Cytoplasmic Β-catenin Levels Research Articles

GM-CSF receptor expression determines opposing innate memory phenotypes at different stages of myelopoiesis

AbstractInflammatory responses must be tightly coordinated with the activation of emergency myelopoiesis to produce potent myeloid cells that fight infection without causing excessive host damage. Here, we show that granulocyte-macrophage colony-stimulating factor (GM-CSF) programs myeloid-committed progenitors to produce trained macrophages (increased cytokine response), but programs the upstream noncommitted LKS+ progenitors (defined as Lin− c-Kit+ Sca-1+ cells) to produce tolerized macrophages (decreased cytokine response). In myeloid progenitors, GM-CSF strongly activates signal transducer and activator of transcription 5 (STAT5), Ras-Raf-extracellular signal regulated kinase (ERK), and Akt-mTOR signaling pathways, which are essential to establish a training program, whereas in LKS+ progenitors, GM-CSF induces NF-κB translocation to the nucleus to establish a tolerization program. These differences arise from higher GM-CSF receptor expression in myeloid progenitors compared with LKS+ cells. We demonstrate that β-catenin regulation of NF-κB nuclear translocation is central in this process. In myeloid progenitors, glycogen synthase kinase 3 (GSK3) inactivation by strong ERK and phosphatidylinositol 3 kinase (PI3K)-Akt signaling increases cytoplasmic β-catenin levels to block NF-κB nuclear translocation. In contrast, when ERK and PI3K-Akt signaling are weak, active GSK3 causes a decrease in β-catenin, allowing NF-κB nuclear translocation in LKS+ progenitors. Finally, GM-CSF-induced LKS+ tolerization takes place in several murine models of trained immunity and in human CD34+ CD38− progenitors. Our study reveals that in addition to activating myelopoiesis, GM-CSF also programs early and immediate myeloid progenitors to produce opposing immune memory phenotypes. We propose that the inflammatory response from immediate myeloid progenitors may be balanced by the tolerized phenotype of early progenitors, thus providing a mechanism for appropriate resolution of inflammation and protection against a prolonged cytokine storm.

MiR-575/RIPK4 axis modulates cell cycle progression and proliferation by inactivating the Wnt/β-catenin signaling pathway through inhibiting RUNX1 in colon cancer.

Receptor interacting protein serine/threonine kinase 4 (RIPK4) is widely involved in human cancer development. Nevertheless, its role in colon cancer (COAD) has not been elucidated till now. Our research aimed at exploring the function and underlying molecular mechanism of RIPK4 in COAD progression. Through bioinformatic analyses and RT-qPCR, RIPK4 was discovered to be increased in COAD cells and tissues, and its high level predicted poor prognosis. Loss-of-function assays revealed that RIPK4 silencing suppressed COAD cell growth, induced cell cycle arrest, and enhanced cell apoptosis. In vivo experiments also proved that tumor growth was inhibited by silencing of RIPK4. Luciferase reporter assay validated that RIPK4 was targeted and negatively regulated by miR-575. Western blotting demonstrated that Wnt3a, phosphorylated (p)-GSK-3β, and cytoplasmic and nuclear β-catenin protein levels, β-catenin nuclear translocation, and Cyclin D1, CDK4, Cyclin E, and c-Myc protein levels were reduced by RIPK4 knockdown, which however was reversed by treatment with LiCl, the Wnt/β-catenin pathway activator. LiCl also offset the influence of RIPK4 knockdown on COAD cell growth, cell cycle process, and apoptosis. Finally, RIPK4 downregulation reduced RUNX1 level, which was upregulated in COAD and its high level predicted poor prognosis. RIPK4 is positively associated with RUNX1 in COAD. Overexpressing RUNX1 antagonized the suppression of RIPK4 knockdown on RUNX1, Wnt3a, p-GSK-3β, cytoplasmic β-catenin, nuclear β-catenin, Cyclin D1, CDK4, Cyclin E, and c-Myc levels. Collectively, miR-575/RIPK4 axis repressed COAD progression via inactivating the Wnt/β-catenin pathway through downregulating RUNX1.

Identification of Moesin (MSN) as a Potential Therapeutic Target for Colorectal Cancer via the β-Catenin-RUNX2 Axis.

