Search

Background: Diabetes, which is characterized by an increase in blood glucose concentration, is accompanied by low bone turnover, increased fracture risk, and the formation of embryonic skeletal malformations. Yet, there are few studies elucidating the underlying alterations in signaling pathways leading to these osteogenic defects. We hypothesized here that bone formation deficiencies in a high glucose environment result from altered activity of beta-catenin (CTNNB1), a key contributor to osteogenic differentiation, dysregulation of which has also been implicated in the development of diabetes. Methods: To test this hypothesis, we used a previously established embryonic stem cell (ESC) model of differentiation that mimics the diabetic environment of the developing embryo. We differentiated murine ESCs within osteogenic-inducing media containing either high (diabetic) or low (physiological) levels of D-glucose and performed time course analyses to study the influence of high glucose on early and late bone cell differentiation. Results: Endpoint measures for osteogenic differentiation were reduced in a glucose-dependent manner and expression of precursor-specific markers altered at multiple time points. Furthermore, transcriptional activity of the lymphoid enhancer factor (LEF)/T cell factor (TCF) transcription factors during precursor formation stages was significantly elevated while levels of CTNNB1 complexed with Forkhead box O 3a (FOXO3a) declined. Modulation of AKT, a known upstream regulator of both LEF/TCF and FOXO3a, as well as CTNNB1 rescued some of the reductions in osteogenic output seen in the high glucose condition. Conclusions: Within our in vitro model, we found a clear involvement of LEF/TCF and FOXO3a signaling pathways in the regulation of osteogenic differentiation, which may account for the skeletal deficiencies found in newborns of diabetic mothers.

Desmoid-type fibromatosis (DF) is a locally aggressive but non-metastatic (myo)fibroblastic neoplasm. A hallmark of the tumor is nuclear positivity for beta-catenin in immunohistochemistry due mostly to CTNNB1 mutations. However, a recent study has reported that even beta-catenin 'nuclear-negative' DFs can harbor CTNNB1 mutations and that the positive ratio of nuclear beta-catenin in DF is different among antibodies. Here, we reviewed soft tissue lesions for which the possibility of DF was considered and compared the sensitivity and specificity of nuclear beta-catenin for the diagnosis of DF among commonly used anti-beta-catenin antibodies, i.e., clone beta-catenin 1, 17C2 and 14. We analyzed 26 cases of DF, 28 cases of benign fibroblastic lesions, and 27 cases of other soft tissue tumors. The sensitivity and specificity of nuclear beta-catenin for the diagnosis of DF were different among antibodies; 54% and 98% in clone beta-catenin 1, 85% and 84% in 17C2, and 96% and 62% in 14. IHC of LEF1 showed comparable results with IHC of beta-catenin, with a sensitivity of 88% and specificity of 76%. Additionally, when beta-catenin 1 was used, DFs showed characteristic dotted cytoplasmic staining, often appearing as rings. Our results might be helpful for making a correct diagnosis of DF.

Bidirectional interactions between plastic tumor cells and the microenvironment critically impact tumor evolution and metastatic dissemination by enabling cancer cells to adapt to microenvironmental stresses by switching phenotype. In melanoma, a key determinant of phenotypic identity is the microphthalmia-associated transcription factor MITF that promotes proliferation, suppresses senescence, and anticorrelates with immune infiltration and therapy resistance. What determines whether MITF can activate or repress genes associated with specific phenotypes, or how signaling regulating MITF might impact immune infiltration is poorly understood. Here, we find that MITF binding to genes associated with high MITF is via classical E/M-box motifs, but genes downregulated when MITF is high contain FOS/JUN/AP1/ATF3 sites. Significantly, the repertoire of MITF-interacting factors identified here includes JUN and ATF3 as well as many previously unidentified interactors. As high AP1 activity is a hallmark of MITFsupLow/sup, invasive, slow-cycling, therapy resistant cells, the ability of MITF to repress AP1-regulated genes provides an insight into how MITF establishes and maintains a pro-proliferative phenotype. Moreover, although β-catenin has been linked to immune exclusion, many Hallmark β-catenin signaling genes are associated with immune infiltration. Instead, low MITF together with Notch signaling is linked to immune infiltration in both mouse and human melanoma tumors.

Objectives Ameloblastoma is a benign, locally aggressive odontogenic tumor with high recurrence rates. Matrix metalloproteinases (MMPs) mediate extracellular integrity in normal and pathological conditions, and exert multiple functions coordinating inflammation and tumor progression. E-cadherin and beta-catenin are adherence junction molecules in cell-to-cell connections. We investigated the involvement of MMP-7, -8, -9, E-cadherin, and beta-catenin in ameloblastoma and the surrounding extracellular matrix. Material and methods Our material consisted of 30-34 tissue samples from ameloblastoma patients of Helsinki University Hospital. We used immunohistochemistry to detect the expression of the biomarkers. Two oral pathologists independently scored the immunoexpression intensities and statistical calculations were made based on the results. Results E-cadherin expression was weaker in the maxillary than in mandibular ameloblastomas. Beta-catenin was expressed in the ameloblastoma cell membranes. We detected MMP-8 and -9 expression in polymorphonuclear neutrophils in the extracellular area and these MMPs correlated positively with each other. Osteoclasts lining bone margins and multinuclear giant cells expressed MMP-9. Neither MMP-8 nor MMP-9 immunoexpression could be detected in ameloblastoma cells. MMP-7 expression was seen in some apoptotic cells. Conclusion The fact that E-cadherin immunoexpression was weaker in maxillary compared to mandibular ameloblastomas might associate to earlier recurrences. It promotes the idea of mandibular and maxillary ameloblastoma exerting differences in their biologies. We detected MMP-8 and -9 in polymorphonuclear neutrophils which relates to these MMPs participating in extracellular remodeling through a mild inflammatory process. Bone degradation around ameloblastoma may be due to MMP-9 in osteoclasts but this phenomenon might be an independent process and needs further investigations.

