scholarly journals A stemness screen reveals C3orf54/INKA1 as a promoter of human leukemia stem cell latency

Blood ◽  
2019 ◽  
Vol 133 (20) ◽  
pp. 2198-2211 ◽  
Author(s):  
Kerstin B. Kaufmann ◽  
Laura Garcia-Prat ◽  
Qiang Liu ◽  
Stanley W. K. Ng ◽  
Shin-Ichiro Takayanagi ◽  
...  

Abstract There is a growing body of evidence that the molecular properties of leukemia stem cells (LSCs) are associated with clinical outcomes in acute myeloid leukemia (AML), and LSCs have been linked to therapy failure and relapse. Thus, a better understanding of the molecular mechanisms that contribute to the persistence and regenerative potential of LSCs is expected to result in the development of more effective therapies. We therefore interrogated functionally validated data sets of LSC-specific genes together with their known protein interactors and selected 64 candidates for a competitive in vivo gain-of-function screen to identify genes that enhanced stemness in human cord blood hematopoietic stem and progenitor cells. A consistent effect observed for the top hits was the ability to restrain early repopulation kinetics while preserving regenerative potential. Overexpression (OE) of the most promising candidate, the orphan gene C3orf54/INKA1, in a patient-derived AML model (8227) promoted the retention of LSCs in a primitive state manifested by relative expansion of CD34+ cells, accumulation of cells in G0, and reduced output of differentiated progeny. Despite delayed early repopulation, at later times, INKA1-OE resulted in the expansion of self-renewing LSCs. In contrast, INKA1 silencing in primary AML reduced regenerative potential. Mechanistically, our multidimensional confocal analysis found that INKA1 regulates G0 exit by interfering with nuclear localization of its target PAK4, with concomitant reduction of global H4K16ac levels. These data identify INKA1 as a novel regulator of LSC latency and reveal a link between the regulation of stem cell kinetics and pool size during regeneration.

Blood ◽  
2001 ◽  
Vol 98 (10) ◽  
pp. 2966-2972 ◽  
Author(s):  
Hartmut Geiger ◽  
Jarrod M. True ◽  
Gerald de Haan ◽  
Gary Van Zant

Abstract The molecular mechanisms that regulate self-renewal and differentiation of very primitive hematopoietic stem and progenitor cells in vivo are still poorly understood. Despite the clinical relevance, even less is known about the mechanisms that regulate these cells in old animals. In a forward genetic approach, using quantitative trait linkage analysis in the mouse BXD recombinant inbred set, this study identified loci that regulate the genetic variation in the size of primitive hematopoietic cell compartments of young and old C57BL6 and DBA/2 animals. Linked loci were confirmed through the generation and analysis of congenic animals. In addition, a comparative linkage analysis revealed that the number of primitive hematopoietic cells and hematopoietic stem cells are regulated in a stage-specific and an age-specific manner.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1691-1691
Author(s):  
Kimberly Klarmann ◽  
Daniel Gough ◽  
Benyam Asefa ◽  
Chris Clarke ◽  
Katie Renn ◽  
...  

Abstract Members of the interferon inducible-200 (IFI-200) family of proteins inhibit cell growth and may be important mediators of differentiation. We examined IFI-204 and IFI-205 mRNA expression in purified populations of hematopoietic stem and progenitor cells at different stages of maturation using quantitative RT-PCR and found that their expression markedly increased during myeloid maturation. To evaluate the effect of IFI-205 and IFI-204 on hematopoietic stem cell (HSC) growth, we transduced these genes into mouse bone marrow cells (BMC) using retroviral vectors. The presence IFI-204 or IFI-205 resulted in a decrease in cell growth in response to hematopoietic growth factors. Further analysis revealed the infected cells were 98% c-Kit+ Sca-1+, indicative of the stem cell surface phenotype, suggesting they may be blocked in a primitive stage of maturation. When transplanted, BMC transduced with IFI-204 or IFI-205 failed to engraft lymphoid, myeloid, or erythroid lineages in both short and long term reconstitution assays, suggesting that constitutive expression of IFI-204 and IFI-205 inhibited HSC development both in vitro and in vivo. However, based on the quantitative RT-PCR results, which show that IFI-205 increased during myeloid differentiation, we know its endogenous, regulated expression must permit the cells to mature. Therefore, to study of the effects of these genes on differentiation we transduced the mulitpotential EML (erythroid, myeloid, lymphoid) cell line with IFI-204 and IFI-205 to circumvent severe growth inhibition caused by expression of IFI-204 and Ifi-205 in normal cells. Single cell analysis of EMLs transduced with IFI-205 demonstrated that expression of IFI-205 in this cell line did not significantly inhibit cell growth. We have isolated EML clones from the transduced cells and verified IFI-205 expression. In addition, we generated transgenic mice that express IFI-205 under control of the Vav and MRP8 promoters, and we identified transgenic lines that express IFI-205 at higher levels compared to wild type controls. Analysis of hematopoiesis in these animals is currently in progress. Altogether, our data demonstrate 3 findings: 1) IFI-204 and IFI-205 expression increases during myeloid development based on quantitative RT-PCR analysis, 2) constitutive expression of IFI-204 and -205 results in potent inhibition of growth and maturation of normal hematopoietic stem and progenitor cells in vivo and in vitro and 3) these genes did not significantly inhibit the proliferation of the EML cell line, which provides us with a means to study the mechanism by which these molecules regulate myeloid maturation. Finally, the considerable inhibitory effects of these family members on normal hematopoietic cell growth suggest their potential as therapeutic modalities for treatment of leukemia.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1293-1293
Author(s):  
Hong Qian ◽  
Sten Eirik W. Jacobsen ◽  
Marja Ekblom

