scholarly journals A Daple-Akt feed-forward loop enhances noncanonical Wnt signals by compartmentalizing β-catenin

2017 ◽  
Vol 28 (25) ◽  
pp. 3709-3723 ◽  
Author(s):  
Nicolas Aznar ◽  
Nina Sun ◽  
Ying Dunkel ◽  
Jason Ear ◽  
Matthew D. Buschman ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Cross Talk ◽  
Cellular Proliferation ◽  
Wnt Signaling Pathway ◽  
Colony Growth ◽  
Cell Contact ◽  
Long Distance ◽  
Canonical Wnt ◽  
The Impact ◽  
E Cadherin

Cellular proliferation is antagonistically regulated by canonical and noncanonical Wnt signals; their dysbalance triggers cancers. We previously showed that a multimodular signal transducer, Daple, enhances PI3-K→Akt signals within the noncanonical Wnt signaling pathway and antagonistically inhibits canonical Wnt responses. Here we demonstrate that the PI3-K→Akt pathway serves as a positive feedback loop that further enhances noncanonical Wnt signals by compartmentalizing β-catenin. By phosphorylating the phosphoinositide- (PI) binding domain of Daple, Akt abolishes Daple’s ability to bind PI3-P-enriched endosomes that engage dynein motor complex for long-distance trafficking of β-catenin/E-cadherin complexes to pericentriolar recycling endosomes (PCREs). Phosphorylation compartmentalizes Daple/β-catenin/E-cadherin complexes to cell–cell contact sites, enhances noncanonical Wnt signals, and thereby suppresses colony growth. Dephosphorylation compartmentalizes β-catenin on PCREs, a specialized compartment for prolonged unopposed canonical Wnt signaling, and enhances colony growth. Cancer-associated Daple mutants that are insensitive to Akt mimic a constitutively dephosphorylated state. This work not only identifies Daple as a platform for cross-talk between Akt and the noncanonical Wnt pathway but also reveals the impact of such cross-talk on tumor cell phenotypes that are critical for cancer initiation and progression.

scholarly journals Akt/PKB enhances non-canonical Wnt signals by compartmentalizing β-Catenin

2017 ◽  
Author(s):  
Nicolas Aznar ◽  
Nina Sun ◽  
Ying Dunkel ◽  
Jason Ear ◽  
Matthew D. Buschman ◽  
...  
Keyword(s):  
Cellular Proliferation ◽  
Colony Growth ◽  
Akt Pathway ◽  
Cell Contact ◽  
Long Distance ◽  
Recycling Endosomes ◽  
Dynein Motor ◽  
Canonical Wnt ◽  
The Impact ◽  
E Cadherin

AbstractCellular proliferation is antagonistically regulated by canonical and non-canonical Wnt signals; their dysbalance triggers cancers. It is widely believed that the PI3-K→ Akt pathway enhances canonical Wnt signals by affecting transcriptional activity and stability of β-catenin. Here we demonstrate that the PI3-K→Akt pathway also enhances non-canonical Wnt signals by compartmentalizing β-catenin. By phosphorylating the phosphoinositide(PI)-binding domain of a multimodular signal transducer, Daple, Akt abolishes Daple’s ability to bind PI3-P-enriched endosomes that engage dynein motor complex for long-distance trafficking of β-catenin/E-cadherin complexes to pericentriolar recycling endosomes (PCREs). Phosphorylation compartmentalizes Daple/β-catenin/E-cadherin complexes to cell-cell contact sites, enhances non-canonical Wnt signals, and thereby, suppresses colony growth. Dephosphorylation compartmentalizes β-catenin on PCREs, a specialized compartment for prolonged unopposed canonical Wnt signaling, and enhances colony growth. Cancer-associated Daple mutants that are insensitive to Akt mimic a constitutively dephosphorylated state. This work not only identifies Daple as a platform for crosstalk between Akt and the non-canonical Wnt pathway, but also reveals the impact of such crosstalk during cancer initiation and progression.