Wnt-Fzd signalling pathway plays a critical role in acute myeloid leukaemia (AML) progression and oncogenicity. There is no study to investigate the prognostic value of Wnt and Fzd gene families in AML. Our study screened 84 AML patients receiving chemotherapy only and 71 also undergoing allogeneic haematopoietic stem cell transplantation (allo-HSCT) from the Cancer Genome Atlas (TCGA) database. We found that some Wnt and Fzd genes had significant positive correlations. The expression levels of Fzd gene family were independent of survival in AML patients. In the chemotherapy group, AML patients with high Wnt2B or Wnt11 expression had significantly shorter event-free survival (EFS) and overall survival (OS); high Wnt10A expressers had significantly longer OS than the low expressers (all P < .05), whereas, in the allo-HSCT group, the expression levels of Wnt gene family were independent of survival. We further found that high expression of Wnt10A and Wnt11 had independent prognostic value, and the patients with high Wnt10A and low Wnt11 expression had the longest EFS and OS in the chemotherapy group. Pathway enrichment analysis showed that genes related to Wnt10A, Wnt11 and Wnt 2B were mainly enriched in 'cell morphogenesis involved in differentiation', 'haematopoietic cell lineage', 'platelet activation, signalling and aggregation' and 'mitochondrial RNA metabolic process' signalling pathways. Our results indicate that high Wnt2B and Wnt11 expression predict poor prognosis, and high Wnt10A expression predicts favourable prognosis in AML, but their prognostic effects could be neutralized by allo-HSCT. Combined Wnt10A and Wnt11 may be a novel prognostic marker in AML.

While the involvement of protease-activated receptors (PARs) in the physiological regulation of human placenta development, as in tumor biology, is recognized, the molecular pathway is unknown. We evaluated the impact of PAR1 and PAR2 function in cytotrophoblast (CTB) proliferation and invasion in a system of extravillous trophoblast (EVT) organ culture and in human cell-lines. Activation of PAR1 - and PAR2 -induced EVT invasion and proliferation, while the shRNA silencing of low-density lipoprotein receptor-related protein 5/6 (LRP5/6) inhibited these processes. PAR1 and PAR2 effectively induce β-catenin stabilization in a manner similar to that shown for the canonical β-catenin stabilization pathway yet independent of Wnts. Immunoprecipitation analyses and protein-protein docking demonstrated the co-association between either PAR1 or PAR2 with LRP5/6 forming an axis of PAR-LRP5/6-Axin. Noticeably, in PAR1 -PAR2 heterodimers a dominant role is assigned to PAR2 over PAR1 as shown by inhibition of PAR1 -induced β-catenin levels, and Dvl nuclear localization. This inhibition takes place either by shRNA silenced hPar2 or in the presence of a TrPAR2 devoid its cytoplasmic tail. Indeed, TrPAR2 cannot form the PAR1 -PAR2 complex, obstructing thereby the flow of signals downstream. Elucidation of the mechanism of PAR-induced invasion contributes to therapeutic options highlighting key partners in the process.

Wnt/beta-catenin signaling may play an essential role in endometrial decidualization, placentation, and the establishment of pregnancy. We investigate here the possible roles, immunolocalizations, and synthesis of the Wnt3, Wnt7a, and beta-catenin proteins in the rat endometrium during the estrous cycle and early postimplantation period. Wnt3 and Wnt7a had a similar localization and dynamic expression relative to the endometrial stages. Wnt7a immunostaining was not limited only to the luminal epithelial cells, but also to strong stainings in the stromal and endothelial cells. Wnt3, Wnt7a, and beta-catenin were highly synthesized and colocalized at the trophoblast-decidual interface; and were more obvious in the primary decidual zone, the GTCs, and the ectoplacental cone. Beta-catenin was strongly localized at the borders of the mature decidual cells; however, Wnt3 and Wnt7a immunolocalizations were decreased in those cells. As such, the immunolocalization of Wnt3, Wnt7a, and beta-catenin shifted with decidualization and placentation. The expression level of Wnt3, Wnt7a, and beta-catenin messenger RNAs increased in early pregnancy, and especially between Days 8.5 and 9.5. The dramatic changes in the expression of Wnt3, Wnt7a, and beta-catenin observed during the early days of pregnancy and the estrous cycle may indicate their roles in decidualization, stromal cell proliferation, and trophoblast invasion.

We present a case of trichoblastic carcinosarcoma with panfollicular differentiation. An 80‐year‐old man presented with a lesion on the left ear, which had been present for several months. Histopathology revealed a well‐demarcated neoplasm in the dermis composed of intimately intermingled malignant epithelial and mesenchymal cells. The epithelial component showed multilineage follicular differentiation toward all of the elements of a normal hair follicle. Molecular analysis revealed identical molecular aberrations in both epithelial and mesenchymal components including CTNNB1 and SUFU mutations. To the best of our knowledge, this is the first report of panfollicular carcinosarcoma and of the presence of a CTNNB1 mutation in trichoblastic carcinosarcoma.

The roles of RNA m6A modification in carcinogenesis have attracted much interest recently. However, the dysregulation of RNA m6A regulators (writers, readers, and erasers) in nasopharyngeal carcinoma (NPC) has never been reported. In this study, we showed that METTL3, one of the writers, was upregulated in NPC. Functional studies revealed that METTL3 promoted the migration and invasion of NPC cells. However, METTL3 knockdown reversed this effect and inhibited the migration, invasion and metastasis of NPC cells. METTL3 activated the luciferase activity of TOPflash (a reporter for beta‐catenin/TCF signaling), and downregulation of METTL3 inhibited the expression of beta‐catenin/TCF target genes vimentin and N‐cadherin, which are two regulators of epithelial‐mesenchymal transition. Moreover, dominant negative beta‐catenin blocked the migration and invasion of NPC cells. Further mechanistic studies showed that METTL3 silencing decreased the m6A methylation and total mRNA levels of Tankyrase, a negative regulator of axin. Moreover, Tankyrase overexpression abrogated the repressive effects of METTL3 silencing on the migration of NPC cells. Collectively, our study demonstrates the oncogenic roles of METTL3 in NPC, and suggests that METTL3 might be a therapeutic target for NPC.

Potentially malignant lesions, commonly referred to as dysplasia, are associated with malignant transformation by mechanisms that remain unclear. We recently reported that increased Wnt secretion promotes the nuclear accumulation of β-catenin and expression of target genes in oral dysplasia. However, the mechanisms accounting for nuclear re-localization of β-catenin in oral dysplasia remain unclear. In this study, we show that endosomal sequestration of the β-catenin destruction complex allows nuclear accumulation of β-catenin in oral dysplasia, and that these events depended on the endocytic protein Rab5. Tissue immunofluorescence analysis showed aberrant accumulation of enlarged early endosomes in oral dysplasia biopsies, when compared with healthy oral mucosa. These observations were confirmed in cell culture models, by comparing dysplastic oral keratinocytes (DOK) and non-dysplastic oral keratinocytes (OKF6). Intriguingly, DOK depicted higher levels of active Rab5, a critical regulator of early endosomes, when compared with OKF6. Increased Rab5 activity in DOK was necessary for nuclear localization of β-catenin and Tcf/Lef-dependent transcription, as shown by expression of dominant negative and constitutively active mutants of Rab5, along with immunofluorescence, subcellular fractionation, transcription, and protease protection assays. Mechanistically, elevated Rab5 activity in DOK accounted for endosomal sequestration of components of the destruction complex, including GSK3β, Axin, and adenomatous polyposis coli (APC), as observed in Rab5 dominant negative experiments. In agreement with these in vitro observations, tissue immunofluorescence analysis showed increased co-localization of GSK3β, APC, and Axin, with early endosome antigen 1- and Rab5-positive early endosomes in clinical samples of oral dysplasia. Collectively, these data indicate that increased Rab5 activity and endosomal sequestration of the β-catenin destruction complex leads to stabilization and nuclear accumulation of β-catenin in oral dysplasia.

