FDA-approved antivirals ledipasvir and daclatasvir downregulate the Src-EPHA2-Akt oncogenic pathway in colorectal and triple-negative breast cancer cells.

Direct-acting antivirals ledipasvir (LDV) and daclatasvir (DCV) are widely used as part of combination therapies to treat Hepatitis C infections. Here we show that these compounds inhibit the proliferation, invasion, and colony formation of triple-negative MDA-MB-231 breast cancer cells, SRC-transduced SW620 colon cancer cells and SRC- transduced NIH3T3 fibroblasts. DCV also inhibits the expression of PDL-1, which is responsible for resistance to immunotherapy in breast cancer cells. The demonstrated low toxicity in many Hepatitis C patients suggests LDV and DCV could be used in combination therapies for cancer patients. At the molecular level, these direct-acting antivirals inhibit the phosphorylation of Akt and the ephrin type A receptor 2 (EPHA2) by destabilizing a Src-EPHA2 complex, although they do not affect the general kinase activity of Src. Thus, LDV and DCV could be effective drugs for Src-associated cancers without the inherent toxicity of classical Src inhibitors.

Hypoxia-Induced Ephrin-B2 Facilitates Proliferation and Induces Glycolytic Metabolism in Cutaneous Squamous Cell Carcinoma by Modulating PKM2/HIF-1α Axis.

BACKGROUND: Cutaneous squamous cell carcinoma (cSCC) is a fatal disease characterized by metabolic dysregulation. The role of ephrin type-B receptor 2 (ephrin-B2), a crucial molecule in cancer cell biology, in regulating glycolysis and cell proliferation of cSCC is not well understood. This study aimed to investigate the biological pathways by which ephrin-B2 impacts the glycolysis and cell proliferation of cSCC. METHODS: Ephrin-B2 expression levels in cSCC were determined using quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blotting. Ephrin-B2 expression in cSCC cells was manipulated using overexpression and knockdown approaches. A series of in vitro assays, such as cell counting kit-8 (CCK-8), Transwell assay, immunofluorescence assay, enzyme-linked immunosorbent assay (ELISA), qRT-PCR, and Western blotting, were employed to delineate the biological roles of ephrin-B2/pyruvate kinase muscle isoenzyme 2 (PKM2)/hypoxia-inducible factor 1 alpha (HIF-1α) in proliferation, migration, invasion, and glucose metabolism of cSCC. RESULTS: This study highlights an upregulation of ephrin-B2 expression in cSCC. Knockdown of ephrin-B2 significantly suppressed the proliferation, migration, invasion, and glucose metabolism of cSCC cells. Moreover, ephrin-B2 expression was upregulated under hypoxic conditions. At the molecular level, ephrin-B2 knockdown resulted in the downregulation of PKM2 and HIF-1α expression. Additionally, the overexpression of PKM2 or HIF-1α successfully rescued the diminished proliferation, migration, invasion and glucose metabolism induced by ephrin-B2 knockdown in cSCC cells. CONCLUSION: These findings suggest that ephrin-B2 suppression may hinder cSCC cell proliferation and glycolytic metabolism, potentially via the PKM2/HIF-1α axis modulation.

Inducible deletion of endothelial cell Efnb2 delays capillary regeneration and attenuates myofibre reinnervation following myotoxin injury in mice.

