ctnnb1 - beta-catenin
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Pubmed
Journal: Cancer research
May/9/2001
Abstract
Inappropriate activation of the Wnt/beta-catenin signaling, resulting mainly from activating mutations of the beta-catenin gene, has been implicated recently in the development of hepatocellular carcinoma (HCC). We have generated transgenic mice expressing an oncogenic form of beta-catenin in their hepatocytes to analyze the effect of deregulated beta-catenin signaling on liver homeostasis. These mice rapidly developed hepatomegaly soon after birth, with livers three to four times heavier than those of nontransgenic littermates. The liver cell hyperplasia resulted from increased cell proliferation without any compensatory apoptosis. Although the genes encoding c-myc and cyclin D1 are potential targets of the beta-catenin signaling pathway, neither of them was overexpressed in the hyperplastic livers of beta-catenin transgenic mice. Thus, the key target genes of the beta-catenin signaling pathway in the liver remain to be identified.
Pubmed
Journal: Molecular biology of the cell
March/7/2010
Abstract
CASK is the mammalian ortholog of LIN2, a component of the LIN2/7/10 protein complex that targets epidermal growth factor receptor (EGFR) to basolateral membranes in Caenorhabditis elegans. A member of the MAGUK family of scaffolding proteins, CASK resides at basolateral membranes in polarized epithelia. Its interaction with LIN7 is evolutionarily conserved. In addition, CASK forms a complex with another MAGUK, the DLG1 tumor suppressor. Although complete knockout of CASK is lethal, the gene is X-linked, enabling us to generate heterozygous female adults that are mosaic for its expression. We also generated intestine-specific CASK knockout mice. Immunofluorescence analysis revealed that in intestine, CASK is not required for epithelial polarity or differentiation but is necessary for the basolateral localization of DLG1 and LIN7C. However, the subcellular distributions of DLG1 and LIN7C are independent of CASK in the stomach. Moreover, CASK and LIN7C show normal localization in dlg1(-/-) intestine. Despite the disappearance of basolateral LIN7C in CASK-deficient intestinal crypts, this epithelium retains normal localization of LIN7A/B, EGFR and ErbB-2. Finally, crypt-to-villus migration rates are unchanged in CASK-deficient intestinal epithelium. Thus, CASK expression and the appropriate localization of DLG1 are not essential for either epithelial polarity or intestinal homeostasis in vivo.
Pubmed
Journal: Development (Cambridge, England)
December/10/2006
Abstract
In the postimplantation mouse embryo, axial patterning begins with the restriction of expression of a set of genes to the distal visceral endoderm (DVE). This proximodistal (PD) axis is subsequently transformed into an anteroposterior axis as the VE migrates anteriorly to form the anterior visceral endoderm (AVE). Both Nodal and Wnt signaling pathways are involved in these events. We show here that loss of function in the adenomatous polyposis coli gene (Apc) leads to constitutive beta-catenin activity that induces a proximalization of the epiblast with the activation of a subset of posterior mesendodermal genes, and loss of ability to induce the DVE. The loss of some DVE genes such as Hex and goosecoid is rescued in chimeras where only the epiblast was wild type; however, these DVE markers were no longer restricted distally but covered the entire epiblast. Thus, the Apc gene is needed in both embryonic and extraembryonic lineages for normal PD patterning around implantation, suggesting that early restricted activation of the Wnt pathway may be important for initiating axial asymmetries. In addition, we found that nuclear beta-catenin and other molecular markers are asymmetrically expressed by 4.5 days.
