Role of the ephrin and Eph receptor tyrosine kinase families in angiogenesis and development of the cardiovascular system

Boron in wound healing: a comprehensive investigation of its diverse mechanisms

Chronic wounds present a significant clinical challenge due to their prolonged healing time and susceptibility to infection. Boron, a trace element with diverse biological functions, has emerged as a promising therapeutic agent in wound healing. This review article comprehensively investigates the mechanisms underlying the beneficial effects of boron compounds in wound healing. Boron exerts its healing properties through multiple pathways, including anti-inflammatory, antimicrobial, antioxidant, and pro-proliferative effects. Inflammation is a crucial component of the wound-healing process, and boron has been shown to modulate inflammatory responses by inhibiting pro-inflammatory cytokines and promoting the resolution of inflammation. Furthermore, boron exhibits antimicrobial activity against a wide range of pathogens commonly associated with chronic wounds, thereby reducing the risk of infection and promoting wound closure. The antioxidant properties of boron help protect cells from oxidative stress, a common feature of chronic wounds that can impair healing. Additionally, boron stimulates cell proliferation and migration, as well as essential tissue regeneration and wound closure processes. Overall, this review highlights the potential of boron as a novel therapeutic approach for treating chronic wounds, offering insights into its diverse mechanisms of action and clinical implications.

Immunohistochemical expression of ephrin receptors in neuroendocrine neoplasms: a case-series of gastroenteropancreatic neuroendocrine neoplasms and a systematic review of the literature

PURPOSE

Erythropoietin-producing hepatocellular (EPH) receptors are the largest known family of tyrosine kinases receptors (TKR) in humans, implicated in cell proliferation, adhesion, migration, tumor angiogenesis, invasion and metastasis. The aim of the present study is to assess the expression of EPHs in neuroendocrine neoplasms (NENs).

METHODS

Immunohistochemical staining of specimens of 30 patients with gastroenteropancreatic and lung NENs was performed for EPH-A1, EPH-A2, EPH-A4, EPH-A5 protein expression, in addition to ki-67 multiplication index and programmed death-ligand 1. Additionally, we performed a systematic review of the available literature in three different databases reporting on the expression of EPH in all neuroendocrine neoplasms.

RESULTS

Positive expression was seen in 16/19 (84%) specimens for EPH-A1, 15/23 (65%) for EPH-A2, 21/24 (88%) for EPH-A4, 24/26 (92%) for EPH-A5. EPH-A1 was expressed in 9/9 pancreatic, 3/4 small intestine, but not in one lung NEN, EPH-A2 in 5/10 pancreatic, 3/4 small intestine and lung, and in one of each of gastric, appendix, colorectal, and cervical NENs, respectively. EPH-A4 showed positive expression in 9/11 pancreatic, 4/4 small intestine, 3/3 lung specimens and EPH-A5 in 10/11, 4/4 and 4/4, respectively. Data retrieved from the systematic review of the literature in combination with the data from the present study are suggestive of a frequent EPH expression in pituitary, thyroid, lung and gastroenteropancreatic NENs, yet, with varying expressions of the single receptor subtypes.

CONCLUSION

EPHs may have a role in NEN tumorigenesis, prognosis as well as a role in the evolving molecular-targeted therapies.

Comprehensive analysis of EphA2 in pan-cancer: A prognostic biomarker associated with cancer immunity

BACKGROUND

Several studies have reported a significant relationship between Ephrin receptor A2 (EphA2) and malignant progression in numerous cancers. However, there is a lack of comprehensive pan-cancer analysis on the prognostic value, mutation status, methylation landscape, and potential immunological function of EphA2.

METHOD

Using The Cancer Genome Atlas, Genotype Tissue Expression Database and GEO data, we analysed the differences in EphA2 expression between normal and tumour tissues and the effects of EphA2 on the prognosis of different tumours. Furthermore, using GSCALite, cBioPortal, TISDB, ULCLAN and TIMER 2.0 databases or platforms, we comprehensively analysed the potential oncogenic mechanisms or manifestations of EphA2 in 33 different tumour types, including tumour mutation status, DNA methylation status and immune cell infiltration. The correlation of EphA2 with immune checkpoints, tumour mutational burden, DNA microsatellite instability and DNA repair genes was also calculated. Finally, the effects of EphA2 inhibitors on the proliferation of human glioma and lung cancer cells were verified in cellular experiments.

RESULTS

EphA2 is differentially expressed in different tumours, and patients with overexpression have poorer overall survival. In addition, gene mutations, gene copy number variation and DNA/RNA methylation of EphA2 have been identified in various tumours. Moreover, EphA2 is positively associated with immune infiltration involving macrophages and CD8+ T cells. Further, EphA2 mRNA expression is significantly associated with immune checkpoint in various cancers, especially programmed death-ligand 1. Finally, the EphA2 inhibitor ALW-II-41-27 shows potent anti-tumour activity.

CONCLUSION

Our first pan-cancer study of EphA2 provides insight into the prognostic and immunological roles of EphA2 in different tumours, suggesting that EphA2 might be a potential biomarker for poor prognosis and immune infiltration in cancer.

Dysregulation of core neurodevelopmental pathways-a common feature of cancers with perineural invasion

Background: High nerve density in tumors and metastasis via nerves (perineural invasion-PNI) have been reported extensively in solid tumors throughout the body including pancreatic, head and neck, gastric, prostate, breast, and colorectal cancers. Ablation of tumor nerves results in improved disease outcomes, suggesting that blocking nerve-tumor communication could be a novel treatment strategy. However, the molecular mechanisms underlying this remain poorly understood. Thus, the aim here was to identify molecular pathways underlying nerve-tumor crosstalk and to determine common molecular features between PNI-associated cancers. Results: Analysis of head and neck (HNSCC), pancreatic, and gastric (STAD) cancer Gene Expression Omnibus datasets was used to identify differentially expressed genes (DEGs). This revealed extracellular matrix components as highly dysregulated. To enrich for pathways associated with PNI, genes previously correlated with PNI in STAD and in 2 HNSCC studies where tumor samples were segregated by PNI status were analyzed. Neurodevelopmental genes were found to be enriched with PNI. In datasets where tumor samples were not segregated by PNI, neurodevelopmental pathways accounted for 12%-16% of the DEGs. Further dysregulation of axon guidance genes was common to all cancers analyzed. By examining paralog genes, a clear pattern emerged where at least one family member from several axon guidance pathways was affected in all cancers examined. Overall 17 different axon guidance gene families were disrupted, including the ephrin-Eph, semaphorin-neuropilin/plexin, and slit-robo pathways. These findings were validated using The Cancer Genome Atlas and cross-referenced to other cancers with a high incidence of PNI including colon, cholangiocarcinoma, prostate, and breast cancers. Survival analysis revealed that the expression levels of neurodevelopmental gene families impacted disease survival. Conclusion: These data highlight the importance of the tumor as a source of signals for neural tropism and neural plasticity as a common feature of cancer. The analysis supports the hypothesis that dysregulation of neurodevelopmental programs is a common feature associated with PNI. Furthermore, the data suggested that different cancers may have evolved to employ alternative genetic strategies to disrupt the same pathways. Overall, these findings provide potential druggable targets for novel therapies of cancer management and provide multi-cancer molecular biomarkers.

Angiogenic signaling pathways and anti-angiogenic therapy for cancer

Angiogenesis, the formation of new blood vessels, is a complex and dynamic process regulated by various pro- and anti-angiogenic molecules, which plays a crucial role in tumor growth, invasion, and metastasis. With the advances in molecular and cellular biology, various biomolecules such as growth factors, chemokines, and adhesion factors involved in tumor angiogenesis has gradually been elucidated. Targeted therapeutic research based on these molecules has driven anti-angiogenic treatment to become a promising strategy in anti-tumor therapy. The most widely used anti-angiogenic agents include monoclonal antibodies and tyrosine kinase inhibitors (TKIs) targeting vascular endothelial growth factor (VEGF) pathway. However, the clinical benefit of this modality has still been limited due to several defects such as adverse events, acquired drug resistance, tumor recurrence, and lack of validated biomarkers, which impel further research on mechanisms of tumor angiogenesis, the development of multiple drugs and the combination therapy to figure out how to improve the therapeutic efficacy. Here, we broadly summarize various signaling pathways in tumor angiogenesis and discuss the development and current challenges of anti-angiogenic therapy. We also propose several new promising approaches to improve anti-angiogenic efficacy and provide a perspective for the development and research of anti-angiogenic therapy.

