scholarly journals Hedgehog Pathway Inhibition Hampers Sphere and Holoclone Formation in Rhabdomyosarcoma

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Ana Almazán-Moga ◽  
Patricia Zarzosa ◽  
Isaac Vidal ◽  
Carla Molist ◽  
Irina Giralt ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Soft Tissue ◽  
Soft Tissue Sarcoma ◽  
Common Type ◽  
Hedgehog Pathway ◽  
Cellular Heterogeneity ◽  
Self Renewal ◽  
Pathway Inhibition

Rhabdomyosarcoma (RMS) is the most common type of soft tissue sarcoma in children and can be divided into two main subtypes: embryonal (eRMS) and alveolar (aRMS). Among the cellular heterogeneity of tumors, the existence of a small fraction of cells called cancer stem cells (CSC), thought to be responsible for the onset and propagation of cancer, has been demonstrated in some neoplasia. Although the existence of CSC has been reported for eRMS, their existence in aRMS, the most malignant subtype, has not been demonstrated to date. Given the lack of suitable markers to identify this subpopulation in aRMS, we used cancer stem cell-enriched supracellular structures (spheres and holoclones) to study this subpopulation. This strategy allowed us to demonstrate the capacity of both aRMS and eRMS cells to form these structures and retain self-renewal capacity. Furthermore, cells contained in spheres and holoclones showed significant Hedgehog pathway induction, the inhibition of which (pharmacologic or genetic) impairs the formation of both holoclones and spheres. Our findings point to a crucial role of this pathway in the maintenance of these structures and suggest that Hedgehog pathway targeting in CSC may have great potential in preventing local relapses and metastases.

scholarly journals Between Fate Choice and Self-Renewal—Heterogeneity of Adult Neural Crest-Derived Stem Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Anna L. Höving ◽  
Beatrice A. Windmöller ◽  
Cornelius Knabbe ◽  
Barbara Kaltschmidt ◽  
Christian Kaltschmidt ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Neural Crest ◽  
Current Knowledge ◽  
Mapk Signaling ◽  
Cellular Heterogeneity ◽  
Self Renewal ◽  
The Impact

Stem cells of the neural crest (NC) vitally participate to embryonic development, but also remain in distinct niches as quiescent neural crest-derived stem cell (NCSC) pools into adulthood. Although NCSC-populations share a high capacity for self-renewal and differentiation resulting in promising preclinical applications within the last two decades, inter- and intrapopulational differences exist in terms of their expression signatures and regenerative capability. Differentiation and self-renewal of stem cells in developmental and regenerative contexts are partially regulated by the niche or culture condition and further influenced by single cell decision processes, making cell-to-cell variation and heterogeneity critical for understanding adult stem cell populations. The present review summarizes current knowledge of the cellular heterogeneity within NCSC-populations located in distinct craniofacial and trunk niches including the nasal cavity, olfactory bulb, oral tissues or skin. We shed light on the impact of intrapopulational heterogeneity on fate specifications and plasticity of NCSCs in their niches in vivo as well as during in vitro culture. We further discuss underlying molecular regulators determining fate specifications of NCSCs, suggesting a regulatory network including NF-κB and NC-related transcription factors like SLUG and SOX9 accompanied by Wnt- and MAPK-signaling to orchestrate NCSC stemness and differentiation. In summary, adult NCSCs show a broad heterogeneity on the level of the donor and the donors’ sex, the cell population and the single stem cell directly impacting their differentiation capability and fate choices in vivo and in vitro. The findings discussed here emphasize heterogeneity of NCSCs as a crucial parameter for understanding their role in tissue homeostasis and regeneration and for improving their applicability in regenerative medicine.

Evaluation of the Role of STAT3 in the Self-Renewal of Primitive Chronic Myelogenous Leukemia (CML) Stem Cells.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1076-1076
Author(s):  
Severine Marti N-Lannerée ◽  
Marie-Laure Bonnet ◽  
Caroline Mayeur-Rousse ◽  
Angelina Bertrand ◽  
Marie-Claude Meunier ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Chronic Myelogenous Leukemia ◽  
The Self ◽  
Myelogenous Leukemia ◽  
Cell Level ◽  
Self Renewal ◽  
Cd34 Cells ◽  
Stat3 Inhibition