CRC is the second leading cause of cancer-related death. The complex mechanisms of metastatic CRC limit available therapeutic choice. Thus, identifying new CRC therapeutic targets is essential. Moesin (MSN), a member of the ezrin-radixin-moesin family, connects the cell membrane to the actin-based cytoskeleton and regulates cell morphology. We investigated the role of MSN in the progression of CRC. GENT2 and oncomine were used to study MSN expression and CRC patient outcomes. MSN-specific shRNAs or MSN-overexpressed plasmid were used to establish MSN-KD and MSN overexpressed cell lines, respectively. SRB, migration, wound healing, and flow cytometry were used to test cell survival and migration. Propidium iodide and annexin V stain were used to analyze the cell cycle and apoptosis. MSN expression was found to be higher in CRC tissues than in normal tissues. Higher MSN expression is associated with poor overall survival, disease-free survival, and relapse-free survival rates in CRC patients. MSN silencing inhibits cell proliferation, adhesion, migration, and invasion in vitro, whereas MSN overexpression accelerates cell proliferation, adhesion, migration, and invasion. RNA sequencing was used to investigate differentially expressed genes, and RUNX2 was discovered as a possible downstream target for MSN. In CRC patients, RUNX2 expression was significantly correlated with MSN expression. We also found that MSN silencing decreased cytoplasmic and nuclear β-catenin levels. Additionally, pharmacological inhibition of β-catenin in MSN-overexpressed cells led to a reduction of RUNX2, and activating β-catenin signaling by inhibiting GSK3β rescued the RUNX2 downregulation in MSN-KD cells. This confirms that MSN regulates RUNX2 expression via activation of β-catenin signaling. Finally, our result further determined that RUNX2 silencing reduced the ability of MSN overexpression cells to proliferate and migrate. MSN accelerated CRC progression via the β-catenin-RUNX2 axis. As a result, MSN holds the potential to become a new target for CRC treatment.

Scutellarin Suppressed Proliferation and Induced Apoptosis in Gastric Cancer via Wnt/β-catenin Signaling Pathway.

Scutellarin exerts anticancer effects on diverse malignancies. However, its function in gastric cancer has not been explored. This study aimed to examine the anticancer effect and molecular mechanism of scutellarin in gastric cancer. Gastric cancer cells were treated with scutellarin and transfected with the Wnt1 overexpression plasmid. Cell viability, proliferation, toxicity, and apoptosis were determined by cell counting kit-8 (CCK-8), colony formation, lactate dehydrogenase (LDH) activity, TdT-mediated dUTP Nick-End Labeling (TUNEL), and flow cytometry assays. Expressions of apoptosis-related and Wnt/β-catenin signaling pathway- related proteins were examined by western blot and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Scutellarin concentration dependently restrained cell viability. Scutellarin (20 and 80 μmol/L) suppressed proliferation and promoted LDH release and apoptosis. Moreover, scutellarin elevated Bax and Cytochrome C levels but diminished the levels of Bcl-2, Wnt1, cytoplasmic β-catenin, and basal cytoplasmic β- catenin. However, the above-mentioned regulatory effects of scutellarin were all reversed by Wnt1 overexpression. Scutellarin suppressed gastric cancer cell proliferation and promoted apoptosis by inhibition of the Wnt/β-catenin pathway.

Cyanidin inhibits glioma stem cells proliferation through the Wnt signaling pathway

Background Cyanidin has a protective effect on the nervous system and has been reported to treat tumor effectively. However, its impact on glioma stem cells (GSC) is unknown. Methods Using seven GSC lines, the anti-tumor effect of cyanidin is tested. The effect of cyanidin on the cell viability in each cell line is evaluated. Wnt signaling pathway-related genes are checked after treatment of cyanidin. Cytoplasmic/nuclear β-catenin protein levels post cyanidin treatment is detected. Protein levels of c-Myc after cyanidin treatment are determined. Twist1 and Snail1 protein levels after cyanidin treatment are checked as well. Results Cyanidin significantly reduces the cell viability of all GSCs, and exhibited the most substantial effect in GBM2 but no apparent effect in 293T cells. It can regulate the Wnt signaling pathway of all GSC lines. In the GBM2, GBM7, G166, and G179 cell lines, there is upregulation of WNT1 and MYC genes, while in the G144 and GliNS2 cell line, these two genes are down-regulated after cyanidin treatment. Cytoplasmic and nuclear protein levels of β-catenin in all cell lines are down-regulated. Cyanidin treatment significantly decreases the protein level for c-Myc in the GBM2 cell line compared with untreated cells, not in G144 or GliNS2 cells. Furthermore, cyanidin strongly reduces the expression of Twist1 and Snail1 in GBM2, G179, and G144 cell lines, while the GliNS2 cells show an opposite change in the cytoplasm and no change in nuclear. Conclusion Cyanidin exerts an anti-tumor effect in glioma stem cell lines, probably through the Wnt signaling pathway.

Expression of hepatocyte nuclear factor 4 alpha, wingless-related integration site, and β-catenin in clinical gastric cancer

BACKGROUNDGastric cancer (GC) is the second most common cause of cancer-related deaths worldwide. Hepatocyte nuclear factor 4 alpha (HNF4α) that belongs to the nuclear hormone receptor superfamily, is overexpressed in GC tissues, and might be involved in the development of GC by regulating its downstream wingless-related integration site (WNT)/β-catenin signaling.AIMTo clarify the expression of HNF4α/WNT5a/β-catenin signaling proteins in clinical GC tissues. METHODSWe immunohistochemically stained pathological blocks of GC and matched para-cancerous tissues. The intensity of HNF4α, WNT5a and β-catenin staining in the tumor cells was determined according to cell rates and staining intensity. The correlations between GC and HNF4α, WNT5a, and β-catenin expression using chi-square and paired chi-square tests. Relationships between double-positive HNF4α and WNT5a expression and types of gastric tumor tissues were assessed using regression analysis. Correlations between HNF4α and WNT5a expression at the RNA level in GC tissues found in the TCGA database were analyzed using Pearson correlation coefficients. RESULTSWe found more abundant HNF4α and WNT5a proteins in GC, especially in mucinous adenocarcinoma and mixed GC than in adjacent tissues (P < 0.001). Low and high levels of cytoplasmic β-catenin respectively expressed in GC and adjacent tissues (P < 0.001) were not significantly associated with pathological parameters. CONCLUSIONThe expressions of HNF4α and WNT5a could serve as early diagnostic biomarkers for GC.