Pubmed
Journal: Molecular biology of the cell
June/3/2007
Abstract
Using phage display, we identified Na+/H+ exchanger regulatory factor (NHERF)-2 as a novel binding partner for the cadherin-associated protein, beta-catenin. We showed that the second of two PSD-95/Dlg/ZO-1 (PDZ) domains of NHERF interacts with a PDZ-binding motif at the very carboxy terminus of beta-catenin. N-cadherin expression has been shown to induce motility in a number of cell types. The first PDZ domain of NHERF is known to bind platelet-derived growth factor-receptor beta (PDGF-Rbeta), and the interaction of PDGF-Rbeta with NHERF leads to enhanced cell spreading and motility. Here we show that beta-catenin and N-cadherin are in a complex with NHERF and PDGF-Rbeta at membrane ruffles in the highly invasive fibrosarcoma cell line HT1080. Using a stable short hairpin RNA system, we showed that HT1080 cells knocked down for either N-cadherin or NHERF had impaired ability to migrate into the wounded area in a scratch assay, similar to cells treated with a PDGF-R kinase inhibitor. Cells expressing a mutant NHERF that is unable to associate with beta-catenin had increased stress fibers, reduced lamellipodia, and impaired cell migration. Using HeLa cells, which express little to no PDGF-R, we introduced PDGF-Rbeta and showed that it coimmunoprecipitates with N-cadherin and that PDGF-dependent cell migration was reduced in these cells when we knocked-down expression of N-cadherin or NHERF. These studies implicate N-cadherin and beta-catenin in cell migration via PDGF-R-mediated signaling through the scaffolding molecule NHERF.
Pubmed
Journal: Calcified tissue international
June/2/2010
Abstract
The Wnt pathway has a bifunctional role in bone mass regulation, influencing osteoblasts and osteoclasts. The Wnt pathway genes are therefore candidate genes for susceptibility to osteoporosis. In our study, we focused on the effects of polymorphisms in selected Wnt pathway genes: low-density lipoprotein receptor-related proteins 5 and 6 (LRP5 and LRP6), Dickkopf1 (DKK1), sclerostin (SOST), and beta-catenin (CTNNB1). We genotyped 652 subjects for the following polymorphisms: A1330V in LRP5; I1062V in LRP6; E232K in DKK1; D32Y, G34V, and N287S in CTNNB1; and -1397_-1396insGGA in SOST. Bone mineral density (BMD) was also measured. The allele frequencies were as follows: for A1330V C:T = 87%:13%, for I1062V C:T = 20%:80%, and for -1397_-1396insGGA-:GGA = 64%:36%. The studied nucleotide changes in the DKK1 and CTNNB1 genes were shown not to be polymorphic. In a Slovenian population, no association was shown between lumbar spine and femoral neck BMD in A1330V (P = 0.151 and 0.243) and in I1062V (P = 0.209 and 0.405). We observed a difference between SOST genotypes, corresponding to an allele dose effect, which was borderline significant for lumbar spine and femoral neck BMD (P = 0.047 and 0.085); but this did not survive the adjustment for multiple testing. These results indicate that a larger sample size would be necessary to detect these subtle effects. Our results suggest that A1330V in LRP5, I1062V in LRP6, and -1397_-1396insGGA in SOST are not associated with BMD in the Slovenian population.
Pubmed
Journal: Development (Cambridge, England)
May/10/2009
Abstract
Impaired cardiac muscle growth and aberrant myocyte arrangement underlie congenital heart disease and cardiomyopathy. We show that cardiac-specific inactivation of the murine homeobox transcription factor Prox1 results in the disruption of expression and localisation of sarcomeric proteins, gross myofibril disarray and growth-retarded hearts. Furthermore, we demonstrate that Prox1 is required for direct transcriptional regulation of the genes encoding the structural proteins alpha-actinin, N-RAP and zyxin, which collectively function to maintain an actin-alpha-actinin interaction as the fundamental association of the sarcomere. Aspects of abnormal heart development and the manifestation of a subset of muscular-based disease have previously been attributed to mutations in key structural proteins. Our study reveals an essential requirement for direct transcriptional regulation of sarcomere integrity, in the context of enabling foetal cardiomyocyte hypertrophy, maintenance of contractile function and progression towards inherited or acquired myopathic disease.