Abstract In previous experiments we have demonstrated that BCR-ABL activates specifically STAT3 in the context of murine ES cells and in leukemic CD34+ cells in patients with chronic myelogenous leukemia. This activation occurs essentially through Tyr705 and Ser 727 phosphorylation and implicates Jak2 and MEK pathways (Coppo et al, Brit J Haematol, 2006). However, it is not known if STAT3 activation plays a role in the self-renewal of primitive stem cells or if it is predominantly involved in BCR-ABL-associated leukemogenesis. To determine the role of STAT3 at the primitive stem cell level, we have inhibited specifically STAT3 expression by using a shRNA-GFP-STAT3 construct which was lentivirally transduced into purified CD34+ cells from patients with CML. Western blot experiments determined the specificity of the shRNA-STAT3 construct in hematopoietic cell lines with specific inhibition of STAT3 with no interference with STAT1, STAT5a or STAT5b expression. 8 patients with CML at diagnosis were included in the study. CD34+ cells purified from cord blood (CB) or peripheral blood stem cell (PBCS) collects were used as controls. Each sample has been transduced with high titer lentiviruses expressing either sh-STAT3 or sh-luciferase control. After transduction, GFP+ cells were purified by cell-sorting and assayed in clonogenic assays as well as in longterm- culture assays in the presence of MS-5 stromal layers with weekly half-medium changes. At week+5, clonogenic assays were performed to evaluate the numbers of LTC-IC- derived progeny. The inhibition of STAT3 expression did not alter significantly the clonogenic cell potentials in CB-CD34+ cells (n=2) or PBSC (n=1) samples. In LTC-IC assays, STAT3 inhibition resulted in 1.8-fold reduced clonogenic output in one CB-CD34+ sample and increased the same clonogenic output by 6.7-fold in the second CB sample, with no effect in LTC-IC output in CD34+ cells purified from PBSC. Amongst CML samples, the numbers of LTC-IC-derived progenitors were reduced 3-fold after shRNA-mediated STAT3 inhibition in one patient (UPN2). In all other 7 patients, inhibition of STAT3 by shRNA led to either stable ( n = 1, UPN 4) or increased ( n= 6 ) LTC-IC derived clonogenic activity, with major increase of 5-week clonogenic output in 3 patients (luciferase vs shSTAT3 clonogenic outputs 28 vs 353 for UPN5; 130 vs 270 for UPN6; 295 vs 806 for UPN8). Thus, our results suggest that STAT3 activation seen in primary CML leukemic cells does not play a role in stem cell self-renewal detectable by LTC-IC assays. On the contrary, STAT3 inhibition seems to lead to a stimulating effect of primitive stem cells in the majority of the patients analyzed. These findings do not rule out the potential role of STAT3 in BCR-ABL induced leukemogenesis but suggest that STAT3 inhibition is not a clinically useful target at the stem cell level in CML.

scholarly journals Glioblastoma Stem Cells as a New Therapeutic Target for Glioblastoma

2015 ◽  
Vol 9 ◽  
pp. CMO.S30271 ◽  
Author(s):  
Rasime Kalkan
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Signaling Pathways ◽  
Therapeutic Target ◽  
Fatal Outcome ◽  
Cellular Heterogeneity ◽  
Cell Phenotype ◽  
Glioblastoma Stem Cells ◽  
Glioblastoma Stem Cell

Primary and secondary glioblastomas (GBMs) are two distinct diseases. The genetic and epigenetic background of these tumors is highly variable. The treatment procedure for these tumors is often unsuccessful because of the cellular heterogeneity and intrinsic ability of the tumor cells to invade healthy tissues. The fatal outcome of these tumors promotes researchers to find out new markers associated with the prognosis and treatment planning. In this communication, the role of glioblastoma stem cells in tumor progression and the malignant behavior of GBMs are summarized with attention to the signaling pathways and molecular regulators that are involved in maintaining the glioblastoma stem cell phenotype. A better understanding of these stem cell-like cells is necessary for designing new effective treatments and developing novel molecular strategies to target glioblastoma stem cells. We discuss hypoxia as a new therapeutic target for GBM. We focus on the inhibition of signaling pathways, which are associated with the hypoxia-mediated maintenance of glioblastoma stem cells, and the knockdown of hypoxia-inducible factors, which could be identified as attractive molecular target approaches for GBM therapeutics.

scholarly journals Aubergine and piRNAs repress the proto-oncogene Cbl for germline stem cell self-renewal

2017 ◽  
Author(s):  
Patricia Rojas-Ríos ◽  
Aymeric Chartier ◽  
Martine Simonelig
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Mrna Translation ◽  
Translational Repression ◽  
Germline Stem Cell ◽  
Germline Stem Cells ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Cell Lineages