β-Catenin is Independently Associated With Outcome in Pancreatic Cancer: An Analysis of NRG Oncology/RTOG 9704

Laboratory experiments show that activation of β-catenin signaling promotes pancreatic cancer (PC) growth, but studies addressing its prognostic value in patients (pts) are scarce and with conflicting results. This question has been examined using samples from a large prospective clinical trial.NRG/RTOG 9704 was a phase III trial which compared 5-fluorouracil - to gemcitabine-based chemotherapy in pts after pancreatectomy. All pts received 5-fluorouracil -based chemoradiotherapy. Quantitative immunofluorescence analysis for β-catenin was performed on a tissue microarray developed from these pts. β-catenin and its active form (total, nuclear, and cytoplasmic) were assayed in pan-cytokeratin positive tumor cells. Assay performers were blinded to all clinical outcomes. Scores were dichotomized at their median. OS and DFS were estimated univariately with the Kaplan-Meier method and groups compared using the log-rank test. Cox proportional hazards models were used to identify the impact of expression on OS and DFS. The following variables were included in the models: β-catenin, treatment, age, gender, race, CA19-9, tumor location, nodal involvement, tumor diameter, and surgical margin status.Of 451 eligible pts, 141 samples were analyzable. There were no significant differences in baseline characteristics/outcomes for pts with and without tissue. For cytoplasmic β-catenin univariately, levels ≥ median were associated with better OS [HR (95% CI): 0.65 (0.45, 0.93); P = 0.02] and DFS [HR (95% CI): 0.70 (0.49, 0.99); P = 0.04]. On multivariable analysis, levels ≥ median were associated with better OS [HR (95% CI): 0.63 (0.43, 0.92), P = 0.02], after adjusting for CA19-9, age, and race, with a 37% risk reduction of death. There was a trend towards better DFS for pts with levels ≥ median [HR (95% CI): 0.70 (0.48, 1.01), P = 0.054], after adjusting for CA19-9. For cytoplasmic active β-catenin univariately, levels ≥ median were associated with better OS [HR (95% CI): 0.65 (0.45, 0.94); P = 0.02], that remained significant on multivariable analysis [HR (95% CI): 0.64 (0.44, 0.94); P = 0.02]. There were no associations with efficacy for nuclear or total β-catenin, nor in its active form.In this high-quality database from a prospective phase III clinical trial, cytoplasmic β-catenin and cytoplasmic active β-catenin are statistically significantly associated with OS and DFS and with OS, respectively, independent of other known prognostic factors. In agreement with one previous publication, high levels of cytoplasmic β-catenin, which is transcriptionally silent, were associated with a reduced risk of death. The significant magnitude of these effects makes them clinically relevant, warranting further investigation. This project was supported by grants U10CA180868 (NRG Oncology Operations), U10CA180822 (NRG Oncology SDMC), UG1CA189867 (NCORP), U24CA196067 (NRG Specimen Bank) from the National Cancer Institute (NCI).

Crosslinked Extracellular Matrix Stiffens Human Trabecular Meshwork Cells Via Dysregulating β-catenin and YAP/TAZ Signaling Pathways.

PurposeThe purpose of this study was to determine whether genipin-induced crosslinked cell-derived matrix (XCDM) precipitates fibrotic phenotypes in human trabecular meshwork (hTM) cells by dysregulating β-catenin and Yes-associated protein (YAP)/ transcriptional coactivator with PDZ-binding motif (TAZ) signaling pathways.MethodsCell-derived matrices were treated with control or genipin for 5 hours to obtain respective uncrosslinked (CDM) and XCDMs and characterized. hTM cells were seeded on these matrices with/without Wnt pathway modulators in serum-free media for 24 hours. Elastic modulus, gene, and protein (whole cell and subcellular fractions) expressions of signaling mediators and targets of Wnt/β-catenin and YAP/TAZ pathways were determined.ResultsAt the highest genipin concentration (10% XCDM), XCDM had increased immunostaining of N-ε(γ-glutamyl)-lysine crosslinks, appeared morphologically fused, and was stiffer (5.3-fold, P < 0.001). On 10% XCDM, hTM cells were 7.8-fold (P < 0.001) stiffer, total β-catenin was unchanged, pβ-catenin was elevated, and pGSK3β was suppressed. Although 10% XCDM had no effect on cytoplasmic β-catenin levels, it reduced nuclear β-catenin, cadherin 11, and key Wnt target genes/proteins. The 10% XCDM increased total TAZ, decreased pTAZ, and increased cytoplasmic TAZ levels in hTM cells. The 10% XCDM increased total YAP, reduced nuclear YAP levels, and critical YAP/TAZ target genes/proteins. Wnt activation rescued hTM cells from 10% XCDM-induced stiffening associated with increased nuclear β-catenin.ConclusionsIncreased cytoplasmic TAZ may inhibit β-catenin from its nuclear shuttling or regulating cadherin 11 important for aqueous homeostasis. Elevated cytoplasmic TAZ may inhibit YAP's probable homeostatic function in the nucleus. Together, TAZ's cytoplasmic localization may be an important downstream event of how increased TM extracellular matrix (ECM) crosslinking may cause increased stiffness and ocular hypertension in vivo. However, Wnt pathway activation may ameliorate ocular hypertensive phenotypes induced by crosslinked ECM.