The rete mirabile: a possible control site for swimbladder function

In a recent study, a large number of transport proteins was detected in the transcriptome and proteome of saline perfused rete mirabile tissue of the European eel. In this study, the data set was reanalyzed for the presence of receptor proteins and proteins involved in intracellular signaling pathways. A large number of expressed receptor proteins and proteins involved in intracellular signal transduction was detected. Several G-protein-coupled receptor signal pathways were significantly enriched in their expression level, in particular receptors and signaling pathways involved in the control of blood flow. The enriched signaling pathways also include pathways involved in trafficking of crucial transport proteins like, monocarboxylate transporters, V-ATPase, and aquaporin. The data, therefore, suggest that the rete mirabile has the capacity to control swimbladder function by regulating blood flow and by modifying countercurrent multiplication.

Wiring the ocular surface: A focus on the comparative anatomy and molecular regulation of sensory innervation of the cornea

The cornea is richly innervated with sensory nerves that function to detect and clear harmful debris from the surface of the eye, promote growth and survival of the corneal epithelium and hasten wound healing following ocular disease or trauma. Given their importance to eye health, the neuroanatomy of the cornea has for many years been a source of intense investigation. Resultantly, complete nerve architecture maps exist for adult human and many animal models and these maps reveal few major differences across species. Interestingly, recent work has revealed considerable variation across species in how sensory nerves are acquired during developmental innervation of the cornea. Highlighting such species-distinct key differences, but also similarities, this review provides a full, comparative anatomy analysis of sensory innervation of the cornea for all species studied to date. Further, this article comprehensively describes the molecules that have been shown to guide and direct nerves toward, into and through developing corneal tissue as the final architectural pattern of the cornea's neuroanatomy is established. Such knowledge is useful for researchers and clinicians seeking to better understand the anatomical and molecular basis of corneal nerve pathologies and to hasten neuro-regeneration following infection, trauma or surgery that damage the ocular surface and its corneal nerves.

Ephrin B Activate Src Family Kinases in Fibroblasts Inducing Stromal Remodeling in Prostate Cancer

Through stromal-epithelial interactions, carcinoma associated fibroblasts (CAF) play a critical role in tumor growth and progression. Activation of erythrophoyetin-producing human hepatocellular (Eph) receptors has been implicated in cancer. Eph receptor interactions with Ephrin ligands lead to bidirectional signals in the recipient and effector cells. The consequences of continuous reverse Ephrin signaling activation in fibroblasts on prostate cancer (PCa) is unknown. When compared to benign prostate fibroblast, CAF displayed higher expression of Ephrin B1, B2, and B3 ligands (EFNB1, EFNB2, and EFNB3). In this study, we found that continuous activation of EFNB1 and EFNB3 in a benign human prostate stromal cell line (BHPrS1) increased the expression of CAF markers and induced a CAF phenotype. BHPrS1EFNB1 and BHPrS1EFNB3 displayed a pro-tumorigenic secretome with multiple effects on neovascularization, collagen deposition, and cancer cell proliferation, overall increasing tumorigenicity of a premalignant prostate epithelial cell line BPH1 and PCa cell line LNCaP, both in vitro and in vivo. Inhibition of Src family kinases (SFK) in BHPrS1EFNB1 and BHPrS1EFNB3 suppressed EFNB-induced ɑ-SMA (Alpha-smooth muscle actin) and TN-C (Tenascin-C) in vitro. Our study suggests that acquisition of CAF characteristics via SFK activation in response to increased EFNB ligands could promote carcinogenesis via modulation of TME in PCa.

Role of receptor tyrosine kinases mediated signal transduction pathways in tumor growth and angiogenesis-New insight and futuristic vision

In the past two decades, significant progress has been made in the past two decades towards the understanding of the basic mechanisms underlying cancer growth and angiogenesis. In this context, receptor tyrosine kinases (RTKs) play a pivotal role in cell proliferation, differentiation, growth, motility, invasion, and angiogenesis, all of which contribute to tumor growth and progression. Mutations in RTKs lead to abnormal signal transductions in several pathways such as Ras-Raf, MEK-MAPK, PI3K-AKT and mTOR pathways, affecting a wide range of biological functions including cell proliferation, survival, migration and vascular permeability. Increasing evidence demonstrates that multiple kinases are involved in angiogenesis including RTKs such as vascular endothelial growth factor, platelet derived growth factor, epidermal growth factor, insulin-like growth factor-1, macrophage colony-stimulating factor, nerve growth factor, fibroblast growth factor, Hepatocyte Growth factor, Tie 1 & 2, Tek, Flt-3, Flt-4 and Eph receptors. Overactivation of RTKs and its downstream regulation is implicated in tumor initiation and angiogenesis, representing one of the hallmarks of cancer. This review discusses the role of RTKs, PI3K, and mTOR, their involvement, and their implication in pro-oncogenic cellular processes and angiogenesis with effective approaches and newly approved drugs to inhibit their unrestrained action.

Endothelial Cells as Tools to Model Tissue Microenvironment in Hypoxia-Dependent Pathologies

Endothelial cells (ECs) lining the blood vessels are important players in many biological phenomena but are crucial in hypoxia-dependent diseases where their deregulation contributes to pathology. On the other hand, processes mediated by ECs, such as angiogenesis, vessel permeability, interactions with cells and factors circulating in the blood, maintain homeostasis of the organism. Understanding the diversity and heterogeneity of ECs in different tissues and during various biological processes is crucial in biomedical research to properly develop our knowledge on many diseases, including cancer. Here, we review the most important aspects related to ECs’ heterogeneity and list the available in vitro tools to study different angiogenesis-related pathologies. We focus on the relationship between functions of ECs and their organo-specificity but also point to how the microenvironment, mainly hypoxia, shapes their activity. We believe that taking into account the specific features of ECs that are relevant to the object of the study (organ or disease state), especially in a simplified in vitro setting, is important to truly depict the biology of endothelium and its consequences. This is possible in many instances with the use of proper in vitro tools as alternative methods to animal testing.

Molecular Bases of VEGFR-2-Mediated Physiological Function and Pathological Role

The vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) play crucial roles in vasculogenesis and angiogenesis. Angiogenesis is an important mechanism in many physiological and pathological processes, and is involved in endothelial cell proliferation, migration, and survival, then leads to further tubulogenesis, and finally promotes formation of vessels. This series of signaling cascade pathways are precisely mediated by VEGF/VEGFR-2 system. The VEGF binding to the IgD2 and IgD3 of VEGFR-2 induces the dimerization of the receptor, subsequently the activation and trans-autophosphorylation of the tyrosine kinase, and then the initiation of the intracellular signaling cascades. Finally the VEGF-activated VEGFR-2 stimulates and mediates variety of signaling transduction, biological responses, and pathological processes in angiogenesis. Several crucial phosphorylated sites Tyr801, Try951, Try1175, and Try1214 in the VEGFR-2 intracellular domains mediate several key signaling processes including PLCγ-PKC, TSAd-Src-PI3K-Akt, SHB-FAK-paxillin, SHB-PI3K-Akt, and NCK-p38-MAPKAPK2/3 pathways. Based on the molecular structure and signaling pathways of VEGFR-2, the strategy of the VEGFR-2-targeted therapy should be considered to employ in the treatment of the VEGF/VEGFR-2-associated diseases by blocking the VEGF/VEGFR-2 signaling pathway, inhibiting VEGF and VEGFR-2 gene expression, blocking the binding of VEGF and VEGFR-2, and preventing the proliferation, migration, and survival of vascular endothelial cells expressing VEGFR-2.

