Normal hematopoiesis and hematologic malignancies: Role of canonical Wnt signaling pathway and stromal microenvironment

2013 ◽  
Vol 1835 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Paul Faustin Seke Etet ◽  
Lorella Vecchio ◽  
Patrice Bogne Kamga ◽  
Elias Nchiwan Nukenine ◽  
Mauro Krampera ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Hematologic Malignancies ◽  
Canonical Wnt Signaling ◽  
Stromal Microenvironment ◽  
Canonical Wnt

The role of magnesium ions in bone regeneration involves the canonical Wnt signaling pathway

2019 ◽  
Vol 98 ◽  
pp. 246-255 ◽  
Author(s):  
Chu-Chih Hung ◽  
Amy Chaya ◽  
Kai Liu ◽  
Konstantinos Verdelis ◽  
Charles Sfeir
Keyword(s):  
Wnt Signaling ◽  
Bone Regeneration ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Magnesium Ions ◽  
Canonical Wnt Signaling ◽  
Canonical Wnt

AML Survival and In Vivo Progression Is Dependent On β-Catenin Signaling.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2398-2398
Author(s):  
Elena K Siapati ◽  
Magda Papadaki ◽  
Zoi Kozaou ◽  
Erasmia Rouka ◽  
Evridiki Michali ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Wnt Signaling ◽  
Signaling Pathway ◽  
Cell Lines ◽  
Wnt Signaling Pathway ◽  
Canonical Wnt Signaling ◽  
Down Regulation ◽  
Canonical Wnt

Abstract Abstract 2398 Poster Board II-375 B-catenin is the central effector molecule of the canonical wnt signaling pathway which governs cell fate and differentiation during embryogenesis as well as self-renewal of hematopoietic stem cells. Deregulation of the pathway has been observed in various malignancies including myeloid leukemias where over-expression of β-catenin is an independent adverse prognostic factor. In the present study we examined the functional outcome of stable β-catenin down-regulation through lentivirus-mediated expression of short hairpin RNA (shRNA). Reduction of the β-catenin levels in AML cell lines and patient samples diminished their in vitro proliferation ability without significantly affecting cell viability. In order to study the role of β-catenin in vivo, we transplanted leukemic cell lines with control or reduced levels of β-catenin in NOD/SCID animals and analyzed the engraftment levels in the bone marrow. We observed that while the immediate homing of the cells was not affected by the β-catenin levels, the bone marrow engraftment was directly dependent on its levels. Subsequent examination of bone marrow sections revealed that the reduced engraftment was partly due to the inability of the cells with lower β-catenin levels to dock to the endosteal niches, a finding that was confirmed in competitive repopulation assays with untransduced cells. When we examined the expression levels of adhesion molecules and integrins in engrafted cells in vivo, we observed a significant down-regulation of CD44 expression, a molecule that participates in the interaction of HSCs with the niche. Gene expression analysis of the components of the wnt signaling pathway showed that the pathway is subject to tight transcriptional regulation with minor expression deviations. We did, however, observe an up-regulation in components that participate in the non-canonical wnt signaling pathways such as the WNT5B ligand. Ongoing experiments in normal cord blood CD34+ cells will determine the in vivo role of β-catenin signaling in normal hematopoietic progenitors. In conclusion, our study showed that β-catenin comprises an integral part in the development and progression of AML in vivo, indicating that manipulation of the wnt pathway may hold a therapeutic potential in the management of AML. Disclosures: No relevant conflicts of interest to declare.

scholarly journals MULTIFACTORIAL PATHOGENESIS OF OSTEOPOROSIS AND THE ROLE OF GENES OF CANONICAL WNT-SIGNALING PATHWAY

2015 ◽  
Vol 18 (2) ◽  
pp. 15-19
Author(s):  
E A Mailyan
Keyword(s):  
Genetic Analysis ◽  
Wnt Signaling ◽  
Candidate Genes ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Scientific Research ◽  
Canonical Wnt Signaling ◽  
Canonical Wnt ◽  
Skeleton Formation

