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.
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.
Project description:To generate IGF1 signatures in human melanoma cell lines. Recombinant human IGF1 (rhIGF1) was added to WM35, known to be responsive to rhIGF1, whereas constitutive IGF1 signaling in Mel-624 was abrogated by siRNA directed against the IGF1 receptor (siIGF1R). Experiments were performed in triplicate in normoxia (O2 concentration, 21%) and hypoxia (1% O2), because hypoxia has been suspected to play an adverse role in melanoma. After generating GEP data, we created signatures of genes significantly (p ≤0.0001, q ≤0.05) and consistently upregulated in rhIGF1-treated WM35 cells, or similarly downregulated in siIGF1R-treated Mel-624 cells, as compared to control cells at the same O2 concentration.
Project description:Insight into the role of Insulin-like Growth Factor (IGF) in development of lungs has come from the study of genetically modified mice. IGF1 is a key factor during lung development. IGF1 deficiency in the neonatal mouse causes respiratory failure collapsed alveoli and altered alveolar septa. To further characterize IGF1 function during lung development we analyzed Igf1-/- mouse prenatal lungs in a C57Bl/6 genetic background. Mutant lungs showed disproportional hypoplasia, disorganized extracellular matrix and dilated alveolar capillaries. IGF1 target genes during lung maturation were identified by analyzing RNA differential expression in Igf1-/- lungs using microarrays. Lungs from E18.5 were isolated from both Igf1+/+ wild type and Igf1-/- null mice and pooled to obtain RNA. Heterozygous male and female with a genetic background C57BL/6J were mated to obtain embryos at embrionic (E) stage 18.5 days post coitum (E18.5). 3 biological replicates per genotype.
Project description:Insight into the role of Insulin-like Growth Factor (IGF) in development of lungs has come from the study of genetically modified mice. IGF1 is a key factor during lung development. IGF1 deficiency in the neonatal mouse causes respiratory failure collapsed alveoli and altered alveolar septa. To further characterize IGF1 function during lung development we analyzed Igf1-/- mouse prenatal lungs in a C57Bl/6 genetic background. Mutant lungs showed disproportional hypoplasia, disorganized extracellular matrix and dilated alveolar capillaries. IGF1 target genes during lung maturation were identified by analyzing RNA differential expression in Igf1-/- lungs using microarrays.
Project description:Primary cultures of Cerebellar Granule Neurons (CGNs) have been extensively utilized to examine the signal transduction mechanisms underlying neuronal apoptosis. We conducted whole-genome expression profiling to decipher the transcriptional program controlling the apoptotic/survival switch in cerebellar granule neurons (CGNs) following the induction of apoptosis by serum and potassium deprivation and their rescue by gastric inhibitory polypeptide (Gip), substance p (Sp), insulin-like growth factor-1 (Igf1) or pituitary adenylyl cyclase-activating polypeptide (Pacap). Our results reveal the transcriptional changes intersecting neuronal apoptosis and survival and form the basis for further functional analyses and pharmacological exploitation to identify neuroprotective drugs. After six days âin vitroâ (DIV), extracellular KCl of CGNs was shifted from 25 to 5 mM for neuronal apoptotic death induction. After two washes with serum-free BME containing 5 mM KCl, neurons were incubated with the same medium for 6 h (K5), while control neurons were incubated with serum free medium supplemented with 25 mM KCl (K25). K5 neurons were also treated with a maximal effective dose of Gip, Sp, Igf1 and Pacap. Four biological replicates (derived from the same litter) for each of the experimental conditions (K25, K5, K5 + Gip; K25, K5, K5 + Sp; K25, K5, K5 + Igf1; K25, K5, K5 + Pacap) were analyzed.
Project description:In a prospective clinical study, we show that increased serum IGF1 levels in a patient may be a predictive marker of melanoma escape to therapies targeting MAPK pathway (BRAFi/MEKi). In addition, our in vitro and in vivo studies suggest that the response of targeted therapies-resistant melanoma cells to IGF1R inhibitor appears to correlate with the level of IGF1 secretion. Overall, our results suggest that monitoring serum IGF1 levels would individually identify melanoma patients who escape BRAFi/MEKi treatment and may benefit from a combination of targeted therapies and IGF1 signaling inhibition to overcome resistance.
Project description:Project in which conditionally immortalised mouse podocytes had either their insulin, IGF1 or both receptors knocked down. 72 hours post receptor knock-down total proteomics was performed on 40 samples.