Acute injury of skeletal muscle disrupts myofibres, microvessels and motor innervation. Myofibre regeneration is well characterized, however its relationship with the regeneration of microvessels and motor nerves is undefined. Endothelial cell (EC) ephrin-B2 (Efnb2) is required for angiogenesis during embryonic development and promotes neurovascular regeneration in the adult. We hypothesized that, following acute injury to skeletal muscle, loss of EC Efnb2 would impair microvascular regeneration and the recovery of neuromuscular junction (NMJ) integrity. Mice (aged 3-6 months) were bred for EC-specific conditional knockout (CKO) of Efnb2 following tamoxifen injection with non-injected CKO mice as controls (CON). The gluteus maximus, tibialis anterior or extensor digitorum longus muscle was then injured with local injection of BaCl2. Intravascular staining with wheat germ agglutinin revealed diminished capillary area in the gluteus maximus of CKO vs. CON at 5 days post-injury (dpi); both recovered to uninjured (0 dpi) level by 10 dpi. At 0 dpi, tibialis anterior isometric force of CKO was less than CON. At 10 dpi, isometric force was reduced by half in both groups. During intermittent contractions (75 Hz, 330 ms s-1, 120 s), isometric force fell during indirect (sciatic nerve) stimulation whereas force was maintained during direct (electrical field) stimulation of myofibres. Neuromuscular transmission failure correlated with perturbed presynaptic (terminal Schwann cells) and postsynaptic (nicotinic acetylcholine receptors) NMJ morphology in CKO. Resident satellite cell number on extensor digitorum longus myofibres did not differ between groups. Following acute injury of skeletal muscle, loss of Efnb2 in ECs delays capillary regeneration and attenuates recovery of NMJ structure and function. KEY POINTS: The relationship between microvascular regeneration and motor nerve regeneration following skeletal muscle injury is undefined. Expression of Efnb2 in endothelial cells (ECs) is essential to vascular development and promotes neurovascular regeneration in the adult. To test the hypothesis that EfnB2 in ECs is required for microvascular regeneration and myofibre reinnervation, we induced conditional knockout of Efnb2 in ECs of mice. Acute injury was then induced by BaCl2 injection into gluteus maximus, tibialis anterior or extensor digitorum longus (EDL) muscle. Capillary regeneration was reduced at 5 days post-injury (dpi) in gluteus maximus of conditional knockout vs. controls; at 10 dpi, neither differed from uninjured. Nerve stimulation revealed neuromuscular transmission failure in tibialis anterior with perturbed neuromuscular junction structure. Resident satellite cell number on EDL myofibres did not differ between groups. Conditional knockout of EC Efnb2 delays capillary regeneration and attenuates recovery of neuromuscular junction structure and function.

Tissue, cellular, and molecular level determinants for eye lens stiffness and elasticity.

The eye lens is a transparent, ellipsoid tissue in the anterior chamber that is required for the fine focusing of light onto the retina to transmit a clear image. The focusing function of the lens is tied to tissue transparency, refractive index, and biomechanical properties. The stiffness and elasticity or resilience of the human lens allows for shape changes during accommodation to focus light from objects near and far. It has long been hypothesized that changes in lens biomechanical properties with age lead to the loss of accommodative ability and the need for reading glasses with age. However, the cellular and molecular mechanisms that influence lens biomechanical properties and/or change with age remain unclear. Studies of lens stiffness and resilience in mouse models with genetic defects or at advanced age inform us of the cytoskeletal, structural, and morphometric parameters that are important for biomechanical stability. In this review, we will explore whether: 1) tissue level changes, including the capsule, lens volume, and nucleus volume, 2) cellular level alterations, including cell packing, suture organization, and complex membrane interdigitations, and 3) molecular scale modifications, including the F-actin and intermediate filament networks, protein modifications, lipids in the cell membrane, and hydrostatic pressure, influence overall lens biomechanical properties.

The EFNA4 gene is a potential prognostic biomarker in pancreatic cancer: a bioinformatics analysis.

