EphB receptor activity suppresses colorectal cancer progression

EPHA5 promotes cell proliferation and inhibits apoptosis in Follicular Thyroid Cancer via the STAT3 signaling pathway

Follicular thyroid carcinoma (FTC) is a common endocrine malignancy characterized by a higher propensity for invasion and metastasis compared to papillary thyroid carcinoma (PTC). Ephrin type A receptor 5 (EPHA5) is a crucial receptor tyrosine kinase involved in orchestrating diverse physiological processes, including apoptosis and proliferation. However, the mechanism of EPHA5 in FTC remains unclear. This study identified significant overexpression of EPHA5 in FTC. In vitro experiments showed that increased expression of EPHA5 promotes proliferation and inhibits apoptosis in FTC. Furthermore, EPHA5 activates the STAT3 signaling pathway. To explore the interaction between EPHA5 and the STAT3 signaling pathway, we used SH-4-54 (a STAT3-specific inhibitor). Interestingly, the influence of EPHA5 on proliferation and apoptosis was reduced upon combination with SH-4-54. In summary, this study unveils the involvement of the EPHA5-STAT3 signaling pathway in FTC and implies that the function of EPHA5 in FTC may partly depend on the STAT3 signaling pathway.

Interface morphodynamics in living tissues

Interfaces between distinct tissues or between tissues and environments are common in multicellular organisms. The evolution and stability of these interfaces are essential for tissue development, and their dysfunction can lead to diseases such as cancer. Mounting efforts, either theoretical or experimental, have been devoted to uncovering the morphodynamics of tissue interfaces. Here, we review the recent progress of studies on interface morphodynamics. The regulatory mechanisms governing interface evolution are dissected, with a focus on adhesion, cortical tension, cell activity, extracellular matrix, and microenvironment. We examine the methodologies used to study morphodynamics, emphasizing the characteristics of experimental techniques and theoretical models. Finally, we explore the broader implications of interface morphodynamics in tissue morphogenesis and diseases, offering a comprehensive perspective on this rapidly developing field.

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.

Ephrin-Eph signaling: an important regulator of epithelial integrity and barrier function

Eph receptor-interacting proteins (ephrin) ligands and their erythropoietin-producing human hepatocellular (Eph) receptors elicit bidirectional signals that regulate cell migration, angiogenesis, neuronal plasticity, and other developmental processes in the embryo. In adulthood, ephrin-Eph signaling regulates numerous homeostatic events, including epithelial cell proliferation and differentiation. Epithelial surfaces, including those of skin and vagina, are lined by layers of stratified squamous epithelium (SSE) that protect against mechanical stress and microbial pathogen invasion. Ephrin-Eph signaling is known to promote cutaneous epithelial barrier function by regulating the expression of specialized cell-cell adhesion junctions termed desmosomes, but the role of this signaling system in maintaining epithelial integrity and barrier function in the vagina is less explored. This review summarizes current understanding of ephrin-Eph signaling that regulates desmosome expression and barrier function in the skin and considers evidence that suggests ephrin-Eph signaling similarly regulates these processes in vaginal SSE.

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

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

Identification and validation of regulatory T cell-associated gene signatures to predict colon adenocarcinoma prognosis

Colon adenocarcinoma (COAD) is a common cause of cancer-related death. Due to the difficulty in early diagnosis and drug resistance, conventional treatments are difficult to be effective. Some studies have found that the functional recovery of T cells in the tumor microenvironment, especially regulatory T cells (Tregs), plays an important role in the progression of cancer. This study used the TCGA data set, clinical information and RNA-seq data of COAD patients to construct a Tregs-related risk score (TRS) through methods such as WGCNA, single-factor Cox, multi-factor Cox and random survival forest (RSF). Moreover, we also used the TCGA test set and internal validation set to verify the predictive ability of TRS, and used functional enrichment analysis and somatic mutation analysis to mine genes related to TRS, such as like thrombin/trypsin receptor 2 (F2RL2), inhibin subunit beta B (INHBB) and melanoma antigen family A12 (MAGEA12). Moreover, this study confirmed the expression of these prognostic genes using scRNA-seq data. We also performed qPCR analysis of various genes in normal and cancerous colon cancer cell lines to verify that these genes indeed play a role in CODA patients. We also constructed a mouse CODA model to study and evaluate the impact of key genes such as MAGEA12 on tumor growth in mice. This study explores the important role of Treg cells in the prognosis of COAD and discovers some potential biomarkers for the occurrence and development of COAD, which provides some new ideas for the treatment of COAD.