Chrysophanol administration alleviates bleomycin-induced pulmonary fibrosis by inhibiting lung fibroblast proliferation and Wnt/β-catenin signaling

Purpose: To determine the functional effect of chrysophanol (CH) on bleomycin (BLM)-induced pulmonary fibrosis (PF) and reveal its mechanism of action.Methods: A mouse model of PF was established by intratracheal instillation of BLM (5 mg/kg), prior to CH administration. Masson’s trichrome staining was used to analyze interstitial fibrosis and collagen deposition. Hydroxyproline (HYP) content was measured, and lung fibroblast viability determined by MTT assay. Bronchoalveolar lavage fluid (BALF) was collected, and levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and interferon-γ (IFN-γ) were evaluated using enzyme-linked immunosorbent assays (ELISA). Expression of cell signaling, adhesion, and apoptotic proteins were determined by western blotting.Results: Administration of CH reduced collagen deposition and HYP content, downregulated α-smooth muscle actin, upregulated E-cadherin, and decreased the levels of TNF-α, IL-1β, IL-6, and IFN-γ in BLM-treated mice. The viability of lung fibroblasts was also reduced, and Bcl-2-associated X protein and cleaved caspase-3 were upregulated after CH treatment in BLM-treated mice. In addition, CH treatment in BLM-treated mice significantly increased levels of cytoplasmic β-catenin but decreased its expression in the nucleus.Conclusion: Administration of CH alleviated BLM-induced PF by inhibiting lung fibroblast proliferation and nuclear translocation of β-catenin. Thus, this study provides a potential therapeutic strategy for PF.&#x0D; Keywords: Chrysophanol, Bleomycin, Pulmonary fibrosis, Hydroxyproline, E-cadherin

Exendin-4 Attenuates Remodeling in the Remote Myocardium of Rats After an Acute Myocardial Infarction by Activating β-Arrestin-2, Protein Phosphatase 2A, and Glycogen Synthase Kinase-3 and Inhibiting β-Catenin.

This study tested if the protective anti-remodeling effect of GLP-1 agonist Exendin-4 after an acute myocardial infarction (MI) in rats involves inhibition of the Wnt1/β-catenin signaling pathway. Rats were divided into sham, sham + Exendin-4 (10μg/day, i.p), MI, and MI + Exendin-4. MI was introduced to rats by permanent left anterior descending coronary artery (LAD) ligation. On day 7 post-infraction, MI rats showed LV dysfunction with higher serum levels of cardiac markers. Their remote myocardia showed increased mRNA and protein levels of collagen I/III with higher levels of reactive oxygen species (ROS) and inflammatory cytokines, as well as protein levels of Wnt1, phospho-Akt, transforming growth factor (TGF-β1), Smad, phospho-Smad3, α-SMA, caspase-3, and Bax. They also showed higher protein levels of phospho-glycogen synthase kinase-3β (p-GSK3β), as well as total, phosphorylated, and nuclear β-catenin with a concomitant decrease in the levels of cyclic adenosine monophosphate (cAMP), mRNA of manganese superoxide dismutase (MnSOD), and protein levels of Bcl-2, β-arrestin-2, and protein phosphatase-2 (PP2A). Administration of Exendin-4 to MI rats reduced the infarct size and reversed the aforementioned signaling molecules without altering protein levels of TGF-1β and Wnt1 or Akt activation. Interestingly, Exendin-4 increased mRNA levels of MnSOD, protein levels of β-arrestin-2 and PP2A, and β-catenin phosphorylation but reduced the phosphorylation of GSK3β and Smad3, and total β-catenin levels in the LV of control rats. Exendin-4 inhibits the remodeling in the remote myocardium of rats following acute MI by attenuating β-catenin activation and activating β-arrestin-2, PP2A, and GSK3β. Graphical Abstract A graphical abstract that illustrates the mechanisms by which Exendin-4 inhibits cardiac remodeling in remote myocardium of left ventricle MI-induced rats. Mechanisms are assumed to occur in the cardiomyocytes and/or other resident cells such as fibroblast. Β-catenin activation and nuclear translocation are associated with increased synthesis of inflammatory cytokines and transforming growth factor β-1 (TGF-β1). GSK3β is inhibited by phosphorylation at Ser9. Under normal conditions, β-catenin is degraded in the cytoplasm by the active GSK3β-dependent degradation complex (un-phosphorylated) which usually phosphorylates β-catenin at Ser33/37/Thr41. After MI, TGF-β1, and Wnt 1 levels are significantly increased, the overproduction of Wnt1 induces β-catenin stabilization and nuclear translocation through increasing the phosphorylation of disheveled (DVL) protein which in turn phosphorylates and inhibits GSK3β. TGF-β1 stimulates the phosphorylation of Smad-3 and subsequent nuclear translocation to activate the transcription of collage 1/III and α-smooth muscle actin (α-SMA). Besides, TGF-β1 stabilizes cytoplasmic β-catenin levels indirectly by phosphorylation of Akt at Thr308-induced inhibition of GSK3β by increasing phosphorylation of Ser9. Exendin-4, and possibly through G protein-coupled receptors (GPCRs), increases levels of cAMP and upregulates β-arrestin-2 levels. Both can result in a positive inotropic effect. Besides, β-arrestin-2 can stimulate PP2A to dephosphorylation Smad3 (inhibition) and GSK3β (activation), thus reduces fibrosis and prevents the activation of β-catenin and collagen deposition.