Abstract Within the bone marrow environment, adhesive interactions between stromal cells and extracellular matrix molecules are required for stem and progenitor cell survival, proliferation and differentiation as well as their transmigration between bone marrow (BM) and the circulation. This regulation is mediated by cell surface adhesion receptors. In experimental mouse stem cell transplantation models, several classes of cell adhesion receptors have been shown to be involved in the homing and engraftment of stem and progenitor cells in BM. We have previously found that integrin a6 mediates human hematopoietic stem and progenitor cell adhesion to and migration on its specific ligands, laminin-8 and laminin-10/11 in vitro (Gu et al, Blood, 2003; 101:877). Using FACS analysis, the integrin a6 chain was now found to be ubiquitously (>95%) expressed in mouse hematopoietic stem and progenitor cells (lin−Sca-1+c-Kit+, lin−Sca-1+c-Kit+CD34+) both in adult bone marrow and in fetal liver. In vitro, about 70% of mouse BM lin−Sca-1+c-Kit+ cells adhered to laminin-10/11 and 40% adhered to laminin-8. This adhesion was mediated by integrin a6b1 receptor, as shown by functional blocking monoclonal antibodies. We also used a functional blocking monoclonal antibody (GoH3) against integrin a6 to analyse the role of the integrin a6 receptor for the in vivo homing of hematopoietic stem and progenitor cells. We found that the integrin a6 antibody inhibited the homing of bone marrow progenitors (CFU-C) into BM of lethally irradiated recipients. The number of homed CFU-C was reduced by about 40% as compared to cells incubated with an isotype matched control antibody. To study homing of long-term repopulating stem cells (LTR), antibody treated bone marrow cells were first injected intravenously into lethally irradiated primary recipients. After three hours, bone marrow cells of the primary recipients were analysed by competitive repopulation assay in secondary recipients. Blood analysis 16 weeks after transplantation revealed an 80% reduction of stem cell activity of integrin a6 antibody treated cells as compared to cells treated with control antibody. These results suggest that integrin a6 plays an important role for hematopoietic stem and progenitor cell homing in vivo.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1387-1387
Author(s):  
Hong Qian ◽  
Sten Eirik W. Jacobsen ◽  
Marja Ekblom