The prognostic value of ephrin type-A2 receptor and Ki-67 in renal cell carcinoma patients: An Immunohistochemical and Bioinformatical Approach; A STROBE - compliant article

Patients with renal cell carcinoma (RCC), the most common malignant renal epithelial tumor, usually present with advanced disease and unpredicted clinical behavior. The receptor tyrosine kinase, ephrin type-A receptor 2 (EphA2) was found to be overexpressed in several malignancies and its expression was found to be associated with poor prognostic features.Our study is an observational study with the aim of investigating the prognostic value of EphA2 in RCC patients and its association with clinicopathological parameters as well as Ki-67 expression, which is a well-known proliferative and prognostic marker in RCC.EphA2 and Ki-67 immunohistochemical staining was performed on whole sections representative of 50 patients diagnosed with primary RCC from 2013 to 2018. In addition, the association between EphA2 mRNA expression and clinicopathological parameters as well as the patients' outcome was also evaluated using two large publicly available databases.Our results showed a significant association between EphA2 immunohistochemical expression and tumor size, nuclear grade, tumor stage, patients' outcome and Ki-67 expression (P < .05 for all). The same trend was also observed with EphA2 mRNA expression using larger patients' cohorts in 2 publicly available databases. Notably, EphA2 protein expression showed higher levels of co-expression with the proliferative marker Ki-67.Our results suggested that higher expression of EphA2 and Ki-67 in tumor tissues predicts a locally aggressive behaviour and poor outcome of patients with RCC. Moreover, our results give a rationale for the potential benefits of using novel therapeutic strategies with the aim of targeting EphA2 receptor in RCC patients that might help in improving their outcome.

EFNB2 facilitates cell proliferation, migration, and invasion in pancreatic ductal adenocarcinoma via the p53/p21 pathway and EMT

Ephrin-2 (EFNB2) is expressed at abnormally high levels in some neoplasms, such as squamous cell carcinoma of the head and neck and colorectal cancer. Its overexpression is associated with the malignant progression of tumors. However, the expression of EFNB2 in pancreatic ductal adenocarcinoma (PDAC) has not been thoroughly studied. EFNB2 expression was evaluated by quantitative real-time PCR, immunohistochemistry, and western blotting. Furthermore, the association between its expression levels and the clinicopathological features of PDAC patients was explored. To determine the underlying mechanisms of EFNB2, we transfected PDAC cells with small interfering RNA and performed in vitro and in vivo experiments. EFNB2 expression levels were significantly increased in cancer tissues and were associated with PDAC clinical stage and Ki67 expression. The down-regulation of EFNB2 inhibited cell proliferation by up-regulating p53/p21-mediated G0/G1 phase blockade. Knockdown of EFNB2 decreased the migration and invasion of PDAC cells by blocking epithelial-mesenchymal transition. These results suggested that EFNB2 may participate in the development of PDAC by promoting cell proliferation, migration, and invasion. Thus, EFNB2 is a potential target for the diagnosis and treatment of PDAC.

MicroRNAs mediate the anti-tumor and protective effects of ginsenosides

MicroRNAs (miRs(, as short non-coding RNAs, regulate important biological processes and mainly are associated with regulation of gene expression. The miRs are beneficial targets for diagnosis of various disorders, particularly cancer, since their expression profile undergoes alterations in pathological conditions. The numerous drugs have been designed with the capability of targeting miRs for treating pathological conditions. On the other hand, the application of naturally occurring compounds has been increased due to their minimal side effects and valuable biological and therapeutic activities. Ginsenosides are able to act as anti-tumor agents via either increasing or decreasing the expression level of miRs. Ginsenosides affect the expression profile of miRNAs to induce their protective impacts. Angiogenesis as a key factor in the progression of cancer can be suppressed by ginsenosides which is mediated by miR regulation. The aim of this review is to shed some light on the protective and anti-tumor activities of ginsenosides mediated by miRNAs.

Mutations in Chromatin Modifier and Ephrin Signaling Genes in Vein of Galen Malformation

Normal vascular development includes the formation and specification of arteries, veins, and intervening capillaries. Vein of Galen malformations (VOGMs) are among the most common and severe neonatal brain arterio-venous malformations, shunting arterial blood into the brain's deep venous system through aberrant direct connections. Exome sequencing of 55 VOGM probands, including 52 parent-offspring trios, revealed enrichment of rare damaging de novo mutations in chromatin modifier genes that play essential roles in brain and vascular development. Other VOGM probands harbored rare inherited damaging mutations in Ephrin signaling genes, including a genome-wide significant mutation burden in EPHB4. Inherited mutations showed incomplete penetrance and variable expressivity, with mutation carriers often exhibiting cutaneous vascular abnormalities, suggesting a two-hit mechanism. The identified mutations collectively account for ∼30% of studied VOGM cases. These findings provide insight into disease biology and may have clinical implications for risk assessment.

Role of IGF1 and EFN-EPH signaling in skeletal metabolism

Insulin-like growth factor 1(IGF1) and ephrin ligand (EFN)-receptor (EPH) signaling are both crucial for bone cell function and skeletal development and maintenance. IGF1 signaling is the major mediator of growth hormone-induced bone growth, but a host of different signals and factors regulate IGF1 signaling at the systemic and local levels. Disruption of the Igf1 gene results in reduced peak bone mass in both experimental animal models and humans. Additionally, EFN-EPH signaling is a complex system which, particularly through cell-cell interactions, contributes to the development and differentiation of many bone cell types. Recent evidence has demonstrated several ways in which the IGF1 and EFN-EPH signaling pathways interact with and depend upon each other to regulate bone cell function. While much remains to be elucidated, the interaction between these two signaling pathways opens a vast array of new opportunities for investigation into the mechanisms of and potential therapies for skeletal conditions such as osteoporosis and fracture repair.

EphB2 receptor tyrosine kinase promotes hepatic fibrogenesis in mice via activation of hepatic stellate cells

Hepatic fibrosis is the result of an excessive wound-healing response subsequent to chronic liver injury. A feature of liver fibrogenesis is the secretion and deposition of extracellular matrix proteins by activated hepatic stellate cells (HSCs). Here we report that upregulation of EphB2 is a prominent feature of two mouse models of hepatic fibrosis and also observed in humans with liver cirrhosis. EphB2 is upregulated and activated in mouse HSCs following chronic carbon tetrachloride (CCl₄) exposure. Moreover, we show that EphB2 deficiency attenuates liver fibrosis and inflammation and this is correlated with an overall reduction in pro-fibrotic markers, inflammatory chemokines and cytokines. In an in vitro system of HSCs activation we observed an impaired proliferation and sub-optimal differentiation into fibrogenic myofibroblasts of HSCs isolated from EphB2-/- mice compared to HSCs isolated from wild type mice. This supports the hypothesis that EphB2 promotes liver fibrosis partly via activation of HSCs. Cellular apoptosis which is generally observed during the regression of liver fibrogenesis was increased in liver specimens of CCl₄-treated EphB2-/- mice compared to littermate controls. This data is suggestive of an active repair/regeneration system in the absence of EphB2. Altogether, our data validate this novel pro-fibrotic function of EphB2 receptor tyrosine kinase.