Pubmed
Journal: The Journal of biological chemistry
June/17/2009
Abstract
Wnt-5a is a non-transforming Wnt protein that is implicated in cell polarity, adhesion, and motility. We have previously shown that low expression of Wnt-5a is a predictor of shorter disease-free survival in human breast cancer. Here, we investigated whether beta-catenin/E-cadherin-mediated cell-cell adhesion was affected by loss of Wnt-5a in breast carcinomas, thereby promoting a metastatic behavior of the tumor. We show that Wnt-5a stimulation of human breast epithelial cells leads to an increased Ca(2+)-dependent cell-cell adhesion. Furthermore, Wnt-5a/casein kinase Ialpha (CKIalpha)-specific Ser-45 phosphorylation of beta-catenin is associated with an increased complex formation of beta-catenin/E-cadherin. Mutation of Ser-45 decreases the beta-catenin/E-cadherin association. Also, the inhibitory effect of Wnt-5a on breast epithelial cell invasion is reduced upon mutation of beta-catenin-Ser-45. The Wnt-5a-CKIalpha-induced Ser-45 phosphorylation does not lead to degradation of beta-catenin. Finally we show that human breast cancers lacking Wnt-5a protein have a significantly lower level of membrane-associated beta-catenin. Down-regulation of Wnt-5a expression and subsequent reduction of membrane-associated beta-catenin in invasive breast cancer, can therefore contribute to a decreased cell-cell adhesion and increased motility resulting in a higher probability for metastatic disease.
Pubmed
Journal: Molecular and cellular biology
May/9/2004
Abstract
Constitutive activation of the Wnt/beta-catenin signaling pathway is a notable feature of a large minority of cases of malignant melanoma, an aggressive and increasingly common cancer. The identification of target genes downstream from this pathway is therefore crucial to our understanding of the disease. The POU domain transcription factor Brn-2 has been implicated in control of proliferation and melanoma survival, and its expression is strongly upregulated in melanoma. We show here that in vivo Brn-2 is expressed in melanocytes but not in embryonic day 11.5 melanoblasts and that its expression is directly controlled by the Wnt/beta-catenin signaling pathway in melanoma cell lines and in transgenic mice. Moreover, silent interfering RNA-mediated inhibition of Brn-2 expression in melanoma cells overexpressing beta-catenin results in significantly decreased proliferation. These results, together with the observation that BRAF signaling also induces Brn-2 expression, reveal that Brn-2 is a focus for the convergence of two key melanoma-associated signaling pathways that are linked to cell proliferation.
Pubmed
Journal: The Journal of biological chemistry
February/6/2005
Abstract
beta-Catenin and plakoglobin are related proteins involved in the regulation of adherens junctions and desmosomes. Moreover, by binding to Tcf-4, they can act as transcriptional modulators of genes involved in embryonic development and tumorigenesis. However, they associate to distinct Tcf-4 subdomains causing opposing effects on Tcf-4 binding to DNA: whereas beta-catenin does not affect this binding, plakoglobin prevents it. Both proteins are composed by two N- and C-tails and a central armadillo repeat domain. Interaction of Tcf-4, as well as other desmosomal or adherens junction components, with beta-catenin or plakoglobin takes place through the central armadillo domain. Here we show that, as reported for beta-catenin, plakoglobin terminal tails also interact with the central domain and regulate the ability of this region to bind to different cofactors. Moreover the specificity of the interaction of beta-catenin and plakoglobin with different subdomains in Tcf-4 or with other junctional components resides within the terminal tails and not in the armadillo domain. For instance, a chimeric protein in which the central domain of beta-catenin was replaced by that of plakoglobin presented the same specificity as wild-type beta-catenin. Therefore, the terminal tails of these proteins are responsible for discerning among binding of factors to the armadillo domain. These results contribute to the understanding of the molecular basis of the interactions established by these key regulators of epithelial tumorigenesis.