Background: Pancreatic cancer is a highly aggressive malignancy with poor prognosis, and there is an urgent need to understand its molecular mechanisms for early diagnosis and treatment. Despite surgical resection being the only effective treatment, most patients are diagnosed at an advanced stage, missing the optimal window for therapy. Identifying novel biomarkers is crucial for prognostic assessment, treatment planning, and early intervention. Ephrin A4 (EFNA4), a member of the receptor tyrosine kinase family, is involved in vascular and epithelial development via regulation of cell migration and rejection. However, the role of EFNA4 in pancreatic cancer has not been reported. Therefore, our study aimed to clarify the role of EFNA4 in pancreatic cancer through bioinformatics analysis and vitro experiments. Methods: The expression of EFNA4 and its potential value as a diagnostic and prognostic biomarker in pancreatic cancer was analyzed using data from The Cancer Genome Atlas (TCGA) and the Gene Expression Profiling Interactive Analysis (GEPIA) database. According to the expression level of EFNA4, patients were divided into high expression group and low expression group, and the correlation between overall survival (OS) and disease-free survival (DFS) with different expression levels of EFNA4 and clinical parameters were analyzed. Subsequently, reverse-transcription quantitative polymerase chain reaction (RT-qPCR) was performed to detect EFNA4 expression. The proliferation, invasion, and cloning ability of the cells were detected via Cell Counting Kit 8 (CCK8), Transwell, and plate cloning assays, respectively. Results: EFNA4 is highly expressed in pancreatic cancer, and upregulation of EFNA4 is associated with poor prognosis. In this study, EFNA4 expression was correlated with T stage and TNM (tumor-node-metastasis) stage of pancreatic cancer, and the median survival time and progression-free survival (PFS) were worse in those with high EFNA4 expression (394 days) than in those with low expression (525 days) [hazard ratio (HR): 1.47, 95% confidence interval (CI): 1.00-2.16, P=0.047]. In addition, EFNA4 was also found to be involved in the regulation of signal pathways such as cell adhesion, cyclic AMP, insulin secretion, pancreatic secretion, and protein digestion and absorption. In vitro experiments demonstrated that EFNA4 knockdown significantly inhibited the proliferation, cloning ability, and invasiveness of the PANC-1 and SW1990 pancreatic cancer cell lines. Conclusions: The abnormal expression of EFNA4 in pancreatic cancer is associated with poor prognosis. Knockout of EFNA4 gene could significantly inhibit the proliferation and invasion of pancreatic cancer cells. Therefore, EFNA4 may be one of the molecular targets for poor prognosis of patients with pancreatic cancer.

Prognostic and therapeutic value of the Eph/Ephrin signaling pathway in pancreatic cancer explored based on bioinformatics.

Pancreatic cancer (PC) is one of the most common malignant tumors of the digestive tract and has a very high mortality rate worldwide. Different PC patients may respond differently to therapy and develop therapeutic resistance due to the complexity and variety of the tumor microenvironment. The Eph/ephrin signaling pathway is extensively involved in tumor-related biological functions. However, the key function of the Eph/ephrin signaling pathway in PC has not been fully elucidated. We first explored a pan-cancer overview of Eph/ephrin signaling pathway genes (EPGs). Then we grouped the PC patients into 3 subgroups based on EPG expression levels. Significantly different prognoses and tumor immune microenvironments between different subtypes further validate Eph/ephrin's important role in the pathophysiology of PC. Additionally, we estimated the IC50 values for several commonly used molecularly targeted drugs used to treat PC in the three clusters, which could help patients receive a more personalized treatment plan. Following a progressive screening of optimal genes, we established a prognostic signature and validated it in internal and external test sets. The receiver operating characteristic (ROC) curves of our model exhibited great predictive performance. Meanwhile, we further validated the results through qRT-PCR and immunohistochemistry. Overall, this research provides fresh clues on the prognosis and therapy of PC as well as the theoretical groundwork for future Eph/ephrin signaling pathway research.

Spatial-temporal comparison of Eph/Ephrin gene expression in ocular lenses from aging and knockout mice.

Cataracts, defined as any opacity in the transparent ocular lens, remain the leading cause of blindness and visual impairment in the world; however, the etiology of this pathology is not fully understood. Studies in mice and humans have found that the EphA2 receptor and the ephrin-A5 ligand play important roles in maintaining lens homeostasis and transparency. However, due to the diversity of the family of Eph receptors and ephrin ligands and their promiscuous binding, identifying functional interacting partners remains a challenge. Previously, 12 of the 14 Ephs and 8 of 8 ephrins in mice were characterized to be expressed in the mouse lens. To further narrow down possible genes of interest in life-long lens homeostasis, we collected and separated the lens epithelium from the fiber cell mass and isolated RNA from each compartment in samples from young adult and middle-aged mice that were either wild-type, EphA2-/- (knockout), or ephrin-A5 -/- . Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was implemented to compare transcript levels of 33 Eph and ephrin gene variants in each tissue compartment. Our results show that, of the Eph and ephrin variants screened, 5 of 33 showed age-related changes, and 2 of 33 showed genotype-related changes in lens epithelium. In the isolated fibers, more dynamic gene expression changes were observed, in which 12 of 33 variants showed age-related changes, and 6 of 33 showed genotype-related changes. These data allow for a more informed decision in determining mechanistic leads in Eph-ephrin-mediated signaling in the lens.

hMAGEA2 Accelerates the Progression of Prostate Cancer via the EFNA3-Erk1/2 Signaling Pathway.