EphrinB-mediated reverse signalling controls junctional integrity and pro-inflammatory differentiation of endothelial cells

The EphB/ephrinB receptor-ligand system is pivotal for the development of the embryonic vasculature and for angiogenesis in the adult organism. We observed that (i) the expression of ephrinB2 and ephrinB1 is up-regulated in capillaries during inflammation, that (ii) these ligands are localised on the luminal endothelial surface, and that (iii) they interact with the ephrinB-receptor EphB2 on monocyte/macrophages. This study delineates the impact of ephrinB-mediated reverse signalling on the integrity and proinflammatory differentiation of the endothelium. To this end, in vitro analyses with human cultured endothelial cells reveal that knockdown of ephrinB2 or ephrinB1 impairs monocyte transmigration through the endothelium. While ephrinB2 but not ephrinB1 interacts with PECAM-1 (CD31) in this context, reverse signalling by ephrinB1 but not ephrinB2 elicits a c-Jun N-terminal kinase (JNK)-dependent up-regulation of E-selectin expression. Furthermore, treatment of endothelial cells with soluble EphB2 receptor bodies or EphB2-overexpressing mouse myeloma cells links ephrinB2 to PECAM-1 and induces its Src-dependent phosphorylation while diminishing Src homology phosphotyrosyl phosphatase-2 (SHP-2) activity and increasing endothelial cell permeability. We conclude that extravasation of EphB2 positive leukocyte populations is facilitated by lowering the integrity of endothelial cell junctions and enhancing the pro-inflammatory phenotype of the endothelium through activation of ephrinB ligands.

EphB4 forward signalling mediates angiogenesis caused by CCM3/PDCD10-ablation

CCM3, also named as PDCD10, is a ubiquitous protein expressed in nearly all tissues and in various types of cells. It is essential for vascular development and post-natal vessel maturation. Loss-of-function mutation of CCM3 predisposes for the familial form of cerebral cavernous malformation (CCM). We have previously shown that knock-down of CCM3 stimulated endothelial angiogenesis via impairing DLL4-Notch signalling; moreover, loss of endothelial CCM3 stimulated tumour angiogenesis and promoted tumour growth. The present study was designed to further elucidate the inside signalling pathway involved in CCM3-ablation-mediated angiogenesis. Here we report for the first time that silencing endothelial CCM3 led to a significant up-regulation of EphB4 mRNA and protein expression and to an increased kinase activity of EphB4, concomitantly accompanied by an activation of Erk1/2, which was reversed by treatment with the specific EphB4 kinase inhibitor NVP-BHG712 (NVP), indicating that silencing CCM3 activates EphB4 kinase forward signalling. Furthermore, treatment with NVP rescued the hyper-angiogenic phenotype induced by knock-down of endothelial CCM3 in vitro and in vivo. Additional study demonstrated that the activation of EphB4 forward signalling in endothelial cells under basal condition and after CCM3-silence was modulated by DLL4/Notch signalling, relying EphB4 at downstream of DLL4/Notch signalling. We conclude that angiogenesis induced by CCM3-silence is mediated by the activation of EphB4 forward signalling. The identified endothelial signalling pathway of CCM3-DLL4/Notch-EphB4-Erk1/2 may provide an insight into mechanism of CCM3-ablation-mediated angiogenesis and could potentially contribute to novel therapeutic concepts for disrupting aberrant angiogenesis in CCM and in hyper-vascularized tumours.

Molecular interactions of EphA4, growth hormone receptor, Janus kinase 2, and signal transducer and activator of transcription 5B

We previously reported that EphA4, a member of the Eph family of receptor tyrosine kinases, is an important modulator of growth hormone (GH) signaling, leading to augmented synthesis of insulin-like growth factor 1 (IGF1) for postnatal body growth. In the present study, we report the molecular interactions of EphA4, GH receptor (GHR), Janus kinase 2 (JAK2), and signal transducer and activator of transcription 5B (STAT5B). EphA4 binds to GHR at both its extracellular and intracellular domains and phosphorylates GHR when stimulated with a ligand. The cytoplasmic domain of EphA4 binds to the carboxy-terminus of JAK2 in contrast to the known binding of GHR to the amino-terminus. STAT5B binds to the amino-terminal kinase domain of EphA4. Ligand-activated EphA4 and JAK2 phosphorylate each other and STAT5B, but JAK2 does not appear to phosphorylate EphA4-bound STAT5B. Ligand-activated EphA4 induces the nuclear translocation of STAT5B in a JAK2-independent manner. GHR expression is required for the activation of STAT5B signaling, even via the JAK2-independent pathway. Various ephrins that have affinity for EphA4 induce STAT5B phosphorylation. These findings suggest the molecular mechanisms by which ephrin/EphA4 signaling enhances the canonical GH-IGF1 axis.

Decreased expression of EphA5 is associated with Fuhrman nuclear grade and pathological tumour stage in ccRCC

The incidence of renal cell carcinoma is increasing all over the world. The molecular mechanisms for tumorigenesis, progression and prognosis are still unknown. The erythropoietin-producing hepatoma amplified sequence (Eph) receptors have been reported to be expressed aberrantly in many types of human cancers and in particular EphA5 may play a role in certain human cancers. In this study, a set of clear cell renal cell carcinoma (ccRCC) tissues were subjected to immunohistochemistry. The relationship between EphA5 protein expression and clinicopathological parameters was statistically analysed. Our data show that EphA5 protein was negatively (0) or weakly (1+) expressed in 48 of 78 (61.5%), moderately (2+) expressed in 15 of 78 (19.2%) and strongly (3+) expressed in 15 of 78 (19.2%) tumour samples of ccRCC. Decreased expression of EphA5 was detected more often in females than in males (P = 0.017, r_s  = -0.267). Expression of EphA5 was related negatively to Fuhrman grade (P = 0.013, r_s  = -0.279) and pathological tumour stage pT (P = 0.003, r_s  = -0.334). No relation between the expression of EphA5 and age of patients was found (P = 0.107, r_s  = 0.184). Fuhrman grade and pT stage are the most important factors used in prognosis of ccRCC. Hence this study may provide a new and useful prognostic marker in the clinical practice of ccRCC.

EphB3 protein is associated with histological grade and FIGO stage in ovarian serous carcinomas

Eph (Erythropoietin-producing human hepatocellular carcinoma cell) is the largest subfamily of receptor tyrosine kinases. Eph receptors and their ephrin ligands are involved in embryonic development and physiological processes. Aberrant expression of Eph/ephrin may contribute to a variety of diseases including cancer. EphB3 is a member of Eph receptors and has been found to play roles in carcinogenesis of some types of human cancer. But, its expression and clinical significance in ovarian serous carcinoma have not been well investigated and are unknown. In this study, a set of ovarian tissues including normal fallopian tube, serous borderline tumor, and serous carcinoma were subjected to immunohistochemistry using a specific polyclonal antibody for EphB3. The relationship between EphB3 expression and clinicopathological parameters was statistically analyzed. EphB3 was strongly expressed in all fallopian tube specimens (19/19, 100%). EphB3 was negatively or weekly expressed in 1 of 17 (5.8%) in borderline tumors and 26 of 50 (52.0%) in serous carcinomas, moderately expressed in 7 of 17 (41.2%) in borderline tumors and 14 of 50 (28%) in serous carcinomas, and strongly expressed in 9 17 (52.9%) in borderline tumors and 10 of 50 (20%) in serous carcinomas. EphB3 expression is significantly reduced in serous carcinomas compared with normal fallopian tubes and borderline tumors (p < 0.001). EphB3 expression is negatively associated with histological grade (p < 0.001, r_s = -0.613) and FIGO stage (p = 0.001, r_s = -0.464) of serous carcinomas. Our results show EphB3 protein lost in ovarian serous carcinoma and is associated with tumor grade and FIGO stage, which indicate EphB3 protein may play a role in carcinogenesis of ovarian serous carcinoma and may be used as a molecular marker for prognosis.

A Transcriptomic and Epigenomic Comparison of Fetal and Adult Human Cardiac Fibroblasts Reveals Novel Key Transcription Factors in Adult Cardiac Fibroblasts

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The interplay between cardiomyocytes and cardiac fibroblasts is increasingly being recognized as important in cardiac disease.