Crosstalk of estrogen receptors and Wnt/β-catenin signaling in endometrial cancer.

To investigate the interaction between Wnt/β-catenin and estrogen signaling pathways in endometrial cancer (EC). 119 women were involved in this study, including 65 women with histologically confirmed EC and 54 healthy women as a control group. Serum protein levels of Dkk1 were measured using ELISA. Protein expression levels of Dkk1, β-catenin, ER-β isoforms (β1, β2, β5), and ER-α were tested in paraffin-embedded tissues using IHC. Gene expression levels of Dkk1, CTNNB, ESR1, and ESR2 were tested in fresh tumorous and normal endometrium tissues using RT-PCR. EC patients had significantly higher serum levels of Dkk1 protein compared with healthy women. Dkk1 and β-catenin showed different expression pattern in tumor cells compared to it in normal cells at the protein level but not at the gene level. Protein expression levels of ERβ2 and ERα were significantly lower in tumor cells compared with tumor-adjacent normal cells. Increased protein expression levels of ERα were associated with favorable clinicopathological features and better overall survival rate (OS). Protein expression levels of ERα were correlated with protein expression levels of Dkk1 and cytoplasmic β-catenin. The association between ERα expression levels and OS was no more significant when tested in regard to Dkk1- and cytoplasmic β-catenin expression levels. Our data demonstrated that Wnt/β-catenin and estrogen signaling systems are dysregulated in EC showing; for the first time, a potential crosstalk between certain components of these two pathways, which in turn has affected the specificity of these molecules in disease characteristics. Understanding the signaling networks in EC is crucial in designing clinical trials to evaluate the efficacy of molecular-targeted agents and providing more successful therapies in the future.

The comprehensive role of E-cadherin in maintaining prostatic epithelial integrity during oncogenic transformation and tumor progression.

E-cadherin complexes with the actin cytoskeleton via cytoplasmic catenins and maintains the functional characteristics and integrity of the epithelia in normal epithelial tissues. Lost expression of E-cadherin disrupts this complex resulting in loss of cell polarity, epithelial denudation and increased epithelial permeability in a variety of tissues. Decreased expression of E-cadherin has also been observed in invasive and metastatic human tumors. In this study, we investigated the effect of E-cadherin loss in prostatic epithelium using newly developed genetically engineered mouse models. Deletion of E-cadherin in prostatic luminal epithelial cells with modified probasin promoter driven Cre (PB-Cre4) induced the development of mouse prostatic intraepithelial neoplasia (PIN). An increase in levels of cytoplasmic and nuclear β-catenin appeared in E-cadherin deleted atypical cells within PIN lesions. Using various experimental approaches, we further demonstrated that the knockdown of E-cadherin expression elevated free cytoplasmic and nuclear β-catenin and enhanced androgen-induced transcription and cell growth. Intriguingly, pathological changes representing prostatic epithelial cell denudation and increased apoptosis accompanied the above PIN lesions. The essential role of E-cadherin in maintaining prostatic epithelial integrity and organization was further demonstrated using organoid culture approaches. To directly assess the role of loss of E-cadherin in prostate tumor progression, we generated a new mouse model with bigenic Cdh1 and Pten deletion in prostate epithelium. Early onset, aggressive tumor phenotypes presented in the compound mice. Strikingly, goblet cell metaplasia was observed, intermixed within prostatic tumor lesions of the compound mice. This study provides multiple lines of novel evidence demonstrating a comprehensive role of E-cadherin in maintaining epithelial integrity during the course of prostate oncogenic transformation, tumor initiation and progression.

