Similar Datasets
Project description:Resistance to Ras pathway inhibition is a major challenge in the treatment of colorectal cancer (CRC), but the underlying mechanisms are incompletely understood. Here we performed large-scale small molecule screens in CRC and identified inhibitors of MEK1/2 as potent activators of Wnt/beta-catenin signalling. Targeting MEK increased Wnt activity in different CRC cell lines and in the murine intestine in vivo. The MEK-induced Wnt response was strongly enhanced by truncating mutations in APC and proteomic experiments identified that AXIN1 levels are depleted upon MEK inhibition. We generated patient-derived colon cancer organoids and showed that a clinically approved MEK inhibitor leads to increased Wnt activity, elevated LGR5 levels and enrichment of gene signatures associated with stem cells and cancer relapse. This reprogramming was reverted by co-treatment with Wnt inhibitors. Our study demonstrates that MEK inhibition affects cellular plasticity and induces an intestinal stem cell program which constitutes a novel mechanism of drug resistance.
2018-05-08 | GSE114060 | GEO
Project description:Resistance to Ras pathway inhibition is a major challenge in the treatment of colorectal cancer (CRC), but the underlying mechanisms are incompletely understood. Here we performed large-scale small molecule screens in CRC and identified inhibitors of MEK1/2 as potent activators of Wnt/beta-catenin signalling. Targeting MEK increased Wnt activity in different CRC cell lines and in the murine intestine in vivo. The MEK-induced Wnt response was strongly enhanced by truncating mutations in APC and proteomic experiments identified that AXIN1 levels are depleted upon MEK inhibition. We generated patient-derived colon cancer organoids and showed that a clinically approved MEK inhibitor leads to increased Wnt activity, elevated LGR5 levels and enrichment of gene signatures associated with stem cells and cancer relapse. This reprogramming was reverted by co-treatment with Wnt inhibitors. Our study demonstrates that MEK inhibition affects cellular plasticity and induces an intestinal stem cell program which constitutes a novel mechanism of drug resistance.
2018-05-08 | GSE114059 | GEO
Project description:Small molecule inhibition of MEK activates Wnt signalling and leads to reprogramming of colon cancer stem cells
| PRJNA464036 | ENA
Project description:Small molecule inhibition of MEK activates Wnt signalling and leads to reprogramming of colon cancer stem cells [Affymetrix]
| PRJNA464039 | ENA
Project description:Small molecule inhibition of MEK activates Wnt signalling and leads to reprogramming of colon cancer stem cells [Illumina]
| PRJNA464038 | ENA
Project description:Lymphotoxin β-receptor (LTβR) signalling promotes lymphoid neogenesis and the development of tertiary lymphoid structures1,2, which are associated with severe chronic inflammatory diseases that span several organ systems3-6. How LTβR signalling drives chronic tissue damage particularly in the lung, the mechanism(s) that regulate this process, and whether LTβR blockade might be of therapeutic value have remained unclear. Here we demonstrate increased expression of LTβR ligands in adaptive and innate immune cells, enhanced non-canonical NF-κB signalling, and enriched LTβR target gene expression in lung epithelial cells from patients with smoking-associated chronic obstructive pulmonary disease (COPD) and from mice chronically exposed to cigarette smoke. Therapeutic inhibition of LTβR signalling in young and aged mice disrupted smoking-related inducible bronchus-associated lymphoid tissue, induced regeneration of lung tissue, and reverted airway fibrosis and systemic muscle wasting. Mechanistically, blockade of LTβR signalling dampened epithelial non-canonical activation of NF-κB, reduced TGFβ signalling in airways, and induced regeneration by preventing epithelial cell death and activating WNT/β-catenin signalling in alveolar epithelial progenitor cells. These findings suggest that inhibition of LTβR signalling represents a viable therapeutic option that combines prevention of tertiary lymphoid structures1 and inhibition of apoptosis with tissue-regenerative strategies.
| S-EPMC7718297 | biostudies-literature
Project description:Wnt proteins control diverse biological processes through ?-catenin-dependent canonical signalling and ?-catenin-independent non-canonical signalling. The mechanisms by which these signalling pathways are differentially triggered and controlled are not fully understood. Dishevelled (Dvl) is a scaffold protein that serves as the branch point of these pathways. Here, we show that cholesterol selectively activates canonical Wnt signalling over non-canonical signalling under physiological conditions by specifically facilitating the membrane recruitment of the PDZ domain of Dvl and its interaction with other proteins. Single-molecule imaging analysis shows that cholesterol is enriched around the Wnt-activated Frizzled and low-density lipoprotein receptor-related protein 5/6 receptors and plays an essential role for Dvl-mediated formation and maintenance of the canonical Wnt signalling complex. Collectively, our results suggest a new regulatory role of cholesterol in Wnt signalling and a potential link between cellular cholesterol levels and the balance between canonical and non-canonical Wnt signalling activities.