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Fetal and adult cardiac fibroblasts influence their neighboring cardiomyocytes in different ways. A genome-wide comparison of the 2 reveals that they share >80% of gene transcripts.

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Motif analysis of empirical regulatory elements located next to differentially expressed genes led to identification of key differential regulators of fibroblast identity.

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STAT1 and PLAGL1 were identified and validated as key transcription factors to maintain the adult cardiac fibroblast phenotype. Loss of either factor led to a significant change in phenotype, including smaller cell size, apoptosis, reduced turnover, and down-regulated collagen gene expression.

Cardiovascular disease remains the number one global cause of death and presents as multiple phenotypes in which the interplay between cardiomyocytes and cardiac fibroblasts (CFs) has become increasingly highlighted. Fetal and adult CFs influence neighboring cardiomyocytes in different ways. Thus far, a detailed comparison between the two is lacking. Using a genome-wide approach, we identified and validated 2 crucial players for maintaining the adult primary human CF phenotype. Knockdown of these factors induced significant phenotypical changes, including senescence and reduced collagen gene expression. These may now represent novel therapeutic targets against deleterious functions of CFs in adult cardiovascular disease.

Bidirectional ephrin signaling in bone

The interaction between ephrin ligands (efn) and their receptors (Eph) is capable of inducing forward signaling, from ligand to receptor, as well as reverse signaling, from receptor to ligand. The ephrins are widely expressed in many tissues, where they mediate cell migration and adherence, properties that make the efn-Eph signaling critically important in establishing and maintaining tissue boundaries. The efn-Eph system has also received considerable attention in skeletal tissues, as ligand and receptor combinations are predicted to mediate interactions between the different types of cells that regulate bone development and homeostasis. This review summarizes our current understanding of efn-Eph signaling with a particular focus on the expression and functions of ephrins and their receptors in bone.

NOTCH4 signaling controls EFNB2-induced endothelial progenitor cell dysfunction in preeclampsia

Preeclampsia is a serious complication of pregnancy and is closely related to endothelial dysfunction, which can be repaired by endothelial progenitor cells (EPCs). The DLL4/NOTCH-EFNB2 (ephrinB2) cascade may be involved in the pathogenesis of preeclampsia by inhibiting the biological activity of EPCs. In addition, both NOTCH1 and NOTCH4, which are specific receptors for DLL4/NOTCH, play critical roles in the various steps of angiogenesis. However, it has not been determined which receptor (NOTCH1, NOTCH4, or both) is specific for the DLL4/NOTCH-EFNB2 cascade. Accordingly, we performed a series of investigations to evaluate it. EFNB2 expression was examined when NOTCH4 or NOTCH1 was downregulated, with or without DLL4 treatment. Then, the effects of NOTCH4 on EPC function were detected. Additionally, we analyzed NOTCH4 and EFNB2 expression in the EPCs from preeclampsia and normal pregnancies. Results showed that NOTCH4 downregulation led to decreased expression of EFNB2, which maintained the same level in the presence of DLL4/NOTCH activation. By contrast, NOTCH1 silencing resulted in a moderate increase in EFNB2 expression, which further increased in the presence of DLL4/NOTCH activation. The downregulation of NOTCH4 resulted in an increase of EPC biological activity, which was similar to EFNB2 silencing. NOTCH4 expression, consistent with the EFNB2 level, increased notably in preeclampsia EPCs compared with the controls. These findings suggest that NOTCH4, not NOTCH1, is the specific receptor for the DLL4/NOTCH-EFNB2 cascade. Blockade of this cascade may enhance the angiogenic property of EPCs, and act as a potential target to promote angiogenesis in patients with preeclampsia.

EphA1 activation promotes the homing of endothelial progenitor cells to hepatocellular carcinoma for tumor neovascularization through the SDF-1/CXCR4 signaling pathway

BACKGROUND

Endothelial progenitor cells (EPCs) can migrate to the tumor tissue and enhance the angiogenesis of hepatocellular carcinoma (HCC); thus, they are associated with a poor prognosis. However, the specific molecular mechanism underlying the homing of EPCs to the HCC neovasculature remains unrevealed.

METHODS

Co-culture experiments of endothelial progenitor cells with HCC cells with modulation of EphA1 were performed in vitro. Using EPCs as angiogenic promoters by injecting them into HCC xenograft-bearing nude mice via their tail veins to test homing ability of EPCs changed according to different EphA1 level in HCC xenograft.

RESULTS

In this study, we found that the up-regulation of EphA1 expression in HCC cells could affect not only the chemotaxis of EPCs to tumor cells and endothelial cells (ECs) but also the tube formation ability of EPCs in a paracrine fashion. Further, we revealed that the increased expression of EphA1 in HCC cells led to an increased SDF-1 concentration in the tumor microenvironment, which in turn activated the SDF-1/CXCR4 axis and enhanced the recruitment of EPCs to HCC. In addition, the EphA1-activated SDF-1 expression and secretion was partially mediated by the PI3K and mTOR pathways. In vivo experiments demonstrated that blocking EphA1/SDF-1/CXCR4 signaling significantly inhibited the growth of HCC xenografts. Using immunohistochemistry and immunofluorescence assays, we verified that the inhibition of tumor angiogenesis was at least partially caused by the decreased number of EPCs homing to tumor tissue.

CONCLUSIONS

Our findings indicate that targeting the EphA1/SDF-1 signaling pathway might be a therapeutic anti-angiogenesis approach for treating HCC.

EphB4 promotes the proliferation, invasion, and angiogenesis of human colorectal cancer

OBJECTIVE

Eph/Ephrin signalling plays an important role in tumorigenesis, neovascularization, and vasculogenesis. However, studies concerning the role of EphB4 in colorectal cancer (CRC) show inconsistent results, and the function of EphB4 in the formation of CRC-related blood vessels is not fully understood. The aim of this study is to investigate the EphB4 expression in CRC and the role of EphB4 in tumour angiogenesis.

MATERIALS AND METHODS

EphB4 and EphrinB2 expressions were detected in 200 CRC samples and 50 paired colorectal mucosae by immunohistochemistry. Xenograft animal models were established by stable knockdown and stable overexpression of EphB4, and control cell lines were used to investigate the role of EphB4 in CRC. Microvessels were stained with anti-CD34, and microvessel density (MVD) was assessed.

RESULTS

EphB4 protein was more highly expressed in CRC tissues compared with adjacent normal mucosae (P<0.05), while EphrinB2 levels were unchanged. Modulation of EphB4 levels in colon cancer cell line SW480 resulted in significant effects on tumour growth and invasion in vivo, with stable overexpression of EphB4 associated with faster growth and invasion. Furthermore, microvessel density values in xenograft tumours were significantly correlated with EphB4 (P<0.05).

CONCLUSION

EphB4 acts as a tumour promoter associated with proliferation, invasion, and angiogenesis, and may be used as a potential CRC therapeutic target.

Immunohistochemical demonstration of EphA2 processing by MT1-MMP in invasive cutaneous squamous cell carcinoma

Erythropoietin-producing hepatocellular receptor-2 (EphA2) overexpression is prevalent in many types of human cancers, and it has been reported that high EphA2 expression is correlated with malignancy. Recent studies revealed that processing of EphA2 by cleaving off the N-terminal portion by membrane-type 1 matrix metalloproteinase (MT1-MMP) promotes invasion via stimulation of Ras in cancer cells in vitro. The objectives of this study were to investigate the presence and role of EphA2 processing in cutaneous squamous cell carcinoma (SCC) tissues. EphA2 (C-terminal and N-terminal) and MT1-MMP expression patterns and levels were analyzed immunohistochemically in SCC (n = 70) and Bowen disease (BD; n = 20). Levels of MT1-MMP and EphA2 expression were evaluated using digital image analysis. Proximity between MT1-MMP and EphA2 in cancer cells and its effect on EphA2 processing were investigated using a combination of in situ proximity ligation assay (PLA) and Western blotting. Immunohistochemical analyses showed that levels of EphA2 N-terminal expression were significantly lower than those of EphA2 C-terminal expression in SCC, whereas levels of EphA2 C- and N-terminal expression were similar in BD. Western blotting showed processed EphA2 fragments in human SCC tissues. Expression levels of MT1-MMP, EphA2, and processed EphA2 fragments were higher in SCC than BD. Proximity between MT1-MMP and EphA2 in SCC was demonstrated by in situ PLA. Our results suggest possible involvement of MT1-MMP processing of EphA2 in invasiveness of cutaneous SCC.

