Overexpression of EPH Receptor B2 in Malignant Mesothelioma Correlates with Oncogenic Behavior

Silencing EPHB2 diminished the malignant biological properties of esophagus cancer cells by blocking autophagy and Wnt/β-catenin pathway

Eph receptor B2 (EPHB2) is overexpressed in some tumors and relevant to unfavorable outcomes of tumor patients. By searching Gene Expression Profiling Interactive Analysis and KM Plot websites, we discovered that EPHB2 was highly expressed in patients with esophageal cancer, leading to poor prognosis. However, the role and molecular mechanism of EPHB2 in esophagus cancer is unknown. Our study aims to unveil the underlying mechanism by which EPHB2 modulates the biological properties of esophagus cancer cells. After si-EPHB2 transfection, the malignant biological properties of esophagus cancer cells were determined by several biological experiments. IWP-4 was applied to block Wnt/β-catenin signaling pathway. The expressions of autophagy and Wnt/β-catenin signaling pathway relevant molecules were tested by western blot assay. An increased expression of EPHB2 was happened in esophagus cancer samples and loss of EPHB2 diminished esophagus cancer cells proliferation, migration, and invasion. Moreover, our data showed that depletion of EPHB2 blocked the autophagy and in-activated Wnt/β-catenin signaling pathway in esophagus cancer cells. While, IWP-4 treatment inhibited the autophagy and limited esophagus cancer cells proliferation, migration, and invasion. Moreover, EPHB2 knocked down strengthened the effect of IWP-4 treatment in regulating esophagus cancer cells proliferation, migration, and invasion. Finally, we illustrated that EPHB2 regulated the biological properties of esophagus cancer cells by modulating autophagy and Wnt/β-catenin signaling pathway. Our study illustrated that EPHB2 might be a worthwhile target considering for the treatment of esophagus cancer.

EPHB2 as a key mediator of glioma progression: Insights from microenvironmental receptor ligand-related prognostic gene signature

Malignant gliomas, characterized by pronounced heterogeneity, a complex microenvironment, and a propensity for relapse and drug resistaniguree, pose significant challenges in oncology. This study aimed to investigate the prognostic value of Ligand and Receptor related genes (LRRGs) within the glioma microenvironment. An intersection of 71 ligand-related genes (LRGs) and 2628 receptor-related genes (RRGs) yielded a total of 69 LRRGs. Utilizing the least absolute shrinkage and selection operator (LASSO) regression analysis, a prognostic RiskScore model comprising 28 LRRGs was constructed. The model demonstrated robust prognostic value, further validated in the TCGA-GBMLGG dataset. Subsequent analyses included differential gene expression, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), gene set enrichment (GSEA), and gene set variation (GSVA) within RiskScore groups. Additionally, evaluations of PPI, mRNA-RBP, mRNA-TF, and mRNA-drug interaction networks were conducted. Four hub genes were identified through differential expression analysis of the 28 LRRGs across various GSE datasets. A multivariate Cox prognostic model was constructed for nomogram analysis, gene mutation analysis, and related expression distribution. This study underscores the role of LRRGs in intercellular communication within the glioma microenvironment and identifies four hub genes crucial for prognostic assessment in clinical glioma patients. These findings offer a potential evaluation framework for glioma patients, enhancing our understanding of the disease and informing future therapeutic strategies.

Extracellular vesicle-mediated ferroptosis, pyroptosis, and necroptosis: potential clinical applications in cancer therapy

Extracellular vesicles (EVs) have gained increasing recognition as significant regulators of intercellular communication in various physiological and pathological processes. These vesicles play a pivotal role in cancer progression by facilitating the transfer of diverse cargoes, including lipids, proteins, and nucleic acids. Regulated cell death (RCD), the orderly and autonomous death of cells, is controlled by a variety of biomacromolecules and, in turn, influences various biological processes and cancer progression. Recent studies have demonstrated that EV cargoes regulate diverse oncogenes and tumor suppressors to mediate different nonapoptotic forms of RCD, notably ferroptosis, pyroptosis, and necroptosis. Nevertheless, comprehensive exploration of EV-mediated nonapoptotic RCD forms in the context of cancer has not been performed. This review summarizes the progress regarding the biological functions and underlying mechanisms of EVs in mediating nonapoptotic RCD by delivery of cargoes to regulate tumor progression. Additionally, the review delves into the potential clinical applications of EV-mediated cell death and its significance in the areas of cancer diagnosis and therapy.