Newcastle disease virus mediated apoptosis and migration inhibition of human oral cancer cells: A probable role of \u03b2-catenin and matrix metalloproteinase-7

Cancer cell metastasis and its dissemination are most enigmatic and challenging aspects in the development of its therapeutics. Newcastle disease virus (NDV) is a well-studied avian paramyxovirus frequently isolated from birds and rarely from mammals. Since the first report of its oncolytic property, many NDV strains were studied for its effect in various cancer cells. In the present study, NDV strain Bareilly was characterized for its apoptotic potential and migration inhibition in human oral cancer cells. The NDV mediated apoptosis was confirmed by flow cytometry, DNA laddering, and immunoblotting. Moreover, NDV decreased the mitochondrial membrane potential suggesting an intrinsic pathway of apoptosis in oral cancer cells. NDV infection in oral cancer cells results in migration inhibition by a reduction in levels of MMP-7. MMP-7 is one of the key target genes of β-catenin. While overexpression of MMP-7 reversed the inhibitory effect of NDV mediated migration suggested its possible involvement. Wnt/β-catenin is an essential pathway for cell growth, differentiation, and metastasis. The involvement of the Wnt/β-catenin pathway in NDV infection has never been reported. Our results showed that NDV dysregulates Wnt/β-catenin by down-regulation of p-Akt and p-GSK3β leading to degradation of β-catenin. Furthermore, NDV infection leads to a reduction in cytoplasmic and nuclear levels of β-catenin. The study will provide us with a better insight into the molecular mechanism of NDV mediated oncolysis and the key cellular partners involved in the process.

Wnt/\u03b2-catenin-mediated signaling re-activates proliferation of matured cardiomyocytes

BackgroundThe Wnt/β-catenin signaling pathway plays an important role in the development of second heart field (SHF Isl1+) that gives rise to the anterior heart field (AHF) cardiac progenitor cells (CPCs) for the formation of the right ventricle, outflow tract (OFT), and a portion of the inflow tract (IFT). During early cardiogenesis, these AHF CPCs reside within the pharyngeal mesoderm (PM) that provides a microenvironment for them to receive signals that direct their cell fates. Here, N-cadherin, which is weakly expressed by CPCs, plays a significant role by promoting the adhesion of CPCs within the AHF, regulating β-catenin levels in the cytoplasm to maintain high Wnt signaling and cardioproliferation while also preventing the premature differentiation of CPCs. On the contrary, strong expression of N-cadherin observed throughout matured myocardium is associated with downregulation of Wnt signaling due to β-catenin sequestration at the cell membrane, inhibiting cardioproliferation. As such, upregulation of Wnt signaling pathway to enhance cardiac tissue proliferation in mature cardiomyocytes can be explored as an interesting avenue for regenerative treatment to patients who have suffered from myocardial infarction.MethodsTo investigate if Wnt signaling is able to enhance cellular proliferation of matured cardiomyocytes, we treated cardiomyocytes isolated from adult mouse heart and both murine and human ES cell-derived matured cardiomyocytes with N-cadherin antibody or CHIR99021 GSK inhibitor in an attempt to increase levels of cytoplasmic β-catenin. Immunostaining, western blot, and quantitative PCR for cell proliferation markers, cell cycling markers, and Wnt signaling pathway markers were used to quantitate re-activation of cardioproliferation and Wnt signaling.ResultsN-cadherin antibody treatment releases sequestered β-catenin at N-cadherin-based adherens junction, resulting in an increased pool of cytoplasmic β-catenin, similar in effect to CHIR99021 GSK inhibitor treatment. Both treatments therefore upregulate Wnt signaling successfully and result in significant increases in matured cardiomyocyte proliferation.ConclusionAlthough both N-cadherin antibody and CHIR99021 treatment resulted in increased Wnt signaling and cardioproliferation, CHIR99021 was found to be the more effective treatment method for human ES cell-derived cardiomyocytes. Therefore, we propose that CHIR99021 could be a potential therapeutic option for myocardial infarction patients in need of regeneration of cardiac tissue.

Kinesin-2 and IFT-A act as a complex promoting nuclear localization of \u03b2-catenin during Wnt signalling

Wnt/Wg-signalling is critical signalling in all metazoans. Recent studies suggest that IFT-A proteins and Kinesin-2 modulate canonical Wnt/Wg-signalling independently of their ciliary role. Whether they function together in Wnt-signalling and their mechanistic role in the pathway remained unresolved. Here we demonstrate that Kinesin-2 and IFT-A proteins act as a complex during Drosophila Wg-signalling, affecting pathway activity in the same manner, interacting genetically and physically, and co-localizing with β-catenin, the mediator of Wnt/Wg-signalling on microtubules. Following pathway activation, Kinesin-2/IFT-A mutant cells exhibit high cytoplasmic β-catenin levels, yet fail to activate Wg-targets. In mutant tissues in both, Drosophila and mouse/MEFs, nuclear localization of β-catenin is markedly reduced. We demonstrate a conserved, motor-domain dependent function of the Kinesin-2/IFT-A complex in promoting nuclear translocation of β-catenin. We show that this is mediated by protecting β-catenin from a conserved cytoplasmic retention process, thus identifying a mechanism for Kinesin-2/IFT-A in Wnt-signalling that is independent of their ciliary role.

Berberine Attenuated Proliferation, Invasion and Migration by Targeting the AMPK/HNF4α/WNT5A Pathway in Gastric Carcinoma.

