Similar Datasets
Project description:Cancer genetics has uncovered many tumor-suppressor and oncogenic pathways, but few alterations have revealed mechanisms involved in tumor spreading. Here, we examined the role of the third most significant chromosomal deletion in human melanoma that inactivates the adherens junction gene NECTIN1 in 55% of cases. We found that NECTIN1 loss stimulates melanoma cell migration in vitro and spreading in vivo in both zebrafish and human tumors specifically in response to decreased IGF1 signaling. In human melanoma biopsy specimens, adherens junctions were seen exclusively in areas with low IGF1 levels, but not in NECTIN1-deficient tumors. Our study establishes NECTIN1 as a major determinant of melanoma dissemination and uncovers a genetic control of the response to microenvironmental signals.
| S-EPMC9729115 | biostudies-literature
Project description:Defects in cell-cell contacts participate in early steps of tumor metastasis, but the mechanism regulating the staying-at-home or leaving decision has not been molecularly defined. We found the adherens junction gene NECTIN1 deleted in 55% of human melanomas. Inactivation of NECTIN1 stimulated cancer cell spreading in zebrafish melanomas in vivo, and increased cell migration in human cell lines specifically in response to decreased IGF1 signaling. IGF1 inhibition induced robust formation of adherens junctions between NECTIN1-wildtype melanoma cells, while NECTIN1-deficient cells were unable to establish these junctions and instead activated integrin/FAK-mediated motility. In 20 human melanoma biopsies, adherens junctions were seen exclusively in areas with low IGF1 levels, but not in NECTIN1-deficient tumors. Our study uncovers a mechanism by which the status of cell-cell contacts modulates the cellular response to microenvironmental signals, effecting a decision switch between leaving and staying in the cancer cell niche.
2022-05-26 | GSE174149 | GEO
Project description:Frequent loss of adhesion gene NECTIN1 triggers melanoma dissemination upon local IGF1 depletion
| PRJNA728590 | ENA
Project description:Frequent loss of adhesion gene NECTIN1 triggers melanoma dissemination upon local IGF1 depletion [RNA-Seq]
| PRJNA728593 | ENA
Project description:Defects in cell-cell contacts have been proposed to participate in early steps of tumor metastasis1 but little is known about the signals from the cancer cell niche that influence this process. Here, we show that the lack of adherens junctions caused by genetic loss of the adhesion molecule NECTIN1 in melanoma promotes tumor dissemination specifically under growth factor deprivation. We found that NECTIN1 was deleted in 53% of human melanomas and that its loss was enriched in metastases. NECTIN1 inactivation in zebrafish melanomas stimulated cancer cell spreading in vivo, while in human cell lines, it increased cell migration specifically in response to serum starvation. We further identified IGF1 as the serum component responsible for this effect. Serum withdrawal or IGF1 inhibition induced formation of strong adherens junctions between NECTIN1-wild-type melanoma cells. In contrast, NECTIN1-deficient cells were unable to establish adherens junctions and instead activated integrin-mediated motility through a FAK/SRC axis. During melanoma dissemination, NECTIN1 loss thus causes a cellular phenotypic switch from cell-cell adhesion to cell-matrix adhesion triggered by IGF1 signaling. Our study uncovers a mechanism by which cancer cells integrate information from the tumor microenvironment and cell-cell contacts to regulate their migratory behavior during spreading.
2022-05-26 | GSE149481 | GEO
Project description:Apoptosis is an important antivirus defense by virtue of its impact on virus multiplication and pathogenesis. To define molecular mechanisms by which viruses are detected and the apoptotic response is initiated, we examined the antiviral role of host inhibitor-of-apoptosis (IAP) proteins in insect cells. We report here that the principal IAPs, DIAP1 and SfIAP, of the model insects Drosophila melanogaster and Spodoptera frugiperda, respectively, are rapidly depleted and thereby inactivated upon infection with the apoptosis-inducing baculovirus Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV). Virus-induced loss of these host IAPs triggered caspase activation and apoptotic death. Elevation of IAP levels by ectopic expression repressed caspase activation. Loss of host IAP in both species was triggered by AcMNPV DNA replication. By using selected inhibitors, we found that virus-induced IAP depletion was mediated in part by the proteasome but not by caspase cleavage. Consistent with this conclusion, mutagenic disruption of the SfIAP RING motif, which acts as an E3 ubiquitin ligase, stabilized SfIAP during infection. Importantly, SfIAP was also stabilized upon the removal of its 99-residue N-terminal leader, which serves as a critical determinant of IAP turnover. These data indicated that a host pathway initiated by virus DNA replication and acting through instability motifs embedded within IAP triggers IAP depletion and thereby causes apoptosis. Taken together, the results of our study suggest that host modulation of cellular IAP levels is a conserved mechanism by which insects mount an apoptotic antiviral response. Thus, host IAPs may function as critical sentinels of virus invasion in insects.