Guidance landscapes unveiled by quantitative proteomics to control reinnervation in adult visual system

In the injured adult central nervous system (CNS), activation of pro-growth molecular pathways in neurons leads to long-distance regeneration. However, most regenerative fibers display guidance defects, which prevent reinnervation and functional recovery. Therefore, the molecular characterization of the proper target regions of regenerative axons is essential to uncover the modalities of adult reinnervation. In this study, we use mass spectrometry (MS)-based quantitative proteomics to address the proteomes of major nuclei of the adult visual system. These analyses reveal that guidance-associated molecules are expressed in adult visual targets. Moreover, we show that bilateral optic nerve injury modulates the expression of specific proteins. In contrast, the expression of guidance molecules remains steady. Finally, we show that regenerative axons are able to respond to guidance cues ex vivo, suggesting that these molecules possibly interfere with brain target reinnervation in adult. Using a long-distance regeneration model, we further demonstrate that the silencing of specific guidance signaling leads to rerouting of regenerative axons in vivo. Altogether, our results suggest ways to modulate axon guidance of regenerative neurons to achieve circuit repair in adult.

The extracellular matrix protein fibulin-3/EFEMP1 promotes pleural mesothelioma growth by activation of PI3K/Akt signaling

Malignant pleural mesothelioma (MPM) is an aggressive tumor with poor prognosis and limited therapeutic options. The extracellular matrix protein fibulin-3/EFEMP1 accumulates in the pleural effusions of MPM patients and has been proposed as a prognostic biomarker of these tumors. However, it is entirely unknown whether fibulin-3 plays a functional role on MPM growth and progression. Here, we demonstrate that fibulin-3 is upregulated in MPM tissue, promotes the malignant behavior of MPM cells, and can be targeted to reduce tumor progression. Overexpression of fibulin-3 increased the viability, clonogenic capacity and invasion of mesothelial cells, whereas fibulin-3 knockdown decreased these phenotypic traits as well as chemoresistance in MPM cells. At the molecular level, fibulin-3 activated PI3K/Akt signaling and increased the expression of a PI3K-dependent gene signature associated with cell adhesion, motility, and invasion. These pro-tumoral effects of fibulin-3 on MPM cells were disrupted by PI3K inhibition as well as by a novel, function-blocking, anti-fibulin-3 chimeric antibody. Anti-fibulin-3 antibody therapy tested in two orthotopic models of MPM inhibited fibulin-3 signaling, resulting in decreased tumor cell proliferation, reduced tumor growth, and extended animal survival. Taken together, these results demonstrate for the first time that fibulin-3 is not only a prognostic factor of MPM but also a relevant molecular target in these tumors. Further development of anti-fibulin-3 approaches are proposed to increase early detection and therapeutic impact against MPM.

The Roles of EphB2 in Cancer

The erythropoietin-producing hepatocellular carcinoma (Eph) receptors and their Eph receptor-interacting (ephrin) ligands together constitute a vital cell communication system with diverse roles. Experimental evidence revealed Eph receptor bidirectional signaling with both tumor-promoting and tumor-suppressing activities in different cancer types and surrounding environment. Eph receptor B2 (EphB2), an important member of the Eph receptor family, has been proved to be aberrantly expressed in many cancer types, such as colorectal cancer, gastric cancer and hepatocellular carcinoma, resulting in tumor occurrence and progression. However, there are no reviews focusing on the dual roles of EphB2 in cancer. Thus, in this paper we systematically summarize and discuss the roles of EphB2 in cancer. Firstly, we review the main biological features and the related signaling regulatory mechanisms of EphB2, and then we summarize the roles of EphB2 in cancer through current studies. Finally, we put forward our viewpoint on the future prospects of cancer research focusing on EphB2, especially with regard to the effects of EphB2 on tumor immunity.

Circular RNA RBM33 contributes to extracellular matrix degradation via miR-4268/EPHB2 axis in abdominal aortic aneurysm

Background

Abdominal aortic aneurysm (AAA) is a complex vascular disease involving expansion of the abdominal aorta. Extracellular matrix (ECM) degradation is crucial to AAA pathogenesis, however, the specific molecular mechanism remains unclear. This study aimed to investigate differentially expressed circular RNAs (DEcircRNAs) involved in ECM degradation of AAA.

Methods

Transcriptome sequencing was used to analyze the DEcircRNAs between the AAA tissues and normal tissues. The expression of circRNAs in tissues and cells was validated using quantitative reverse transcription PCR (RT-qPCR). Overexpression of circRNAs in vascular smooth muscle cells (VSMCs) treated with angiotensin II (Ang II) was employed to explore its effect on ECM degradation of AAA. Bioinformatic technology, luciferase reporter gene assay, RT-qPCR, and rescue experiment were employed to evaluate the regulatory mechanism of circRNA.

