scholarly journals Polycomb group genes Psc and Su(z)2 restrict follicle stem cell self-renewal and extrusion by controlling canonical and noncanonical Wnt signaling

2010 ◽  
Vol 24 (9) ◽  
pp. 933-946 ◽  
Author(s):  
X. Li ◽  
Y. Han ◽  
R. Xi
Keyword(s):  
Stem Cell ◽  
Wnt Signaling ◽  
Polycomb Group ◽  
Self Renewal ◽  
Polycomb Group Genes

scholarly journals Polycomb group genes in stem cell self-renewal: A double-edged sword

Epigenetics ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. 16-19 ◽  
Author(s):  
Yulong Su ◽  
Bowen Deng ◽  
Rongwen Xi
Keyword(s):  
Stem Cell ◽  
Polycomb Group ◽  
Self Renewal ◽  
Polycomb Group Genes

Epigenetic Regulation of Hematopoietic Stem Cell Self-Renewal by Polycomb Group Genes

2005 ◽  
Vol 81 (4) ◽  
pp. 294-300 ◽  
Author(s):  
Atsushi Iwama ◽  
Hideyuki Oguro ◽  
Masamitsu Negishi ◽  
Yuko Kato ◽  
Hiromitsu Nakauchi
Keyword(s):  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Epigenetic Regulation ◽  
Polycomb Group ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Polycomb Group Genes

scholarly journals Polycomb Group Genes Psc and Su(z)2 Maintain Somatic Stem Cell Identity and Activity in Drosophila

PLoS ONE ◽  
2012 ◽  
Vol 7 (12) ◽  
pp. e52892 ◽  
Author(s):  
Jose Rafael Morillo Prado ◽  
Xin Chen ◽  
Margaret T. Fuller
Keyword(s):  
Stem Cell ◽  
Polycomb Group ◽  
Somatic Stem Cell ◽  
Cell Identity ◽  
Polycomb Group Genes

scholarly journals Silencing of long noncoding RNA HOXA11-AS inhibits the Wnt signaling pathway via the upregulation of HOXA11 and thereby inhibits the proliferation, invasion, and self-renewal of hepatocellular carcinoma stem cells

2019 ◽  
Vol 51 (11) ◽  
pp. 1-20 ◽  
Author(s):  
Jun-Cheng Guo ◽  
Yi-Jun Yang ◽  
Jin-Fang Zheng ◽  
Jian-Quan Zhang ◽  
Min Guo ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Stem Cells ◽  
Stem Cell ◽  
Wnt Signaling ◽  
Signaling Pathway ◽  
Methylation Level ◽  
Wnt Signaling Pathway ◽  
The Self ◽  
Self Renewal

AbstractHepatocellular carcinoma (HCC) is a major cause of cancer-related deaths, but its molecular mechanisms are not yet well characterized. Long noncoding RNAs (lncRNAs) play crucial roles in tumorigenesis, including that of HCC. However, the role of homeobox A11 antisense (HOXA11-AS) in determining HCC stem cell characteristics remains to be explained; hence, this study aimed to investigate the effects of HOXA11-AS on HCC stem cell characteristics. Initially, the expression patterns of HOXA11-AS and HOXA11 in HCC tissues, cells, and stem cells were determined. HCC stem cells, successfully sorted from Hep3B and Huh7 cells, were transfected with short hairpin or overexpression plasmids for HOXA11-AS or HOXA11 overexpression and depletion, with an aim to study the influences of these mediators on the self-renewal, proliferation, migration, and tumorigenicity of HCC stem cells in vivo. Additionally, the potential relationship and the regulatory mechanisms that link HOXA11-AS, HOXA11, and the Wnt signaling pathway were explored through treatment with Dickkopf-1 (a Wnt signaling pathway inhibitor). HCC stem cells showed high expression of HOXA11-AS and low expression of HOXA11. Both HOXA11-AS silencing and HOXA11 overexpression suppressed the self-renewal, proliferation, migration, and tumorigenicity of HCC stem cells in vivo, as evidenced by the decreased expression of cancer stem cell surface markers (CD133 and CD44) and stemness-related transcription factors (Nanog, Sox2, and Oct4). Moreover, silencing HOXA11-AS inactivated the Wnt signaling pathway by decreasing the methylation level of the HOXA11 promoter, thereby inhibiting HCC stem cell characteristics. Collectively, this study suggested that HOXA11-AS silencing exerts an antitumor effect, suppressing HCC development via Wnt signaling pathway inactivation by decreasing the methylation level of the HOXA11 promoter.