Activation of multiple angiogenic signaling pathways in hemangiopericytoma

Hemangiopericytoma (HPC) is a highly vascularized mesenchymal tumor. Local recurrence and distant metastasis are common features of HPC. Considering the remarkable hyper-vasculature phenotype of HPC, we assumed that dysregulated angiogenic signaling pathways were involved in HPC. The key components of angiogenic signaling pathways including VEGF-VEGF-R2, EphrinB2-EphB4 and DLL4-Notch were examined by real-time RT-PCR, Western blotting and immunostaining in 17 surgical specimens of HPC patients and in 6 controls. A significant upregulation of VEGF and VEGF-R2 associated with elevated levels of p-Akt and proliferating cell nuclear antigen (PCNA) was detected in HPC. Moreover, a dramatic increase in the mRNA and protein expression of EphB4 and its downstream factor p-Erk1/2 was found in HPC. A massive activation of core-components of DLL4-Notch signaling was detected in HPC. Double-immunofluorescent staining confirmed the expression of these upregulated key factors in the endothelial cells of tumor vessels. The present study identified the activation of multiple and crucial angiogenic signaling pathways, which could function individually and/or synergistically to stimulate angiogenesis in HPC and eventually contribute to tumor growth and progression. Our findings emphasize the importance to target multiple angiogenic signaling pathways when an anti-angiogenic therapy is considered for this highly vascularized tumor.

Clinical Significance of EphB4 and EphB6 Expression in Human Malignant and Benign Thyroid Lesions

Ephrin receptors (Ephs) are frequently overexpressed in a wide variety of human malignant tumors, being associated with tumor growth, invasion, angiogenesis and metastasis. The present study aimed to evaluate the clinical significance of EphB4 and EphB6 protein expression in human malignant and benign thyroid lesions. EphB4 and EphB6 protein expression was assessed immunohistochemically on paraffin-embedded thyroid tissues obtained from 127 patients with benign (n = 71) and malignant (n = 56) thyroid lesions. Enhanced EphB4 and EphB6 expression was more frequently observed in malignant compared to benign thyroid lesions (p = 0.0508 and p = 0.0006, respectively). EphB4 and EphB6 expression also provided a distinct discrimination between papillary carcinoma and hyperplastic nodules (p = 0.0302 and p = 0.0013, respectively). In malignant thyroid lesions, enhanced EphB4 expression was significantly associated with larger tumor size (p = 0.0366). Enhanced EphB6 expression was significantly associated with larger tumor size (p = 0.0366), the presence of lymph node metastases (p = 0.0023), the presence of capsular (p = 0.0038), lymphatic (p = 0.0053) and vascular invasion (p = 0.0018) and increased risk of recurrence rate (p = 0.0038). The present study supported evidence that EphB4 and mainly EphB6 may participate in the malignant thyroid transformation, reinforcing their utility as useful biomarkers and possible therapeutic targets in this type of neoplasia.

Role of microRNA-520h in 20(R)-ginsenoside-Rg3-mediated angiosuppression

Background

Ginsenoside-Rg3, the pharmacologically active component of red ginseng, has been found to inhibit tumor growth, invasion, metastasis, and angiogenesis in various cancer models. Previously, we found that 20(R)-ginsenoside-Rg3 (Rg3) could inhibit angiogenesis. Since microRNAs (miRNAs) have been shown to affect many biological processes, they might play an important role in ginsenoside-mediated angiomodulation.

Methods

In this study, we examined the underlying mechanisms of Rg3-induced angiosuppression through modulating the miRNA expression. In the miRNA-expression profiling analysis, six miRNAs and three miRNAs were found to be up- or down-regulated in vascular-endothelial-growth-factor-induced human-umbilical-vein endothelial cells (HUVECs) after Rg3 treatment, respectively.

Results

A computational prediction suggested that mature hsa-miR-520h (miR-520h) targets ephrin receptor (Eph) B2 and EphB4, and hence, affecting angiogenesis. The up-regulation of miR-520h after Rg3 treatment was validated by quantitative real-time polymerase chain reaction, while the protein expressions of EphB2 and EphB4 were found to decrease, respectively. The mimics and inhibitors of miR-520h were transfected into HUVECs and injected into zebra-fish embryos. The results showed that overexpression of miR-520h could significantly suppress the EphB2 and EphB4 protein expression, proliferation, and tubulogenesis of HUVECs, and the subintestinal-vessel formation of the zebra fish.

Conclusion

These results might provide further information on the mechanism of Rg3-induced angiosuppression and the involvement of miRNAs in angiogenesis.

The Binding Receptors of Aβ: an Alternative Therapeutic Target for Alzheimer's Disease

Alzheimer's disease (AD) is one of the most common neurodegenerative disorders, which causes the deterioration of memory and other cognitive abilities of the elderly. Previous lines of research have shown that Aβ is an essential factor in AD pathology and the soluble oligomeric species of Aβ peptide is presumed to be the drivers of synaptic impairment in AD. However, the exact mechanisms underlying Aβ-induced synapse dysfunction are still not fully understood. Recently, increasing evidence suggests that some potential receptors which bind specifically with Aβ may play important roles in inducing the toxicity of the neurons in AD pathology. These receptors include the cellular prion protein (PrPc), the α7 nicotinic acetylcholine receptor (α7nAChR), the p75 neurotrophin receptor (p75(NTR)), the beta-adrenergic receptors (β-ARs), the Eph receptors, the paired immunoglobulin-like receptor B (PirB), the PirB's human ortholog receptor (LilrB2), and the Fcγ receptor II-b (FcγRIIb). This review summarizes the characters of these prominent receptors and how the bindings of them with Aβ inhibit the LTP, decrease the number of dendritic spine, damage the neurons, and so on in AD pathogenesis. Blocking or rescuing these receptors may have significant importance for AD treatments.

Detailed morphological characterisation of Hendra virus infection of different cell types using super-resolution and conventional imaging

BACKGROUND

Hendra virus (HeV) is a pleomorphic virus belonging to the Paramyxovirus family. Our long-term aim is to understand the process of assembly of HeV virions. As a first step, we sought to determine the most appropriate cell culture system with which to study this process, and then to use this model to define the morphology of the virus and identify the site of assembly by imaging key virus encoded proteins in infected cells.

METHODS

A range of primary cells and immortalised cell lines were infected with HeV, fixed at various time points post-infection, labelled for HeV proteins and imaged by confocal, super-resolution and transmission electron microscopy.

RESULTS

Significant differences were noted in viral protein distribution depending on the infected cell type. At 8 hpi HeV G protein was detected in the endoplasmic reticulum and M protein was seen predominantly in the nucleus in all cells tested. At 18 hpi, HeV-infected Vero cells showed M and G proteins throughout the cell and in transmission electron microscope (TEM) sections, in pleomorphic virus-like structures. In HeV infected MDBK, A549 and HeLa cells, HeV M protein was seen predominantly in the nucleus with G protein at the membrane. In HeV-infected primary bovine and porcine aortic endothelial cells and two bat-derived cell lines, HeV M protein was not seen at such high levels in the nucleus at any time point tested (8,12, 18, 24, 48 hpi) but was observed predominantly at the cell surface in a punctate pattern co-localised with G protein. These HeV M and G positive structures were confirmed as round HeV virions by TEM and super-resolution (SR) microscopy. SR imaging demonstrated for the first time sub-virion imaging of paramyxovirus proteins and the respective localisation of HeV G, M and N proteins within virions.