Results

We identified 65 DEcircRNAs in AAA tissues compared with normal abdominal aortic tissues, including 30 up-regulated and 35 down-regulated circRNAs, which were mainly involved in inflammation and ECM-related functions and pathways. Moreover, circRBM33 was significantly increased in AAA tissues and Ang II-induced VSMCs compared with control samples. Overexpression of circRBM33 increased the expression of ECM-related molecule matrix metalloproteinase-2 and reduced the tissue inhibitor of matrix metalloproteinases-1 expression. Mechanistically, miR-4268 targeted binding to circRBM33 and inhibited the luciferase activity of circRBM33. Overexpression of circRBM33 induced the expression of EPH receptor B2 (EPHB2), and this effect was countered by miR-4268 mimics.

Conclusions

Overall, our data suggest that circRBM33 might be involved in AAA progression by regulating ECM degradation via the miR-4268/EPHB2 axis.

A live single-cell reporter assay links intratumor heterogeneity to metastatic proclivity in Ewing sarcoma

Targeting of the most aggressive tumor cell subpopulations is key for effective management of most solid malignancies. However, the metastable nature of tumor heterogeneity, which allows cells to transition between strong and weak tumorigenic phenotypes, and the lack of reliable markers of tumor-promoting properties hamper identification of the most relevant cells. To overcome these obstacles, we designed a functional microRNA (miR)-based live-cell reporter assay to identify highly tumorigenic cells in xenotransplants of primary Ewing sarcoma (EwS) 3D cultures. Leveraging the inverse relationship between cell pluripotency and miR-145 expression, we successfully separated highly tumorigenic, metastasis-prone (miR-145low) cells from poorly tumorigenic, nonmetastatic (miR-145high) counterparts. Gene expression and functional studies of the two cell populations identified the EPHB2 receptor as a prognostic biomarker in patients with EwS and a major promoter of metastasis. Our study provides a simple and powerful means to identify and isolate tumor cells that display aggressive behavior.

Genomics and Functional Genomics of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare, aggressive cancer of the mesothelial cells lining the pleural surface of the chest wall and lung. The etiology of MPM is strongly associated with prior exposure to asbestos fibers, and the median survival rate of the diagnosed patients is approximately one year. Despite the latest advancements in surgical techniques and systemic therapies, currently available treatment modalities of MPM fail to provide long-term survival. The increasing incidence of MPM highlights the need for finding effective treatments. Targeted therapies offer personalized treatments in many cancers. However, targeted therapy in MPM is not recommended by clinical guidelines mainly because of poor target definition. A better understanding of the molecular and cellular mechanisms and the predictors of poor clinical outcomes of MPM is required to identify novel targets and develop precise and effective treatments. Recent advances in the genomics and functional genomics fields have provided groundbreaking insights into the genomic and molecular profiles of MPM and enabled the functional characterization of the genetic alterations. This review provides a comprehensive overview of the relevant literature and highlights the potential of state-of-the-art genomics and functional genomics research to facilitate the development of novel diagnostics and therapeutic modalities in MPM.

Downregulation of hsa-microRNA-204-5p and identification of its potential regulatory network in non-small cell lung cancer: RT-qPCR, bioinformatic- and meta-analyses

Background

Pulmonary malignant neoplasms have a high worldwide morbidity and mortality, so the study of these malignancies using microRNAs (miRNAs) has attracted great interest and enthusiasm. The aim of this study was to determine the clinical effect of hsa-microRNA-204-5p (miR-204-5p) and its underlying molecular mechanisms in non-small cell lung cancer (NSCLC).

Methods

Expression of miR-204-5p was investigated by real-time quantitative PCR (RT-qPCR). After data mining from public online repositories, several integrative assessment methods, including receiver operating characteristic (ROC) curves, hazard ratios (HR) with 95% confidence intervals (95% CI), and comprehensive meta-analyses, were conducted to explore the expression and clinical utility of miR-204-5p. The potential objects regulated and controlled by miR-204-5p in the course of NSCLC were identified by estimated target prediction and analysis. The regulatory network of miR-204-5p, with its target genes and transcription factors (TFs), was structured from database evidence and literature references.