BACKGROUND/AIM: Human melanoma-associated antigen A2 (hMAGEA2) family members play several roles in many types of cancer and have been explored as potential prognostic markers. In this study, we investigated the molecular mechanism underlying hMAGEA2-mediated tumorigenesis of prostate cancer. MATERIALS AND METHODS: Immunohistochemistry and western blot were used to assess protein expression whereas microarray and quantitative reverse transcription-PCR determined mRNA expression. CCK-8 assay was used to determine cell proliferation. Colony formation assay was used to examine tumorigenesis. Migration and invasion were examined using a transwell assay. Propidium iodide (PI)/Annexin V double staining was performed to measure apoptosis. Transcriptional activity was measured using Dual-luciferase reporter assay. RESULTS: hMAGEA2 was highly over-expressed in human prostate cancer tissues compared to benign prostatic hyperplasia tissues. To elucidate its biological function in prostate cancer, we established two stable hMAGEA2-knockdown prostate cancer cell lines, PC3M and 22RV1, and found that they presented significantly decreased proliferation, anchorage-independent colony formation, migration, and invasion. As hMAGEA2 knockdown suppressed prostate cancer cell growth, we examined its potential influence on tumor apoptosis. hMAGEA2-knockdown cell lines displayed early apoptosis. Moreover, knockdown of hMAGEA2 resulted in the down-regulation of EFNA3 expression. Luciferase assay showed that hMAGEA2 bound to the EFNA promoter region and regulated its transcription. Down-regulation of EFNA3 expression led to decreased Ras/Braf/MEK/Erk1/2 phosphorylation and, consequently, inhibited prostate cancer progression. CONCLUSION: hMAGEA2 promotes prostate cancer growth, metastasis, and tumorigenesis by regulating the EFNA3-Erk1/2 signaling pathway, indicating its potential as a therapeutic marker for prostate cancer.

Pseudomonas fluorescens 15 small RNA Pfs1 mediates transgenerational epigenetic inheritance of pathogen avoidance in C. elegans through the Ephrin receptor VAB-1.

C. elegans are exposed to a variety of pathogenic and non-pathogenic bacteria species in their natural environment. Correspondingly, C. elegans has evolved an ability to discern between nutritive and infectious bacterial food sources. Here we show that C. elegans can learn to avoid the pathogenic bacteria Pseudomonas fluorescens 15 (PF15), and that this learned avoidance behavior is passed on to progeny for four generations, as we previously demonstrated for Pseudomonas aeruginosa (PA14) and Pseudomonas vranovensis, using similar mechanisms, including the involvement of both the TGF-ß ligand DAF-7 and Cer1 retrotransposon-encoded virus-like particles. PF15 small RNAs are both necessary and sufficient to induce this transgenerational avoidance behavior. Unlike PA14 or P. vranovensis, PF15 does not use P11, Pv1, or a small RNA with maco-1 homology for this avoidance; instead, an unrelated PF15 small RNA, Pfs1, that targets the C. elegans vab-1 Ephrin receptor gene is necessary and sufficient for learned avoidance, suggesting the evolution of yet another bacterial sRNA/C. elegans gene target pair involved in transgenerational inheritance of pathogen avoidance. As VAB-2 Ephrin receptor ligand and MACO-1 knockdown also induce PF15 avoidance, we have begun to understand the genetic pathway involved in small RNA targeted pathogenic avoidance. Moreover, these data show that axon guidance pathway genes (VAB-1 and VAB-2) have previously unknown adult roles in regulating neuronal function. C. elegans may have evolved multiple bacterial specificity-encoded small RNA-dependent mechanisms to avoid different pathogenic bacteria species, thereby providing progeny with a survival advantage in a dynamic environment.

ephrin-B2 promotes nociceptive plasticity and hyperalgesic priming through EphB2-MNK-eIF4E signaling in both mice and humans.