| S-EPMC4100210 | biostudies-literature
Project description:Hypothesis and proof of concept:
Our hypothesis is that increase in cellular iron import proteins (TfR1, DMT1) occur early in the adenoma-carcinoma sequence through mutations in APC and lead to cellular iron loading. As demonstrated in our previous work the effects of this iron loading is to mediate increased Wnt signalling resulting in c-myc induction. This in turn serves to increase the expression of iron import proteins (TfR1, DMT1) and decrease the expression of iron export (ferroportin [FPN]) and storage (ferritin) proteins. Such a hypothesis explains how Wnt signalling controls iron metabolism and ensures that there is adequate cellular iron for ATP generation and cellular proliferation.
Experimental design:
To test such a hypothesis we aim to prospectively collect the following colorectal tissue from patients attending for colonoscopy:
1. Normal colonic mucosa in patients with no colorectal pathology (n = 30)
2. Polyps and matched normal colon (n = 30)
3. Colorectal cancers and matched normal colon (n = 30)
We also intend to collect serum and urine from the following patient groups:
4. Normal colonoscopy (n = 30)
5. Colorectal adenomas (n = 30)
6. Colorectal cancers (n = 30)
Primary outcome(s): Measured at baseline, using the expression of proteins in the tissue and serum to detect the cellular and systemic iron transport proteins. The techniques used will include mass spectrometry, western blotting, real time PCR and immunohistochemistry.
| 2416626 | ecrin-mdr-crc
Project description:Wnt/?-catenin signaling is critically involved in metazoan development, stem cell maintenance and human disease. Using Xenopus laevis egg extract to screen for compounds that both stabilize Axin and promote ?-catenin turnover, we identified an FDA-approved drug, pyrvinium, as a potent inhibitor of Wnt signaling (EC(50) of ?10 nM). We show pyrvinium binds all casein kinase 1 (CK1) family members in vitro at low nanomolar concentrations and pyrvinium selectively potentiates casein kinase 1? (CK1?) kinase activity. CK1? knockdown abrogates the effects of pyrvinium on the Wnt pathway. In addition to its effects on Axin and ?-catenin levels, pyrvinium promotes degradation of Pygopus, a Wnt transcriptional component. Pyrvinium treatment of colon cancer cells with mutation of the gene for adenomatous polyposis coli (APC) or ?-catenin inhibits both Wnt signaling and proliferation. Our findings reveal allosteric activation of CK1? as an effective mechanism to inhibit Wnt signaling and highlight a new strategy for targeted therapeutics directed against the Wnt pathway.
| S-EPMC3681608 | biostudies-literature
Project description:The PI3K/AKT/mTOR pathway is frequently activated in advanced prostate cancer, due to loss of the tumour suppressor PTEN, and is an important axis for drug development. We have assessed the molecular and functional consequences of pathway blockade by inhibiting AKT and mTOR kinases either in combination or as individual drug treatments. In established prostate cancer cell lines, a decrease in cell viability and in phospho-biomarker expression was observed. Although apoptosis was not induced, a G1 growth arrest was observed in PTEN null LNCaP cells, but not in BPH1 or PC3 cells. In contrast, when the AKT inhibitor AZD7328 was applied to patient-derived prostate cultures that retained expression of PTEN, activation of a compensatory Ras/MEK/ERK pathway was observed. Moreover, whilst autophagy was induced following treatment with AZD7328, cell viability was less affected in the patient-derived cultures than in cell lines. Surprisingly, treatment with a combination of both AZD7328 and two separate MEK1/2 inhibitors further enhanced phosphorylation of ERK1/2 in primary prostate cultures. However, it also induced irreversible growth arrest and senescence. Ex vivo treatment of a patient-derived xenograft (PDX) of prostate cancer with a combination of AZD7328 and the mTOR inhibitor KU-0063794, significantly reduced tumour frequency upon re-engraftment of tumour cells. The results demonstrate that single agent targeting of the PI3K/AKT/mTOR pathway triggers activation of the Ras/MEK/ERK compensatory pathway in near-patient samples. Therefore, blockade of one pathway is insufficient to treat prostate cancer in man.
| S-EPMC5593594 | biostudies-literature