CONCLUSION

These findings provide novel insights into the structure of HeV and show that for HeV imaging studies the choice of tissue culture cells may affect the experimental results. The results also indicate that HeV should be considered a predominantly round virus with a mean diameter of approximately 280 nm by TEM and 310 nm by SR imaging.

EphB2 regulates contact-dependent and contact-independent signaling to control platelet function

The Eph kinases, EphA4 and EphB1, and their ligand, ephrinB1, have been previously reported to be present in platelets where they contribute to thrombus stability. Although thrombus formation allows for Eph-ephrin engagement and bidirectional signaling, the importance specifically of Eph kinase or ephrin signaling in regulating platelet function remained unidentified. In the present study, a genetic approach was used in mice to establish the contribution of signaling orchestrated by the cytoplasmic domain of EphB2 (a newly discovered Eph kinase in platelets) in platelet activation and thrombus formation. We conclude that EphB2 signaling is involved in the regulation of thrombus formation and clot retraction. Furthermore, the cytoplasmic tail of this Eph kinase regulates initial platelet activation in a contact-independent manner in the absence of Eph-ephrin ligation between platelets. Together, these data demonstrate that EphB2 signaling not only modulates platelet function within a thrombus but is also involved in the regulation of the function of isolated platelets in a contact-independent manner.

High EphA2 protein expression in renal cell carcinoma is associated with a poor disease outcome

The receptor tyrosine kinase, ephrin type-A receptor 2 (EphA2), is normally expressed at sites of cell-to-cell contact in adult epithelial tissues, however, recent studies have shown that it is also overexpressed in various types of epithelial carcinomas, with the greatest level of EphA2 expression observed in metastatic lesions. In the present study, the association between the expression of EphA2 and the outcome of RCC patients was assessed. The high expression level of EphA2 was identified by log-rank test for a statistically significant prediction of the RCC outcome. In an overall multivariate analysis, the high expression level of EphA2 was identified as an independent predictor of RCC outcome. The length of survival of the patients with high EphA2 expression was shorter than that of the patients with a low level of expression (relative risk, 2.304; 95% CI, 1.102–4.818; P=0.027). The analysis of the expression levels of EphA2 in tumor tissues may aid in the identification of the patient subgroup that are at a high risk of a poor disease outcome.

Overexpression of EphB4 in the mammary epithelium shifts the differentiation pathway of progenitor cells and promotes branching activity and vascularization

Postnatally, the mammary gland undergoes continuous morphogenesis and thereby is especially prone to malignant transformation. Thus, the maintenance of the epithelium depends on a tight control of stem cell recruitment. We have previously shown that epithelial overexpression of the EphB4 receptor results in defective mammary epithelial development and conferred a metastasizing tumor phenotype on experimental mouse mammary tumors accompanied by a preponderance of progenitor cells. To analyze the effect of EphB4 overexpression on mammary epithelial cell fate, we have used Fluorescence Activated Cell Sorting (FACS) analyses to quantify epithelial sub-populations and repopulation assays of cleared fat pads to investigate their regenerative potential. These experiments revealed that deregulated EphB4 expression leads to an augmentation of bi-potent progenitor cells and to a shift of the differentiation pathway towards the luminal lineage. The analyses of the ductal outgrowths indicated that EphB4 overexpression leads to enforced branching activity, impedes ductal differentiation and stimulates angiogenesis. To elucidate the mechanisms forwarding EphB4 signals, we have compared the expression profile of defined cell populations between EphB4 transgene and wild type mammary glands concentrating on the wnt signaling pathway and on genes implicated in cell migration. With respect to wnt signaling, the progenitor cell population was the most affected, whereas the stem cell-enriched population showed the most pronounced deregulation of migration-associated genes. Thus, the luminal epithelial EphB4 signaling contributes, most likely via wnt signaling, to the regulation of migration and cell fate of early progenitors and is involved in the determination of branching points along the ductal tree.

Ephrin (Eph) receptor A1, A4, A5 and A7 expression in human non-small cell lung carcinoma: associations with clinicopathological parameters, tumor proliferative capacity and patients' survival

Background

Ephrin (Eph) receptors are frequently overexpressed in a wide variety of human malignant tumors, being associated with tumor growth, invasion, metastasis and angiogenesis. The present study aimed to evaluate the clinical significance of EphA1, A4, A5 and A7 protein expression in non-small cell lung carcinoma (NSCLC).

Methods

EphA1, A4, A5 and A7 protein expression was assessed immunohistochemically in tissue microarrays of 88 surgically resected NSCLC and was analyzed in relation with clinicopathological characteristics and patients’ survival.

Results

Elevated EphA4 expression was significantly associated with low histopathological stage and presence of inflammation (p = 0.047 and p = 0.026, respectively). Elevated EphA7 expression was significantly associated with older patients’ age, presence of fibrosis and smaller tumor size (p = 0.036, p = 0.029 and p = 0.018, respectively). EphA1, A5 and A7 expression were positively associated with tumor proliferative capacity (p = 0.047, p = 0.002 and p = 0.046, respectively). Elevated EphA4, A5 and A7 expression were identified as predictors of favourable patients’ survival at both univariate (Log-rank test, 0 = 0.019, p = 0.006 and p = 0.012, respectively) and multivariate levels (Cox-regression analysis, p = 0.029, p = 0.068 and p = 0.044, respectively).

Conclusions

The present study supported evidence that Ephs may be involved in lung cancer progression, reinforcing their utility as clinical biomarkers for patients’ management and prognosis, as also as potential targets for future therapeutic interventions.

The role of ephrins' receptors and ephrins' ligands in normal placental development and disease

INTRODUCTION

Ephrin (Eph) receptors and their membrane-anchored ligands, the ephrins, participate in a wide spectrum of pathophysiological processes, regulating cellular adhesion, migration or chemo-repulsion and tissue/cell boundary formation. Recent evidence has further extended the role of Eph receptors and their ligands as critical regulators of vascular remodelling during embryogenesis. The role of Ephs/ephrins signalling in the angiogenic development of murine placentas and in the invasion of the maternal tissues and the development of the placental vasculature in humans has currently attracted considerable interest.

AREAS COVERED

A literature review summarising the most recent data in terms of the role of Ephs/ephrins in normal placental development and disease, highlighting on their expression status in the different cellular populations of the placental vascularity.

EXPERT OPINION

Despite the fact that the role of Eph/ephrins signalling in normal placental development is still unclear, some studies tried to investigate their potential implication in placental pathologies, such as preeclampsia and placenta accreta. Even though no evidence for their direct implication occurred, their role is an interesting field for future research.

Smooth-muscle progenitor cells isolated from patients with moyamoya disease: novel experimental cell model

OBJECT

Moyamoya disease (MMD) is a cerebrovascular occlusive disease affecting bilateral internal carotid termini. Smooth-muscle cells are one of the major cell types involved in this disease process. The characteristics of circulating smooth-muscle progenitor cells (SPCs) in MMD are poorly understood. The authors purified SPCs from the peripheral blood of patients with MMD and sought to identify differentially expressed genes (DEGs) in SPCs from these patients.

METHODS

The authors cultured and isolated SPCs from the peripheral blood of patients with MMD (n = 25) and healthy control volunteers (n = 22). After confirmation of the cellular phenotype, RNA was extracted from the cells and DEGs were identified using a commercially available gene chip. Real-time quantitative reverse transcription polymerase chain reaction was performed to confirm the putative pathogenetic DEGs.

RESULTS

The SPC-type outgrowth cells in patients with MMD invariably showed a hill-and-valley appearance under microscopic examination, and demonstrated high α-smooth muscle actin, myosin heavy chain, and calponin expression (96.5% ± 2.1%, 42.8% ± 18.6%, and 87.1% ± 8.2%, respectively), and minimal CD31 expression (less than 1%) on fluorescence-activated cell sorter analysis. The SPCs in the MMD group tended to make more irregularly arranged and thickened tubules on the tube formation assay. In the SPCs from patients with MMD, 286 genes (124 upregulated and 162 downregulated) were differentially expressed; they were related to cell adhesion, cell migration, immune response, and vascular development.