Background: Recent epidemiologic studies have found that patients with diabetes have a higher risk of gastric cancer (GC), and the long-term use of metformin is associated with a lower risk of gastric cancer. It is believed that blocking tumor energy metabolic alterations is now emerging as a new therapeutic approach of cancer. Berberine, a natural isoquinoline alkaloid, could modulate lipid metabolism and glucose homeostasis by regulating the expression of HNF4α in many metabolic diseases. Here, we investigated the effect of Berberine on GC and its possible molecular mechanism through targeting HNF4α.Methods and Results: (1) AGS and SGC7901 gastric cancer cells were treated with Berberine (BBR). We found that in AGS and SGC7901 cell, BBR inhibited cell proliferation in a time- and dose-dependent manner through downregulating C-myc. BBR also induced G0-G1 phase arrest with the decreased expression of cyclin D1. Moreover, BBR attenuated the migration and invasion by downregulating MMP-3. (2) The lentivirus infection was used to silence the expression of HNF4α in SGC7901 cell. The results demonstrated that the knockdown of HNF4α in SGC7901 slowed cells proliferation, induced S phase arrest and dramatically attenuated gastric cancer cells’ metastasis and invasion. (3) We performed GC cells perturbation experiments through BI6015 (an HNF4α antagonist), AICAR (an AMPK activator), Compound C (AMPK-kinase inhibitor), metformin and BBR. Our findings indicated that BBR downregulated HNF4α while upregulating p-AMPK. Moreover, the inhibition of HNF4α by BBR was AMPK dependent. (4) Then the LV-HNF4α-RNAi SGC7901 cell model was used to detect the downstream of HNF4α in vitro. The results showed that the knockdown of HNF4α significantly decreased WNT5A and cytoplasmic β-catenin, but increased E-cadherin in vitro. Berberine also downregulated WNT5A and cytoplasmic β-catenin, the same as LV-HNF4α-RNAi and BI6015 in GC cells. (5) Finally, the SGC7901 and LV-HNF4α-RNAi SGC7901 mouse-xenograft model to evaluate the effect of BBR and HNF4α gene on GC tumor growth. The result illustrated that BBR and knockdown of HNF4α suppressed tumor growth in vivo, and BBR decreased HNF4α, WNT5A and cytoplasmic β-catenin levels, the same effect as HNF4α knockout in vivo.Conclusion: BBR not only had proliferation inhibition effect, attenuated the invasion and migration on GC cell lines, but also suppressed the GC tumor growth in vivo. The anti-gastric cancer mechanism of BBR might be involved in AMPK-HNF4α-WNT5A signaling pathway. HNF4α antagonists, such as BBR, could be a promising anti-gastric cancer treatment supplement.

A Prokineticin-Driven Epigenetic Switch Regulates Human Epicardial Cell Stemness and Fate.

Epicardial adipose tissues (EATs) and vascular tissues may both belong to the mesoepithelial lineage that develops from epicardium-derived progenitor cells (EPDCs) in developing and injured hearts. Very little is known of the molecular mechanisms of EPDC contribution in EAT development and neovascularization in adult heart, which the topic remains a subject of intense therapeutic interest and scientific debate. Here we studied the epigenetic control of stemness and anti-adipogenic and pro-vasculogenic fate of human EPDCs (hEPDCs), through investigating an angiogenic hormone, prokineticin-2 (PK2) signaling via its receptor PKR1. We found that hEPDCs spontaneously undergoes epithelial-to-mesenchymal transformation (EMT), and are not predestined for the vascular lineages. However, PK2 via a histone demethylase KDM6A inhibits EMT, and induces asymmetric division, leading to self-renewal and formation of vascular and epithelial/endothelial precursors with angiogenic potential capable of differentiating into vascular smooth muscle and endothelial cells. PK2 upregulates and activates KDM6A to inhibit repressive histone H3K27me3 marks on promoters of vascular genes (Flk-1 and SM22α) involved in vascular lineage commitment and maturation. In PK2-mediated anti-adipogenic signaling, KDM6A stabilizes and increases cytoplasmic β-catenin levels to repress peroxisome proliferator-activated receptor-γ expression and activity. Our findings offer additional molecular targets to manipulate hEPDCs-involved tissue repair/regeneration in cardiometabolic and ischemic heart diseases. Stem Cells 2018;36:1589-1602.

Abstract 4508: Glypican-3 (GPC3) signaling pathway involved in breast cancer progression