Pubmed
Journal: Glia
February/23/2017
Abstract
Ischemia not only leads to tissue damage, but also induces seizures, which in turn worsens the outcome of ischemia. Recent studies have revealed the impaired homeostatic functions of reactive astrocytes, which were thought to facilitate the development of seizures. However, how this phenotype of reactive astrocytes is regulated remains unclear. Here, using pentylenetetrazole (PTZ)-kindling model, we investigated the roles of reactive astrocytes and their intracellular Wnt/β-catenin signaling in the ischemia-increased seizure susceptibility. Our data showed that somatosensory cortical ischemia significantly increased the susceptibility to PTZ-induced seizure. Genetic ablation of Nestin-positive reactive astrocytes significantly decreased the incidence and severity of seizures. By using a Wnt signaling reporter mice line Topgal mice, we found that Wnt/β-catenin signaling was upregulated in reactive astrocytes after ischemia. Depletion of β-catenin in reactive astrocytes significantly decreased the susceptibility of seizures and the expression of c-Fos induced by PTZ in the ischemic cortex. Overexpression of β-catenin in reactive astrocytes, in contrast, significantly increased seizure susceptibility and the expression of c-Fos. Furthermore, the expression of aquaporin-4 (AQP-4) and inwardly rectifying K(+) channel 4.1 (Kir4.1), two molecules reportedly associated with seizure development, was oppositely affected in reactive astrocytes with β-catenin depletion or overexpression. Taken together, these data indicated that astrocytic Wnt/β-catenin signaling accounts, at least partially, for the ischemia-increased seizure susceptibility. Inhibiting Wnt/β-catenin signaling may be utilized in the future for preventing postischemic seizures.
Pubmed
Journal: Biochemical and biophysical research communications
September/5/2012
Abstract
Multiple myeloma (MM) is thrombogenic as a consequence of multiple hemostatic effects. Overexpression of β-catenin has been observed in several types of malignant tumors, including MM. However, the relationship between β-catenin expression and MM remains unclear. In the present study, RNA interference was used to inhibit β-catenin expression in RPMI8226 cells. RT-PCR and Western blotting analyses showed that β-catenin mRNA and protein expression were markedly down-regulated by CTNNB1 shRNA. Western blotting showed that the protein levels of cyclin D1 and glutamine synthetase were downregulated and supported the transcriptional regulatory function of β-catenin. The MTT assay showed that CTNNB1 shRNA could have significant inhibitory effects on the proliferation of RPMI8226 cells. The TOPflash reporter assay demonstrated significant downregulation after CTNNB1 shRNA transfection in RPMI8226 cells. Flow cytometric analyses also showed significantly profound apoptosis in CTNNB1 shRNA cells. We found CTNNB1 silence led to growth inhibition of MM growth in vivo. Immunohistochemical analyses showed that c-myc and β-catenin were reduced in CTNNB1 shRNA tumor tissues, but that expression of cleaved caspase-3 was increased. These results show that β-catenin could be a new therapeutic agent that targets the biology of MM cells.
Pubmed
Journal: Zhonghua xue ye xue za zhi = Zhonghua xueyexue zazhi
September/29/2009
Abstract
OBJECTIVE
To investigate the expression of beta-catenin in patients with leukemia and explore its significance in leukemias.
METHODS
RT-PCR was used to detect the expression of beta-catenin in bone marrow mononuclear cells (BMMNCs) from patients with leukemia. Immunocytochemistry was in some of patients to detect the distribution of beta-catenin at the same time. The clinical significance of beta-catenin was analyzed in combination with patients' clinical information.
RESULTS
Expression of beta-catenin was statistically higher in acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL) samples than in normal donors (P = 0.001 and 0.016 respectively) and chronic phase chronic myeloid leukemia (CML) patients (P = 0.001 and P = 0.008 respectively), while there was no statistic difference between AML and ALL patients (P = 0.58). In addition, beta-catenin expression in chronic phase CML patients was like that in normal donors (P = 0.49), but increased significantly in blast crisis and accelerated phase. Immunocytochemical analysis revealed that BMMNCs from normal donors expressed beta-catenin on the plasma membrane and cytoplasma, while those from acute leukemia expressed beta-catenin to varying degrees in the nucleus as well. The expression of beta-catenin gene statistically showed the highest level in M5 (n = 15) and the lowest level in M3 (n = 18). No clinical features, such as, age, initial WBC count, therapy response rate, blast cell numbers or cytogenetic risk was found to be correlated with the expression of beta-catenin excepting for CD34+ positive rate (P = 0.004) in AML.
CONCLUSIONS
As a key mediator of Wnt signal transduction way, overexpression of beta-catenin in leukemia cells indicates that it might be aberrantly activated in acute leukemia, accelerated or blastic phase of CML.
