Project description:Neuromedin U (NMU), which is thought to contribute to putative metastasis processes in various tumor entities, was identified as being up-regulated in breast cancer. Therefore, we aimed to uncover the role of NMU in breast cancer subtypes deciphering for the first time NMU-driven signalling pathways and downstream targets. Stable gain-of-function in vitro models were generated to decipher the biological role of NMU in breast cancer cells. To uncover underlying signalling pathways and key molecules affected by NMU in the luminal-like SKBR3 model, microarray analysis was carried out.
Project description:Our data show that Wnt and FGF signalling, and the downstream transcription factors NKX2.1 and TFAP2C, promote human alveolar or airway fate respectively. Moreover, we have functionally validated cell-cell interactions in human lung alveolar patterning. We show that Wnt signalling from differentiating fibroblasts promotes alveolar type 2 cell identity, whereas myofibroblasts secrete the Wnt inhibitor, NOTUM, providing spatial patterning. Our organoid system recapitulates key aspects of human lung development allowing mechanistic experiments to determine the underpinning molecular regulation.
Project description:The Wnt-signalling pathway is one of the core de-regulated pathways in chronic lymphocytic leukemia (CLL), activated in a subset of patients by somatic coding mutations. Here we describe an alternative mechanism of Wnt-activation in malignant B cells, mediated by Notch2 activity in mesenchymal stromal cells (MSC) in the tumor microenvironment. We identified that tumor cells specifically induce and activate Notch2 in MSCs. Notch2 orchestrates the expression of target genes essential for the activation of canonical Wnt-signaling in CLL cells. Mechanistically, stromal Notch2 mediates the stabilization of â-catenin by inhibiting the activation of Gsk3-â in malignant B cells. Pharmacological inhibition of the Wnt-pathway mitigates microenvironment-mediated survival of malignant B cells in vitro. Similarly, inhibition of Notch-signaling impaired survival of CLL cells and disease engraftment in a PDX mouse model. Notch2 activation in the tumour microenvironment is a pre-requisite for the GSK3-â dependent activation of the canonical Wnt-signaling in tumor cells.
Project description:The function of the FAM83F protein, like the functions of many members of the FAM83 family, is poorly understood. Here we show that injection of Fam83f mRNA into Xenopus embryos causes axis duplication, a phenotype indicative of enhanced Wnt signalling. Consistent with this, overexpression of FAM83F activates Wnt signalling, whilst ablation of FAM83F from human colorectal cancer (CRC) cells attenuates it. We demonstrate that FAM83F is farnesylated and interacts and co-localises with CK1α at the plasma membrane. This interaction with CK1α is essential for FAM83F to activate Wnt signalling, and FAM83F mutants that do not interact with CK1α fail to induce axis duplication in Xenopus embryos and to activate Wnt signalling in cells. FAM83F acts upstream of GSK-3β, because the attenuation of Wnt signalling caused by loss of FAM83F can be rescued by GSK-3 inhibition. Introduction of a farnesyl-deficient mutant of FAM83F in cells through CRISPR/Cas9 genome editing redirects the FAM83F-CK1α complex away from the plasma membrane and significantly attenuates Wnt signalling, indicating that FAM83F exerts its effects on Wnt signalling at the plasma membrane.
Project description:The secretion of mammalian Wnt Ligands within the cell is dependent on the activity of Porcupine, a gene located on the X chromosome that encodes for a membrane bound o-acyl transferase. Porcupine-dependent Wnt signalling was previously shown to be essential for the post-natal maintenance of endometrial glands, structures that are essential for implantation and fertility. Previous data has implicated the multiple members of the Wnt family expressed in the female uterus to be involved in a coordinated crosstalk between the luminal and stromal compartments of the uterus, ensuring the proper development of the uterus and successful fertility. We have generated a conditional mutant of Porcupine in the luminal epithelium (cKOepi) of the uterus, thus eliminating Wnt7a/b and Wnt11, to address the nature of this crosstalk. Unlike global luminal-stromal mutants, post-natal ablation of Porcupine in the luminal epithelium alone does not affect the maintenance of the endometrial glands in adults. Uterine glands are still visible in the adult cKOepi, albeit in a smaller number than that of control uteri. Despite having uterine glands, cKOepi females remain completely infertile. We have attributed the sterility of these females to be in part due to defects in implantation and decidualization; cKOepi fail to respond to decidual induction by artificial means. Interestingly, progesterone supplementation rescues the observed implantation defects, although observed decidual soon seem to become resorptive. Microarray analysis of cKOepi during implantation has reveals several potential targets for luminal WNT that may be responsible for the observed phenotype including: Lef1, Hoxa10, Wnt4, Wnt16 Notch1, Notch4 and Dll4 .