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

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

Singleton mutations in large-scale cancer genome studies: uncovering the tail of cancer genome

Singleton or low-frequency driver mutations are challenging to identify. We present a domain driver mutation estimator (DOME) to identify rare candidate driver mutations. DOME analyzes positions analogous to known statistical hotspots and resistant mutations in combination with their functional and biochemical residue context as determined by protein structures and somatic mutation propensity within conserved PFAM domains, integrating the CADD scoring scheme. Benchmarked against seven other tools, DOME exhibited superior or comparable accuracy compared to all evaluated tools in the prediction of functional cancer drivers, with the exception of one tool. DOME identified a unique set of 32 917 high-confidence predicted driver mutations from the analysis of whole proteome missense variants within domain boundaries across 1331 genes, including 1192 noncancer gene census genes, emphasizing its unique place in cancer genome analysis. Additionally, analysis of 8799 TCGA (The Cancer Genome Atlas) and in-house tumor samples revealed 847 potential driver mutations, with mutations in tyrosine kinase members forming the dominant burden, underscoring its higher significance in cancer. Overall, DOME complements current approaches for identifying novel, low-frequency drivers and resistant mutations in personalized therapy.

Cell Death, by Any Other Name…

Studies trying to understand cell death, this ultimate biological process, can be traced back to a century ago. Yet, unlike many other fashionable research interests, research on cell death is more alive than ever. New modes of cell death are discovered in specific contexts, as are new molecular pathways. But what is "cell death", really? This question has not found a definitive answer yet. Nevertheless, part of the answer is irreversibility, whereby cells can no longer recover from stress or injury. Here, we identify the most distinctive features of different modes of cell death, focusing on the executive final stages. In addition to the final stages, these modes can differ in their triggering stimulus, thus referring to the initial stages. Within this framework, we use a few illustrative examples to examine how intercellular communication factors in the demise of cells. First, we discuss the interplay between cell-cell communication and cell death during a few steps in the early development of multicellular organisms. Next, we will discuss this interplay in a fully developed and functional tissue, the gut, which is among the most rapidly renewing tissues in the body and, therefore, makes extensive use of cell death. Furthermore, we will discuss how the balance between cell death and communication is modified during a pathological condition, i.e., colon tumorigenesis, and how it could shed light on resistance to cancer therapy. Finally, we briefly review data on the role of cell-cell communication modes in the propagation of cell death signals and how this has been considered as a potential therapeutic approach. Far from vainly trying to provide a comprehensive review, we launch an invitation to ponder over the significance of cell death diversity and how it provides multiple opportunities for the contribution of various modes of intercellular communication.

The cholesterol biosynthesis enzyme FAXDC2 couples Wnt/β-catenin to RTK/MAPK signaling

Wnts, cholesterol, and MAPK signaling are essential for development and adult homeostasis. Here, we report that fatty acid hydroxylase domain containing 2 (FAXDC2), a previously uncharacterized enzyme, functions as a methyl sterol oxidase catalyzing C4 demethylation in the Kandutsch-Russell branch of the cholesterol biosynthesis pathway. FAXDC2, a paralog of MSMO1, regulated the abundance of the specific C4-methyl sterols lophenol and dihydro-T-MAS. Highlighting its clinical relevance, FAXDC2 was repressed in Wnt/β-catenin-high cancer xenografts, in a mouse genetic model of Wnt activation, and in human colorectal cancers. Moreover, in primary human colorectal cancers, the sterol lophenol, regulated by FAXDC2, accumulated in the cancerous tissues and not in adjacent normal tissues. FAXDC2 linked Wnts to RTK/MAPK signaling. Wnt inhibition drove increased recycling of RTKs and activation of the MAPK pathway, and this required FAXDC2. Blocking Wnt signaling in Wnt-high cancers caused both differentiation and senescence; and this was prevented by knockout of FAXDC2. Our data show the integration of 3 ancient pathways, Wnts, cholesterol synthesis, and RTK/MAPK signaling, in cellular proliferation and differentiation.

Eph receptors and ephrins in cancer progression

Evidence implicating Eph receptor tyrosine kinases and their ephrin ligands (that together make up the 'Eph system') in cancer development and progression has been accumulating since the discovery of the first Eph receptor approximately 35 years ago. Advances in the past decade and a half have considerably increased the understanding of Eph receptor-ephrin signalling mechanisms in cancer and have uncovered intriguing new roles in cancer progression and drug resistance. This Review focuses mainly on these more recent developments. I provide an update on the different mechanisms of Eph receptor-ephrin-mediated cell-cell communication and cell autonomous signalling, as well as on the interplay of the Eph system with other signalling systems. I further discuss recent advances in elucidating how the Eph system controls tumour expansion, invasiveness and metastasis, supports cancer stem cells, and drives therapy resistance. In addition to functioning within cancer cells, the Eph system also mediates the reciprocal communication between cancer cells and cells of the tumour microenvironment. The involvement of the Eph system in tumour angiogenesis is well established, but recent findings also demonstrate roles in immune cells, cancer-associated fibroblasts and the extracellular matrix. Lastly, I discuss strategies under evaluation for therapeutic targeting of Eph receptors-ephrins in cancer and conclude with an outlook on promising future research directions.

