Eph Receptors and Ephrins in Retinal Diseases.
Ontology highlight
ABSTRACT:
SUBMITTER: Kaczmarek R
PROVIDER: S-EPMC8227845 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The cornea, while appearing to be simple tissue, is actually an extremely complex structure. In order for it to retain its biomechanical and optical properties, perfect organization of its cells is essential. Proper regeneration is especially important after injuries and in the course of various diseases. Eph receptors and ephrin are mainly responsible for the proper organization of tissues as well as cell migration and communication. In this review, we present the current state of knowledge on the role of Eph and ephrins in corneal physiology and diseases, in particular, we focused on the functions of the epithelium and endothelium. Since the role of Eph and ephrins in the angiogenesis process has been well established, we also analyzed their influence on conditions with corneal neovascularization.
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Project description:Eph-ephrin interactions control the signal transduction between cells and play an important role in carcinogenesis and other diseases. The interactions between Eph receptors and ephrins of the same subclass are promiscuous; there are cross-interactions between some subclasses, but not all. To understand how Eph-ephrin interactions can be both promiscuous and specific, we investigated sixteen energy landscapes of four Eph receptors (A2, A4, B2, and B4) interacting with four ephrin ligands (A1, A2, A5, and B2). We generated conformational ensembles and recognition energy landscapes starting from separated Eph and ephrin molecules and proceeding up to the formation of Eph-ephrin complexes. Analysis of the Eph-ephrin recognition trajectories and the co-evolution entropy of 400 ligand binding domains of Eph receptor and 241 ephrin ligands identified conserved residues during the recognition process. Our study correctly predicted the promiscuity and specificity of the interactions and provided insights into their recognition. The dynamic conformational changes during Eph-ephrin recognition can be described by progressive conformational selection and population shift events, with two dynamic salt bridges between EphB4 and ephrin-B2 contributing to the specific recognition. EphA3 cancer-related mutations lowered the binding energies. The specificity is not only controlled by the final stage of the interaction across the protein-protein interface, but also has large contributions from binding kinetics with the help of dynamic intermediates along the pathway from the separated Eph and ephrin to the Eph-ephrin complex.
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Project description:The Eph receptor tyrosine kinases and their ephrin ligands have intriguing expression patterns in cancer cells and tumour blood vessels, which suggest important roles for their bidirectional signals in many aspects of cancer development and progression. Eph gene mutations probably also contribute to cancer pathogenesis. Eph receptors and ephrins have been shown to affect the growth, migration and invasion of cancer cells in culture as well as tumour growth, invasiveness, angiogenesis and metastasis in vivo. However, Eph signalling activities in cancer seem to be complex, and are characterized by puzzling dichotomies. Nevertheless, the Eph receptors are promising new therapeutic targets in cancer.
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Project description:The Eph family of receptors is the largest family of receptor tyrosine kinases, but it remains poorly studied in lung cancer. We aimed to systematically explore the human Eph receptors and their ligands, the ephrins, in lung adenocarcinoma. The prognostic impact of Eph receptor and ephrin gene expression was analyzed using 2 independent cohorts of lung adenocarcinoma. Gene expression profiles in lung adenocarcinoma compared with normal adjacent lung were studied in 3 independent cohorts and in cell lines. Gene expression profiles were validated with quantitative polymerase chain reaction (qPCR) and Western blotting in cell lines. Functional studies to assess the role of Eph receptor A4 (EphA4) were carried out in vitro. The biological effects of EphA4 in lung cancer cell lines were assayed following overexpression and knockdown. Of the 11 Eph receptors and 8 ephrins analyzed, only EphA4 and ephrin A1 gene expression were consistently associated with an improved outcome in patients with lung adenocarcinoma. Expression levels of EphA4 by microarray correlated well with expression levels measured by qPCR and Western blotting. EphA4 overexpression reduced cell migration and invasion but did not affect cell cycle, apoptosis, or drug sensitivity. Surprisingly, EphA4 was expressed at higher levels in cancer compared with non-cancer tissues and cell lines. EphA4 gene expression is associated with an improved outcome in patients with resected lung adenocarcinoma, possibly by affecting cancer cell migration and invasion.
