Project description:In this study we analyzed the effect of TG2 on the modulation of gene expression by defining its effects on the cellular mRNA profile. To address this point we analyzed, by RNA seq, the effect of TG2 on the overall transcriptome after heat shock treatment. The data obtained reveal that TG2 markedly influences the overall cellular transcriptome profile and specifically the Wnt and HSF1 pathways. In particular, its ablation leads to a drastic downregulation of many key members of both these pathways. We found that key components of the Wnt/β-catenin pathway are also downregulated in cells lacking HSF1, thus confirming that TG2 regulates the HSF1 and this axis controls the Wnt signaling.
Project description:Aortic valve stenosis (AVS) is a prevailing and life-threatening cardiovascular disease in adults over 75 years of age. However, the molecular mechanisms governing the pathogenesis of AVS are yet to be fully unraveled. With accumulating evidence that Wnt signaling plays a key role in the development of AVS, the involvement of intracellular Wnt molecules has become an integral study target in AVS pathogenesis. Thus, we hypothesized that the Wnt/β‐catenin pathway Wnt intracellular mediators, SFRP2, DVL2, GSK3β and β‐catenin are dysregulated in patients with AVS. Using immunohistochemistry, Real‐Time qPCR and Western blotting, we investigated the presence of SFRP2, GSK‐3β, DVL2 and β‐catenin in normal and stenotic human aortic valves. Markedly higher mRNA and protein expression of GSK‐3β, DVL2, β‐catenin and SFRP2 were found in stenotic aortic valves. This was further corroborated by observation of their abundant immunostaining, which displayed strong immunoreactivity in diseased aortic valves. Proteomic analyses of selective GSK3b inhibition in calcifying human aortic valve interstitial cells (HAVICs) revealed enrichment of proteins involved organophosphate metabolism, while reducing the activation of pathogenic biomolecular processes. Lastly, use of the potent calcification inhibitor, Fetuin A, in calcifying HAVICs significantly reduced the expression of Wnt signaling genes Wnt3a, Wnt5a, Wnt5b and Wnt11. The current findings of altered expression of canonical Wnt signaling in AVS suggest a possible role for regulatory Wnts in AVS. Hence, future studies focused on targeting these molecules are warranted to underline their role in the pathogenesis of the disease.
Project description:The Wnt/β-catenin signaling pathway is a critical regulator of development and stem cell maintenance. Mounting evidence suggests that the context-specific outcome of Wnt signaling is determined by the collaborative action of multiple transcription factors, including members of the highly conserved forkhead box (FOX) protein family. The contribution of FOX transcription factors to Wnt signaling has not been investigated in a systemic manner. Here, by combining β-catenin reporter assays with Wnt pathway-focused qPCR arrays and proximity proteomics of selected FOX family members, we determine that most FOX proteins are involved in the regulation of Wnt pathway activity and the expression of Wnt ligands and target genes. We conclude that FOX proteins are common regulators of the Wnt/β-catenin pathway that may control the outcome of Wnt signaling in a tissue-specific manner.
Project description:Colorectal cancer (CRC) is the second leading cause of cancer mortality worldwide. However, the molecular mechanisms underlying CRC progression remain to be further defined to improve patient outcomes. In this study, we found that KCTD9, a member of the potassium channel tetramerization domain-containing (KCTD) gene family, was commonly downregulated in CRC tissues and that KCTD9 expression was negatively correlated with the clinical CRC stage. Survival analysis showed that patients whose tumors expressed low KCTD9 levels had poorer outcomes. Functional analyses revealed that KCTD9 overexpression inhibited CRC cell proliferation and metastasis, whereas KCTD9 knockdown promoted CRC cell proliferation and metastasis in both in vitro and in vivo models. Manipulating KCTD9 levels in CRC cells via overexpression or knockdown showed KCTD9 expression positively influenced the degradation of β-catenin levels leading to inhibition of Wnt signaling and reductions in Wnt pathway target gene expression. Mechanistically, we found KCTD9 associated with ZNT9 (Zinc Transporter 9), a coactivator of β-catenin-mediated gene transcription. The overexpression of KCTD9 or knockdown of ZNT9 in CRC cells increased the polyubiquitination and proteasomal degradation of β-catenin. In turn, the KCTD9-ZNT9 interaction disrupted interactions between β-catenin and ZNT9, thereby leading to decreased β-catenin target gene expression and the inhibition of Wnt signaling. In conclusion, our findings propose that KCTD9 functions as a tumor suppressor that inhibits CRC cell proliferation and metastasis by inactivating the Wnt/β-catenin pathway. Moreover, its frequent downregulation in CRC suggests KCTD9 as a potential prognostic and therapeutic target in CRC.
Project description:Breast cancer is one of the most common types of cancer in women. One key signaling pathway known to regulate tumor growth, metabolic adaptation, and cellular stress response in breast cancer is Wnt signaling. Breast cancer patients, specifically triple negative breast cancer (TNBC), with upregulated Wnt signaling often have a poor clinical prognosis. However, the effects of Wnt/β-catenin signaling on the nucleolus and the resultant impact on cancer development and progression remain unclear. A notable reduction was observed in the number of nucleoli per nucleus in response to Wnt/β-catenin signaling inhibition in multiple TNBC cell lines. Our comparative proteomic analysis revealed several changes in the composition of the nucleolar proteome of TNBC cells upon inhibition of Wnt signaling. Overall, we demonstrate that Wnt/β-catenin signaling will affects nucleolar functionality and thus influences breast cancer progression. Understanding the role of Wnt signaling in the nucleolus and breast cancer is a critical step towards developing novel therapeutic options for the treatment of breast cancer.