Abstract GPC3 is a proteoglycan downregulated in breast tumors. Employing LM3 murine mammary adenocarcinoma cell line (ER-, PR-), we have previously shown that GPC3 acts as a metastasis suppressor and induces a reversion of the epithelial to mesenchymal transition (EMT). GPC3 overexpressing LM3 cells presented an inhibition of canonical Wnt and Akt pathways. On the other hand, non-canonical Wnt (JNK) and p38 signaling were activated. However, the hierarchical sequence through which GPC3 modulates those pathways has not been determined yet.The aim of this work was to study the molecular mechanism involved in the GPC3 effect on breast tumor progression, focusing on canonical Wnt pathway. We investigated the receptor complex with which GPC3 is interacting and the relationships among the pathways modulated by this glypican. We determined by IP that GPC3 could physically interact with the Wnt receptor Fz. Our results suggested that GPC3 binds to Fz and blocks the binding of the canonical Wnt factors. We also confirmed by the determination of cytoplasmic β-Catenin levels through WB and their transcriptional activity employing gene reporter assay, that GPC3 is inhibiting this pathway. We showed by qPCR array that GPC3 also modulates canonical Wnt signaling in a genomic way. Of 84 examined genes, only Wnt5b (non-canonical factor) was upregulated in LM3-GPC3 cells, 66 genes were downregulated (several Fzds, LRP5/6, DVL1 and DVL2, Frat1, Ccnd1, Ccnd2, Ccnd3, Csnk1d, jun and myc, among others), and the expression of 17 genes was not modified (including several Wnt factors). Finally, LM3-GPC3 cells were treated with SB203589, SP600125 (p38 and JNK pharmacological inhibitors respectively), LiCl (canonical Wnt activator) or transduced with a constitutively active variant of Akt1 (CA Akt). The effect of the treatments on the other pathways activity was evaluated by WB. We showed that the Akt inhibition found in LM3-GPC3 cells is required for the activation of the non-canonical Wnt pathway, as well as for the inhibition of the canonical one, but it had no effects on p38 signaling. p38 activation was necessary for non-canonical Wnt upregulation and for Akt and canonical Wnt inhibition. Canonical Wnt inhibition was essential for Akt downregulation as well as for p38 and non-canonical Wnt signaling activation. We demonstrated that in addition to the significant role of JNK in the non-canonical Wnt pathway, it also regulates canonical signalling. Non-canonical Wnt activity also participates in p38 activation but has no effect on Akt activity.In sum, we have described the receptor complex with which GPC3 interacts, as well as the canonical Wnt signaling inhibition induced by GPC3 - both genomic and non-genomic - and finally several interactions among Wnt, Akt and p38 pathways. We believe that our results provide additional information regarding the molecular mechanism of GPC3 involved in metastasis suppression. Citation Format: Dolores Fernandez, Magali Cercato, Macarena Guereño, Maria G. Peters. Glypican-3 (GPC3) signaling pathway involved in breast cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4508.

Involvement of GSK3/β-catenin in the action of extracellular ATP on differentiation of primary cultures from rat calvaria into osteoblasts.

Modulation of purinergic receptors play an important role in the regulation of osteoblasts differentiation and bone formation. In this study, we investigated the involvement of the GSK3/βcatenin signaling in the action of ATPγ-S on osteogenic differentiation of primary cell cultures from rat calvaria. Our results indicate that the cell treatment with 10 or 100 µM ATPγ-S for 96 h increase the cytoplasmic levels of β-catenin and its translocation to nucleus respect to control. A similar effect was observed after cell treatment with the GSK3 inhibitor LiCl (10 mM). Cell treatments with 4-10 mM LiCl significantly stimulated ALP activity respect to control at 4 and 7 days, suggesting that inhibition of GSK-3 mediates osteoblastic differentiation of rat calvarial cells. Effects comparison between ATP and LiCl shown that ALP activity was significantly increased by 10 µM ATPγ-S and decreased by 10 mM LiCl at 10 day of treatment, respect to control, suggesting that the effect of ATPγ-S was less potent but more persistent than of LiCl in stimulating this osteogenic marker in calvarial cells. Cell culture mineralization was significantly increased by treatment with 10 µM ATPγ-S and decreased by 10 mM LiCl, respect to control. In together, these results suggest that GSK3 inhibition is involved in ATPγ-S action on rat calvarial cell differentiation into osteoblasts at early steadies. In addition such inhibition by LiCl appear promote osteoblasts differentiation at beginning but has a deleterious effect on its function at later steadies as the extracellular matrix mineralization.

Feeding and GLP-1 receptor activation stabilize β-catenin in specific hypothalamic nuclei in male rats.

β-catenin is a multifunctional protein that can act in the canonical Wnt/β-catenin pathway to regulate gene expression but can also bind to cadherin proteins in adherens junctions where it plays a key role in regulating cytoskeleton linked with these junctions. Recently, evidence has been presented indicating an essential role for β-catenin in regulating trafficking of insulin vesicles in β-cells and showing that changes in nutrient levels rapidly alter levels of β-catenin in these cells. Given the importance of neuroendocrine hormone secretion in the regulation of whole body glucose homeostasis, the objective of this study was to investigate whether β-catenin signalling is regulated in the hypothalamus during the normal physiological response to food intake. Rats were subjected to a fasting/re-feeding paradigm, and then samples collected at specific timepoints for analysis of β-catenin expression by immunohistochemistry and Western blotting. Changes in gene expression were assessed by RT-qPCR. Using immunohistochemistry, feeding acutely increased detectable cytoplasmic levels of β-catenin ('stabilized β-catenin') in neurons in specific regions of the hypothalamus involved in metabolic regulation, including the arcuate, dorsomedial and paraventricular nuclei of the hypothalamus. Feeding-induced elevations in β-catenin in these nuclei were associated with increased transcription of several genes that are known to be responsive to Wnt/β-catenin signalling. The effect of feeding was mimicked by administration of the GLP-1 agonist exendin-4, and was characterized by cAMP-dependent phosphorylation of β-catenin at serine residues 552 and 675. The data suggest that β-catenin/TCF signalling is involved in metabolic sensing in the hypothalamus. This article is protected by copyright. All rights reserved.