The Sry‐related high‐mobility group box6 (SOX6) has been implicated in the development of cancer, but its role in lung cancer is incompletely understood. Here, we report that SOX6 expression is frequently down‐regulated in lung adenocarcinoma tissues. Moreover, SOX6 can inhibit the proliferation and invasion of lung adenocarcinoma cells, which may occur through cell cycle arrest at G1/S due to up‐regulation of p53 and p21CIPI and down‐regulation of cyclin D1 and β‐catenin. Univariate and multivariate analyses revealed that the expression of SOX6 is significantly associated with patient disease‐related survival and is an independent prognostic factor for lung adenocarcinoma. These data suggest that SOX6 may act as a suppressor of lung adenocarcinoma., We found that Sry‐related high‐mobility group box6 (SOX6) may be a tumor suppressor in lung adenocarcinoma, and prognosis of patients with lung adenocarcinoma with low SOX6 expression is poor. In this study, SOX6 inhibits the G1/S phase transition of cell cycle by up‐regulation of p53 and p21CIPI and down‐regulation of cyclin D1 and β‐catenin expression, thereby inhibiting the proliferation, migration and invasion of lung adenocarcinoma cells.

The interaction between Axin and DVL2 is critical for the breaking down of the beta‐catenin destruction complex and the activation of the Wnt/beta‐catenin cascade. However, this biological process remains poorly understood. In the present study, TM4SF1 was identified as the interacting partner of DVL2 and positively regulated as Wnt/beta‐catenin signalling by strengthening the DVL2‐Axin interaction. The expression levels of TM4SF1 were elevated in hepatocellular carcinoma (HCC) and were induced by Kras signalling. The overexpression of TM4SF1 promoted the growth and motility of HCC cells, and up‐regulated the target genes (Axin2 and cyclin D1). The down‐regulation of TM4SF1 impaired the capability of HCC cells for growth, migration and metastasis. In addition, the down‐regulation of TM4SF1 promoted the ubiquitination of beta‐catenin. In summary, these results reveal the oncogenic functions of TM4SF1 in HCC progression and suggest that TM4SF1 might be a target for treatment.

We have recently shown that loss of β‐catenin prevents the development of cholestatic liver injury and fibrosis after bile duct ligation (BDL) due to loss of the inhibitory farnesoid X receptor (FXR)/β‐catenin complex, which results in decreased hepatic bile acids (BAs) through activation of FXR. To further understand the role of Wnt/β‐catenin signaling in regulating BA metabolism and cholestasis, we performed BDL on mice in which hepatocyte Wnt signaling is deficient but β‐catenin is intact (low‐density lipoprotein receptor‐related protein [LRP]5/6 knockout [DKO]) as well as mice that have enhanced hepatocyte β‐catenin expression (serine 45 mutated to aspartic acid [S45D] transgenic [TG] mice). Despite decreased biliary injury after BDL, hepatic injury, fibrosis, and inflammation were comparable in DKO and wild‐type (WT) mice. Notably, the FXR/β‐catenin complex was maintained in DKO livers after BDL, coincident with significantly elevated hepatic BA levels. Similarly, TG mice did not display accelerated injury or increased mortality despite overexpression of β‐catenin. There was no augmentation of FXR/β‐catenin association in TG livers; this resulted in equivalent hepatic BAs in WT and TG mice after BDL. Finally, we analyzed the effect of BDL on β‐catenin activity and identified an increase in periportal cytoplasmic stabilization and association with T‐cell factor 4 that correlated with increased expression of distinct downstream target genes. Conclusion: Localization of β‐catenin and expression of Wnt‐regulated genes were altered in liver after BDL; however, neither elimination of Wnt/β‐catenin signaling nor overexpression of β‐catenin in hepatocytes significantly impacted the phenotype or progression of BA‐driven cholestatic injury., β‐catenin plays a role in regulating bile acid metabolism through an inhibitory association with farnesoid X receptor (FXR), and β‐catenin loss protects mice from bile duct ligation (BDL)‐induced liver injury. In this study, we show that FXR/β‐catenin association and progression of injury is unaffected by either loss of Wnt signaling or overexpression of β‐catenin. We also show that localization of β‐catenin was altered in liver after BDL, and may be activating target genes that are involved in hepatocyte reprogramming.

Hepatocellular carcinoma (HCC) is one of the most common malignancies and the fourth leading cause of cancer‐related death worldwide. Our previous study showed that EYA4 functioned by suppressing growth of HCC tumor cells, but its molecular mechanism is still not elucidated. Based on the results of gene microassay, EYA4 was inversely correlated with MYCBP and was verified in human HCC tissues by immunohistochemistry and western blot. Overexpressed and KO EYA4 in human HCC cell lines confirmed the negative correlation between EYA4 and MYCBP by qRT‐PCR and western blot. Transfected siRNA of MYCBP in EYA4 overexpressed cells and overexpressed MYCBP in EYA4 KO cells could efficiently rescue the proliferation and G2/M arrest effects of EYA4 on HCC cells. Mechanistically, armed with serine/threonine‐specific protein phosphatase activity, EYA4 reduced nuclear translocation of β‐catenin by dephosphorylating β‐catenin at Ser552, thereby suppressing the transcription of MYCBP which was induced by β‐catenin/LEF1 binding to the promoter of MYCBP. Clinically, HCC patients with highly expressed EYA4 and poorly expressed MYCBP had significantly longer disease‐free survival and overall survival than HCC patients with poorly expressed EYA4 and highly expressed MYCBP. In conclusion, EYA4 suppressed HCC tumor cell growth by repressing MYCBP by dephosphorylating β‐catenin S552. EYA4 combined with MYCBP could be potential prognostic biomarkers in HCC.