AbstractPIWI proteins have essential roles in germ cells and stem cell lineages. In Drosophila, Piwi is required in somatic niche cells and germline stem cells (GSCs) for GSC self-renewal and differentiation. Whether and how other PIWI proteins are involved in GSC biology remains unknown. Here, we show that Aubergine (Aub), another PIWI protein, is intrinsically required in GSCs for their self-renewal and differentiation. Aub loading with piRNAs is essential for these functions. The major role of Aub is in self-renewal and depends on mRNA regulation. We identify the Cbl proto-oncogene, a regulator of mammalian hematopoietic stem cells, as a novel GSC differentiation factor. Aub represses Cbl mRNA translation for GSC self-renewal, and does so through recruitment of the CCR4-NOT complex. This study reveals the role of piRNAs and PIWI proteins in translational repression for stem cell homeostasis and highlights piRNAs as major post-transcriptional regulators in key developmental decisions.

scholarly journals PEDF Can Rescue the Inhibition of Injured Endothelial Cells on Hematopoietic Stem Cell Expansion Ex Vivo

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5008-5008
Author(s):  
Lingyu Zeng ◽  
Wenyi Lu ◽  
Lan Ding ◽  
Wen Ju ◽  
Jianlin Qiao ◽  
...  
Keyword(s):  
Stem Cells ◽  
Endothelial Cells ◽  
Stem Cell ◽  
Hematopoietic Stem Cells ◽  
Hematopoietic Stem Cell ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Mesenchymal Transition ◽  
Endothelial To Mesenchymal Transition

Introduction: Endothelial cells (ECs) provide a fertile niche for hematopoietic stem cell (HSC) maintenance, differentiation, and migration.Several studies have indicated that bone marrow (BM) vascular niche was impaired after HSC transplantation and severely inhibited hematopoietic reconstruction. Pigment epithelium-derived factor (PEDF) is an important potential cytoprotection and therapeutic agent for injured cells. The direct role of the injured endothelial cells on hematopoietic stem cells and whether PEDF has protective effect in this system remain unknown. This study aims to observe the influence of enjured ECs on HSCs and to explore the role of PEDF in endothelial-HSC coculture system. Methods: Injury of Endothelial cells by two important preparative regimenconditioning radiation and Busulfan respectively was evaluated with CCK8 assay. The expression of endothelial tight junctions(TJs),adherent junctions related molecules and endothelial to Mesenchymal Transition molecules such as ZO-1, Occludin,VE-cadherin, ICAM, α-SMA, CD31 and VCAM were detected by RT-qPCR, flow cytometry, immunofluorescence and western blot. The effects of injured endothelial cells on HSC self-renewal, differentiation, cell cycle and apoptosis were evaluated by flow cytometry, photography, viable cell count and clone formation assay. Hematopoiesis regulation factors SCF, IL-6, TGF-β and TNF-α were detected by ELISA. The protective effect of PEDF was also explored. Results: Both radiation and Busulfan could decrease cell viability of endothelial cells. The expression level of ZO-1, Occludin, VE-cadherin, ICAM, CD31 and VCAM were decreased and α-SMA was increased when EC exposed to radiation or Busulfan suggesting endothelial activation, impaired EC permeability and endothelial to Mesenchymal Transition after EC injured. Compared with normal endothelial cells and hematopoietic stem cell co-culture group, the HSC% of injured endothelial cells and hematopoietic stem cells co-cultured group were significantly decreased, the cell colony formation ability was decreased, the proportion of mature cells increased, and the damage of endothelial cells could not maintain the characteristics of HSC, weakened the self-renewal and multidirectional differentiation potential of HSC and promoted the maturation of HSC. After the administration of PEDF, endothelial to Mesenchymal Transition of EC was suppressed and the EC permeability was improved. Most importantly, the proportion of HSC was significantly increased, and the proportion of mature cells decreased in the coculture system. Conclusion: Injured endothelial cells can inhibit proliferation of hematopoietic stem cells, self-renewal and promote HSC differentiation. PEDF could ameliorate endothelial injury and promote HSC expansion by suppressing endothelial-mesenchymal transition and protecting TJs and AJs. Disclosures No relevant conflicts of interest to declare.