Results

The expression of miR-204-5p was downregulated in NSCLC, and the downtrend was related to gender, histological type, vascular invasion, tumor size, clinicopathologic grade and lymph node metastasis (P<0.05). MiR-204-5p was useful in prognosis, but was deemed unsuitable at present as an auxiliary diagnostic or prognostic risk factor for NSCLC due to the lack of statistical significance in meta-analyses and absence of large-scale investigations. Gene enrichment and annotation analyses identified miR-204-5p candidate targets that took part in various genetic activities and biological functions. The predicted TFs, like MAX, MYC, and RUNX1, interfered in regulatory networks involving miR-204-5p and its predicted hub genes, though a modulatory loop or axis of the miRNA-TF-gene that was out of range with shortage in database prediction, experimental proof and literature confirmation.

Conclusions

The frequently observed decrease in miR-204-5p was helpful for NSCLC diagnosis. The estimated target genes and TFs contributed to the anti-oncogene effects of miR-204-5p.

Quantitative mass spectrometry to identify protein markers for diagnosis of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a devastating malignancy with a prognosis of <12 months. Even with bans on the use of asbestos in most Western countries, the incidence is still increasing due to the long latency periods between exposure and development of the disease. Diagnosis is often delayed due to invasive biopsies and lack of distinguishable markers. Patients frequently present with pleural effusions months to years before a radiologically detectable mass appears. This study aimed to investigate the proteome of pleural effusions taken from patients with MPM, adenocarcinoma and benign conditions in an attempt to identify a biomarker for early diagnosis. We identified several proteins that may be possible targets and warrant further investigation. Due to the predominance of up regulated proteins involved in VEGF signalling in MPM, we analysed VEGFA levels in effusions and found a strong correlation between VEGFA levels and survival in MPM.

Tumor angiogenesis revisited: Regulators and clinical implications

Since Judah Folkman hypothesized in 1971 that angiogenesis is required for solid tumor growth, numerous studies have been conducted to unravel the angiogenesis process, analyze its role in primary tumor growth, metastasis and angiogenic diseases, and to develop inhibitors of proangiogenic factors. These studies have led in 2004 to the approval of the first antiangiogenic agent (bevacizumab, a humanized antibody targeting vascular endothelial growth factor) for the treatment of patients with metastatic colorectal cancer. This approval launched great expectations for the use of antiangiogenic therapy for malignant diseases. However, these expectations have not been met and, as knowledge of blood vessel formation accumulates, many of the original paradigms no longer hold. Therefore, the regulators and clinical implications of angiogenesis need to be revisited. In this review, we discuss recently identified angiogenesis mediators and pathways, new concepts that have emerged over the past 10 years, tumor resistance and toxicity associated with the use of currently available antiangiogenic treatment and potentially new targets and/or approaches for malignant and nonmalignant neovascular diseases.

Combined EphB2 receptor knockdown with radiation decreases cell viability and invasion in medulloblastoma

Background

Medulloblastoma is one of the most common types of pediatric brain tumor characterized by the subpopulation of cells that exhibit high invasive potential and radioresistant properties. In addition, dysregulated function and signaling by Eph family of receptors have been shown to impart pro-tumorigenic characteristics in this brain malignancy. In the current study, we investigated whether EphB2 knockdown in combination with radiation can alter invasiveness and decrease medulloblastoma tumor growth or viability in vitro.

Methods

The expression of EphB2 receptor was analyzed by immunohistochemistry and Western blotting. Microarray analysis and mRNA analysis was performed on medulloblastoma patient datasets and compared to the normal cerebellum. The radiosensitization effect following EphB2 knockdown was determined by clonogenic assay in human medulloblastoma cells. Effects of EphB2-siRNA in absence or presence of radiation on cell cycle distribution, cell viability, and invasion were analyzed by flow cytometry, MTT assay, trypan blue exclusion assay, xcelligence system, and Western blotting.

Results

We observed that EphB2 is expressed in both medulloblastoma cell lines and patient samples and its downregulation sensitized these cells to radiation as evident by decreased clonogenic survival fractions. EphB2 expression was also high across different medulloblastoma subgroups compared to normal cerebellum. The radiosensitization effect observed following EphB2 knockdown was in part mediated by enhanced G2/M cell cycle arrest. We also found that the combined approach of EphB2 knockdown and radiation exposure significantly reduced overall cell viability in medulloblastoma cells compared to control groups. Similar results were obtained in the xcelligence-based invasion assay. Western blot analysis also demonstrated changes in the protein expression of cell proliferation, cell survival, and invasion molecules in the combination group versus others.

Conclusions

Overall, our findings indicate that specific targeting of EphB2 receptor in combination with radiation may serve as an effective therapeutic strategy in medulloblastoma. Future studies are warranted to test the efficacy of this approach in in vivo preclinical models.