Ephrin-Eph receptor tyrosine kinases for potential therapeutics against hepatic pathologies

Hepatic fibrosis is the common pathological change that occurs due to increased synthesis and accumulation of extracellular matrix components. Chronic insult from hepatotoxicants leads to liver cirrhosis, which if not reversed timely using appropriate therapeutics, liver transplantation remains the only effective therapy. Often the disease further progresses into hepatic carcinoma. Although there is an increased advancement in understanding the pathological phenotypes of the disease, additional knowledge of the novel molecular signaling mechanisms involved in the disease progression would enable the development of efficacious therapeutics. Ephrin-Eph molecules belong to the largest family of receptor tyrosine kinases (RTKs) which are identified to play a crucial role in cellular migratory functions, during morphological and developmental stages. Additionally, they contribute to the growth of a multicellular organism as well as in pathological conditions like cancer, and diabetes. A wide spectrum of mechanistic studies has been performed on ephrin-Eph RTKs in various hepatic tissues under both normal and diseased conditions revealing their diverse roles in hepatic pathology. This systematic review summarizes the liver-specific ephrin-Eph RTK signaling mechanisms and recognizes them as druggable targets for mitigating hepatic pathology.

Colorectal cancer-associated mutations impair EphB1 kinase function

Erythropoietin-producing hepatoma (Eph) receptor tyrosine kinases regulate the migration and adhesion of cells that are required for many developmental processes and adult tissue homeostasis. In the intestinal epithelium, Eph signaling controls the positioning of cell types along the crypt-villus axis. Eph activity can suppress the progression of colorectal cancer (CRC). The most frequently mutated Eph receptor in metastatic CRC is EphB1. However, the functional effects of EphB1 mutations are mostly unknown. We expressed and purified the kinase domains of WT and five cancer-associated mutant EphB1 and developed assays to assess the functional effects of the mutations. Using purified proteins, we determined that CRC-associated mutations reduce the activity and stability of the folded structure of EphB1. By mammalian cell expression, we determined that CRC-associated mutant EphB1 receptors inhibit signal transducer and activator of transcription 3 and extracellular signal-regulated kinases 1 and 2 signaling. In contrast to the WT, the mutant EphB1 receptors are unable to suppress the migration of human CRC cells. The CRC-associated mutations also impair cell compartmentalization in an assay in which EphB1-expressing cells are cocultured with ligand (ephrin B1)-expressing cells. These results suggest that somatic mutations impair the kinase-dependent tumor suppressor function of EphB1 in CRC.

Mouse models in colon cancer, inferences, and implications

Mouse models of colorectal cancer (CRC) have been crucial in the identification of the role of genes responsible for the full range of pathology of the human disease and have proved to be dependable for testing anti-cancer drugs. Recent research points toward the relevance of tumor, angiogenic, and immune microenvironments in CRC progression to late-stage disease, as well as the treatment of it. This study examines important mouse models in CRC, discussing inherent strengths and weaknesses disclosed during their construction. It endeavors to provide both a synopsis of previous work covering how investigators have defined various models and to evaluate critically how researchers are most likely to use them in the future. Accumulated evidence regarding the metastatic process and the hope of using checkpoint inhibitors and immunological inhibitor therapies points to the need for a genetically engineered mouse model that is both immunocompetent and autochthonous.

Oncogenic signaling is coupled to colorectal cancer cell differentiation state

Colorectal cancer progression is intrinsically linked to stepwise deregulation of the intestinal differentiation trajectory. In this process, sequential mutations of APC, KRAS, TP53, and SMAD4 enable oncogenic signaling and establish the hallmarks of cancer. Here, we use mass cytometry of isogenic human colon organoids and patient-derived cancer organoids to capture oncogenic signaling, cell phenotypes, and differentiation states in a high-dimensional single-cell map. We define a differentiation axis in all tumor progression states from normal to cancer. Our data show that colorectal cancer driver mutations shape the distribution of cells along the differentiation axis. In this regard, subsequent mutations can have stem cell promoting or restricting effects. Individual nodes of the cancer cell signaling network remain coupled to the differentiation state, regardless of the presence of driver mutations. We use single-cell RNA sequencing to link the (phospho-)protein signaling network to transcriptomic states with biological and clinical relevance. Our work highlights how oncogenes gradually shape signaling and transcriptomes during tumor progression.