Pubmed
Journal: Nature neuroscience
August/29/2007
Abstract
The polarity and adhesion of radial glial cells (RGCs), which function as progenitors and migrational guides for neurons, are critical for morphogenesis of the cerebral cortex. These characteristics largely depend on cadherin-based adherens junctions, which anchor apical end-feet of adjacent RGCs to each other at the ventricular surface. Here, we show that mouse numb and numb-like are required for maintaining radial glial adherens junctions. Numb accumulates in the apical end-feet, where it localizes to adherens junction-associated vesicles and interacts with cadherins. Numb and Numbl inactivation in RGCs decreases proper basolateral insertion of cadherins and disrupts adherens junctions and polarity, leading to progenitor dispersion and disorganized cortical lamination. Conversely, overexpression of Numb prolongs RGC polarization, in a cadherin-dependent manner, beyond the normal neurogenic period. Thus, by regulating RGC adhesion and polarity, Numb and Numbl are required for the tissue architecture of neurogenic niches and the cerebral cortex.
Pubmed
Journal: Developmental biology
January/24/2013
Abstract
Androgens initiate a complex network of signals within the UGS that trigger prostate lineage commitment and bud formation. Given its contributions to organogenesis in other systems, we investigated a role for canonical Wnt signaling in prostate development. We developed a new method to achieve complete deletion of beta-catenin, the transcriptional coactivator required for canonical Wnt signaling, in early prostate development. Beta-catenin deletion abrogated canonical Wnt signaling and yielded prostate rudiments that exhibited dramatically decreased budding and failed to adopt prostatic identity. This requirement for canonical Wnt signaling was limited to a brief critical period during the initial molecular phase of prostate identity specification. Deletion of beta-catenin in the adult prostate did not significantly affect organ homeostasis. Collectively, these data establish that beta-catenin and Wnt signaling play key roles in prostate lineage specification and bud outgrowth.
Pubmed
Journal: Zhonghua gan zang bing za zhi = Zhonghua ganzangbing zazhi = Chinese journal of hepatology
December/14/2011
Abstract
OBJECTIVE
To investigate the role and significance of Wnt/beta-catenin signaling pathway regulating GSK-3beta, STAT3, Smad3 and TERT in hepatocellular carcinoma (HCC).
METHODS
The HCC cell line HepG2 was transfected with small interfering RNA (siRNA) directed against beta-catenin. Proteins were extracted and the expressions of beta-catenin, GSK-3beta, p-GSK-3beta, STAT3, Smad3 and TERT were detected by Western blot at 72 h and 96 h respectively after transfection.
RESULTS
beta-catenin expression was inhibited at both time points and the expression at 96 h was higher than that at 72 h (t = 4.43, P < 0.05). Interestingly, GSK-3beta and p-GSK-3beta expressions increased gradually at 72 and 96 h (tGSK-3beta= 4.98, tp-GSK-3beta= 29.83, P < 0.05) respectively, and STAT3 expression showed no alteration after transfection (F = 0.49, P > 0.05). Smad3 expression was increased at 72 h (t = 10.67, P < 0.05) and decreased to normal at 96 h (t = 1.26, P < 0.05), while TERT expression decreased at 72 h (t = 4.18, P is less than 0.05) and increased to normal at 96 h (t = 1.26, P > 0.05).
CONCLUSIONS
Wnt/beta-catenin signaling pathway is related to the expressions of GSK-3beta, Smad3 and TERT, but perhaps not related to STAT3 protein expression in HCC. It suggested that Wnt/beta-catenin signaling pathway might participate in HCC genesis and development through regulating the above three factors.
Pubmed
Journal: PloS one
October/12/2017
Abstract
Wnt signaling regulates self-renewal and fate commitment of stem and progenitor cells in development and homeostasis. Leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5) is a co-receptor for Wnt signaling that marks highly proliferative stem and progenitor cells in many epithelial tissue types. Wnt signaling instructs neural developmental and homeostatic processes; however, Lgr5 expression in the developing and adult brain has not been characterized. Here we report that Lgr5 is expressed in the postnatal cerebellum during the maturation and synaptogenesis of cerebellar granule neurons (CGNs), processes controlled by Wnt signaling. Using a transgenic reporter mouse for in vivo Lgr5 expression analysis and lineage tracing, we reveal that Lgr5 specifically identified CGNs and was restricted temporally to the CGN maturation phase within the internal granule layer, but absent in the adult brain. Cells marked by Lgr5 were lineage restricted, post-mitotic and long-lived. The ligand for Lgr5, R-spondin, was secreted in a paracrine fashion that evolved during the maturation of CGNs, which coincided with the Lgr5 expression pattern. Our findings provide potential new insight into the critical regulation of Wnt signaling in the developing cerebellum and support a novel role for Lgr5 in the regulation of post-mitotic cells.