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.

scholarly journals The Regulation of Bone Metabolism and Disorders by Wnt Signaling

2019 ◽  
Vol 20 (22) ◽  
pp. 5525 ◽  
Author(s):  
Kazuhiro Maeda ◽  
Yasuhiro Kobayashi ◽  
Masanori Koide ◽  
Shunsuke Uehara ◽  
Masanori Okamoto ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Wnt Signaling ◽  
Bone Metabolism ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Osteoporosis Treatment ◽  
Biological Phenomena ◽  
Approximate Molecular Weight ◽  
Skeletal Disorders ◽  
Canonical Wnt

Wnt, a secreted glycoprotein, has an approximate molecular weight of 40 kDa, and it is a cytokine involved in various biological phenomena including ontogeny, morphogenesis, carcinogenesis, and maintenance of stem cells. The Wnt signaling pathway can be classified into two main pathways: canonical and non-canonical. Of these, the canonical Wnt signaling pathway promotes osteogenesis. Sclerostin produced by osteocytes is an inhibitor of this pathway, thereby inhibiting osteogenesis. Recently, osteoporosis treatment using an anti-sclerostin therapy has been introduced. In this review, the basics of Wnt signaling, its role in bone metabolism and its involvement in skeletal disorders have been covered. Furthermore, the clinical significance and future scopes of Wnt signaling in osteoporosis, osteoarthritis, rheumatoid arthritis and neoplasia are discussed.

Cell-to-cell contact influences proliferative marker expression and apoptosis in MIN6 cells grown in islet-like structures

2005 ◽  
Vol 288 (3) ◽  
pp. E502-E509 ◽  
Author(s):  
Melanie J. Luther ◽  
Emma Davies ◽  
Dany Muller ◽  
Moira Harrison ◽  
Adrian J. Bone ◽  
...  
Keyword(s):  
Cellular Proliferation ◽  
Kinase Inhibitors ◽  
Three Dimensional ◽  
Cell Aggregation ◽  
Cell Interactions ◽  
Cell Phenotype ◽  
Cell Contact ◽  
Min6 Cells ◽  
Primary Mouse ◽  
E Cadherin

Cell-to-cell interactions play an important role in the development and maintenance of the β-cell phenotype. Here, we have investigated whether E-cadherin plays a role in regulating the growth of insulin-secreting MIN6 cells configured as three-dimensional islet-like clusters (pseudoislets). Pseudoislets form by cell aggregation rather than by proliferation from individual cells and attain the size of primary mouse islets after ∼7 days of maintenance in culture. E-cadherin is known to mediate homotypic cell adhesion between β-cells and has also been implicated in a number of cellular processes, including proliferation, apoptosis, and differentiation. E-cadherin and its associated intracellular elements, α- and β-catenin, were upregulated in MIN6 pseudoislets. Pseudoislet formation was associated with an increased expression of cyclin-dependent kinase inhibitors and a concomitant downregulation of Ki67, suggesting an overall reduction in cellular proliferation. However, measurements of 5-bromo-2′-deoxyuridine incorporation revealed that there were no differences in the rate of MIN6 cell proliferation whether they were configured as monolayers or as pseudoislets, which is likely to be a result of their being a transformed cell line. Cells within pseudoislets were not necrotic, but apoptosis appeared to be upregulated in the islet-like structures. However, no differential expression of Fas and FasL was detected in monolayers and pseudoislets. These results suggest that cell-to-cell interactions within islet-like structures may initiate antiproliferative and proapoptotic signals.

Cross-talk between canonical Wnt signaling and the sirtuin-FoxO longevity pathway to protect against muscular pathology induced by mutant PABPN1 expression in C. elegans

2010 ◽  
Vol 38 (3) ◽  
pp. 425-433 ◽  
Author(s):  
Matthieu Y. Pasco ◽  
Hélène Catoire ◽  
J. Alex Parker ◽  
Bernard Brais ◽  
Guy A. Rouleau ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Cross Talk ◽  
Canonical Wnt Signaling ◽  
C Elegans ◽  
Canonical Wnt
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