Eph Receptors in Cancer

Eph receptor tyrosine kinases play critical functions during development, in the formation of tissue and organ borders, and the vascular and neural systems. Uniquely among tyrosine kinases, their activities are controlled by binding to membrane-bound ligands, called ephrins. Ephs and ephrins generally have a low expression in adults, functioning mainly in tissue homeostasis and plasticity, but are often overexpressed in cancers, where they are especially associated with undifferentiated or progenitor cells, and with tumour development, vasculature, and invasion. Mutations in Eph receptors also occur in various tumour types and are suspected to promote tumourigenesis. Ephs and ephrins have the capacity to operate as both tumour promoters and tumour suppressors, depending on the circumstances. They have been demonstrated to impact tumour cell proliferation, migration, and invasion in vitro, as well as tumour development, angiogenesis, and metastases in vivo, making them potential therapeutic targets. However, successful development of therapies will require detailed understanding of the opposing roles of Ephs in various cancers. In this review, we discuss the variations in Eph expression and functions in a variety of malignancies. We also describe the multiple strategies that are currently available to target them in tumours, including preclinical and clinical development.

RNF186/EPHB2 Axis Is Essential in Regulating TNF Signaling for Colorectal Tumorigenesis in Colorectal Epithelial Cells

The receptor tyrosine kinase EPHB2 (EPH receptor B2) is highly expressed in many human cancer types, especially in gastrointestinal cancers, such as colorectal cancer. Several coding mutations of the EPHB2 gene have been identified in many cancer types, suggesting that EPHB2 plays a critical role in carcinogenesis. However, the exact functional mechanism of EPHB2 in carcinogenesis remains unknown. In this study, we find that EPHB2 is required for TNF-induced signaling activation and proinflammatory cytokine production in colorectal epithelial cells. Mechanistically, after TNF stimulation, EPHB2 is ubiquitinated by its E3 ligase RNF186. Then, ubiquitinated EPHB2 recruits and further phosphorylates TAB2 at nine tyrosine sites, which is a critical step for the binding between TAB2 and TAK1. Due to defects in TNF signaling in RNF186-knockout colorectal epithelial cells, the phenotype of colitis-propelled colorectal cancer model in RNF186-knockout mice is significantly reduced compared with that in wild-type control mice. Moreover, we find that a genetic mutation in EPHB2 identified in a family with colorectal cancer is a gain-of-function mutation that promoted TNF signaling activation compared with wild-type EPHB2. We provide evidence that the EPHB2-RNF186-TAB2-TAK1 signaling cascade plays an essential role in TNF-mediated signal transduction in colorectal epithelial cells and the carcinogenesis of colorectal cancer, which may provide potential targets for the treatment of colorectal cancer.

Metalloprotease ADAM9 cleaves ephrin-B ligands and differentially regulates Wnt and mTOR signaling downstream of Akt kinase in colorectal cancer cells

Ephrin-B signaling has been implicated in many normal and pathological processes, including neural crest development and tumor metastasis. We showed previously that proteolysis of ephrin-B ligands by the disintegrin metalloprotease ADAM13 is necessary for canonical Wnt signal activation and neural crest induction in Xenopus, but it was unclear if these mechanisms are conserved in mammals. Here, we report that mammalian ADAM9 cleaves ephrin-B1 and ephrin-B2 and can substitute for Xenopus ADAM13 to induce the neural crest. We found that ADAM9 expression is elevated in human colorectal cancer (CRC) tissues and that knockdown (KD) of ADAM9 inhibits the migration and invasion of SW620 and HCT116 CRC cells by reducing the activity of Akt kinase, which is antagonized by ephrin-Bs. Akt is a signaling node that activates multiple downstream pathways, including the Wnt and mTOR pathways, both of which can promote CRC cell migration/invasion. Surprisingly, we also found that KD of ADAM9 downregulates Wnt signaling but has negligible effects on mTOR signaling in SW620 cells; in contrast, mTOR activity is suppressed while Wnt signaling remains unaffected by ADAM9 KD in HCT116 cells. These results suggest that mammalian ADAM9 cleaves ephrin-Bs to derepress Akt and promote CRC migration and invasion; however, the signaling pathways downstream of Akt are differentially regulated by ADAM9 in different CRC cell lines, reflecting the heterogeneity of CRC cells in responding to manipulations of upstream Akt regulators.