Nowadays, multifactorial nature of osteoporosis does not raise any doubts. Besides, it should be noted that about 90% disease cases are determined genetically. In 1990-s a number of candidate genes mutations were established which increase the risk of osteoporosis development. VDR, ESR1, ESR2, COLIA1, PTH, CT, CTR, BGP, AR, GCCR, TGFB1, IL-6, IGF1, IL-1ra, OPG were considered to be this kind of genes. New genetic analysis technologies (GWAS, etc.) gave the opportunity to expand our conception about multi genomic pathogenesis of osteoporosis and to point out a new group of genes candidate - a canonical Wnt-signaling pathway genes (CTNNB1, SOST, FOXC2, FOXL1, LRP4, LRP5, WNT1, WNT3, WNT16, DKK1, AXIN1, JAG1, etc.). Extreme importance of canonical Wnt-signaling pathway and genes given above in skeleton formation and its strength necessitate the need for further scientific research and opens perspective to improve osteoporosis diagnostics, treatment and prognosis.

Polycomb Repressive Complex 1 Enhances HSC Self-Renewal through Repressing the Canonical Wnt Signaling Pathway

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2378-2378
Author(s):  
Sisi Chen ◽  
Xicheng Liu ◽  
Rui Gao ◽  
Michihiro Kobayashi ◽  
Hao Yu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Wnt Signaling ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Canonical Wnt Signaling ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Canonical Wnt

Abstract Polycomb group (PcG) proteins are epigenetic gene silencers that have been implicated in stem cell maintenance and cancer development. Genetic and biochemical studies indicate that Polycomb group proteins exist in at least two protein complexes, Polycomb repressive complex 2 (PRC2) and Polycomb repressive complex 1 (PRC1), that act in concert to initiate and maintain stable gene repression. While studies on individual PRC1 component suggest that PRC1 plays an important role in hematopoiesis, how PRC1 regulates transcriptional repression in hematopoietic stem cells (HSCs) is largely unknown. Bmi1 and Mel18 are two major homologs of the PCGF subunit within the PRC1 complex. Bmi1 is a positive regulator of HSC self-renewal; however, the role of Mel18 in hematopoiesis has been controversial. To determine whether Bmi1 and Mel18 play redundant or distinct role in HSC self-renewal, we have generated Bmi1 and Mel18 conditional knockout mice. While acute deletion of Mel18 affects neither HSC frequency nor lineage commitment, we found that Mel18-deficent hematopoietic progenitor cells showed enhanced replating potential compared to wild type cells. To determine the role of Mel18 in HSC self-renewal, we performed serial HSC transplantation assays and found that the repopulating ability of Mel18-/- HSCs was significantly higher than WT HSCs in both primary and secondary transplantation assays, demonstrating that the loss of Mel18 enhances HSC self-renewal in vivo. We hypothesize that loss of Bmi1 and Mel18 in hematopoietic stem cells will disrupt PRC1 complex and impairs HSC self-renewal. To determine the role of PRC1 complex in HSCs, we analyzed the HSC behavior in Bmi1 and Mel18 double-deficient mice. While we found that Bmi1-deficient HSCs showed decreased repopulating potential compared to WT HSCs 16 weeks following transplantation, loss of both Bmi1 and Mel18 in HSCs resulted in even more severe self-renewal defects. In addition, loss of both Bmi1 and Mel18 resulted in decreased myeloid differentiation and increased B cell differentiation compared to WT, Mel18 KO, and Bmi1 KO mice. These data demonstrate that Bmi1 and Mel18 have non-overlapping role in HSC maintenance and lineage commitment. Given that Bmi1 plays a dominant role in the PRC1 complex, we decided to identify Bmi1 target genes in hematopoietic stem cells to understand how PRC1 complex regulates HSC self-renewal. We performed transcript profiling assays to compare gene expression in HSCs isolated from wild type and Bmi1-/- mice. The Ingenuity Pathways indicates that the canonical Wnt signaling is significantly elevated in Bmi1 null HSCs compared to WT HSCs. We confirmed the upregulation of several genes of the Wnt pathway in Bmi1 null HSCs by quantitative real-time PCR analysis. To determine whether Bmi1 can repress the activation of Wnt signaling in cells, we utilized the Top-Flash Wnt reporter system. Stimulation of 293T cells with Wnt3a activates the Wnt reporter and this activation can be efficiently repressed by Bmi1. Furthermore, we detected the association of Bmi1 with the Lef1, Tcf4, and Axin2 promoters in Baf3 cells by ChIP experiment. Thus, Bmi1 directly represses the expression of several Wnt genes in hematopoietic cells. To determine the functional significance of activation of Wnt signaling in Bmi1 null HSCs, we have generated R26StopFL Bmi1-Apcf/f-Mx1-Cre+ and Bmi1f/f-Ctnnb1f/f-Mx1-Cre+ mice. Loss of Apc in hematopoietic cells activates the Wnt signaling pathway and impairs HSC self-renewal. We found that expressing three-copies of Bmi1 from the Rosa26 locus enhanced the self-renewal capabilities of Apc deficient HSCs in transplantation assays. Ctnnb1 encodes b-catenin and loss of Ctnnb1 in HSCs diminishes Wnt signaling. Acute deletion of Bmi1 in hematopoietic compartments resulted in decreased bone marrow cellularity and enhanced apoptosis of hematopoietic stem and progenitor cells. Deletion of Ctnnb1 in Bmi1 null hematopoietic cells rescued these defects. Thus, impaired HSC self-renewal seen in Bmi1 null mice is, at least in part, due to activation of the canonical Wnt signaling pathway. Taken together, we demonstrate that PRC1 complex enhances HSC self-renewal through inhibiting the canonical Wnt signaling. Disclosures No relevant conflicts of interest to declare.