Project description:Tumor: tumor microenvironment (TME) interactions are critical for tumor progression and the composition and structure of the local extracellular matrix (ECM) are key determinants of tumor metastasis. We recently reported that activation of Wnt/beta- catenin signaling in Ewing sarcoma cells induces widespread transcriptional changes that are associated with acquisition of a metastatic tumor phenotype. Significantly, ECM protein-encoding genes were found to be enriched among Wnt/beta-catenin induced transcripts, leading us to hypothesize that activation of canonical Wnt signaling might induce changes in the Ewing sarcoma secretome. To address this hypothesis, conditioned media from Ewing sarcoma cell lines cultured in the presence or absence of Wnt3a was collected for proteomic analysis. Label-free mass spectrometry was used to identify and quantify differentially secreted proteins. We then used in silico databases to identify only proteins annotated as secreted. Comparison of the secretomes of two Ewing sarcoma cell lines revealed numerous shared proteins, as well as a degree of heterogeneity, in both basal and Wnt-stimulated conditions. Gene set enrichment analysis of secreted proteins revealed that Wnt stimulation reproducibly resulted in increased secretion of proteins involved in ECM organization, ECM receptor interactions, and collagen formation. In particular, Wnt-stimulated Ewing sarcoma cells upregulated secretion of structural collagens, as well as matricellular proteins, such as the metastasis-associated protein, tenascin C (TNC). Interrogation of published databases confirmed reproducible correlations between Wnt/beta-catenin activation and TNC and COL1A1 expression in patient tumors. In summary, this first study of the Ewing sarcoma secretome reveals that Wnt/beta-catenin activated tumor cells upregulate secretion of ECM proteins. Such Wnt/beta-catenin mediated changes are likely to impact on tumor: TME interactions that contribute to metastatic progression.
Project description:To screen the associated lncRNAs with wnt/β-catenin pathway activation of TNBC,through lncRNA microarray profiling between activated and inactivated wnt/β-catenin pathway of TNBC tissues, lnc-WAL (wnt/β-catenin associated lncRNA; WAL) was selected as the top upregulated lncRNA in wnt/β-catenin pathway activation compared with the inactivation group.
Project description:Wnt/β-catenin signaling regulates both mouse embryonic stem cell (mESC) self-renewal and differentiation. Here we show that the activity of the Wnt/β-catenin signaling pathway safeguards normal DNA methylation of mESCs. Indeed, loss of Wnt activity correlated with loss of DNA methylation, especially at the imprinting control regions (ICRs) in prolonged in vitro mESC cultures. To address the role of Wnt signaling on ICR methylation we performed Reduced Representation Bisulfite Sequencing (RRBS) on both “Young” and “Old” mESCs, being at early and late passages, respectively. We found that several ICRs (both maternal and paternal) showed loss of methylation in “Old” cells that correlates with lower Wnt downstream target expression and lower β-catenin protein level, when compared to “Young” mESCs. In parallel, we analyzed the ICR methylation level also in two Wnt mutant clones after prolonged in vitro culture (O-S33Y #1 and #2). The mutant clones maintained high Wnt activity with passages, similar to “Young” mESCs and ICR methylation level at around 50%, further supporting the beneficial role of Wnt/β-catenin pathway on mESC epigenetic stability and homeostasis.
Project description:Wnt signaling plays a major role in early neural development. An aberrant activation in Wnt/β-catenin pathway leads to defective anteroposterior patterning, resulting in neural tube closure defects (NTDs). Changes in folate metabolism may participate in early embryo fate determination. We report here that in C57BL/6C mouse embryonic stem cells (mESC), folate deficiency activates Wnt/β-catenin pathway by upregulating a chorion-specific transcription factor Gcm1. Specifically, folate deficiency promotes the formation of the Gcm1/β-catenin/T-cell factor (TCF4) complex to regulate the Wnt target gene transactivation through the Wnt-responsive elements. Moreover, the enhanced transcriptional activity of Gcm1 is found to be dependent on CREB binding protein. Lastly, in NTDs mouse models and low folate NTDs human brain samples, Gcm1 and Wnt/β-catenin target genes related to neural tube closure are specifically overexpressed. These results indicate that low folate promotes Wnt/β-catenin signaling via activating Gcm1, leading to aberrant vertebrate neural development
Project description:The forkhead box transcription factor FOXQ1 is aberrantly induced in various cancers, and contributes to tumour growth and metastasis. It has been suggested that the oncogenic potential of FOXQ1 may be explained by its activation of the Wnt/β-catenin signalling pathway.However, the mode of action of FOXQ1 in the Wnt pathway remains to be resolved. Here we report that FOXQ1 is bimodal transcriptional activator of Wnt target gene expression in normal and cancer cells. Using co-immunoprecipitation, proximity proteomics, and reporter assays, we show that FOXQ1 engages the Wnt transcriptional complex to promote gene expressionvia TCF/LEF transcription factors.