Jagged 2b induces intercellular signaling within somites to establish hematopoietic stem cell fate in zebrafish

During development, the somites play a key role in the specification of hematopoietic stem cells (HSCs). In zebrafish, the somitic Notch ligands Delta-c (Dlc) and Dld, both of which are regulated by Wnt16, directly instruct HSC fate in a shared vascular precursor. However, it remains unclear how this signaling cascade is spatially and temporally regulated within somites. Here, we show in zebrafish that an additional somitic Notch ligand, Jagged 2b (Jag2b), induces intercellular signaling to drive wnt16 expression. Jag2b activated Notch signaling in segmented somites at the early stage of somitogenesis. Loss of jag2b led to a reduction in the expression of wnt16 in the somites and an HSC marker, runx1, in the dorsal aorta, whereas overexpression of jag2b increased both. However, Notch-activated cells were adjacent to, but did not overlap with, wnt16-expressing cells within the somites, suggesting that an additional signaling molecule mediates this intercellular signal transduction. We uncover that Jag2b-driven Notch signaling induces efna1b expression, which regulates wnt16 expression in neighboring somitic cells. Collectively, we provide evidence for previously unidentified spatiotemporal regulatory mechanisms of HSC specification by somites.

The EPH/Ephrin System in Colorectal Cancer

The EPH/ephrin system constitutes a bidirectional signaling pathway comprised of a family of tyrosine kinase receptors in tandem with their plasma membrane-bound ligand (ephrins). Its significance in a wide variety of physiologic and pathologic processes has been recognized during the past decades. In carcinogenesis, EPH/ephrins coordinate a wide spectrum of pathologic processes, such as angiogenesis, vessel infiltration, and metastasis. Despite the recent advances in colorectal cancer (CRC) diagnosis and treatment, it remains a leading cause of death globally, accounting for 9.2% of all cancer deaths. A growing body of literature has been published lately revitalizing our scientific interest towards the role of EPH/ephrins in pathogenesis and the treatment of CRC. The aim of the present review is to present the recent CRC data which might lead to clinical practice changes in the future.

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.

Long non-coding RNAs as the critical regulators of epithelial mesenchymal transition in colorectal tumor cells: an overview

Colorectal cancer (CRC) is the second most common cause of cancer mortality and a major health challenge worldwide. Despite advances in therapeutic and diagnostic methods, there is still a poor prognosis in CRC patients. Tumor recurrence and metastasis are the main causes of high mortality rate in these patients, which are due to late diagnosis in advanced tumor stages. Epithelial-mesenchymal transition (EMT) is known to be the most important cause of CRC metastasis, during which tumor cells obtain metastasis ability by losing epithelial features and gaining mesenchymal features. Long non-coding RNAs (lncRNAs) are pivotal regulators of EMT process. Regarding the higher stability of lncRNAs compared with coding RNAs in body fluids, they can be used as non-invasive diagnostic markers for EMT process. In the present review, we summarized all of the lncRNAs involved in regulation of EMT process during CRC progression and metastasis. It was observed that lncRNAs mainly induced the EMT process in CRC cells by regulation of EMT-related transcription factors, Poly comb repressive complex (PRC), and also signaling pathways such as WNT, NOTCH, MAPK, and Hippo.

EPHA2, EPHA4, and EPHA7 Expression in Triple-Negative Breast Cancer

Ongoing research continues to elucidate the complex role of ephrin receptors (EPHs) and their ligands (ephrins) in breast cancer pathogenesis, with their varying expression patterns implied to have an important impact on patients’ outcome. The current study aims to investigate the clinical significance of EPHA2, EPHA4, and EPHA7 expression in triple-negative breast cancer (TNBC) cases. EPHA2, EPHA4, and EPHA7 protein expression was assessed immunohistochemically on formalin-fixed and paraffin-embedded (FFPE) TNBC tissue sections from 52 TNBC patients and correlated with key clinicopathologic parameters and patients’ survival data (overall survival (OS); disease-free survival (DFS)). EPHA2, EPHA4, and EPHA7 expression was further examined in TNBC cell lines. EPHA2 overexpression was observed in 26 (50%) of the TNBC cases, who exhibited a shorter OS and DFS than their low-expression counterparts, with EPHA2 representing an independent prognostic factor for OS and DFS (p = 0.0041 and p = 0.0232, respectively). EPHA4 overexpression was associated with lymph node metastasis in TNBC patients (p = 0.0546). Alterations in EPHA2, EPHA4, and EPHA7 expression levels were also noted in the examined TNBC cell lines. Our study stresses that EPHA2 expression constitutes a potential prognostic factor for TNBC patients. Given the limited treatment options and poorer outcome that accompany the TNBC subtype, EPHA2 could also pose as a target for novel, more personalized, and effective therapeutic approaches for those patients.