Obg-like ATPase 1 (OLA1) that possesses both GTP and ATP hydrolyzing activities has been shown to be involved in translational regulation of cancer cell growth and survival. Also, GSK3β signalling has been implicated in cardiac development and disease. However, the role of OLA1 in pathological cardiac hypertrophy is unknown. We sought to understand the mechanism by which OLA1 regulates GSK3β-β-Catenin signalling and its functional significance in angiotensin-II (ANG II)-induced cardiac hypertrophic response. OLA1 function and its endogenous interaction with GSK3β/β-catenin signalling in cultured human ventricular cardiomyocytes (AC16 cells) and mouse hearts (in vivo) was evaluated with/without ANG II-stimulated hypertrophic response. ANG II administration in mice increases myocardial OLA1 protein expression with a corresponding increase in GSK3β phosphorylation and decrease in β-Catenin phosphorylation. Cultured cardiomyocytes treated with ANG II show endogenous interaction between OLA1 and GSK3β, nuclear accumulation of β-Catenin and significant increase in cell size and expression of hypertrophic marker genes such as atrial natriuretic factor (ANF; NPPA) and β-myosin heavy chain (MYH7). Intriguingly, OLA1 inhibition attenuates the above hypertrophic response in cardiomyocytes. Taken together, our data suggest that OLA1 plays a detrimental role in hypertrophic response via GSK3β/β-catenin signalling. Translation strategies to target OLA1 might potentially limit the underlying molecular derangements leading to left ventricular dysfunction in patients with maladaptive cardiac hypertrophy.

BACKGROUND/OBJECTIVES Progranulin (PGRN) is a secreted glycoprotein that was investigated in many skin diseases. It plays an important role in inflammatory response and autophagy which could be mediated through Wnt/β-catenin pathway. However, the role of PGRN in pathogenesis of psoriasis has not been clearly well-known. Therefore, we aimed by this study to investigate the possible role of progranulin in psoriasis pathogenesis through evaluation of its immunohistochemical expression in lesional and perilesional skin of psoriasis patients and to investigate if its hypothesized role is mediated through β-catenin or not. METHODS This case-control study was carried out on 37 patients presented with variable degrees of psoriasis vulgaris severity vs 37 age and sex-matched apparently healthy volunteers. Psoriasis area and severity index (PASI) score was used to evaluate the severity of psoriasis. From all cases (lesional and perilesional) and controls, skin biopsies were taken for histopathological and immunohistochemical evaluation of PGRN and β-catenin. RESULTS There was a significant stepwise upregulation of PGRN from controls (76.2 ± 11.9) to perilesional (178.7 ± 11.8) and lesional (242.7 ± 12.7) psoriatic skin (P

Solid pseudopapillary neoplasms of the pancreas are rare neoplasms that have been shown to harbor recurrent somatic pathogenic variants in the beta-catenin gene, CTNNB1. Here, we used targeted next generation sequencing to analyze these tumors for other associated mutations. Six cases of solid pseudopapillary neoplasms were studied. DNA extracted from formalin-fixed paraffin embedded tissue blocks was analyzed using the Ion Torrent platform, with the 50-gene Ampliseq Cancer Hotspot Panel v2 (CHPv2), with further variant validation performed by Sanger sequencing. Four tumors (67%) were confirmed to harbor mutations within CTNNB1, two with c.109T > G p.(Ser37Ala) and two with c.94G > A p.(Asp32Asn). One case showed a frameshift deletion in the Adenomatous Polyposis Coli gene, APC c.3964delG p.(Glu1322Lysfs*93) with a variant allele frequency of 42.6%. Sanger sequencing on non-tumoral tissue confirmed the variant was somatic. The patient with the APC mutation developed metastasis and died. In addition to the four cases harboring CTNNB1 variants, we found a case characterized by poor outcome, showing a rare frameshift deletion in the APC gene. Since the APC product interacts with beta-catenin, APC variants may, in addition to CTNNB1, contribute to the pathogenesis of solid pseudopapillary neoplasms via the Wnt signaling pathway.

Prohibitin1 (PHB1) is a mitochondrial chaperone with diverse functions that include cell proliferation, apoptosis, and mitochondrial homoeostasis. Liver-specific Phb1 knockout (KO) mice develop spontaneous injury and hepatocellular carcinoma (HCC). Our previous work demonstrated that PHB1 negatively regulates the H19-insulin-like growth factor 2 (IGF2)-H19-IGF2 axis signaling pathway and E-box activity in hepatocytes and HCC cells. Phb1 KO livers exhibited increased expression of multiple wingless/integrated (WNT) target genes compared to control littermates. Therefore, we hypothesized that PHB1 is a negative regulator of WNT-beta-catenin signaling in the liver. Analysis of livers from Phb1 KO mice demonstrated an activation of the WNT-beta-catenin pathway as determined by phosphorylation of glycogen synthase kinase 3 (GSK3)betaserine [Ser]9 and protein kinase B (AKT)Ser473. Phb1 KO livers showed increased messenger RNA (mRNA) levels of multiple WNT ligands, with Wnt7a (79-fold), Wnt10a (12-fold), and Wnt16 (48-fold) being most highly overexpressed compared to control littermates. Subcellular fractionation of liver cells from Phb1 KO mice indicated that hepatocytes are the main source of WNT ligands. Immunostaining and cellular colocalization analysis of Phb1 KO livers demonstrated expression of WNT7a, WNT10a, and WNT16 in hepatocytes. Chromatin immunoprecipitation revealed increased binding of transcription factor E2F1 (E2F1) to the Wnt10a promoter in Phb1 KO livers and WNT9A in HepG2 cells. PHB1 silencing in HepG2 cells activated WNT signaling, whereas its overexpression caused inactivation of this pathway. PHB1 silencing in HepG2 cells induced the expression of multiple WNT ligands of which WNT9A induction was partly regulated through E2F1. Conclusion: PHB1 acts as a negative regulator of WNT signaling, and its down-regulation causes the induction of multiple WNT ligands and downstream activation of canonical WNT-beta-catenin signaling in murine liver and human HCC cells, in part through E2F1.

Wnt signal transduction controls tissue morphogenesis, maintenance and regeneration in all multicellular animals. In mammals, the WNT/CTNNB1 (Wnt/β‐catenin) pathway controls cell proliferation and cell fate decisions before and after birth. It plays a critical role at multiple stages of embryonic development, but also governs stem cell maintenance and homeostasis in adult tissues. However, it remains challenging to monitor endogenous WNT/CTNNB1 signaling dynamics in vivo. Here, we report the generation and characterization of a new knock‐in mouse strain that doubles as a fluorescent reporter and lineage tracing driver for WNT/CTNNB1 responsive cells. We introduced a multi‐cistronic targeting cassette at the 3′ end of the universal WNT/CTNNB1 target gene Axin2. The resulting knock‐in allele expresses a bright fluorescent reporter (3xNLS‐SGFP2) and a doxycycline‐inducible driver for lineage tracing (rtTA3). We show that the Axin2P2A‐rtTA3‐T2A‐3xNLS‐SGFP2 strain labels WNT/CTNNB1 responsive cells at multiple anatomical sites during different stages of embryonic and postnatal development. It faithfully reports the subtle and dynamic changes in physiological WNT/CTNNB1 signaling activity that occur in vivo. We expect this mouse strain to be a useful resource for biologists who want to track and trace the location and developmental fate of WNT/CTNNB1 responsive stem cells in different contexts.