The Expression of Polycomb Group Genes Products, Bmi1 and Mel-18, Regulate the Function of Murine Primitive Hematopoietic Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1261-1261
Author(s):  
Teruyuki Kajiume ◽  
Takashi Sato ◽  
Masao Kobayashi
Keyword(s):  
Gene Expression ◽  
Hematopoietic Cells ◽  
Inverse Function ◽  
Complex Form ◽  
Negative Control ◽  
Polycomb Group ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Polycomb Group Genes ◽  
Marrow Cells

Abstract The Polycomb group (PcG) genes (bmi1 and mel-18) known as negative control factors of the Hox gene is thought to regulate the differentiation and self-renewal of hematopoietic stem cells (HSCs). The loss of mel-18 results in the promotion of HSC self-renewal, and the increase of mel-18 expression inversely leads to the differentiation of HSCs. On the other hand, the loss of bmi1 does not lead to self-renewal activity of HSCs. In this study we examined the effect of expression of bmi1 and mel-18 on the role of function in murine HSCs. Lineage-negative, Sca1-positive, and cKit-positive primitive hematopoietic cells were purified and the expression of PcG protein was evaluated from the intra-nuclear distribution of PcG proteins. The Bmi1-positive hematopoietic cells barely contained Mel-18, and the Mel-18-positive cells barely contained Bmi1. the frequency of positive cells for both Bmi1 and Mel-18 was less than 0.5% of purified primitive hematopoietic cells. The expression levels of the PcG genes, bmi1 and mel-18, in HSCs were knocked down by siRNA and then gene expression was assessed by quantitative real-time PCR. The introduction of siRNA against bmi1 or mell-18 resulted in approximate 50 to 60% decrease of each gene expression without affecting another gene expression. Primary colony-forming activity of knocked down cells in response to stem cell factor, thrombopoietin and the ligand for flt3 was not affected by the induction of siRNA. However, secondary colony-forming activity from primary colony-forming cells in bmi1-knockdown cells was significantly decreased when compared with that of control cells. Conversely, the mel-18-knockdown cells significantly increased, suggesting that mel-18-knockdown cells are capable of proliferating activity. Finally, bone marrow reconstitutive activity was examined by using Ly5.1 and Ly5.2 system. While the bmi1-knockdown marrow cells decreased the reconstitutive activity, the mel-18-knockdown marrow cells showed the increase of engraftment activity after 6 months of transplantation. From these results, we consider that mel-18 and bmi1 have reciprocal functions in HSCs. Mammalian PcG protein complexes can be classified into two distinct types, Polycomb repressive complexes 1 and 2 (PRC1 and PRC2). The Mel-18 protein is a constituent of mammalian PRC1 together with M33, Bmi1 or rae28, and Scmh1. The Mel-18 protein is composed of 342 amino acids and the N-terminal region of the 102 amino acid, which includes the RING finger motif, shares 93% homology with Bmi1 protein. In addition, its secondary structure shows high homology with the Mel-18 and Bmi1 proteins. We hypothesized that the opposite function is expressed in HSCs because Mel-18 and Bmi1 share the same structure and compete when in the complex form. These results suggest that mel-18 and bmi1 have inverse function in HSCs and that the balance of Bmi1 and Mel-18 may regulate the fate of self-renewal and differentiation in HSCs.