Modeling Intestinal Stem Cell Function with Organoids

Intestinal epithelial cells (IECs) are crucial for the digestive process and nutrient absorption. The intestinal epithelium is composed of the different cell types of the small intestine (mainly, enterocytes, goblet cells, Paneth cells, enteroendocrine cells, and tuft cells). The small intestine is characterized by the presence of crypt-villus units that are in a state of homeostatic cell turnover. Organoid technology enables an efficient expansion of intestinal epithelial tissue in vitro. Thus, organoids hold great promise for use in medical research and in the development of new treatments. At present, the cholinergic system involved in IECs and intestinal stem cells (ISCs) are attracting a great deal of attention. Thus, understanding the biological processes triggered by epithelial cholinergic activation by acetylcholine (ACh), which is produced and released from neuronal and/or non-neuronal tissue, is of key importance. Cholinergic signaling via ACh receptors plays a pivotal role in IEC growth and differentiation. Here, we discuss current views on neuronal innervation and non-neuronal control of the small intestinal crypts and their impact on ISC proliferation, differentiation, and maintenance. Since technology using intestinal organoid culture systems is advancing, we also outline an organoid-based organ replacement approach for intestinal diseases.

Loss of mismatch repair signaling impairs the WNT-bone morphogenetic protein crosstalk and the colonic homeostasis

The fine balance between proliferation, differentiation, and apoptosis in the colonic epithelium is tightly controlled by the interplay between WNT, Notch, and bone morphogenetic protein (BMP) signaling. How these complex networks coordinate the colonic homeostasis, especially if cancer predisposing mutations such as mutations in the DNA mismatch repair (MMR) are present, is unclear. Inactivation of the MMR system has long been linked to colorectal cancer; however, little is known about its role in the regulation of the colonic homeostasis. It has been shown that loss of MMR promotes the proliferation of colon epithelial cells that renders them highly susceptible to transformation. The mechanism through which MMR mediates this effect, yet, remains to be determined. Using an MMR-deficient mouse model, we show that increased methylation of Dickkopf1 impacts its expression, and consequently, the ability to negatively regulate WNT signaling. As a result, excessive levels of active β-catenin promote strong crypt progenitor-like phenotype and abnormal proliferation. Under these settings, the development and function of the goblet cells are affected. MMR-deficient mice have fewer goblet cells with enlarged mucin-loaded vesicles. We further show that MMR inactivation impacts the WNT–BMP signaling crosstalk.

The Clinical Impact of the EPH/Ephrin System in Cancer: Unwinding the Thread

Erythropoietin-producing human hepatocellular receptors (EPHs) compose the largest known subfamily of receptor tyrosine kinases (RTKs). They bind and interact with the EPH family receptor interacting proteins (ephrins). EPHs/ephrins are implicated in a variety of physiological processes, as well as in cancer pathogenesis. With neoplastic disease remaining a leading cause of death world-wide, the development of novel biomarkers aiding in the field of diagnosis, prognosis, and disease monitoring is of utmost importance. A multitude of studies have proven the association between the expression of members of the EPH/ephrin system and various clinicopathological parameters, including disease stage, tumor histologic grade, and patients' overall survival. Besides their utilization in timely disease detection and assessment of outcome, EPHs/ephrins could also represent possible novel therapeutic targets. The aim of the current review of the literature was to present the existing data regarding the association between EPH/ephrin system expression and the clinical characteristics of malignant tumors.

Low Expression of EphB2, EphB3, and EphB4 in Bladder Cancer: Novel Potential Indicators of Muscular Invasion

PURPOSE

Eph receptors are differentially expressed in numerous malignant tumors. This study intended to analyze the roles of EphB receptors (EphB2, B3, and B4) in urinary bladder cancer.

MATERIALS AND METHODS

Tissue microarray-based immunohistochemical analysis was used to investigate the expression patterns of EphB2, EphB3, and EphB4 in 154 bladder cancer specimens. Immunohistochemical staining was conducted examining the extent of stained cells and staining intensity. EphB was considered to be highly expressed when the intensity of staining was more than moderate in >25% of cells in the tissue section. Small interfering RNA (siRNA) was used to knock down EphB expression in bladder cancer cell lines (T24, 5637) to determine the effects of EphB on tumor cell invasion, proliferation, and migration.

RESULTS

EphB receptors (B2, B3, and B4) were detected in 40.9% (EphB2, 63/154), 71.4% (EphB3, 110/154), and 53.2% (EphB4, 82/154) of bladder cancer specimens. Low expression of EphB2, B3, and B4 receptors were significantly associated with higher tumor grade (EphB2, p<0.001; EphB3, p=0.032; EphB4, p<0.001) and muscular invasion (EphB2, p=0.002; EphB3, p=0.009; EphB4, p<0.001). No obvious correlation was observed with other clinicopathological variables, such as age, sex, recurrence, lymph node involvement, metastasis, and overall survival. Inactivation of EphB receptors by siRNA transfection increased cell viability, tumor cell invasion, proliferation, and migration in comparison with untransfected cancer cells.