Pathological observations show that cancer cells frequently invade the surrounding stroma in collective groups rather than through single cell migration. Here, we studied the role of the actin-binding protein Girdin, a specific regulator of collective migration of neuroblasts in the brain, in collective cancer cell migration. We found that Girdin was essential for the collective migration of the skin cancer cell line A431 on collagen gels as well as their fibroblast-led collective invasion in an organotypic culture model. We provide evidence that Girdin binds to β-catenin that plays important roles in the Wnt signaling pathway and in E-cadherin-mediated cell-cell adhesion. Girdin-depleted cells displayed scattering and impaired E-cadherin-specific cell-cell adhesion. Importantly, Girdin depletion led to impaired cytoskeletal association of the β-catenin complex, which was accompanied by changes in the supracellular actin cytoskeletal organization of cancer cell cohorts on collagen gels. Although the underlying mechanism is unclear, this observation is consistent with the established role of the actin cytoskeletal system and cell-cell adhesion in the collective behavior of cells. Finally, we showed the correlation of the expression of Girdin with that of the components of the E-cadherin complex and the differentiation of human skin cancer. Collectively, our results suggest that Girdin is an important modulator of the collective behavior of cancer cells.

It has been shown that long noncoding RNAs (lncRNAs) are involved in the carcinogenesis of multiple cancers. However, the roles of lncRNAs in gastroenteropancreatic neuroendocrine neoplasms (GEP‐NENs) remain elusive. In the present study, we found that lncNEN885 was markedly decreased in human gastric NEN samples compared to adjacent normal tissues by transcriptome sequencing. Functionally, silencing or overexpression of lncNEN885 could not obviously affect cell proliferation or apoptosis in BON‐1 or LCC‐18 cells but could affect cell migration and invasion as well as wound‐healing rates. Furthermore, dysregulation of lncNEN885 affected these biological functions by activating epithelial‐mesenchymal transition through increased expression of Snail, vimentin, and N‐cadherin as well as decreased E‐cadherin levels in BON‐1 and LCC‐18 cells. Silencing of lncNEN885 could dramatically increase the phosphorylation of glycogen synthase kinase‐3β and decrease the expression of adenomatous polyposis coli and Axin, with the subsequent accumulation of β‐catenin. Taken together, dysregulation of lncNEN885 can regulate cell migration and invasion by activating epithelial‐mesenchymal transition process partially through canonical Wnt/β‐catenin signaling in GEP‐NEN cells, which may be a novel biomarker for the metastasis of GEP‐NENs.

β-catenin is important in development of lung cancer. In our previous study, GMI, a fungal immunomodulatory protein, inhibits lung cancer cell survival. The aim of this study is to evaluate the effect of GMI on β-catenin inhibition and apoptosis induction. GMI induced apoptosis in lung cancer cells bearing wild-type and mutated EGFR. GMI did not reduce the β-catenin mRNA expression but suppressed the protein expressions of β-catenin that resulted in the transcriptional downregulation of its target genes: survivin and cyclin-D1. The transcriptional activation activity of β-catenin was demonstrated by TOPFLASH/FOPFLASH luciferase reporter assay. Inhibition of GSK-3β and proteasome blocked the inhibiting effect of GMI on β-catenin and its target genes. β-catenin silencing increased activation of apoptosis in GMI-treated H1355 cells. This is the first study to reveal the novel function of GMI in inducing apoptosis via β-catenin inhibition. These results provide a new potential of GMI in against lung cancer.

The odd-skipped related 1 (OSR1) gene encodes a zinc-finger transcription factor. The expression and significance of OSR1 in human tumors remains unclear. We found that OSR1 was downregulated in lung cancers, and its expression was correlated with poor differentiation. Overexpression of OSR1 by OSR1 gene transfection into H1299 cells (H1299-OSR1) inhibited the proliferation and invasion of lung cancer cells. Knockdown of OSR1 with small interfering (si)RNA against OSR1 in A549 cells (A549-siOSR1) enhanced the proliferation and invasion of lung cancer cells. Western blot analysis showed that the expression level of GSK3β increased, while that of p-GSK3β, nuclear β-catenin, cyclin D1, c-Myc and matrix metallopeptidase 7 significantly decreased in the H1299-OSR1 cells, and this pattern was reversed in the A549-siOSR1 cells compared to that in the control cells. Furthermore, upregulation of sex-determining region Y-box 9 (SOX9) by SOX9 gene transfection increased the expression of β-catenin, which was inhibited by OSR1. The mRNA and protein expression levels of SOX9 and β-catenin were reduced in H1299-OSR1 cells and increased in A549-siOSR1 cells. In conclusion, the expression of OSR1 was more reduced in lung cancer tissues than in normal lung tissues, and was correlated with poor differentiation. OSR1 downregulated the activity of the Wnt signaling pathway by suppressing the expression of SOX9 and β-catenin.

Tumor suppressor/transcription factor p53 is mutated in over 50% of all cancers. Some mutant p53 proteins have not only lost tumor suppressor activities but they also gain oncogenic functions (GOF). One of the most frequently expressed GOF p53 mutants is Arg175His (p53R175H ) with well-documented roles in cancer development and progression. Plakoglobin is a cell adhesion and signaling protein and a paralog of β-catenin. Unlike β-catenin that has oncogenic function through its role in the Wnt pathway, plakoglobin generally acts as a tumor/metastasis suppressor. We have shown that plakoglobin interacted with wild type and a number of p53 mutants in various carcinoma cell lines. Plakoglobin and mutant p53 interacted with the promoter and regulated the expression of several p53 target genes. Furthermore, plakoglobin interactions with p53 mutants restored their tumor suppressor/metastasis activities in vitro. GOF p53 mutants induce accumulation and oncogenic activation of β-catenin. Previously, we showed that one mechanism by which plakoglobin may suppress tumorigenesis is by sequestering β-catenin's oncogenic activity. Here, we examined the effects of p53R175H expression on β-catenin accumulation and transcriptional activation and their modifications by plakoglobin coexpression. We showed that p53R175H expression in plakoglobin null cells increased total and nuclear levels of β-catenin and its transcriptional activity. Coexpression of plakoglobin in these cells promoted β-catenin's proteasomal degradation, and decreased its nuclear levels and transactivation. Wnt/β-catenin targets, c-MYC and S100A4 were upregulated in p53R175H cells and were downregulated when plakoglobin was coexpressed. Plakoglobin-p53R175H cells also showed significant reduction in their migration and invasion in vitro.