Project description:Understanding the mechanisms underlying tumor heterogeneity is key to development of treatments that can target specific tumor subtypes. We have previously targeted CRE recombinase-dependent conditional deletion of the tumor suppressor genes Brca1, Brca2, p53 and/or Pten to basal or luminal ER- cells of the mouse mammary epithelium. We demonstrated that both the cell-of-origin and the tumor-initiating genetic lesions co-operate to influence mammary tumor phenotype. Here, we use a CRE-activated HER2 orthologue to specifically target HER2/ERBB2 oncogenic activity to basal or luminal ER- mammary epithelial cells and carry out a detailed analysis of the tumors which develop. We find that in contrast to our previous studies, basal epithelial cells are refractory to transformation by the activated NeuKI allele, with mammary epithelial tumor formation largely confined to luminal ER- cells. Histologically, the majority of tumors that developed were classified as either adenocarcinomas of no special type or metaplastic adenosquamous tumors. Remarkably, the former were more strongly associated with virgin animals and were typically characterised by amplification of the NeuNT/ErbB2 locus and activation of non-canonical WNT signalling. In contrast, tumors characterised by squamous metaplasia were associated with animals that had been through at least one pregnancy and typically had lower levels of NeuNT/ErbB2 locus amplification but had activated canonical WNT signalling. Squamous changes in these tumors were associated with activation of the Epidermal Differentiation Cluster. Thus, in this model of HER2 breast cancer, cell-of-origin, reproductive history, NeuNT/ErbB2 locus amplification, and the activation of specific branches of the WNT signalling pathway all interact to drive inter-tumor heterogeneity.
Project description:Understanding the mechanisms underlying tumor heterogeneity is key to development of treatments that can target specific tumor subtypes. We have previously targeted CRE recombinase-dependent conditional deletion of the tumor suppressor genes Brca1, Brca2, p53 and/or Pten to basal or luminal ER- cells of the mouse mammary epithelium. We demonstrated that both the cell-of-origin and the tumor-initiating genetic lesions co-operate to influence mammary tumor phenotype. Here, we use a CRE-activated HER2 orthologue to specifically target HER2/ERBB2 oncogenic activity to basal or luminal ER- mammary epithelial cells and carry out a detailed analysis of the tumors which develop. We find that in contrast to our previous studies, basal epithelial cells are refractory to transformation by the activated NeuKI allele, with mammary epithelial tumor formation largely confined to luminal ER- cells. Histologically, the majority of tumors that developed were classified as either adenocarcinomas of no special type or metaplastic adenosquamous tumors. Remarkably, the former were more strongly associated with virgin animals and were typically characterised by amplification of the NeuNT/ErbB2 locus and activation of non-canonical WNT signalling. In contrast, tumors characterised by squamous metaplasia were associated with animals that had been through at least one pregnancy and typically had lower levels of NeuNT/ErbB2 locus amplification but had activated canonical WNT signalling. Squamous changes in these tumors were associated with activation of the Epidermal Differentiation Cluster. Thus, in this model of HER2 breast cancer, cell-of-origin, reproductive history, NeuNT/ErbB2 locus amplification, and the activation of specific branches of the WNT signalling pathway all interact to drive inter-tumor heterogeneity.
Project description:The unfolded protein response (UPR) maintains endoplasmic reticulum (ER) homeostasis by sensing protein-folding stress and orchestrating cellular adaptation via the ER-transmembrane proteins IRE1, PERK and ATF6. Malignant cells can co-opt UPR signaling by IRE1 and PERK to sustain tumor growth; however, the importance of ATF6 in cancer remains poorly deciphered. We observed elevated ATF6 transcriptional activity in several cancers including colorectal carcinoma (CRC). Genetic silencing or small molecule inhibition of ATF6 blocked cell cycle progression and reduced viability of several human CRC cell lines in vitro and disrupted tumor progression in vivo. Unexpectedly, ATF6 interference also disabled Myc and Wnt signaling and reduced stemness. ATF6 inhibition attenuated growth of organoids derived from malignant but not normal human intestinal tissue, reducing Wnt-pathway activity and driving cellular differentiation. Wnt-surrogate agonism rescued the growth inhibitory phenotype of ATF6 interference. Our findings identify ATF6 as an unexpected facilitator of oncogenic Wnt signaling in CRC.
Project description:Targeted therapies against cancer stem cells which are enriched in side populations (SP) involves interruption of Wnt-signalling. Furthermore, EpCAM is a SP marker and modulator of Wnt-signalling. Therefore, the effects of an anti-EpCAM treatment on SP-cells and WNT/β-catenin signalling was studied. SP of the human lung adenocarcinoma cell line A549 was obtained by fluorescence activated cell sorting and whole genome scans helped to define their molecular phenotype after anti-EpCAM antibody treatment.
Project description:Targeted therapies against cancer stem cells which are enriched in side populations (SP) involves interruption of Wnt-signalling. Furthermore, EpCAM is a SP marker and modulator of Wnt-signalling. Therefore, the effects of an anti-EpCAM treatment on SP-cells and WNT/β-catenin signalling was studied. SP of the murine lung adenocarcinoma cell line A2C12 was obtained by fluorescence activated cell sorting and whole genome scans helped to define their molecular phenotype after anti-EpCAM antibody treatment.