CONCLUSION

Low expression of EphB receptors (B2, B3, and B4) can be a predictive marker for muscular invasion of bladder cancer.

The Value of EphB2 Receptor and Cognate Ephrin Ligands in Prognostic and Predictive Assessments of Human Breast Cancer

Cell–cell communication proteins Eph and ephrin constitute the largest family of receptor tyrosine kinases (RTKs). They are distinguished by the fact that both receptors and ligands are membrane-bound, and both can drive intracellular signaling in their respective cells. Ever since these RTKs have been found to be involved in cancer development, strategies to target them therapeutically have been actively pursued. However, before this goal can be rationally achieved, the contributions of either Eph receptors or their ephrin ligands to cancer development and progression should be scrutinized in depth. To assess the clinical pertinence of this concern, we performed a systematic review and meta-analysis of the prognostic/predictive value of EphB2 and its multiple cognate ephrin ligands in breast cancer. We found that EphB2 has prognostic value, as indicated by the association of higher EphB2 expression levels with lower distant metastasis-free survival (DMFS), and the association of lower EphB2 expression levels with poorer relapse-free survival (RFS). We also found that higher EphB2 expression could be a prognostic factor for distant metastasis, specifically in the luminal subtypes of breast cancer. EFNB2 showed a marked correlation between higher expression levels and shorter DMFS. EFNA5 or EFNB1 overexpression is correlated with longer RFS. Increased EFNB1 expression is correlated with longer OS in lymph node (LN)-negative patients and the luminal B subtype. Higher levels of EFNB2 or EFNA5 are significantly correlated with shorter RFS, regardless of LN status. However, while this correlation with shorter RFS is true for EFNB2 in all subtypes except basal, it is also true for EFNA5 in all subtypes except HER2+. The analysis also points to possible predictive value for EphB2. In systemically treated patients who have undergone either endocrine therapy or chemotherapy, we found that higher expression of EphB2 is correlated with better rates of RFS. Bearing in mind the limitations inherent to any mRNA-based profiling method, we complemented our analysis with an immunohistochemical assessment of expression levels of both the EphB2 receptor and cognate ephrin ligands. We found that the latter are significantly more expressed in cancers than in normal tissues, and even more so in invasive and metastatic samples than in ductal carcinoma in situ (DCIS). Finally, in an in vitro cellular model of breast cancer progression, based on H-Ras-transformation of the MCF10A benign mammary cell line, we observed dramatic increases in the mRNA expression of EphB2 receptor and EFNB1 and EFNB2 ligands in transformed and invasive cells in comparison with their benign counterparts. Taken together, these data show the clinical validity of a model whereby EphB2, along with its cognate ephrin ligands, have dual anti- and pro-tumor progression effects. In so doing, they reinforce the necessity of further biological investigations into Ephs and ephrins, prior to using them in targeted therapies.

Myosin cables control the timing of tissue internalization in the Drosophila embryo

Compartment boundaries prevent cell mixing during animal development. In the early Drosophila embryo, the mesectoderm is a group of glial precursors that separate ectoderm and mesoderm, forming the ventral midline. Mesectoderm cells undergo one round of oriented divisions during axis elongation and are eventually internalized 6 h later. Using spinning disk confocal microscopy and image analysis, we found that after dividing, mesectoderm cells reversed their planar polarity. The polarity factor Bazooka was redistributed to mesectoderm-mesectoderm cell interfaces, and the molecular motor non-muscle Myosin II and its upstream activator Rho-kinase (Rok) accumulated at mesectoderm-ectoderm (ME) interfaces, forming supracellular cables flanking the mesectoderm on either side of the tissue. Laser ablation revealed the presence of increased tension at ME cables, where Myosin was stabilized, as shown by fluorescence recovery after photobleaching. We used laser nanosurgery to reduce tension at the ME boundary, and we found that Myosin fluorescence decreased rapidly, suggesting a role for tension in ME boundary maintenance. Mathematical modelling predicted that increased tension at the ME boundary was necessary to prevent the premature establishment of contacts between the two ectodermal sheets on opposite sides of the mesectoderm, thus controlling the timing of mesectoderm internalization. We validated the model in vivo: Myosin inhibition disrupted the linearity of the ME boundary and resulted in early internalization of the mesectoderm. Our results suggest that the redistribution of Rok polarizes Myosin and Bazooka within the mesectoderm to establish tissue boundaries, and that ME boundaries control the timely internalization of the mesectoderm as embryos develop.

