Project description:Ligand binding induces extensive spatial reorganization and clustering of the EphA2 receptor at the cell membrane. It has previously been shown that the nanoscale spatial distribution of ligands modulates EphA2 receptor reorganization, activation and the invasive properties of cancer cells. However, the mechanisms by which cells transduce ligand nanoscale spatial distribution signals have not been elucidated. Here we used DNA origami nanocalipers to control the positions of ephrin-A5 ligands at the nanoscale and investigated the transcriptional responses following ligand binding. Using mRNA sequencing, we determined the transcriptional profiles of glioblastoma cells treated with nanocalipers presenting a single ephrin-A5 dimer or two dimers spaced 14, 40 or 100 nm apart. We observed divergent transcriptional responses to ephrin-A5 nano-organization, with ephrin-A5 dimers spaced 40 or 100 nm apart showing the highest levels of differential expressed genes compared to treatment with n anocalipers that do not present ephrin-A5. These findings show that the nanoscale organization of ephrin-A5 modulates transcriptional responses to EphA2 activation.
Project description:Ligand binding induces extensive spatial reorganization and clustering of the EphA2 receptor at the cell membrane. It has previously been shown that the nanoscale spatial distribution of ligands modulates EphA2 receptor reorganization, activation and the invasive properties of cancer cells. However, the mechanisms by which cells transduce ligand nanoscale spatial distribution signals have not been elucidated. Here we used DNA origami nanocalipers to control the positions of ephrin-A5 ligands at the nanoscale and investigated the transcriptional responses following ligand binding. Using mRNA sequencing, we determined the transcriptional profiles of glioblastoma cells treated with nanocalipers presenting a single ephrin-A5 dimer or two dimers spaced 14, 40 or 100 nm apart. We observed divergent transcriptional responses to ephrin-A5 nano-organization, with ephrin-A5 dimers spaced 40 or 100 nm apart showing the highest levels of differential expressed genes compared to treatment with n anocalipers that do not present ephrin-A5. These findings show that the nanoscale organization of ephrin-A5 modulates transcriptional responses to EphA2 activation.
Project description:Enlarged vestibular aqueducts (EVA) is one of the most commonly identified inner ear malformations in hearing loss patients including Pendred syndrome. While biallelic mutations of the SLC26A4 gene, encoding pendrin, causes non-syndromic hearing loss with EVA or Pendred syndrome, a considerable number of patients appear to carry mono-allelic mutation. This suggests faulty pendrin regulatory machinery results in hearing loss. Here we identify EPHA2 as another causative gene of Pendred syndrome with SLC26A4. EphA2 forms a protein complex with pendrin controlling pendrin localization, which is disrupted in some pathogenic forms of pendrin. Moreover, point mutations leading to amino acid substitution in the EPHA2 gene are identified from patients bearing mono-allelic mutation of SLC26A4. Ephrin-B2 binds to EphA2 triggering internalization with pendrin inducing EphA2 autophosphorylation weakly. The identified EphA2 mutants attenuate ephrin-B2- but not ephrin-A1-induced EphA2 internalization with pendrin. Our results uncover an unexpected role of the Eph/ephrin system in epithelial function.
Project description:Cellular senescence prevents the proliferation of cells at risk for neoplastic transformation. However, the altered secretome of senescent cells can promote the growth of the surrounding cancer cells. Although extracellular vesicles (EVs) have emerged as new players in intercellular communication, their role in the function of senescent cell secretome has been largely unexplored. Here, we show that exosome-like small EVs (sEVs) are important mediators of the pro-tumorigenic function of senescent cells. sEV-associated EphA2 secreted from senescent cells binds to ephrin-A1 that is highly expressed in several types of cancer cells and promotes cell proliferation through EphA2/ephrin-A1 reverse signalling. sEV sorting of EphA2 is increased in senescent cells due to its enhanced phosphorylation resulting from oxidative inactivation of PTP1B phosphatase. Our results demonstrate a novel mechanism of reactive oxygen species (ROS)-regulated cargo sorting into sEVs, which is critical for the potentially deleterious growth-promoting effect of the senescent cell secretome.
Project description:Genetic variations in ephrin type-A receptor 2 (EPHA2) have been associated with inherited and age-related forms of cataract in humans. Here we have characterized the eye lens phenotype and transcript profile of germline Epha2 knock-in mutant mice homozygous for either a missense variant associated with age-related cataract in humans (Epha2-Q722) or a novel insertion-deletion mutation (Epha2-indel722) that were both located within the tyrosine-kinase domain of EPHA2. Whole-mount confocal imaging of clear lenses from Epha2-indel722 mice on a fluorescent reporter background revealed misalignment of epithelial-to-fiber cell meridional-rows at the lens equator and severe disturbance of Y-suture formation at the lens poles, whereas, Epha2-Q722 lenses displayed mild disturbance of posterior sutures. Immunofluorescent labeling showed that EPHA2 was mostly localized to lens fiber cell membranes with some sub-membrane localization observed in Epha2-Q722 lenses and diffuse membrane and perinuclear localization in Epha2-indel722 lenses. Immunoprecipitation/blotting studies indicated that EPHA2 formed strong complexes with Src kinase but not with catenin beta 1 or cadherin 2 and was mostly serine phosphorylated in the lens. RNA-sequencing analysis revealed differential expression of several cytoskeleton-associated genes in Epha2-mutant and Epha2-null lenses including strong downregulation of Lgsn and Clic5. Collectively, our data suggest that mutations within the tyrosine-kinase domain of EPHA2 result in lens cell patterning defects and dysregulated expression of several cytoskeletal proteins.
Project description:Objective We have previously shown that expression of the CEACAM1 long isoform (CC1-L) in metastatic colorectal cancer (CRC) cells results in significant inhibition of liver metastasis via Chemokine (C-C motif) Ligand 2 (CCL2) and Signal Transducer and Activator of Transcription 3 (STAT3) signaling. Yet, despite recent advances in identifying molecules involved in the CC1-L inhibition of metastasis, much remains to be elucidated regarding the molecular mechanisms orchestrating this pathway. Design We performed an untargeted transcript profiling and a phosphokinase screen between CC1-L-expressing and non-expressing (CT) CRC cells. Identified targets were validated in vitro and in vivo for their involvement in signaling and invasion or metastasis. We validated our conclusions in CRC patient cohorts for time to metastasis development and long-term survival. Results Untargeted transcript profiling revealed high Decorin (Dcn) expression in CC1-L-expressing cells versus CT cells. Decorin was detected at the peri-endothelial layers of large blood vessels and in liver stellate cells. In metastatic lesions, it was expressed in pericyte-like cells covering capillary endothelium. Phosphokinase differential screening revealed reduced Ephrin type-A receptor 2 (EphA2) expression and activity in CC1-L- versus CT-expressing cells. Treatment of CT cells with recombinant Dcn led to decreased migration and invasion and decreased EphA2-mediated Erk and Akt signaling. CRC patients exhibiting high CC1 and DCN expression, in combination with low EPHA2 expression, benefit from longer 10-year survival than those with high EPHA2 expression. Conclusion CC1-L expression in poorly differentiated CRC inhibits liver metastasis through increased Decorin expression and EphA2-mediated signaling. Quadriplicate samples of each mouse colon cancer cell lines (control cells versus those expressing either short or long isoform of CEACAM1) have been used for RNA extraction