Akt-Mediated Phosphorylation of Bmi1 Regulates Its Chromatin Association and Growth Promoting Properties.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3605-3605
Author(s):  
Yan Liu ◽  
Fan Liu ◽  
Xinyang Zhao ◽  
Goro Sashida ◽  
Anthony Deblasio ◽  
...  
Keyword(s):  
Stem Cell ◽  
Signaling Pathway ◽  
Conflicts Of Interest ◽  
Bone Marrow Failure ◽  
Akt Signaling ◽  
Polycomb Group ◽  
Akt Pathway ◽  
Akt Signaling Pathway ◽  
Self Renewal ◽  
Hematopoietic Stem

Abstract Abstract 3605 Poster Board III-541 The Polycomb group (PcG) protein Bmi1 maintains silencing of the Ink4a-Arf locus and plays a key role in stem cell self-renewal and oncogenesis. The phosphoinositide 3-kinase-Akt (PI3K-Akt) signaling pathway regulates cell survival, growth, metabolism, migration and angiogenesis. In response to acute Pten loss (which results in Akt activation), mouse embryonic fibroblasts (mefs) accumulate p16Ink4a and p19Arf and undergo senescence. Similarly, Bmi1 −/− mefs undergo premature senescence and accumulate p16Ink4a and p19Arf. PTEN and Bmi1 have similar effects on hematopoiesis; Pten deletion promotes hematopoietic stem cell (HSC) proliferation, resulting in HSC depletion, whereas loss of Bmi1 impairs HSC self-renewal capability, also leading to bone marrow failure. These similarities led us to examine whether the PI3K/Akt pathway functions upstream of Bmi1 to negatively regulate its function and indeed we found that PKB/Akt phosphorylates Bmi1 in vivo, which results in its dissociation from chromatin and in de-repression of the Ink4a-Arf locus. Furthermore, activation of the PI3K/Akt pathway suppresses the ability of Bmi1 to promote cell growth and tumourigenesis and decreases the global level of histone H2A ubiquitination. PI3K/Akt signaling is not active in hematopoietic stem cells, but it is active in more committed progenitor cells. Thus, phosphorylation and inactivation of Bmi1 by Akt may limit HSC self-renewal. Our study also provides a mechanism for the upregulation of p16Ink4a and p19Arf seen in cancer cells that have activation of the PI3K/Akt signaling pathway, and identifies important crosstalk between phosphorylation and chromatin structure. Disclosures: No relevant conflicts of interest to declare.

scholarly journals sFRP2 Suppression of Bone Morphogenic Protein (BMP) and Wnt Signaling Mediates Mesenchymal Stem Cell (MSC) Self-renewal Promoting Engraftment and Myocardial Repair

2010 ◽  
Vol 285 (46) ◽  
pp. 35645-35653 ◽  
Author(s):  
Maria P. Alfaro ◽  
Alicia Vincent ◽  
Sarika Saraswati ◽  
Curtis A. Thorne ◽  
Charles C. Hong ◽  
...  
Keyword(s):  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Wnt Signaling ◽  
Bone Morphogenic Protein ◽  
Myocardial Repair ◽  
Self Renewal

scholarly journals Wnt Signaling in the Niche Enforces Hematopoietic Stem Cell Quiescence and Is Necessary to Preserve Self-Renewal In Vivo

2008 ◽  
Vol 2 (3) ◽  
pp. 274-283 ◽  
Author(s):  
Heather E. Fleming ◽  
Viktor Janzen ◽  
Cristina Lo Celso ◽  
Jun Guo ◽  
Kathleen M. Leahy ◽  
...  
Keyword(s):  
Stem Cell ◽  
Wnt Signaling ◽  
Hematopoietic Stem Cell ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Stem Cell Quiescence ◽  
Cell Quiescence
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