| S-EPMC3147993 | biostudies-literature
Project description:During development, epithelial sheets sculpt organs by folding, either apically or basally, into complex 3D structures. Given the presence of actomyosin networks and cell adhesion sites on both sides of cells, a common machinery mediating apical and basal epithelial tissue folding has been proposed. However, unlike for apical folding, little is known about the mechanisms that regulate epithelial folding towards the basal side. Here, using the Drosophila wing imaginal disc and combining genetic perturbations and computational modelling, we demonstrate opposing roles for cell-cell and cell-extracellular matrix (ECM) adhesion systems during epithelial folding. While cadherin-mediated adhesion, linked to actomyosin network, regulates apical folding, a localized reduction on integrin-dependent adhesion, followed by changes in cell shape and re-organization of the basal actomyosin cytoskeleton and E-Cadherin (E-Cad) levels, is necessary and sufficient to trigger basal folding. These results suggest that modulation of the cell mechanical landscape through the crosstalk between integrins and cadherins is essential for correct epithelial folding.
| S-SCDT-10_1038-S44318-025-00384-6 | biostudies-other
Project description:Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P(2)], a phosphoinositide concentrated predominantly in the plasma membrane, binds endocytic clathrin adaptors, many of their accessory factors, and a variety of actin-regulatory proteins. Here we have used fluorescent fusion proteins and total internal reflection fluorescence microscopy to investigate the effect of acute PI(4,5)P(2) breakdown on the dynamics of endocytic clathrin-coated pit components and of the actin regulatory complex, Arp2/3. PI(4,5)P(2) breakdown was achieved by the inducible recruitment to the plasma membrane of an inositol 5-phosphatase module through the rapamycin/FRB/FKBP system or by treatment with ionomycin. PI(4,5)P(2) depletion resulted in a dramatic loss of clathrin puncta, which correlated with a massive dissociation of endocytic adaptors from the plasma membrane. Remaining clathrin spots at the cell surface had only weak fluorescence and were static over time. Dynamin and the p20 subunit of the Arp2/3 actin regulatory complex, which were concentrated at late-stage clathrin-coated pits and in lamellipodia, also dissociated from the plasma membrane, and these changes correlated with an arrest of motility at the cell edge. These findings demonstrate the critical importance of PI(4,5)P(2) in clathrin coat dynamics and Arp2/3-dependent actin regulation.
| S-EPMC1805489 | biostudies-literature
Project description:Epithelial cells usually trigger their "migratory machinery" upon loss of adhesion to their neighbors. This default is important for both physiological (e.g., wound healing) and pathological (e.g., tumor metastasis) processes. However, the underlying mechanism for such a default remains unclear. In this study, we used the human head and neck squamous cell carcinoma (HNSCC) SAS cells as a model and found that loss of cell-cell adhesion induced reactive oxygen species (ROS) generation and vimentin expression, both of which were required for SAS cell migration upon loss of cell-cell adhesion. We demonstrated that Tiam1-mediated Rac1 activation was responsible for the ROS generation through NADPH-dependent oxidases. Moreover, the ROS-Src-STAT3 signaling pathway that led to vimentin expression was important for SAS cell migration. The activation of ROS, Src, and STAT3 was also detected in tumor biopsies from HNSCC patients. Notably, activated STAT3 was more abundant at the tumor invasive front and correlated with metastatic progression of HNSCC. Together, our results unveil a mechanism of how cells trigger their migration upon loss of cell-cell adhesion and highlight an important role of the ROS-Src-STAT3 signaling pathway in the progression of HNSCC.
| S-EPMC9711860 | biostudies-literature
Project description:Loss of expression of the cell-cell adhesion molecule E-cadherin is a hallmark of epithelial-mesenchymal transition (EMT) in development and in the progression from epithelial tumours to invasive and metastatic cancers. Here, we demonstrate that the loss of E-cadherin function upregulates expression of the neuronal cell adhesion molecule (NCAM). Subsequently, a subset of NCAM translocates from fibroblast growth factor receptor (FGFR) complexes outside lipid rafts into lipid rafts where it stimulates the non-receptor tyrosine kinase p59(Fyn) leading to the phosphorylation and activation of focal adhesion kinase and the assembly of integrin-mediated focal adhesions. Ablation of NCAM expression during EMT inhibits focal adhesion assembly, cell spreading and EMT. Conversely, forced expression of NCAM induces epithelial cell delamination and migration, and high NCAM expression correlates with tumour invasion. These results establish a mechanistic link between the loss of E-cadherin expression, NCAM function, focal adhesion assembly and cell migration and invasion.
| S-EPMC2567408 | biostudies-literature