Objective To investigate the molecular mechanism underlying inflammation-related ectopic new bone formation in ankylosing spondylitis (AS). Methods Spinal tissues and sera were collected from patients with AS and healthy volunteers and examined for the expression of Wnt proteins. An in vitro cell culture system mimicking the local inflammatory microenvironment of bone-forming sites was established to study the relationship between inflammation and Wnt expression, the regulatory mechanism of inflammation-induced Wnt expression, and the role of Wnt signaling in new bone formation. Modified collagen-induced arthritis (CIA) and proteoglycan-induced spondylitis (PGIS) animal models were used to confirm the key findings in vivo. Results The levels of osteoinductive Wnt proteins were increased in sera and spinal ligament tissues from patients with AS. Constitutive low-intensity tumor necrosis factor (TNF) stimulation, but not short-term or high-intensity TNF stimulation, induced persistent expression of osteoinductive Wnt proteins and subsequent bone formation through NF-κB (p65) and JNK/activator protein 1 (c-Jun) signaling pathways. Furthermore, inhibition of either the Wnt/β-catenin or Wnt/protein kinase Cδ (PKCδ) pathway significantly suppressed new bone formation. The increased expression of Wnt proteins was confirmed in both the modified CIA and PGIS models. A kyphotic and ankylosing phenotype of the spine was seen during long-term observation in the modified CIA model. Inhibition of either the Wnt/β-catenin or Wnt/PKCδ signaling pathway significantly reduced the incidence and severity of this phenotype. Conclusion Inflammation intensity-dependent expression of osteoinductive Wnt proteins is a key link between inflammation and ectopic new bone formation in AS. Activation of both the canonical Wnt/β-catenin and noncanonical Wnt/PKCδ pathways is required for inflammation-induced new bone formation.

Wnt signaling pathway plays important role in all aspects of skeletal development which include chondrogenesis, osteoblastogenesis, and osteoclastogenesis. Induction of the Wnt-3 signaling pathway promotes bone formation while inactivation of the pathway leads to bone related disorders like osteoporosis. Wnt signaling thus has become a desired target to treat osteogenic disorders. MicroRNAs (miRNAs) represent an important category of elements that interact with Wnt signaling molecules to regulate osteogenesis. Here, we show that miR-376c, a well-characterized tumor suppressor which inhibits cell proliferation and invasion in osteosarcoma by targeting to transforming growth factor-alpha, suppresses osteoblast proliferation, and differentiation. Over-expression of miR-376c inhibited osteoblast differentiation, whereas inhibition of miR-376c function by antimiR-376c promoted expression of osteoblast-specific genes, alkaline phosphatase (ALP) activity, and matrix mineralization. Target prediction analysis tools and experimental validation by luciferase 3' UTR reporter assay along with qRT-PCR identified Wnt-3 and ARF-GEF-1 as direct targets of miR-376c. It was seen that over-expression of miR-376c leads to repression of canonical Wnt/β-catenin signaling. Our overall results suggest that miR-376c targets Wnt-3 and ARF-GEF-1 suppresses ARF-6 activation which prevents the release of β-catenin and its transactivation thereby inhibiting osteoblast differentiation. Although miR-376c is known to be a tumor repressor; we have identified a second complementary function of miR-376c where it inhibits Wnt-3-mediated osteogenesis and promotes bone loss.

Regulatory mechanisms for acute inflammatory responses post myocardial infarction (MI) have yet to be fully understood. In particular, the mechanisms by which cardiac macrophages modulate MI-induced myocardial inflammation remains unclear. In this study, using a mouse MI model, we showed that β-catenin-mediated signaling was activated in cardiac macrophages post-MI, especially in Ly-6C-positive proinflammatory macrophages. Using a RAW264.7-based β-catenin reporter cell line, we confirmed the presence of active β-catenin and its downstream signaling in cardiac macrophages after MI. Moreover, lentivirus-mediated inducible expression of constitutively active β-catenin revealed that β-catenin plays a role in promoting the inflammatory response by RAW264.7 cells. Depletion of endogenous macrophages and adoptive transfer of active β-catenin-expressing RAW264.7 cells resulted in enhancement of acute myocardial inflammation in recipient mice after MI, as demonstrated by elevated levels of lymphocyte infiltrates and increased expression of proinflammatory cytokines. However, infarct volume, myocardial tissue repair, and left ventricle function were not influenced by the expression of active β-catenin in the adoptive transfer assay. Our research has demonstrated that β-catenin-mediated signaling is important for cardiac macrophages to modulate post-MI inflammatory responses. These findings may be valuable for developing novel therapeutic strategies for MI.

Targeted refinement of regenerative materials requires mechanistic understanding of cell-material interactions. The nanoparticulate mineralized collagen glycosaminoglycan (MC-GAG) scaffold has been shown to promote skull regeneration in vivo without additive exogenous growth factors or progenitor cells, suggesting potential for clinical translation. This work evaluates modulation of MC-GAG stiffness on canonical Wnt (cWnt) signaling. Primary human bone marrow-derived mesenchymal stem cells (hMSCs) were differentiated on two MC-GAG scaffolds (non-crosslinked, NX-MC, 0.3 kPa vs. conventionally crosslinked, MC, 3.9 kPa). hMSCs increased expression of activated β-catenin, the major cWnt intracellular mediator, and the mechanosensitive YAP protein with near complete subcellular colocalization on stiffer MC scaffolds. Overall Wnt pathway inhibition reduced activated β-catenin and osteogenic differentiation, while elevating BMP4 and phosphorylated Smad1/5 (p-Smad1/5) expression on MC, but not NX-MC. Unlike Wnt pathway downregulation, isolated canonical Wnt inhibition with β-catenin knockdown increased osteogenic differentiation and mineralization specifically on the stiffer MC. β-catenin knockdown also increased p-Smad1/5, Runx2, and BMP4 expression only on the stiffer MC material. Thus, while stiffness-induced activation of the Wnt and mechanotransduction pathways promotes osteogenesis on MC-GAG, activated β-catenin is a limiting agent and may serve as a useful target or readout for optimal modulation of stiffness in skeletal regenerative materials.