Ephrin-B-EphB signaling can promote pain through ligand-receptor interactions between peripheral cells, like immune cells expressing ephrin-Bs, and EphB receptors expressed by DRG neurons. Previous studies have shown increased ephrin-B2 expression in peripheral tissues like synovium of rheumatoid and osteoarthritis patients, indicating the clinical significance of this signaling. The primary goal of this study was to understand how ephrin-B2 acts on mouse and human DRG neurons, which express EphB receptors, to promote pain and nociceptor plasticity. We hypothesized that ephrin-B2 would promote nociceptor plasticity and hyperalgesic priming through MNK-eIF4E signaling, a critical mechanism for nociceptive plasticity induced by growth factors, cytokines and nerve injury. Both male and female mice developed dose-dependent mechanical hypersensitivity in response to ephrin-B2, and both sexes showed hyperalgesic priming when challenged with PGE2 injection either to the paw or the cranial dura. Acute nociceptive behaviors and hyperalgesic priming were blocked in mice lacking MNK1 (Mknk1 knockout mice) and by eFT508, a specific MNK inhibitor. Sensory neuron-specific knockout of EphB2 using Pirt-Cre demonstrated that ephrin-B2 actions require this receptor. In Ca2+-imaging experiments on cultured DRG neurons, ephrin-B2 treatment enhanced Ca2+ transients in response to PGE2 and these effects were absent in DRG neurons from MNK1-/- and EphB2-PirtCre mice. In experiments on human DRG neurons, ephrin-B2 increased eIF4E phosphorylation and enhanced Ca2+ responses to PGE2 treatment, both blocked by eFT508. We conclude that ephrin-B2 acts directly on mouse and human sensory neurons to induce nociceptor plasticity via MNK-eIF4E signaling, offering new insight into how ephrin-B signaling promotes pain.

Identification of potent pan-ephrin receptor kinase inhibitors using DNA-encoded chemistry technology.

EPH receptors (EPHs), the largest family of tyrosine kinases, phosphorylate downstream substrates upon binding of ephrin cell surface-associated ligands. In a large cohort of endometriotic lesions from individuals with endometriosis, we found that EPHA2 and EPHA4 expressions are increased in endometriotic lesions relative to normal eutopic endometrium. Because signaling through EPHs is associated with increased cell migration and invasion, we hypothesized that chemical inhibition of EPHA2/4 could have therapeutic value. We screened DNA-encoded chemical libraries (DECL) to rapidly identify EPHA2/4 kinase inhibitors. Hit compound, CDD-2693, exhibited picomolar/nanomolar kinase activity against EPHA2 (Ki: 4.0 nM) and EPHA4 (Ki: 0.81 nM). Kinome profiling revealed that CDD-2693 bound to most EPH family and SRC family kinases. Using NanoBRET target engagement assays, CDD-2693 had nanomolar activity versus EPHA2 (IC50: 461 nM) and EPHA4 (IC50: 40 nM) but was a micromolar inhibitor of SRC, YES, and FGR. Chemical optimization produced CDD-3167, having picomolar biochemical activity toward EPHA2 (Ki: 0.13 nM) and EPHA4 (Ki: 0.38 nM) with excellent cell-based potency EPHA2 (IC50: 8.0 nM) and EPHA4 (IC50: 2.3 nM). Moreover, CDD-3167 maintained superior off-target cellular selectivity. In 12Z endometriotic epithelial cells, CDD-2693 and CDD-3167 significantly decreased EFNA5 (ligand) induced phosphorylation of EPHA2/4, decreased 12Z cell viability, and decreased IL-1ß-mediated expression of prostaglandin synthase 2 (PTGS2). CDD-2693 and CDD-3167 decreased expansion of primary endometrial epithelial organoids from patients with endometriosis and decreased Ewing's sarcoma viability. Thus, using DECL, we identified potent pan-EPH inhibitors that show specificity and activity in cellular models of endometriosis and cancer.