Pubmed
Journal: Romanian journal of morphology and embryology = Revue roumaine de morphologie et embryologie
April/5/2015
Abstract
OBJECTIVE
The present study was aimed to investigate the importance of Pin1 expression in Squamous Cell Carcinoma (SCC) of cervix and to assess its level with β-catenin and APC to understand the possible involvement of Pin1 in the regulation of these proteins and subsequent activation of Wnt/β-catenin signaling.
METHODS
Expression of Pin1, β-catenin and APC was examined in 153 SCC patients by immunohistochemistry and revalidated by western blotting.
RESULTS
Of the 153 SCC analyzed, Pin1 was overexpressed in 73 (47.71%) cases. Loss of membranous β-catenin was noticed in 117 (76.47%) SCCs, whereas 66/153 (43.13%) and 93/153 (60.78%) cases showed its distinct cytoplasmic as well as nuclear accumulation respectively. Down regulation/loss of APC was observed in 69 (45.09%) cases, suggesting the activation of Wnt/β-catenin pathway in SCCs. Pin1 showed the significant association with nuclear β-catenin (r=.349, p<0.0001) and cytoplasmic loss of APC (r=-.287, p<0.0001). Both Pin1 as well as nuclear β-catenin were found to be associated with tumor stage (p=0.004, p=0.031) and tumor size (p=0.022, p=0.003). The Pin1 overexpression showed the significant association with disease free survival (p=0.002) but not with overall survival (p=0.421) of SCC patients.
CONCLUSIONS
Current results explore the expressional relationship between Pin1, β-catenin and APC suggesting that Pin1 regulates the activation of Wnt/β-catenin pathway in SCCs via modulating the interaction between β-catenin and APC. Furthermore, the significant association of Pin1 and β-catenin with tumor variables underscores the clinical utility of these proteins in cervical cancer.
Pubmed
Journal: Journal of leukocyte biology
April/1/2010
Abstract
Increasing evidence includes Wnt proteins inside the group of master-signaling pathways that govern immune and nonimmune differentiation systems, fundamental for normal development and homeostasis. Although their precise functions in bone marrow and thymus are still controversial, numerous studies have shown that Wnt signaling is able to control the proliferation of hematopoietic stem cells and thymic progenitors and might also affect their cell-fate decisions and subsequent maturation. In the present work, we analyze the effect of transient stimulation of the canonical Wnt pathway in the differentiation potential of Lin(-)CD34(+) CD1a(-) human thymic progenitors, a multipotent and heterogeneous cell population that has the capacity to develop into T cells, NK cells, monocytes, cDC, and pDC. Our results demonstrate that giving a boost to canonical Wnt signaling, triggered by transient exposure to Wnt3a or LiCl, the differentiation capacity of thymic progenitors changes, enhancing NK cell production. On the contrary, Wnt3a- or LiCl-pretreated thymic progenitors generate a significantly lower number of myeloid lineage cells, monocytes, and cDC and exhibit a reduced capacity to differentiate into pDC lineage. As a possible mechanism for this effect, we show that Wnt3a- and LiCl-pretreated progenitors change their membrane levels of receptors for cytokines pivotal for their expansion and differentiation, such as Flt3L. Moreover, canonical Wnt pathway stimulation modifies the transcription factor profile of CD34(+)CD1(-) thymocytes, increasing Hes-1 and ID3 expression levels.