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Project description:Climbing fibres and parallel fibres compete for dendritic space on Purkinje cells in the cerebellum. Normally, climbing fibres populate the proximal dendrites, where they suppress the multiple small spines typical of parallel fibres, leading to their replacement by the few large spines that contact climbing fibres. Previous work has shown that ephrins acting via EphA4 are a signal for this change in spine type and density. We have used an in vitro culture model in which to investigate the ephrin effect on Purkinje cell dendritic spines and the role of integrins in these changes. We found that integrins ?3, ?5 and ?4 are present in many of the dendritic spines of cultured Purkinje cells. pFAK, the main downstream signalling molecule from integrins, has a similar distribution, although the intenstity of pFAK staining and the percentage of pFAK+ spines was consistently higher in the proximal dendrites. Activating integrins with Mg2+ led to an increase in the intensity of pFAK staining and an increase in the proportion of pFAK+ spines in both the proximal and distal dendrites, but no change in spine length, density or morphology. Blocking integrin binding with an RGD-containing peptide led to a reduction in spine length, with more stubby spines on both proximal and distal dendrites. Treatment of the cultures with ephrinA3-Fc chimera suppressed dendritic spines specifically on the proximal dendrites and there was also a decrease of pFAK in spines on this domain. This effect was blocked by simultaneous activation of integrins with Mn2+. We conclude that Eph/ephrin signaling regulates proximal dendritic spines in Purkinje cells by inactivating integrin downstream signalling.
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Project description:Eph receptors and their ephrin ligands are viewed as promising targets for cancer treatment, however targeting them is hindered by their context-dependent functionalities. To circumvent this, we explored molecular landscapes underlying their pro- and anti-malignant activities. Using unbiased bioinformatics approaches, we constructed a cancer-related network of genetic interactions (GIs) of all Ephs and ephrins to assist their therapeutic manipulation. We also applied genome-wide genetic screening and BioID proteomics, and integrated them with machine learning approaches to select the most relevant GIs of one of Eph receptors, EPHB6. This revealed a crosstalk between EPHB6 and EGFR, and further experiments confirmed EPHB6 ability to modulate EGFR signaling, enhancing both proliferation of cancer cells and tumor development. Taken together, our observations identify a new mechanism of action of EPHB6, suggesting its targeting might be beneficial in EGFR-dependent tumors, and confirm that Eph family genetic interactome presented here can be effectively exploited in developing new treatment approaches.
2023-05-23 | GSE206981 | GEO
Project description:Eph receptor tyrosine kinases play critical functions during development, in the formation of tissue and organ borders, and the vascular and neural systems. Uniquely among tyrosine kinases, their activities are controlled by binding to membrane-bound ligands, called ephrins. Ephs and ephrins generally have a low expression in adults, functioning mainly in tissue homeostasis and plasticity, but are often overexpressed in cancers, where they are especially associated with undifferentiated or progenitor cells, and with tumour development, vasculature, and invasion. Mutations in Eph receptors also occur in various tumour types and are suspected to promote tumourigenesis. Ephs and ephrins have the capacity to operate as both tumour promoters and tumour suppressors, depending on the circumstances. They have been demonstrated to impact tumour cell proliferation, migration, and invasion in vitro, as well as tumour development, angiogenesis, and metastases in vivo, making them potential therapeutic targets. However, successful development of therapies will require detailed understanding of the opposing roles of Ephs in various cancers. In this review, we discuss the variations in Eph expression and functions in a variety of malignancies. We also describe the multiple strategies that are currently available to target them in tumours, including preclinical and clinical development.
