9%). Phenotypic analyses of AML specimens with respect to primitive cell surface markers indicated that the ROSlow gate represented 18 ± 17% of the phenotypically primitive CD34+/CD38- cells and was significantly more enriched in CD34-/CD38- leukemic cells in comparison to ROShigh. We isolated ROSlow and ROShigh leukemic subsets by flow cytometric sorting on the basis of their DCF fluorescence from 11 AML patients' samples and analyzed them for stem cell properties and drug sensitivity. Importantly, we used the differential redox state and not phenotypic markers to isolate distinct leukemic subpopulations. Morphological evaluation of sorted CD45/SS blast gated, DCFlow and DCFhigh cells demonstrated that both subpopulations were leukemic. Comparative analysis of the cell cycle distribution after staining with Ki67 and 7AAD indicated in most cases that ROSlow cells are quiescent, in contrast to ROShigh and total blast cells which are more actively cycling. Despite their predominant quiescent state, ROSlow leukemic cells were able both to grow as colonies in CFU assays and also to engraft in NOD SCID mice in pilot experiments, suggesting the existence of both leukemic “progenitor” and “stem” cell types within the ROSlow leukemic fraction. Based on these data, we challenged primary AML specimens with conventional chemotherapy agents (daunorubicin and AraC). Intriguingly, ROSlow cells preferentially survived exposure to either antileukemic agent in vitro. Taken together, our data identify a novel quiescent “oxidative state – low” leukemic population from patients with AML/MDS at diagnosis, which displays stem cell properties and exhibits functional differences related to drug sensitivity. The detailed molecular and functional characterization of this novel leukemic population is the subject of our ongoing studies. Disclosures: No relevant conflicts of interest to declare.

Metabolic Regulation and Related Molecular Mechanisms in Various Stem Cell Functions

2020 ◽  
Vol 15 (6) ◽  
pp. 531-546 ◽  
Author(s):  
Hwa-Yong Lee ◽  
In-Sun Hong
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Oxidative Phosphorylation ◽  
Metabolic Pathways ◽  
Critical Role ◽  
The Self ◽  
Specific Cell ◽  
Differentiation Potential ◽  
Self Renewal ◽  
Cell Functions

Recent studies on the mechanisms that link metabolic changes with stem cell fate have deepened our understanding of how specific metabolic pathways can regulate various stem cell functions during the development of an organism. Although it was originally thought to be merely a consequence of the specific cell state, metabolism is currently known to play a critical role in regulating the self-renewal capacity, differentiation potential, and quiescence of stem cells. Many studies in recent years have revealed that metabolic pathways regulate various stem cell behaviors (e.g., selfrenewal, migration, and differentiation) by modulating energy production through glycolysis or oxidative phosphorylation and by regulating the generation of metabolites, which can modulate multiple signaling pathways. Therefore, a more comprehensive understanding of stem cell metabolism could allow us to establish optimal culture conditions and differentiation methods that would increase stem cell expansion and function for cell-based therapies. However, little is known about how metabolic pathways regulate various stem cell functions. In this context, we review the current advances in metabolic research that have revealed functional roles for mitochondrial oxidative phosphorylation, anaerobic glycolysis, and oxidative stress during the self-renewal, differentiation and aging of various adult stem cell types. These approaches could provide novel strategies for the development of metabolic or pharmacological therapies to promote the regenerative potential of stem cells and subsequently promote their therapeutic utility.

scholarly journals Molecular analysis of relapse in chronic myeloid leukemia after allogeneic bone marrow transplantation

Blood ◽  
1987 ◽  
Vol 70 (3) ◽  
pp. 873-876 ◽  
Author(s):  
TS Ganesan ◽  
GL Min ◽  
JM Goldman ◽  
BD Young
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Transplantation ◽  
Chronic Myeloid Leukemia ◽  
Marrow Transplantation ◽  
Myeloid Leukemia ◽  
Allogeneic Bone Marrow Transplantation ◽  
Allogeneic Bone Marrow ◽  
Leukemic Cells ◽  
Allogeneic Bone ◽  
Leukemic Clone

Abstract Four patients with Philadelphia (Ph′) positive chronic myeloid leukemia (CML) were studied before, after, and on relapse following allogeneic bone marrow transplantation (BMT). Southern analysis of DNA from cells collected before and at relapse after BMT was performed in order to investigate the origin of the leukemia at relapse. Using minisatellite probes we showed that the relapse occurred in cells of host origin in all four patients and this was confirmed with a Y chromosome specific probe in two male patients who had a female donor. Furthermore, using two probes for the breakpoint cluster region (bcr) on chromosome 22, we showed that leukemic cells at relapse bore identical rearrangements to those in the disease at time of presentation of each patient. We conclude that relapse in all four patients is due to re-emergence of the original leukemic clone.

scholarly journals Molecular analysis of relapse in chronic myeloid leukemia after allogeneic bone marrow transplantation

Blood ◽  
1987 ◽  
Vol 70 (3) ◽  
pp. 873-876
Author(s):  
TS Ganesan ◽  
GL Min ◽  
JM Goldman ◽  
BD Young
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Transplantation ◽  
Chronic Myeloid Leukemia ◽  
Marrow Transplantation ◽  
Myeloid Leukemia ◽  
Allogeneic Bone Marrow Transplantation ◽  
Allogeneic Bone Marrow ◽  
Leukemic Cells ◽  
Allogeneic Bone ◽  
Leukemic Clone

Four patients with Philadelphia (Ph′) positive chronic myeloid leukemia (CML) were studied before, after, and on relapse following allogeneic bone marrow transplantation (BMT). Southern analysis of DNA from cells collected before and at relapse after BMT was performed in order to investigate the origin of the leukemia at relapse. Using minisatellite probes we showed that the relapse occurred in cells of host origin in all four patients and this was confirmed with a Y chromosome specific probe in two male patients who had a female donor. Furthermore, using two probes for the breakpoint cluster region (bcr) on chromosome 22, we showed that leukemic cells at relapse bore identical rearrangements to those in the disease at time of presentation of each patient. We conclude that relapse in all four patients is due to re-emergence of the original leukemic clone.

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