Project description:Beta-catenin is an essential mediator of canonical Wnt signaling and a central component of the cadherin-catenin epithelial adhesion complex. Dysregulation of beta-catenin expression has been described in pancreatic neoplasia. Newly published studies have suggested that beta-catenin is critical for normal pancreatic development although these reports reached somewhat different conclusions. In addition, the molecular mechanisms by which loss of beta-catenin affects pancreas development are not well understood. The goals of this study then were; 1] to further investigate the role of beta-catenin in pancreatic development using a conditional knockout approach and 2] to identify possible mechanisms by which loss of beta-catenin disrupts pancreatic development. A Pdx1-cre mouse line was used to delete a floxed beta-catenin allele specifically in the developing pancreas, and embryonic pancreata were studied by immunohistochemistry and microarray analysis. Experiment Overall Design: Parameter: embryonic pancreas from wild type and Pdx1Cre/+; beta-cateninflox/flox Experiment Overall Design: Sample type: RNA Experiment Overall Design: Source name: Embryonic day 14.6 and 16.5 pancreas Experiment Overall Design: Organism: Mus Musculus Experiment Overall Design: Strain: Derived from an intercross of Pdx1Cre/+ ; beta-cateninflox/+ mice. Experiment Overall Design: Extracted molecule:Total RNA Experiment Overall Design: In the study, we hybridized RNA from Embryonic day 14.6 and 16.5 pancreas of wild type (WT) control and Pdx1Cre/+; beta-cateninflox/flox beta-catenin null in the pancreas) embryonic pancreas to Affymetrix MOE430 2.0 GeneChip® arrays containing 45,101 well characterized mouse genes/ESTs.
Project description:beta-catenin is an essential mediator of canonical Wnt signaling and a central component of the cadherin-catenin epithelial adhesion complex. Dysregulation of beta-catenin expression has been described in pancreatic neoplasia. Newly published studies have suggested that beta-catenin is critical for normal pancreatic development although these reports reached somewhat different conclusions. In addition, the molecular mechanisms by which loss of beta-catenin affects pancreas development are not well understood. The goals of this study then were; 1] to further investigate the role of beta-catenin in pancreatic development using a conditional knockout approach and 2] to identify possible mechanisms by which loss of beta-catenin disrupts pancreatic development. A Pdx1-cre mouse line was used to delete a floxed beta-catenin allele specifically in the developing pancreas, and embryonic pancreata were studied by immunohistochemistry and microarray analysis. Keywords: Time course
Project description:The Wnt/β-catenin signaling pathway is crucial for the development of variety of organs including the mammary gland. However, the precise role of Wnt/β-catenin signaling during embryonic mammary gland morphogenesis is still poorly understood. Here, we used an epithelial gain-of-function β-catenin mouse model to study the role of Wnt/β-catenin signaling in embryonic mammary gland development and profiled the transcriptomes of E13.5 and E16.5 control and mutant mammary epithelia.
Project description:Wnt/β-catenin signaling regulates progenitor cell fate decisions during lung development and in various adult tissues. Ectopic activation of Wnt/β-catenin signaling promotes tissue repair in emphysema, a devastating lung disease with progressive loss of parenchymal lung tissue. The identity of Wnt/β-catenin responsive progenitor cells and the potential impact of Wnt/β-catenin signaling on adult distal lung epithelial progenitor cell function in emphysema, are poorly understood. Here, we used a TCF/Lef:H2B/GFP reporter mice to investigate the role of Wnt/β-catenin signaling in lung organoid formation. We identified an organoid-forming adult distal lung epithelial progenitor cell population characterized by a low Wnt/β-catenin activity, which was enriched in club and alveolar epithelial type (AT)II cells. To further characterize the lung epithelial populations with different Wnt activities, we perform microarray analysis using freshly isolated Wnthigh/low/negative lung epithelial cells to study their transcriptome, specially the enriched genes and signaling pathways in the Wnt low population related epithelial stem cell functions.