Electronic supplementary material

The online version of this article (doi:10.1186/s12935-017-0409-7) contains supplementary material, which is available to authorized users.

The Genetic Landscape of Malignant Pleural Mesothelioma: Results from Massively Parallel Sequencing

Malignant pleural mesothelioma (MPM) is a rare yet aggressive tumor that is causally associated with-mostly professional-asbestos exposure. Given the long latency between exposure and disease, and because asbestos is still being used, MPM will remain a global health issue for decades to come. Notwithstanding the increasing incidence of MPM and the fact that patients with MPM face a poor prognosis, currently available treatment options are limited. To enable the development of novel targeted therapies, identification of the genetic alterations underlying MPM will be crucial. The first studies reporting on the genomic background of MPM identified recurrent somatic mutations in a number of tumor suppressor genes (i.e., cyclin-dependent kinase inhibitor 2A gene [CDKN2A], neurofibromin 2 (merlin) gene [NF2], and BRCA1 associated protein 1 gene [BAP1]). More recently, massively parallel sequencing strategies have been used and have provided a more genome-wide view on the genetic landscape of MPM. This review summarizes their results, describing alterations that cluster mainly in four pathways: the tumor protein p53/DNA repair, cell cycle, mitogen-activated protein kinase, and phosphoinisitide 3-kinase (PI3K)/AKT pathways. As these pathways are important during tumor development, they provide interesting candidates for targeting with novel drugs.

Investigation of the interactions between the EphB2 receptor and SNEW peptide variants

EphB2 interacts with cell surface-bound ephrin ligands to relay bidirectional signals. Overexpression of the EphB2 receptor protein has been linked to different types of cancer. The SNEW (SNEWIQPRLPQH) peptide binds with high selectivity and moderate affinity to EphB2, inhibiting Eph-ephrin interactions by competing with ephrin ligands for the EphB2 high-affinity pocket. We used rigorous free energy perturbation (FEP) calculations to re-evaluate the binding interactions of SNEW peptide with the EphB2 receptor, followed by experimental testing of the computational results. Our results provide insight into dynamic interactions of EphB2 with SNEW peptide. While the first four residues of the SNEW peptide are already highly optimized, change of the C-terminal end of the peptide has the potential to improve SNEW-binding affinity. We identified a PXSPY motif that can be similarly aligned with several other EphB2-binding peptides.

Eph- and ephrin-dependent mechanisms in tumor and stem cell dynamics

The erythropoietin-producing hepatocellular (Eph) receptors comprise the largest family of receptor tyrosine kinases (RTKs). Initially regarded as axon-guidance and tissue-patterning molecules, Eph receptors have now been attributed with various functions during development, tissue homeostasis, and disease pathogenesis. Their ligands, ephrins, are synthesized as membrane-associated molecules. At least two properties make this signaling system unique: (1) the signal can be simultaneously transduced in the receptor- and the ligand-expressing cell, (2) the signaling outcome through the same molecules can be opposite depending on cellular context. Moreover, shedding of Eph and ephrin ectodomains as well as ligand-dependent and -independent receptor crosstalk with other RTKs, proteases, and adhesion molecules broadens the repertoire of Eph/ephrin functions. These integrated pathways provide plasticity to cell-microenvironment communication in varying tissue contexts. The complex molecular networks and dynamic cellular outcomes connected to the Eph/ephrin signaling in tumor-host communication and stem cell niche are the main focus of this review.

Eph receptors: new players in Alzheimer's disease pathogenesis

Alzheimer's disease (AD) is devastating and leads to permanent losses of memory and other cognitive functions. Although recent genetic evidences strongly argue for a causative role of Aβ in AD onset and progression (Jonsson et al., 2012), its role in AD etiology remains a matter of debate. However, even if not the sole culprit or pathological trigger, genetic and anatomical evidences in conjunction with numerous pharmacological studies, suggest that Aβ peptides, at least contribute to the disease. How Aβ contributes to memory loss remains largely unknown. Soluble Aβ species referred to as Aβ oligomers have been shown to be neurotoxic and induce network failure and cognitive deficits in animal models of the disease. In recent years, several proteins were described as potential Aβ oligomers receptors, amongst which are the receptor tyrosine kinases of Eph family. These receptors together with their natural ligands referred to as ephrins have been involved in a plethora of physiological and pathological processes, including embryonic neurogenesis, learning and memory, diabetes, cancers and anxiety. Here we review recent discoveries on Eph receptors-mediated protection against Aβ oligomers neurotoxicity as well as their potential as therapeutic targets in AD pathogenesis.