The lack of EphB3 receptor prevents bone loss in mouse models of osteoporosis.

Bone homeostasis is a complex process in which some Eph kinase receptors and their ephrin ligands appear to be involved. In the present study, we address this issue by examining, both in vitro and in vivo, the role of EphB2 and EphB3 in mesenchymal stromal/stem cell (MSC) differentiation into bone tissue. This was first evaluated by quantitative reverse transcription PCR (RT-qPCR) and histological staining in MSCs cultured in specific mediums revealing that although EphB2-/- MSCs mainly expressed pro-adipogenic transcription factors, EphB3-/- MSCs showed abundant osteogenic transcripts, such as Runx2, Msx2, and Sp7. To clarify the underlying molecular mechanisms, we found that the lack of EphB3 signaling alters the genetic profile of differentiating MSCs, reducing the expression of many inhibitory molecules and antagonists of the BMP signaling pathway, and increasing Bmp7 expression, a robust bone inductor. Then, to confirm the osteogenic role of EphB3 in vivo, we studied the condition of 2 mouse models of induced bone loss (ovariectomy or long-term glucocorticoid treatment). Interestingly, in both models, both WT and EphB2-/- mice equally developed the disease but EphB3-/- mice did not exhibit the typical bone loss, nor an increase in urine Ca2+ or blood serum CTX-1. This phenotype in EphB3-KO mice could be due to their significantly higher proportions of osteoprogenitor cells and preosteoblasts, and their lower number of osteoclasts, as compared with WT and EphB2-KO mice. Thus, we conclude that EphB3 acts as a negative regulator of the osteogenic differentiation, and its absence prevents bone loss in mice subjected to ovariectomy or dexamethasone treatment.

Osteoporosis affects more than 200 million people, mostly women. Our work shows that the EphB3 receptor restricts bone formation, and its absence prevents bone loss in osteoporotic mice. The bone protection observed in EphB3-deficient mice is due to the presence of more bone-forming cells and fewer bone-degrading cells. Molecularly, we found that when there's no EphB3 in mesenchymal stem cells, some bone-promoting genes are increased while many inhibitors are reduced. Therefore, this receptor could become a key target for new therapies that would help to improve the quality of life for those suffering from bone diseases. We're really excited to share our findings with a broad audience, including patients, healthcare professionals, researchers, and the life sciences industry.

The role of glial and neuronal Eph/ephrin signaling in Drosophila mushroom body development and sleep and circadian behavior.

The Eph receptor, a prototypically large receptor protein tyrosine kinase, interacts with ephrin ligands, forming a bidirectional signaling system that impacts diverse brain functions. Eph receptors and ephrins mediate forward and reverse signaling, affecting neurogenesis, axon guidance, and synaptic signaling. While mammalian studies have emphasized their roles in neurogenesis and synaptic plasticity, the Drosophila counterparts are less studied, especially in glial cells, despite structural similarities. Using RNAi to modulate Eph/ephrin expression in Drosophila neurons and glia, we studied their roles in brain development and sleep and circadian behavior. Knockdown of neuronal ephrin disrupted mushroom body development, while glial knockdown had minimal impact. Surprisingly, disrupting ephrin in neurons or glial cells altered sleep and circadian rhythms, indicating a direct involvement in these behaviors independent from developmental effects. Further analysis revealed distinct sleep phenotypes between neuronal and glial knockdowns, underscoring the intricate interplay within the neural circuits that govern behavior. Glia-specific knockdowns showed altered sleep patterns and reduced circadian rhythmicity, suggesting an intricate role of glia in sleep regulation. Our findings challenge simplistic models of Eph/ephrin signaling limited to neuron-glia communication and emphasize the complexity of the regulatory networks modulating behavior. Future investigations targeting specific glial subtypes will enhance our understanding of Eph/ephrin signaling's role in sleep regulation across species.

Ephs in cancer progression: complexity and context-dependent nature in signaling, angiogenesis and immunity.