Abstract Homing of transplanted hematopoietic stem cells (HSC) in the bone marrow (BM) is a prerequisite for establishment of hematopoiesis following transplantation. However, although multiple adhesive interactions of HSCs with BM microenviroment are thought to critically influence their homing and subsequently their engraftment, the molecular pathways that control the homing of transplanted HSCs, in particular, of fetal HSCs are still not well understood. In experimental mouse stem cell transplantation models, several integrins have been shown to be involved in the homing and engraftment of both adult and fetal stem and progenitor cells in BM. We have previously found that integrin a6 mediates human hematopoietic stem and progenitor cell adhesion to and migration on its specific ligands, laminin-8 and laminin-10/11 in vitro (Gu et al, Blood, 2003; 101:877). Furthermore, integrin a6 is required for adult mouse HSC homing to BM in vivo (Qian et al., Abstract American Society of Hematology, Blood 2004 ). We have now found that the integrin a6 chain like in adult HSC is ubiquitously (>99%) expressed also in fetal liver hematopoietic stem and progenitor cells (lin−Sca-1+c-Kit+, LSK ). In vitro, fetal liver LSK cells adhere to laminin-10/11 and laminin-8 in an integrin a6b1 receptor-dependent manner, as shown by function blocking monoclonal antibodies. We have now used a function blocking monoclonal antibody (GoH3) against integrin a6 to analyse the role of the integrin a6 receptor for the in vivo homing of fetal liver hematopoietic stem and progenitor cells to BM. The integrin a6 antibody inhibited homing of fetal liver progenitors (CFU-C) into BM of lethally irradiated recipients. The number of homed CFU-C in BM was reduced by about 40% as compared to the cells incubated with an isotype matched control antibody. To study homing of long-term repopulating stem cells, BM cells were first incubated with anti-integrin alpha 6 or anti-integrin alpha 4 or control antibody, and then injected intravenously into lethally irradiated primary recipients. After three hours, BM cells of the primary recipients were analysed by competitive repopulation assay in secondary recipients. Blood analysis up to 16 weeks after transplantation showed that no reduction of stem cell reconstitution from integrin a6 antibody treated cells as compared to cells treated with control antibody. In accordance with this, fetal liver HSC from integrin a6 gene deleted embryos did not show any impairment of homing and engraftment in BM as compared to normal littermates. These results suggest that integrin a6 plays an important developmentally regulated role for homing of distinct hematopoietic stem and progenitor cell populations in vivo.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 83-83
Author(s):  
Alex J. Tipping ◽  
Cristina Pina ◽  
Anders Castor ◽  
Ann Atzberger ◽  
Dengli Hong ◽  
...  

Abstract Hematopoietic stem cells (HSCs) in adults are largely quiescent, periodically entering and exiting cell cycle to replenish the progenitor pool or to self-renew, without exhausting their number. Expression profiling of quiescent HSCs in our and other laboratories suggests that high expression of the zinc finger transcription factor GATA-2 correlates with quiescence. We show here that TGFβ1-induced quiescence of wild-type human cord blood CD34+ cells in vitro correlated with induction of endogenous GATA-2 expression. To directly test if GATA-2 has a causative role in HSC quiescence we constitutively expressed GATA-2 in human cord blood stem and progenitor cells using lentiviral vectors, and assessed the functional output from these cells. In both CD34+ and CD34+ CD38− populations, enforced GATA-2 expression conferred increased quiescence as assessed by Hoechst/Pyronin Y staining. CD34+ cells with enforced GATA-2 expression showed reductions in both colony number and size when assessed in multipotential CFC assays. In CFC assays conducted with more primitive CD34+ CD38− cells, colony number and size were also reduced, with myeloid and mixed colony number more reduced than erythroid colonies. Reduced CFC activity was not due to increased apoptosis, as judged by Annexin V staining of GATA-2-transduced CD34+ or CD34+ CD38− cells. To the contrary, in vitro cultures from GATA-2-transduced CD34+ CD38− cells showed increased protection from apoptosis. In vitro, proliferation of CD34+ CD38− cells was severely impaired by constitutive expression of GATA-2. Real-time PCR analysis showed no upregulation of classic cell cycle inhibitors such as p21, p57 or p16INK4A. However GATA-2 expression did cause repression of cyclin D3, EGR2, E2F4, ANGPT1 and C/EBPα. In stem cell assays, CD34+ CD38− cells constitutively expressing GATA-2 showed little or no LTC-IC activity. In xenografted NOD/SCID mice, transduced CD34+ CD38−cells expressing high levels of GATA-2 did not contribute to hematopoiesis, although cells expressing lower levels of GATA-2 did. This threshold effect is presumably due to DNA binding by GATA-2, as a zinc-finger deletion variant of GATA-2 shows contribution to hematopoiesis from cells irrespective of expression level. These NOD/SCID data suggest that levels of GATA-2 may play a part in the in vivo control of stem and progenitor cell proliferation. Taken together, our data demonstrate that GATA-2 enforces a transcriptional program on stem and progenitor cells which suppresses their responses to proliferative stimuli with the result that they remain quiescent in vitro and in vivo.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2955-2955
Author(s):  
Kolja Eppert ◽  
Karin G Hermans ◽  
John E. Dick