Colorectal cancer results from the malignant transformation of colonic epithelial cells. Stromal fibroblasts are the main component of the tumour microenvironment, and play an important role in the progression of this and other neoplasias. Wnt/β-catenin signalling is essential for colon homeostasis, but aberrant, constitutive activation of this pathway is a hallmark of colorectal cancer. Here we present the first transcriptomic study on the effect of a Wnt factor on human colonic myofibroblasts. Wnt3A regulates the expression of 1,136 genes, of which 662 are upregulated and 474 are downregulated in CCD-18Co cells. A set of genes encoding inhibitors of the Wnt/β-catenin pathway stand out among those induced by Wnt3A, which suggests that there is a feedback inhibitory mechanism. We also show that the PKP2 gene encoding the desmosomal protein Plakophilin-2 is a novel direct transcriptional target of Wnt/β-catenin in normal and colon cancer-associated fibroblasts. PKP2 is induced by β-catenin/TCF through three binding sites in the gene promoter and one additional binding site located in an enhancer 20 kb upstream from the transcription start site. Moreover, Plakophilin-2 antagonizes Wnt/β-catenin transcriptional activity in HEK-293T cells, which suggests that it may act as an intracellular inhibitor of the Wnt/β-catenin pathway. Our results demonstrate that stromal fibroblasts respond to canonical Wnt signalling and that Plakophilin-2 plays a role in the feedback control of this effect suggesting that the response to Wnt factors in the stroma may modulate Wnt activity in the tumour cells.

Fas signaling promotes colorectal cancer (CRC) metastasis by inducing epithelial-mesenchymal transition (EMT). The acquisition of EMT properties in turn induces stemness but the mechanism by which Fas signaling contributes to it still remains unclear. Hence, the aim of this study was to investigate how Fas signaling regulates CRC stemness. For this purpose, soft agar assay, sphere formation assay, cell survival analysis, immunoblot, qRT-PCR, chromatin immunoprecipitation, and luciferase reporter assay were performed. Expression of FasL, Bmi1, and the miR-200c in CRC specimens was examined through immunohistochemistry, qRT-PCR, and immunoblot. In our study, Fas signaling induced stem cell properties in CRC specimens, relying on ERK1/2 MAPK pathway, with Bmi1 being mainly responsible for FasL-induced stemness. FasL treatment promoted Bmi1 expression by inhibiting miR-200c, which targets Bmi1 3'UTR region. Furthermore, FasL-induced Zeb1 binded with miR-200c promoter and inhibited its expression. Moreover, FasL-induced β-catenin nuclear expression promoted Zeb1 expression by binding with Zeb1 promoter. GSK-3β, which regulates β-catenin, was inhibited by FasL-induced ERK1/2 MAPK signaling. Finally, FasL and Bmi1 expression in clinical samples increased during CRC progression, and a positive correlation between them was observed. Patients with high FasL and Bmi1 expression had a worse prognosis than patients with low expression. In conclusion, our results showed that Fas signaling can promote stemness in CRC through the modulation of Bmi1 expression via the ERK1/2 MAPK/GSK-3β/β-catenin/Zeb1/miR-200c axis, suggesting that Fas signaling-based cancer therapies should be administered cautiously, as the activation of this pathway not only leads to apoptosis but also induces stemness in CRC.

Metastasis associated lung adenocarcinoma transcript 1(MALAT1) is a long non‐coding RNA, broadly expressed in mammalian tissues including kidney and up‐regulated in a variety of cancer cells. To date, its functions in podocytes are largely unknown. β‐catenin is a key mediator in the canonical and non‐canonical Wnt signalling pathway; its aberrant expression promotes podocyte malfunction and albuminuria, and contributes to kidney fibrosis. In this study, we found that MALAT1 levels were increased in kidney cortices from C57BL/6 mice with streptozocin (STZ)‐induced diabetic nephropathy, and dynamically regulated in cultured mouse podocytes stimulated with high glucose, which showed a trend from rise to decline. The decline of MALAT1 levels was accompanied with β‐catenin translocation to the nuclei and enhanced expression of serine/arginine splicing factor 1 (SRSF1), a MALAT1 RNA‐binding protein. Further we showed early interference with MALAT1 siRNA partially restored podocytes function and prohibited β‐catenin nuclear accumulation and SRSF1 overexpression. Intriguingly, we showed that β‐catenin was involved in MALAT1 transcription by binding to the promotor region of MALAT1; β‐catenin knock‐down also decreased MALAT1 levels, suggesting a novel feedback regulation between MALAT1 and β‐catenin. Notably, β‐catenin deletion had limited effects on SRSF1 expression, demonstrating β‐catenin might serve as a downstream signal of SRSF1. These findings provided evidence for a pivotal role of MALAT1 in diabetic nephropathy and high glucose‐induced podocyte damage.

Although mutations in the phosphoinositide 3‐kinase catalytic subunit (PIK3CA) are common in breast cancer, PI3K inhibitors alone have shown modest efficacy. We sought to identify additional pathways altered in PIK3CA‐mutant tumors that might be targeted in combination with PI3K inhibitors. We generated two transgenic mouse models expressing the human PIK3CA‐H1047R‐ and the ‐E545K hotspot‐mutant genes in the mammary gland and evaluated their effects on development and tumor formation. Molecular analysis identified pathways altered in these mutant tumors, which were also targeted in multiple cell lines derived from the PIK3CA tumors. Finally, public databases were analyzed to determine whether novel pathways identified in the mouse tumors were altered in human tumors harboring mutant PIK3CA. Mutant mice showed increased branching and delayed involution of the mammary gland compared to parental FVB/N mice. Mammary tumors arose in 30% of the MMTV‐PIK3CA‐H1047R and in 13% of ‐E545K mice. Compared to MMTV‐Her‐2 transgenic mouse mammary tumors, H1047R tumors showed increased upregulation of Wnt/β‐catenin/Axin2, hepatocyte growth factor (Hgf)/Stat3, insulin‐like growth factor 2 (Igf‐2), and Igf‐1R pathways. Inhibitors of STAT3, β‐catenin, and IGF‐1R sensitized H1047R‐derived mouse tumor cells and PIK3CA‐H1047R overexpressing human HS578T breast cancer cells to the cytotoxic effects of PI3K inhibitors. Analysis of The Cancer Genome Atlas database showed that, unlike primary PIK3CA‐wild‐type and HER‐2+ breast carcinomas, PIK3CA‐mutant tumors display increased expression of AXIN2, HGF, STAT3, IGF‐1, and IGF‐2 mRNA and activation of AKT, IGF1‐MTOR, and WNT canonical signaling pathways. Drugs targeting additional pathways that are altered in PIK3CA‐mutant tumors may improve treatment regimens using PI3K inhibitors alone.