Eph receptors constitute the largest family of receptor tyrosine kinases, comprising 14 distinct members classified into two subgroups: EphAs and EphBs.. Despite their essential functions in normal physiological processes, accumulating evidence suggests that the involvement of the Eph family in cancer is characterized by a dual and often contradictory nature. Research indicates that Eph/ephrin bidirectional signaling influences cell-cell communication, subsequently regulating cell migration, adhesion, differentiation and proliferation. The contradictory functionalities may arise from the diversity of Eph signaling pathways and the heterogeneity of different cancer microenvironment. In this review, we aim to discuss the dual role of the Eph receptors in tumor development, attempting to elucidate the paradoxical functionality through an exploration of Eph receptor signaling pathways, angiogenesis, immune responses, and more. Our objective is to provide a comprehensive understanding of the molecular mechanisms underlying tumor development. Additionally, we will explore the evolving landscape of utilizing Eph receptors as potential targets for tumor therapy and diagnostic tools.

Potential role of the Eph/ephrin system in colorectal cancer: emerging druggable molecular targets.

The Eph/ephrin system regulates many developmental processes and adult tissue homeostasis. In colorectal cancer (CRC), it is involved in different processes including tumorigenesis, tumor angiogenesis, metastasis development, and cancer stem cell regeneration. However, conflicting data regarding Eph receptors in CRC, especially in its putative role as an oncogene or a suppressor gene, make the precise role of Eph-ephrin interaction confusing in CRC development. In this review, we provide an overview of the literature and highlight evidence that collaborates with these ambiguous roles of the Eph/ephrin system in CRC, as well as the molecular findings that represent promising therapeutic targets.

MIR137 polygenic risk for schizophrenia and ephrin-regulated pathway: Role in lateral ventricles and corpus callosum volume.

Background/Objective. Enlarged lateral ventricle (LV) volume and decreased volume in the corpus callosum (CC) are hallmarks of schizophrenia (SZ). We previously showed an inverse correlation between LV and CC volumes in SZ, with global functioning decreasing with increased LV volume. This study investigates the relationship between LV volume, CC abnormalities, and the microRNA MIR137 and its regulated genes in SZ, because of MIR137's essential role in neurodevelopment. Methods. Participants were 1224 SZ probands and 1466 unaffected controls from the GENUS Consortium. Brain MRI scans, genotype, and clinical data were harmonized across cohorts and employed in the analyses. Results. Increased LV volumes and decreased CC central, mid-anterior, and mid-posterior volumes were observed in SZ probands. The MIR137-regulated ephrin pathway was significantly associated with CC:LV ratio, explaining a significant proportion (3.42 %) of CC:LV variance, and more than for LV and CC separately. Other pathways explained variance in either CC or LV, but not both. CC:LV ratio was also positively correlated with Global Assessment of Functioning, supporting previous subsample findings. SNP-based heritability estimates were higher for CC central:LV ratio (0.79) compared to CC or LV separately. Discussion. Our results indicate that the CC:LV ratio is highly heritable, influenced in part by variation in the MIR137-regulated ephrin pathway. Findings suggest that the CC:LV ratio may be a risk indicator in SZ that correlates with global functioning.

Peripheral T-cell responses of EphB2- and EphB3-deficient mice in a model of collagen-induced arthritis.

Both EphB2- and EphB3-deficient mice exhibit profound histological alterations in the thymic epithelial network but few changes in T-cell differentiation, suggesting that this organization would be sufficient to produce functional T lymphocytes. Also, other antigen-presenting cells involved in immunological education could substitute the thymic epithelium. Accordingly, we found an increased frequency of plasmacytoid dendritic cells but not of conventional dendritic cells, medullary fibroblasts or intrathymic B lymphocytes. In addition, there are no lymphoid infiltrates in the organs of mutant mice nor do they contain circulating autoantibodies. Furthermore, attempts to induce arthritic lesions after chicken type II collagen administration fail totally in EphB2-deficient mice whereas all WT and half of the immunized EphB3-/- mice develop a typical collagen-induced arthritis. Our results point out that Th17 cells, IL4-producing Th2 cells and regulatory T cells are key for the induction of disease, but mutant mice appear to have deficits in T cell activation or cell migration properties. EphB2-/- T cells show reduced in vitro proliferative responses to anti-CD3/anti-CD28 antibodies, produce low levels of anti-type II collagen antibodies, and exhibit low proportions of T follicular helper cells. On the contrary, EphB3-/- lymph node cells respond accurately to the different immune stimuli although in lower levels than WT cells but show a significantly reduced migration in in vitro transwell assays, suggesting that no sufficient type II collagen-dependent activated lymphoid cells reached the joints, resulting in reduced arthritic lesions.