Pubmed
Journal: Nature communications
November/15/2015
Abstract
β-Catenin mediates the canonical Wnt pathway by stimulating Tcf-dependent transcription and also associates to N-cadherin at the apical complex (AC) of neuroblasts. Here, we show that while β-catenin activity is required to form the AC and to maintain the cell polarity, oncogenic mutations that render stable forms of β-catenin (sβ-catenin) maintain the stemness of neuroblasts, inhibiting their differentiation and provoking aberrant growth. In examining the transcriptional and structural roles of β-catenin, we find that while β-catenin/Tcf transcriptional activity induces atypical protein kinase C (aPKC) expression, an alternative effect of β-catenin restricts aPKC to the apical pole of neuroepithelial cells. In agreement, we show that a constitutively active form of aPKC reproduces the neuroepithelial aberrations induced by β-catenin. Therefore, we conclude that β-catenin controls the cell fate and polarity of the neuroblasts through the expression and localization of aPKC.
Pubmed
Journal: PloS one
July/13/2015
Abstract
BACKGROUND
The β-catenin is an important effector in WNT/β-catenin signaling pathway, which exerts a crucial role in the development and progression of hepatocellular carcinoma (HCC). Some researchers have suggested that the overexpression of β-catenin in cytoplasm and/or nucleus was closely correlated to metastasis, poor differentiation and malignant phenotype of HCC while some other researchers hold opposite point. So far, no consensus was obtained on the prognostic and clinicopathological significance of cytoplasmic/nuclear β-catenin overexpression for HCCs.
METHODS
Systematic strategies were applied to search eligible studies in all available databases. Subgroup analyses, sensitivity analyses and multivariate analysis were performed. In this meta-analysis, we utilized either fixed- or random-effects model to calculate the pooled odds ratios (OR) and its 95% confidence intervals (CI).
RESULTS
A total of 22 studies containing 2334 cases were enrolled in this meta-analysis. Pooled data suggested that accumulation of β-catenin in cytoplasm and/or nucleus significantly correlated with poor 1-, 3- and 5-year OS and RFS. Moreover, nuclear accumulation combined with cytoplasmic accumulation of β-catenin tended to be associated with dismal metastasis and vascular invasion while cytoplasmic or nuclear expression alone showed no significant effect. Besides, no significant association was observed between cytoplasmic and/or nuclear β-catenin expression and poor differentiation grade, advanced TNM stage, liver cirrhosis, tumor size, tumor encapsulation, AFP and etiologies. Additional subgroup analysis by origin suggested that the prognostic value and clinicopathological significance of cytoplasmic and/or nuclear β-catenin expression was more validated in Asian population. Multivariate analyses of factors showed that cytoplasmic and/or nuclear β-catenin expression, as well as TNM stage, metastasis and tumor size, was an independent risk factors for OS and RFS.
CONCLUSIONS
Cytoplasmic and/or nuclear accumulation of β-catenin, as an independent prognostic factor, significantly associated with poor prognosis and deeper invasion of HCC, and could serve as a valuable prognostic predictor for HCC.
Pubmed
Journal: Development (Cambridge, England)
March/25/2010
Abstract
Embryonic development requires a complex series of relative cellular movements and shape changes that are generally referred to as morphogenesis. Although some of the mechanisms underlying morphogenesis have been identified, the process is still poorly understood. Here, we address mechanisms of epithelial morphogenesis using the vertebrate lens as a model system. We show that the apical constriction of lens epithelial cells that accompanies invagination of the lens placode is dependent on Shroom3, a molecule previously associated with apical constriction during morphogenesis of the neural plate. We show that Shroom3 is required for the apical localization of F-actin and myosin II, both crucial components of the contractile complexes required for apical constriction, and for the apical localization of Vasp, a Mena family protein with F-actin anti-capping function that is also required for morphogenesis. Finally, we show that the expression of Shroom3 is dependent on the crucial lens-induction transcription factor Pax6. This provides a previously missing link between lens-induction pathways and the morphogenesis machinery and partly explains the absence of lens morphogenesis in Pax6-deficient mutants.