CONCLUSIONS

With adequate culture conditions, SPCs could be established from the peripheral blood of patients with MMD. These cells showed specific DEGs compared with healthy control volunteers. This study provides a novel experimental cell model for further research of MMD.

Ephrin receptor (Eph) -A1, -A2, -A4 and -A7 expression in mobile tongue squamous cell carcinoma: associations with clinicopathological parameters and patients survival

Ephrin receptors (Ephs) are frequently overexpressed in a wide variety of human malignant tumors, being associated with tumor growth, invasion, metastasis and angiogenesis. The present study aimed to evaluate the clinical significance of Eph-A1, -A2, -A4 and -A7 protein expression in mobile tongue squamous cell carcinoma (SCC). Eph-A1, -A2, -A4 and -A7 protein expression was assessed immunohistochemically on 37 mobile tongue SCC tissue samples and was analyzed in relation with clinicopathological characteristics, overall and disease-free patients' survival. All the examined mobile tongue SCC cases were found positive for Eph-A1, -A2, -A4 and -A7. Significant associations were noted between high Eph-A1, -A4 and -A7 expression and absence of lymph node metastases (p = 0.0263, p = 0.0461 and p = 0.0461, respectively). High Eph-A1, -A2 and -A7 expression was significantly more frequently observed in patients presenting absence of vascular invasion (p = 0.0444), dense stromal inflammatory reaction (p = 0.0063) and female gender (p = 0.0327), respectively. Mobile tongue SCC patients with high Eph-A7 expression presented longer overall and disease-free survival compared to those with low Eph-A7 expression (log-rank test, p = 0.0093 and p = 0.0164, respectively). In multivariate analysis, Eph-A7 expression was identified as independent prognostic factor of overall survival (Cox-regression analysis, p = 0.0426). The present study supported evidence that Ephs may participate in the malignant transformation of mobile tongue SCC, reinforcing their utility as clinical markers for patients' management and prognosis, as also as targets for potential therapeutic intervention in tongue chemoprevention.

Protective effects of EphB2 on Aβ1-42 oligomer-induced neurotoxicity and synaptic NMDA receptor signaling in hippocampal neurons

Alzheimer's disease (AD) is a neurodegenerative disorder characterized pathologically by the abnormal deposition of extracellular amyloid-β (Aβ) oligomers. However, the nature and precise mechanism of the toxicity of Aβ oligomers are not clearly understood. Aβ oligomers have been previously shown to cause a major loss of EphB2, a member of the EphB family of receptor tyrosine kinases. To determine the effect of EphB2 on Aβ oligomer-induced neurotoxicity and the underlying molecular mechanisms, we examined the EphB2 gene in cultured hippocampal neurons. Using a cellular model of AD, Aβ1-42 oligomers were confirmed to induce neurotoxicity in a time-dependent manner and result in a major decrease of EphB2. EphB2 overexpression could prevent the neurotoxicity of hippocampal neurons from exposure to Aβ1-42 oligomers for 1h. Further analysis revealed that EphB2 overexpression increased synaptic NR1 and NR2B expression in Aβ1-42 oligomer-treated neurons. Moreover, EphB2 overexpression prevented Aβ1-42 oligomer-induced downregulation of dephosphorylated p38 MAPK and phosphorylated CREB. Together, these results suggest that EphB2 is a factor which protects hippocampal neurons against the toxicity of Aβ1-42 oligomers, and we infer that the protection of EphB2 is achieved by increasing the synaptic NMDA receptor level and downstream p38 MAPK and CREB signaling in hippocampal neurons. This study provides new molecular insights into the neuroprotective effect of EphB2 and highlights its potential therapeutic role in the management of AD.

Ephrin-A1/EphA4-mediated adhesion of monocytes to endothelial cells

The Eph receptors represent the largest family of receptor tyrosine kinases. Both Eph receptors and their ephrin ligands are cell-surface proteins, and they typically mediate cell-to-cell communication by interacting at sites of intercellular contact. The major aim of the present study was to investigate the involvement of EphA4-ephrin-A1 interaction in monocyte adhesion to endothelial cells, as this process is a crucial step during the initiation and progression of the atherosclerotic plaque. Immunohistochemical analysis of human atherosclerotic plaques revealed expression of EphA4 receptor and ephrin-A1 ligand in major cell types within the plaque. Short-time stimulation of endothelial cells with the soluble ligand ephrin-A1 leads to a fourfold increase in adhesion of human monocytes to endothelial cells. In addition, ephrin-A1 further increases monocyte adhesion to already inflamed endothelial cells. EphrinA1 mediates its effect on monocyte adhesion via the activated receptor EphA4. This ephrinA1/EphA4 induced process involves the activation of the Rho signaling pathway and does not require active transcription. Rho activation downstream of EphA4 leads to increased polymerization of actin filaments in endothelial cells. This process was shown to be crucial for the proadhesive effect of ephrin-A1. The results of the present study show that ephrin-A1-induced EphA4 forward signaling promotes monocyte adhesion to endothelial cells via activation of RhoA and subsequent stress-fiber formation by a non-transcriptional mechanism.

Ephrin-Eph signaling as a potential therapeutic target for the treatment of myocardial infarction

Although numerous strategies have been developed to reduce the initial ischemic insult and cellular injury that occurs during myocardial infarction (MI), few have progressed into the clinical arena. The epidemiologic and economic impact of MI necessitates the development of innovative therapies to rapidly and effectively reduce the initial injury and subsequent cardiac dysfunction. The Eph receptors and their cognate ligands, the ephrins, are the largest family of receptor tyrosine kinases, and their signaling has been shown to play a diverse role in various cellular processes. The recent advances in the study of ephrin-Eph signaling have shown promising progress in many fields of medicine. They have been implicated in the pathophysiology of various cancers and in the regulation of inflammation and apoptosis. Recent studies have shown that manipulation of ephrin-Eph cell signaling can favorably influence cardiomyocyte viability and ultimately preserve cardiac function post-MI. In this article, we explore the hypothesis that manipulation of ephrin-Eph signaling may potentially be a novel therapeutic target in the treatment of MI through alteration of the cellular processes that govern injury and wound healing.

Inhibition of choroidal neovascularization by anti-EphB4 monoclonal antibody

The aim of this study was to determine the effect of the EphB4 monoclonal antibody on experimental choroidal neovascularization (CNV) progression. Experimental CNV was established by argon laser photocoagulation. In the experimental group, the EphB4 monoclonal antibody was injected into the vitreous space in the eye specimens on days 0, 3, 6 and 9 after CNV model establishment. In the control group, an equal amount of balanced salt solution was injected at the same time points. On day 10 after CNV model establishment, fluorescein isothiocyanate-dextran endocardial perfusion and choroidal stretched preparation were conducted, respectively, for the two groups. The CNV area in each light spot and the mean values were determined. Histopathological examination was conducted and the ratio of the maximum thickness of the CNV in each light spot to the surrounding normal choroidal thickness, as well as the mean ratio, were calculated. Choroidal stretched preparation confirmed that the CNV of the experimental group was smaller, whereas the CNV of the control group was wider and larger. Quantitative analysis revealed that CNV in the experimental group was significantly inhibited (t=11.84, P<0.01) and that CNV progression in the experimental group was significantly suppressed (t=7.45, P<0.01). Histopathological examination revealed that CNV in the experimental group was thinner and smaller. Vitreous injection of the EphB4 monoclonal antibody inhibits experimental CNV progression. However, its specific mechanism remains unclear. Endogenous EphrinB2/EphB4 regulates ocular neovascularization and may become a new target in treating CNV diseases.