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:The Wnt signaling pathway is deregulated in over 90% of human colorectal cancers. β Catenin, the central signal transducer of the Wnt pathway, can directly modulate gene expression by interacting with transcription factors of the TCF/LEF-family. In the present study we investigate the role of Wnt signaling in the homeostasis of intestinal epithelium using tissue-specific, inducible beta-catenin gene ablation in adult mice. Block of Wnt/beta-catenin signaling resulted in rapid loss of transient-amplifying cells and crypt structures. Importantly, intestinal stem cells were induced to terminally differentiate upon deletion of beta-catenin resulting in a complete block of intestinal homeostasis and fatal loss of intestinal function. Transcriptional profiling of mutant crypt mRNA isolated by laser capture micro dissection confirmed those observations and allowed to identify genes potentially responsible for the functional preservation of intestinal stem cells. Experiment Overall Design: laser capture microdissection of intestinal crypts, control vs. beta-catenin mutant (2days after induction of deletion by tamoxifen), two rounds of amplification of mRNA
Project description:Activation of Wnt/β-catenin signaling plays a central role in the development and progression of colorectal cancer (CRC). Previously, we demonstrated that the Wnt transcription factor, TCF7L2, was overexpressed in primary rectal cancers that were resistant to chemoradiotherapy (CRT), and that TCF7L2 functionally mediates resistance of CRC cells to CRT. However, it remained unclear whether the resistance was mediated by a TCF7L2 inherent mechanism or Wnt/β-catenin signaling in general. We now show that silencing of β-catenin resulted in sensitization of the CRC cell lines LS1034, SW480, and SW837 to CRT, demonstrating a relationship between Wnt/β-catenin signaling and CRT resistance. To investigate the potential role of Wnt/β-catenin signaling in controlling therapeutic responsiveness, non-tumorigenic RPE-1 cells were stimulated with Wnt-3a, a physiological ligand at the Frizzled receptor, which significantly increased resistance to CRT. This effect could be recapitulated by overexpression of mutated, undegradable β-catenin (S33Y). Again, this resulted in a significantly boosted resistance of RPE-1 cells to CRT, which was abrogated by siRNA-mediated silencing of β-catenin. Consistent with these findings, we observed higher expression levels of active (unphosphorylated) β-catenin as well as increased TCF/LEF reporter activity in SW1463 cells that evolved radiation-resistance due to repeated radiation-treatment. Global gene expression profiling identified several altered pathways associated with treatment response as a consequence of Wnt/β-catenin pathway activation, sheading new light on PPARD signaling as a possible mechanism of Wnt mediated resistance. Hence, synergistic pathway inhibition of either Wnt and/or one of the downstream-pathways may represent a promising strategy to increase therapeutic responsiveness to CRT.
Project description:The Wnt pathway is a key regulator of embryonic development, cell growth, differentiation, polarity formation, neural development, carcinogenesis, and stem cell self-renewal, and deregulation of the Wnt signalling is associated with many human disease. The central player in the Wnt pathway is β-catenin, A recent study has shown that β-catenin/Tcf/Lef signaling pathway is an essential growth-regulatory pathway in cardiomyocytes. We used DNA microarrays to detail the global trends in gene expression underlying β-catenin-overexpressed cardiomyocytes and identified distinct classes of up- or down-regulated genes during this process. Our findings suggest that β-catenin plays a critical role in regulating cardiac dysfunction at transcriptional level and may provide novel insight into how β-catenin modulates heart diseases. Cardiomyocytes were infected with GFP control or β-catenin adenoviruses for RNA extraction and hybridization on Affymetrix microarrays. We sought to define the effects of β-catenin on the global programme of gene expression in primary cardiomyocytes. To that end, neonatal rat cardiomyocytes were infected with GFP control (G) or β-catenin adenovirus (B) for 24 hours.
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.