Pubmed
Journal: Molecular and cellular biology
February/9/2014
Abstract
First identified in Drosophila, the Crumbs (Crb) proteins are important in epithelial polarity, apical membrane formation, and tight junction (TJ) assembly. The conserved Crb intracellular region includes a FERM (band 4.1/ezrin/radixin/moesin) binding domain (FBD) whose mammalian binding partners are not well understood and a PDZ binding motif that interacts with mammalian Pals1 (protein associated with lin seven) (also known as MPP5). Pals1 binds Patj (Pals1-associated tight-junction protein), a multi-PDZ-domain protein that associates with many tight junction proteins. The Crb complex also binds the conserved Par3/Par6/atypical protein kinase C (aPKC) polarity cassette that restricts migration of basolateral proteins through phosphorylation. Here, we describe a Crb3 knockout mouse that demonstrates extensive defects in epithelial morphogenesis. The mice die shortly after birth, with cystic kidneys and proteinaceous debris throughout the lungs. The intestines display villus fusion, apical membrane blebs, and disrupted microvilli. These intestinal defects phenocopy those of Ezrin knockout mice, and we demonstrate an interaction between Crumbs3 and ezrin. Taken together, our data indicate that Crumbs3 is crucial for epithelial morphogenesis and plays a role in linking the apical membrane to the underlying ezrin-containing cytoskeleton.
Pubmed
Journal: PloS one
July/25/2016
Abstract
Asthma is a common chronic respiratory disease. In a previous study, we found several circulating microRNA signatures associated with childhood asthma and selected miR-3162-3p for subsequent studies. Since the target proteins and underlying molecular mechanisms of miR-3162-3p in asthma etiopathogenesis are not well characterized, we designed this study to clarify its role. We employed bioinformatics and quantitative PCR methods as a first step to determine the target of miR-3162-3p, and we elucidated β-catenin. Luciferase assays and western blot analysis confirmed β-catenin as a direct target of miR-3162-3p as the 3'-untranslated region of β-catenin mRNA possesses a specific miR-3162-3p pairing site. The correlation between the expression levels of miR-3162-3p and β-catenin is confirmed by quantitative PCR and western blot studies in A549, Beas-2B and H1299 cell lines and OVA-induced asthma mouse model. Of note, upregulation of the endogenous miR-3162-3p level is concomitant with the reduction of β-catenin mRNA and protein expression levels. MiR-3162-3p antagomir treatment antagonizes the endogenous miR-3162-3p and effectively rescues the attenuation of endogenous β-catenin in OVA-induced asthmatic mice, which alleviates airway hyperresponsiveness and ameliorates airway inflammation. Collectively, our findings suggest a novel relationship between miR-3162-3p and β-catenin and clarify their mechanistic role in asthma etiopathogenesis.
Pubmed
Journal: Human molecular genetics
October/11/2017
Abstract
Scribble1 (Scrib1) is a tumor suppressor gene that has long been established as an essential component of apicobasal polarity (ABP). In mouse models, mutations in Scrib1 cause a severe form of neural tube defects (NTDs) as a result of a defective planar cell polarity (PCP) signaling. In this study, we dissected the role of Scrib1 in the pathogenesis of NTDs in its mouse mutant Circletail (Crc), in cell lines and in a human NTD cohort. While there were no obvious defects in ABP in the Scrib1Crc/Crc neuroepihelial cells, we identified an abnormal localization of the apical protein Par-3 and of the PCP protein Vangl2. These results were concordant with those obtained following a partial knockdown of Scrib1 in MDCK II cells. Par-3 was able to rescue the localization defect of Vangl1 (paralog of Vangl2) caused by partial knockdown of Scrib1 suggesting that Scrib1 exerts its effect on Vangl1 localization indirectly through Par-3. This conclusion is supported by our findings of an apical enrichment of Vangl1 following a partial knockdown of Par-3. Re-sequencing analysis of SCRIB1 in 473 NTD patients led to the identification of 5 rare heterozygous missense mutations that were predicted to be pathogenic. Two of these mutations, p.Gly263Ser and p.Gln808His, and 2 mouse NTD mutations, p.Ile285Lys and p.Glu814Gly, affected Scrib1 membrane localization and its modulating role of Par-3 and Vangl1 localization. Our study demonstrates an important role of Scrib1 in the pathogenesis of NTDs through its mediating effect of Par-3 and Vangl1/2 localization and most likely independently of ABP.
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