Zinc finger protein X-linked (ZFX) is frequently upregulated in multiple human malignancies and also plays a critical role in the maintenance of self-renewal in embryonic stem cells. However, the role of ZFX in liver cancer stem cells (CSCs) remains obscure. We observed that the elevated expression of both ZFX and epithelial cell adhesion molecule (EpCAM) was associated with aggressive clinicopathological features and indicated poor prognosis in patients with hepatocellular carcinoma (HCC). ZFX was commonly enriched in liver EpCAM+ CSCs. Knockdown of ZFX decreased the proportion of EpCAM+ CSCs in HCC cells and suppressed their expression of stemness-related genes, self-renewal capacity, chemoresistance, metastatic potential, and tumorigenicity. Conversely, upregulation of ZFX in CSCs rescued these inhibitory effects and enhanced stem-like properties. Mechanistically, depletion of ZFX reduced nuclear translocation and transactivation of β-catenin, thereby inhibiting the self-renewal capacity of EpCAM+ CSCs. Moreover, knockdown of β-catenin attenuated the self-renewal of EpCAM+ HCC cells stably expressing ZFX, further indicating that β-catenin is required for ZFX-mediated expansion and maintenance of EpCAM+ CSCs. Taken together, our findings indicate that ZFX activates and maintains EpCAM+ liver CSCs by promoting nuclear translocation and transactivation of β-catenin. Furthermore, combination of ZFX and EpCAM may serve as a significant indicator for prognosis of patients with HCC.

Wilms tumor (WT) is the most common renal neoplasm of childhood and affects 1 in 10 000 children aged less than 15 years. These embryonal tumors are thought to arise from primitive nephrogenic rests that derive from the metanephric mesenchyme during kidney development and are characterized partly by increased Wnt/β-catenin signaling. We previously showed that coordinate activation of Ras and β-catenin accelerates the growth and metastatic progression of a murine WT model. Here, we show that activating KRAS mutations can be found in human WT. In addition, high levels of phosphorylated AKT are present in the majority of WT. We further show in a mouse model and in renal epithelial cells that Ras cooperates with β-catenin to drive metastatic disease progression and promotes in vitro tumor cell growth, migration, and colony formation in soft agar. Cellular transformation and metastatic disease progression of WT cells are in part dependent on PI3K/AKT activation and are inhibited via pharmacological inhibition of this pathway. Our studies suggest both KRAS mutations and AKT activation are present in WT and may represent novel therapeutic targets for this disease.

Nuclear factor I-C (NFIC) has recently been identified as an important player in osteogenesis and bone homeostasis in vivo However, the molecular mechanisms involved have yet to be defined. In the current study, Nfic expression was altered in primary marrow stromal cells and established progenitor lines after adipogenic and osteogenic treatment. Overexpression of Nfic in stromal cells ST2, mesenchymal cells C3H10T1/2, and primary marrow stromal cells inhibited adipogenic differentiation, whereas it promoted osteogenic differentiation. Conversely, silencing of endogenous Nfic in the cell lines enhanced adipogenic differentiation, whereas it blocked osteogenic differentiation. Mechanism investigations revealed that Nfic overexpression promoted nuclear translocation of β-catenin and increased nuclear protein levels of β-catenin and transcription factor 7-like 2 (TCF7L2). Promoter studies and the chromatin immunoprecipitation (ChIP) assay revealed that NFIC directly binds to the promoter of low-density lipoprotein receptor-related protein 5 (Lrp5) and thereafter transactivates the promoter. Finally, inactivation of canonical Wnt signaling in ST2 attenuated the inhibition of adipogenic differentiation and stimulation of osteogenic differentiation by NFIC. Our study suggests that NFIC balances adipogenic and osteogenic differentiation from progenitor cells through controlling canonical Wnt signaling and highlights the potential of NFIC as a target for new therapies to control metabolic disorders like osteoporosis and obesity.-Zhou, J., Wang, S., Qi, Q., Yang, X., Zhu, E., Yuan, H., Li, X., Liu, Y., Li, X., Wang, B. Nuclear factor I-C reciprocally regulates adipocyte and osteoblast differentiation via control of canonical Wnt signaling.

Long-term exposure to peritoneal dialysate with high glucose (HG) leads to peritoneal fibrosis and thus decreases dialysis efficiency. In this study, we explored the role of β-catenin in this process. C57BL/6 mice received daily intraperitoneal injection with 10% of the body weight of saline (control), 4.25% glucose peritoneal dialysis fluid (PDF), or PDF combined with 5 mg·kg-1 of the β-catenin inhibitor ICG-001 (PDF+ICG) for 30 days. Also, mice peritoneal epithelial cells (mPECs) were cultured in 4.25% glucose (HG) or combined with 10 μm ICG-001 (HG+ICG) for 48 h. We found greater thickness of the parietal peritoneum in the PDF-treated mice. Additionally, lower expression of E-cadherin, higher expression of Vimentin, β-catenin, and Snail, and activation of β-catenin was observed in the mice and in HG-treated mPECs, all of which were reversed by ICG-001. The changes in E-cadherin and Vimentin indicated occurrence of the epithelial-to-mesenchymal transition (EMT). Thus, β-catenin signaling participates in the process of HG-induced peritoneal fibrosis, and the EMT of peritoneal epithelial cells is one of the underlying mechanisms of this pathological change.

Excessive signaling through gp130, the shared receptor for the interleukin (IL)6 family of cytokines, is a common hallmark in solid malignancies and promotes their progression. Here, we established the in vivo utility of bazedoxifene, a steroid analog clinically approved for the treatment of osteoporosis, to suppress gp130‐dependent tumor growth of the gastrointestinal epithelium. Bazedoxifene administration reduced gastric tumor burden in gp130 Y757F mice, where tumors arise exclusively through excessive gp130/STAT3 signaling in response to the IL6 family cytokine IL11. Likewise, in mouse models of sporadic colon and intestinal cancers, which arise from oncogenic mutations in the tumor suppressor gene Apc and the associated β‐catenin/canonical WNT pathway, bazedoxifene treatment reduces tumor burden. Consistent with the proposed orthogonal tumor‐promoting activity of IL11‐dependent gp130/STAT3 signaling, tumors of bazedoxifene‐treated Apc‐mutant mice retain excessive nuclear accumulation of β‐catenin and aberrant WNT pathway activation. Likewise, bazedoxifene treatment of human colon cancer cells harboring mutant APC did not reduce aberrant canonical WNT signaling, but suppressed IL11‐dependent STAT3 signaling. Our findings provide compelling proof of concept to support the repurposing of bazedoxifene for the treatment of gastrointestinal cancers in which IL11 plays a tumor‐promoting role.