Abstract Abstract 2955 Emerging evidence shows that many cancers are organized as cellular hierarchies sustained by a subpopulation of cancer stem cells (CSC). It is thought that CSC properties influence therapy response, disease relapse, and overall survival. However, little is currently known about the molecular pathways that control stem cell behaviour. Our goal is to identify and characterize the molecular regulatory networks that govern the self-renewal and developmental program of human leukemia stem cells (LSC). To expand our understanding of LSC function, we selected genes from our previously established LSC transcriptional program as novel candidate regulators of stem cell function. The LSC transcriptional program was identified by fractionation of 16 primary human acute myeloid leukemia (AML) samples into four populations that were subjected to sensitive in vivo LSC assays. mRNA expression analysis was performed on each fraction and a global LSC-specific signature was determined from functionally defined LSC fractions. Using similar methodology, a hematopoietic stem cell (HSC) enriched gene signature was established from human cord blood. Bioinformatic analysis identified a core transcriptional program that LSCs and HSCs share, revealing the molecular machinery that underlies stemness properties. The LSC and HSC signatures have prognostic significance independent of other factors when validated on a large cohort of cytogenetically normal AML patients. We have begun experiments to determine the role of 17 candidate stem cell regulators using functional in vivo and in vitro assays. We first examined the effect of candidate gene overexpression in normal HSC using xenograft assays. Lineage negative cord blood cells were transduced with lentiviral overexpression vectors, injected into immune-deficient mice and engraftment of human cells was measured after 12 weeks. In the preliminary round of in vivo analysis, over-expression of GPR56 increased the engraftment capability of HSCs in immune-deficient recipients compared to control (p=0.0019). GPR56 is involved in cell adhesion and differentiation and evidence is accumulating for a role in various cancers such as melanoma, esophageal cancer, and glioma. By qPCR analysis we observed that GPR56 mRNA is more highly expressed in both LSC-enriched and primitive normal hematopoietic cell populations, including highly purified HSC, compared to more mature cell populations such as AML blasts and normal lineage committed progenitor cells. In conclusion, our LSC and HSC data established that determinants of stemness influence clinical outcome of AML patients. We have identified multiple novel candidate stem cell-related genes and provided evidence for a role for GPR56 in hematopoietic stem cell regulation. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1647-1647
Author(s):  
Eric R. Lechman ◽  
Bernhard Gentner ◽  
Peter van Galen ◽  
Stanley Wai-Kwong Ng ◽  
Kolja Eppert ◽  
...  

Abstract miRNA expression is deregulated in human acute myeloid leukemia (AML), however the impact of altered post-transcriptional programs on the genesis and maintenance of leukemia stem cells (LSC) remains undefined. In order to elucidate the functional role of miRNA in LSC and identify relevant miRNA candidates, we performed global miRNA profiling on sorted cell subpopulations from 16 AML patient and 3 umbilical cord blood samples (Eppert et al, Nature Medicine 2011). Supervised analysis guided by the ability of each sub-population to initiate leukemic engraftment after xenotransplantation into immune-deficient mice generated a unique miRNA signature. miR-126, a miRNA that we previously demonstrated to have a conserved role in maintaining hematopoietic stem cell (HSC) quiescence (Lechman et al. Cell Stem Cell, 2012), was more highly expressed in LSC-enriched fractions and chosen for further validation. To confirm that miR-126 is a bona fide LSC determinant, we utilized a bidirectional lentiviral reporter vector specific for miR-126 (Gentner et al. Science Translational Medicine, 2010) to sort cells from AML patient samples based on miR-126 bioactivity, and demonstrated that all in vivo leukemia-initiating capacity was confined to cells with elevated miR-126 bioactivity. Lentiviral enforced expression of miR-126 in primary AML patient samples significantly increased LSC frequency (3.5-52.3 fold) as assessed by limiting dilution transplantation assays, while diminishing cell cycle entry, differentiation marker expression (CD14,CD15) and colony forming potential. Sponge-mediated knockdown of miR-126 expression resulted in the opposite effects. These findings suggest that high levels of miR-126 bioactivity support self-renewal/maintenance of primitive AML cells at the cost of aberrant differentiation. Moreover, by preserving LSC quiescence miR-126 promoted chemotherapy resistance, in part through suppression of CDK3, a gatekeeper of G0 to G1 cell cycle transit. Enforced expression of CDK3 partially rescued the functional consequences of supra-physiological levels of miR-126 bioactivity, rendering previously resistant LSC susceptible to killing by AraC/Daunorubicin combination chemotherapy. Our human LSC miRNA signature, optimized by regression analysis on a cytogenetically normal AML patient cohort, was prognostic for survival in a large independent AML patient cohort (Ley et. al N Engl. J Med, 2013) further validating the clinical significance of miRNA as stem cell determinants. Furthermore, miRNA-126 alone was prognostic for survival in two independent cohorts of AML patients with normal cytogenetics. These data demonstrate a mechanistic role for miR-126 in governing intrinsic LSC properties and establish miR-126 as a critical biomarker for clinical outcome. Disclosures: Wang: Trillium Therapeutics/Stem Cell Therapeutics: Research Funding.