ETO2 Controls Hematopoietic Stem Cell Expansion.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 396-396
Author(s):  
Stephane Barakat ◽  
Julie Lambert ◽  
Guy Sauvageau ◽  
Trang Hoang
Keyword(s):  
Stem Cells ◽  
Transcription Factor ◽  
Stem Cell ◽  
Hematopoietic Stem Cells ◽  
Short Term ◽  
Self Renewal ◽  
Hematopoietic Stem

Abstract Abstract 396 Hematopoietic stem cells that provide short term reconstitution (ST-HSCs) as well as hematopoietic progenitors expand from a small population of long term hematopoietic stem cells (LT-HSCs) that are mostly dormant cells. The mechanisms underlying this expansion remain to be clarified. SCL (stem cell leukemia), is a bHLH transcription factor that controls HSC quiescence and long term competence. Using a proteomics approach to identify components of the SCL complex in erythroid cells, we and others recently showed that the ETO2 co-repressor limits the activity of the SCL complex via direct interaction with the E2A transcription factor. ETO2/CBF2T3 is highly homologous to ETO/CBFA2T1 and both are translocation partners for AML1. We took several approaches to identify ETO2 function in HSCs. We initially found by Q-PCR that ETO2 is highly expressed in populations of cells enriched in short-term HSC (CD34+Flt3-Kit+Sca+Lin-) and lympho-myeloid progenitors (CD34+Flt3+Kit+Sca+Lin-) and at lower levels in LT-HSCs (CD34-Kit+Sca+Lin- or CD150+CD48-Kit+Sca+Lin-). Next, the role of ETO2 was studied by overexpression or downregulation combined with transplantation in mice. Ectopic ETO2 expression induces a 100 fold expansion of LT-HSCs in vivo in transplanted mice associated with differentiation blockade in all lineages, suggesting that ETO2 overexpression overcomes the mechanisms that limit HSC expansion in vivo. We are currently testing the role of the NHR1 domain of ETO2 in this expansion. Conversely, shRNAs directed against ETO2 knock down ET02 levels in Kit+Sca+Lin- cells, causing a ten-fold decrease in this population after transplantation, associated with reduced short-term reconstitution in mice. Finally, proliferation assays using Hoechst and CFSE indicate that ETO2 downregulation affects cell division (CFSE) and leads to an accumulation of Kit+Sca+Lin-cells in G0/G1 state (Hoescht). In conclusion, we show that ETO2 is highly expressed in ST-HSCs and lymphoid progenitors, and controls their expansion by regulating cell cycle entry at the G1-S checkpoint. In addition, ETO2 overexpression converts the self-renewal of maintenance into self-renewal of expansion in LT-HSCs. Disclosures: No relevant conflicts of interest to declare.

Enforced Expression Of Mir-125b Promotes the in vivo expansion Of Human Linneg cord Blood Multi-Lymphoid Progenitors and Leukemia Stem Cells

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1648-1648
Author(s):  
Karin G. Hermans ◽  
Eric R. Lechman ◽  
Stephanie M. Dobson ◽  
Mark D. Minden ◽  
John E. Dick
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Fold Increase ◽  
Control Vector ◽  
Self Renewal ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Non Coding Rnas