| S-EPMC9953285 | biostudies-literature
Project description:The Eph receptors are the largest receptors tyrosine kinases (RTKs) family in humans and together with ephrin ligands constitute a complex cellular communication system often dysregulated in many tumors. The role of the Eph-ephrin system in colorectal cancer (CRC) has been investigated and different expression of Eph receptors have been associated with tumor development and progression. In light of this evidence, we investigated if a pharmacological approach aimed at inhibiting Eph/ephrin interaction through small molecules could prevent tumor growth in APC min/J mice. The 8-week treatment with the Eph-ephrin antagonist UniPR129 significantly reduced the number of adenomas in the ileum and decreased the diameter of adenomas in the same region. Overall our data suggested as UniPR129 could be able to slow down the tumor development in APC min/J mice. These results further confirm literature data about Eph kinases as a new valuable target in the intestinal cancer and for the first time showed the feasibility of the Eph-ephrin inhibition as a useful pharmacological approach against the intestinal tumorigenesis. In conclusion this work paves the way for further studies with Eph-ephrin inhibitors in order to confirm the Eph antagonism as innovative pharmacological approach with preventive benefit in the intestinal tumor development.
| S-EPMC7243115 | biostudies-literature
Project description:Aberrant activities of fourteen Eph receptor tyrosine kinases (RTKs) and their eight ephrin ligands are often observed in human malignancies, where they control cancer development, progression, and aggressiveness. While multiple attempts have been made to target Eph receptors in tumors, their effectiveness has been hindered by distinct contexts in which these proteins operate to enhance or suppress the disease. One of the strategies to overcoming this challenge is to define the molecular landscape/genetic interactions (GIs) associated with pro- and anti-malignant activities of Ephs and ephrins, as this should outline context-specific genetic dependencies associated with these molecules. Here, we used a multi-step bioinformatics analysis of the TCGA database and the DepMap gene essentiality data from cancer cell lines to construct a network of GIs of Ephs and ephrins in human malignancies. Validation of the relevance of this network was centered on an unusual Eph receptor EPHB6, which is innately kinase-incompetent, but nevertheless, actively controls aggressiveness and tumor initiation in several cancer types. To select the most relevant GI from the generated network, we performed genome-wide screening and EPHB6 BioID analysis. While, the BioID approach pointed towards EPHB6 interactions with several RTKs, including all kinase-active members of the EGFR/ErbB class, its integration with shRNA screening and computationally predicted GIs, unambiguously pointed towards EGFR as a key EPHB6 partner. Indeed, our further experiments confirmed EPHB6 interactions with all kinase-competent ErbBs, including EGFR, and revealed its ability to modulate EGF-induced EGFR tyrosine phosphorylation and downstream signaling. This ultimately, enhanced proliferation of cancer cells, culminating in efficient tumor development. In agreement, we found high levels of EGFR to positively correlate with higher EPHB6 expression in several tumor types. Taken together, these observations indicate that EPHB6 should serve as an effective target in tumors with high EGFR levels and that co-targeting these receptors might provide therapeutic benefits. More importantly, these experiments provide a strong support for the relevance of our computational strategy and suggest that the generated network describing GIs of Eph receptors and their ligands is a valuable resource that can be used for developing new treatment approaches aiming to hunt these proteins in human malignancies.
2023-05-16 | PXD033912 | Pride
Project description:The Eph subfamily of receptor tyrosine kinases mediate cell-cell communication controlling cell and tissue patterning during development. While generally less active in adult tissues, they often re-emerge in cancers, particularly on undifferentiated or progenitor cells in tumors and the tumor microenvironment, associated with tumor initiation, angiogenesis and metastasis. Eph receptors are thus attractive therapeutic targets, and monoclonal antibodies have been commonly developed and tested for anti-cancer activity in preclinical models, and in some cases in the clinic. This review summarizes 20 years of research on various antibody-based approaches to target Eph receptors in tumors and the tumor microenvironment, including their mode of action, tumor specificity, and efficacy in pre-clinical and clinical testing.
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