Diversity of Intercellular Communication Modes: A Cancer Biology Perspective.

From the moment a cell is on the path to malignant transformation, its interaction with other cells from the microenvironment becomes altered. The flow of molecular information is at the heart of the cellular and systemic fate in tumors, and various processes participate in conveying key molecular information from or to certain cancer cells. For instance, the loss of tight junction molecules is part of the signal sent to cancer cells so that they are no longer bound to the primary tumors and are thus free to travel and metastasize. Upon the targeting of a single cell by a therapeutic drug, gap junctions are able to communicate death information to by-standing cells. The discovery of the importance of novel modes of cell-cell communication such as different types of extracellular vesicles or tunneling nanotubes is changing the way scientists look at these processes. However, are they all actively involved in different contexts at the same time or are they recruited to fulfill specific tasks? What does the multiplicity of modes mean for the overall progression of the disease? Here, we extend an open invitation to think about the overall significance of these questions, rather than engage in an elusive attempt at a systematic repertory of the mechanisms at play.

Ephrin B1 Regulates Inflammatory Pathways in Retinal Müller Cells.

The role of inflammation has been accepted as a factor in the complications of diabetic retinopathy. Discovery of the upstream regulation of these inflammatory factors has remained a challenge. In this study, we explored the actions of ephrin B1 in retinal Müller cells and their actions on inflammatory proteins. We used diabetic human and mouse samples, as well as Müller cells in culture to measure ephrin B1 in Müller cells. We then generated Müller cell specific ephrin B1 knockout mice. We measure levels of key inflammatory proteins, including high mobility group box 1 (HMGB1) and NOD-like receptor protein 3 (NLRP3) pathway proteins in retinal lysates from the ephrin B1 floxed and ephrin B1 Müller cell specific knockout mice. Data show that ephrin B1 is significantly increased in the retina of diabetic humans and mice, as well as in Müller cells grown in high glucose. Elimination of ephrin B1 in mouse Müller cells led to a significant decline in all inflammatory proteins studied. In conclusion, a reduction in ephrin B1 in the diabetic retina may offer a new therapeutic modality for diabetic retinopathy.

PHF6-mediated transcriptional control of NSC via Ephrin receptors is impaired in the intellectual disability syndrome BFLS.

The plant homeodomain zinc-finger protein, PHF6, is a transcriptional regulator, and PHF6 germline mutations cause the X-linked intellectual disability (XLID) Börjeson-Forssman-Lehmann syndrome (BFLS). The mechanisms by which PHF6 regulates transcription and how its mutations cause BFLS remain poorly characterized. Here, we show genome-wide binding of PHF6 in the developing cortex in the vicinity of genes involved in central nervous system development and neurogenesis. Characterization of BFLS mice harbouring PHF6 patient mutations reveals an increase in embryonic neural stem cell (eNSC) self-renewal and a reduction of neural progenitors. We identify a panel of Ephrin receptors (EphRs) as direct transcriptional targets of PHF6. Mechanistically, we show that PHF6 regulation of EphR is impaired in BFLS mice and in conditional Phf6 knock-out mice. Knockdown of EphR-A phenocopies the PHF6 loss-of-function defects in altering eNSCs, and its forced expression rescues defects of BFLS mice-derived eNSCs. Our data indicate that PHF6 directly promotes Ephrin receptor expression to control eNSC behaviour in the developing brain, and that this pathway is impaired in BFLS.