Blood ◽  
1995 ◽  
Vol 85 (6) ◽  
pp. 1472-1479 ◽  
Author(s):  
CL Li ◽  
GR Johnson

Murine bone marrow cells were fractionated by fluorescence-activated cell sorting into Rh123lo Lin- c-kit+ Ly6A+, Rh123hi Lin-c-kit+ Ly6A+, and Lin- c-kit+ Ly6A- populations within which most, if not all, of the hematopoietic activities of the marrow resided. The Rh123lo Lin- c- kit+Ly6A+ cells, which consist exclusively of small- or medium-sized lymphocyte-like cells, are highly enriched for long-term hematopoietic in vivo repopulating cells. The enrichment factor for these cells from the marrow was estimated as 2,000-fold. The Rh123hi Lin- c-kit+ Ly6A+ cells, although also highly enriched for day-12 spleen colony-forming units, were relatively depleted of long-term in vivo repopulation capacity. Most, if not all Lin- c-kit+ Ly6A- cells were Rb123hi. In contrast to both Rh123lo and Rh123hi Lin- c-kit+ Ly6A+ stem cell populations, the Lin- c-kit+ Ly6A- cells can be stimulated to proliferate in vitro in the presence of single cytokines, which is a characteristic of committed progenitor cells. No marked synergistic interactions between individual cytokines were observed with this cell population. Both Rh123hi Lin- c-kit+ Ly6A+ mature stem cell and Lin- c- kit+ Ly6A- progenitor cell populations displayed in vivo repopulation kinetics resembling those of the putative short-term hematopoietic repopulating cells.


Blood ◽  
2018 ◽  
Vol 132 (26) ◽  
pp. 2707-2721 ◽  
Author(s):  
Sebastien Jacquelin ◽  
Jasmin Straube ◽  
Leanne Cooper ◽  
Therese Vu ◽  
Axia Song ◽  
...  

Abstract Myeloproliferative neoplasms (MPNs) are a group of blood cancers that arise following the sequential acquisition of genetic lesions in hematopoietic stem and progenitor cells (HSPCs). We identify mutational cooperation between Jak2V617F expression and Dnmt3a loss that drives progression from early-stage polycythemia vera to advanced myelofibrosis. Using in vivo, clustered regularly interspaced short palindromic repeats (CRISPR) with CRISPR-associated protein 9 (Cas9) disruption of Dnmt3a in Jak2V617F knockin HSPC, we show that Dnmt3a loss blocks the accumulation of erythroid elements and causes fibrotic infiltration within the bone marrow and spleen. Transcriptional analysis and integration with human data sets identified a core DNMT3A-driven gene-expression program shared across multiple models and contexts of Dnmt3a loss. Aberrant self-renewal and inflammatory signaling were seen in Dnmt3a−/− Jak2V617F HSPC, driven by increased chromatin accessibility at enhancer elements. These findings identify oncogenic cooperativity between Jak2V617F-driven MPN and Dnmt3a loss, leading to activation of HSPC enhancer–driven inflammatory signaling.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Rasmus O Bak ◽  
Daniel P Dever ◽  
Andreas Reinisch ◽  
David Cruz Hernandez ◽  
Ravindra Majeti ◽  
...  

Precise and efficient manipulation of genes is crucial for understanding the molecular mechanisms that govern human hematopoiesis and for developing novel therapies for diseases of the blood and immune system. Current methods do not enable precise engineering of complex genotypes that can be easily tracked in a mixed population of cells. We describe a method to multiplex homologous recombination (HR) in human hematopoietic stem and progenitor cells and primary human T cells by combining rAAV6 donor delivery and the CRISPR/Cas9 system delivered as ribonucleoproteins (RNPs). In addition, the use of reporter genes allows FACS-purification and tracking of cells that have had multiple alleles or loci modified by HR. We believe this method will enable broad applications not only to the study of human hematopoietic gene function and networks, but also to perform sophisticated synthetic biology to develop innovative engineered stem cell-based therapeutics.


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