scholarly journals The Role of Canonical Wnt Signaling in Regulating Radioresistance

2018 ◽  
Vol 48 (2) ◽  
pp. 419-432 ◽  
Author(s):  
Yuanyuan Zhao ◽  
Leilei Tao ◽  
Jun Yi ◽  
Haizhu Song ◽  
Longbang Chen
Keyword(s):  
Wnt Signaling ◽  
Cancer Progression ◽  
Wnt Signaling Pathway ◽  
Growth Factor Receptor ◽  
Cancer Resistance ◽  
Canonical Wnt Signaling ◽  
Damage Repair ◽  
Epidermal Growth ◽  
Canonical Wnt

Radioresistance is a major obstacle in radiotherapy for cancer, and strategies are needed to overcome this problem. Currently, radiotherapy combined with targeted therapy such as inhibitors of phosphoinosotide 3-kinase/Akt and epidermal growth factor receptor signaling have become the focus of studies on radiosensitization. Apart from these two signaling pathways, which promote radioresistance, deregulation of Wnt signaling is also associated with the radioresistance of multiple cancers. Wnts, as important messengers in the tumor microenvironment, are involved in cancer progression mainly via canonical Wnt signaling. Their role in promoting DNA damage repair and inhibiting apoptosis facilitates cancer resistance to radiation. Thus, it seems reasonable to target Wnt signaling as a method for overcoming radioresistance. Many small-molecule inhibitors that target the Wnt signaling pathway have been identified and shown to promote radiosensitization. Therefore, a Wnt signaling inhibitor may help to overcome radioresistance in cancer therapy.

AB0070 Wnt and wisp1 expression in the synovium induces cartilage damage by skewing of tgf-beta signaling via the canonical wnt signaling pathway

2013 ◽  
Vol 72 (Suppl 3) ◽  
pp. A807.1-A807
Author(s):  
M. H. van den Bosch ◽  
A. B. Blom ◽  
P. L. van Lent ◽  
H. M. van Beuningen ◽  
F. A. van de Loo ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Cartilage Damage ◽  
Wnt Signaling Pathway ◽  
Tgf Beta ◽  
Canonical Wnt Signaling ◽  
Canonical Wnt
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