Abstract Acute Myeloid Leukemia (AML) is a heterogeneous disease with a relapse rate of up to 80% depending on patient age and AML subtype. AML is organized as a functional cellular hierarchy and is sustained by a rare population of leukemia stem cells (LSC). Recent work suggests that LSC properties influence therapy response, overall survival, and disease relapse. In order to develop more effective novel therapies that target this rare cell population; it is imperative that we better understand LSCs at the molecular level. Although it is generally accepted that oncogenic mutations underlie cancer initiation and progression, most studies have focused on protein coding genes. However, there is increasing recognition that non-coding RNAs can also play a role in leukemogenesis. microRNAs (miRNA) are a family of small non-coding RNAs that function as important regulators of mRNA stability and translation of protein-coding genes with significant roles in maintenance of human hematopoietic stem cells (HSC) (Lechman et. al., Cell Stem Cell, 2012). To understand the functional role of miRNA in human hematopoiesis, we generated HSC- and leukemia stem cell (LSC)-specific microRNA (miRNA) profiles by microarray analysis of sorted cell fractions from umbilical cord blood (CB) and AML patient samples that have been validated in xenograft assays. We identified ten miRNA candidates over-represented in HSC and/or LSC. To determine whether these were functional and impacted on stem cell properties we transduced lineage depleted CB cells with lentivirus expressing either a candidate miRNA or control vector followed by transplantation into immune deficient mice. Three miRNAs (miR-125b, miR-130a, miR-155) conferred a competitive growth advantage while four miRNAs (miR-99a, miR133a, miR194, miR-196b) conferred a growth disadvantage. miR-125b, a top LSC array candidate, showed the most pronounced phenotype with an overt expansion of transduced cells (19% to 96.2%) and enlarged spleens (2.4 fold increase). Detailed flow cytometric analysis of the miR-125b human grafts in recipient mice revealed a greatly expanded proportion of multi-lymphoid progenitors (MLP), in comparison to HSC and multi-potent progenitors. Furthermore, upon enforced in vivo expression of miR-125b in three AML patient samples, we observed large increases in the primitive primitive CD34+CD117+ populations (CD34+: 2.4-4.6 fold increase; CD117+: 1.3-4.1 fold increase) and a decrease in the proportion of differentiated CD14+/CD15+ cells (CD14+: 6.2-7.6 fold decrease; CD15+: 1.2-6 fold decrease) in leukemic grafts. Limiting dilution assays into secondary recipients revealed up to a 34-fold increase in LSC frequency compared to control vector transduced AML cells. Overall, these data suggest that miR-125b normally functions in the limited self-renewal of lymphoid committed early progenitors and this function may be usurped during leukemogenesis to enhance LSC self-renewal. miR-125b belongs to an evolutionarily conserved family consisting of three paralogs (miR-125a; miR-125b1; miR-125b2). Recent studies present strong evidence for a role of the miR-125 family in normal and malignant murine hematopoiesis, yet comprehensive functional inconsistencies remain in regards to the precise roles for each paralog. We are currently carrying out additional enforced expression studies directly comparing these family members in vitro and in vivo in order to clarify the functional roles of miR-125a (a top HSC array candidate) and miR-125b (a top LSC array candidate) in both normal and malignant human hematopoiesis. These studies will determine whether the miR-125 family is a suitable target for therapy of hematological malignancies. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Glycolipids Recognized by A2B5 Antibody Promote Proliferation, Migration, and Clonogenicity in Glioblastoma Cells

Cancers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1267 ◽  
Author(s):  
Baeza-Kallee ◽  
Bergès ◽  
Soubéran ◽  
Colin ◽  
Denicolaï ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cell Proliferation ◽  
Stem Cell ◽  
Cell Growth ◽  
Self Renewal ◽  
Neuraminidase Treatment ◽  
Attractive Therapeutic Target ◽  
And Migration

A2B5+ cells isolated from human glioblastomas exhibit cancer stem cell properties. The A2B5 epitope belongs to the sialoganglioside family and is synthetized by the ST8 alpha-N-acetyl-neuraminidase α-2,8-sialyltransferase 3 (ST8SIA3) enzyme. Glycolipids represent attractive targets for solid tumors; therefore, the aim of this study was to decipher A2B5 function in glioblastomas. To this end, we developed cell lines expressing various levels of A2B5 either by genetically manipulating ST8SIA3 or by using neuraminidase. The overexpression of ST8SIA3 in low-A2B5-expressing cells resulted in a dramatic increase of A2B5 immunoreactivity. ST8SIA3 overexpression increased cell proliferation, migration, and clonogenicity in vitro and tumor growth when cells were intracranially grafted. Conversely, lentiviral ST8SIA3 inactivation in low-A2B5-expressing cells resulted in reduced proliferation, migration, and clonogenicity in vitro and extended mouse survival. Furthermore, in the shST8SIA3 cells, we found an active apoptotic phenotype. In high-A2B5-expressing cancer stem cells, lentiviral delivery of shST8SIA3 stopped cell growth. Neuraminidase treatment, which modifies the A2B5 epitope, impaired cell survival, proliferation, self-renewal, and migration. Our findings prove the crucial role of the A2B5 epitope in the promotion of proliferation, migration, clonogenicity, and tumorigenesis, pointing at A2B5 as an attractive therapeutic target for glioblastomas.

scholarly journals Expression of the stem cell self-renewal gene Hiwi and risk of tumour-related death in patients with soft-tissue sarcoma

Oncogene ◽  
2006 ◽  
Vol 26 (7) ◽  
pp. 1098-1100 ◽  
Author(s):  
H Taubert ◽  
T Greither ◽  
D Kaushal ◽  
P Würl ◽  
M Bache ◽  
...  
Keyword(s):  
Stem Cell ◽  
Soft Tissue ◽  
Soft Tissue Sarcoma ◽  
Self Renewal
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