Muscarinic receptor M3 contributes to intestinal stem cell maintenance via EphB/ephrin-B signaling

Acetylcholine (ACh) signaling through activation of nicotinic and muscarinic ACh receptors regulates expression of specific genes that mediate and sustain proliferation, differentiation, and homeostasis in the intestinal crypts. This signaling plays a pivotal role in the regulation of intestinal stem cell function, but the details have not been clarified. Here, we performed experiments using type 3 muscarinic acetylcholine receptor (M3) knockout mice and their intestinal organoids and report that endogenous ACh affects the size of the intestinal stem niche via M3 signaling. RNA sequencing of crypts identified up-regulation of the EphB/ephrin-B signaling pathway. Furthermore, using an MEK inhibitor (U0126), we found that mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling, which is downstream of EphB/ephrin-B signaling, is activated in M3-deficient crypts. Collectively, M3, EphB/ephrin-B, and the MAPK/ERK signaling cascade work together to maintain the homeostasis of intestinal epithelial cell growth and differentiation following modifications of the cholinergic intestinal niche.

Barcoded viral tracing of single-cell interactions in central nervous system inflammation

Cell-cell interactions control the physiology and pathology of the central nervous system (CNS). To study astrocyte cell interactions in vivo, we developed rabies barcode interaction detection followed by sequencing (RABID-seq), which combines barcoded viral tracing and single-cell RNA sequencing (scRNA-seq). Using RABID-seq, we identified axon guidance molecules as candidate mediators of microglia-astrocyte interactions that promote CNS pathology in experimental autoimmune encephalomyelitis (EAE) and, potentially, multiple sclerosis (MS). In vivo cell-specific genetic perturbation EAE studies, in vitro systems, and the analysis of MS scRNA-seq datasets and CNS tissue established that Sema4D and Ephrin-B3 expressed in microglia control astrocyte responses via PlexinB2 and EphB3, respectively. Furthermore, a CNS-penetrant EphB3 inhibitor suppressed astrocyte and microglia proinflammatory responses and ameliorated EAE. In summary, RABID-seq identified microglia-astrocyte interactions and candidate therapeutic targets.

The Multifaced Role of STAT3 in Cancer and Its Implication for Anticancer Therapy

Signal transducer and activator of transcription (STAT) 3 is one of the most complex regulators of transcription. Constitutive activation of STAT3 has been reported in many types of tumors and depends on mechanisms such as hyperactivation of receptors for pro-oncogenic cytokines and growth factors, loss of negative regulation, and excessive cytokine stimulation. In contrast, somatic STAT3 mutations are less frequent in cancer. Several oncogenic targets of STAT3 have been recently identified such as c-myc, c-Jun, PLK-1, Pim1/2, Bcl-2, VEGF, bFGF, and Cten, and inhibitors of STAT3 have been developed for cancer prevention and treatment. However, despite the oncogenic role of STAT3 having been widely demonstrated, an increasing amount of data indicate that STAT3 functions are multifaced and not easy to classify. In fact, the specific cellular role of STAT3 seems to be determined by the integration of multiple signals, by the oncogenic environment, and by the alternative splicing into two distinct isoforms, STAT3α and STAT3β. On the basis of these different conditions, STAT3 can act both as a potent tumor promoter or tumor suppressor factor. This implies that the therapies based on STAT3 modulators should be performed considering the pleiotropic functions of this transcription factor and tailored to the specific tumor type.

The Role of the Eph Receptor Family in Tumorigenesis

Simple Summary

The Eph receptor family is implicated in both tumour promotion and suppression, depending on the tissue-specific context of available receptor interactions with ligands, adaptor proteins and triggered downstream signalling pathways. This complex interplay has not only consequences for tumorigenesis but also offers a basis from which new cancer-targeting strategies can be developed. This review comprehensively summarises the current knowledge of Eph receptor implications in oncogenesis in a tissue- and receptor-specific manner, with the aim to develop a better understanding of Eph signalling pathways for potential targeting in novel cancer therapies.

Abstract

The Eph receptor tyrosine kinase family, activated by binding to their cognate ephrin ligands, are important components of signalling pathways involved in animal development. More recently, they have received significant interest due to their involvement in oncogenesis. In most cases, their expression is altered, affecting the likes of cell proliferation and migration. Depending on the context, Eph receptors have the potential to act as both tumour promoters and suppressors in a number of cancers, such as breast cancer, colorectal cancer, lung cancer, prostate cancer, brain cancer and Kaposi’s sarcoma (KS), the latter being intrinsically linked to EphA2 as this is the receptor used for endothelial cell entry by the Kaposi’s sarcoma-associated herpesvirus (KSHV). In addition, EphA2 deregulation is associated with KS, indicating that it has a dual role in this case. Associations between EphA2 sequence variation and KSHV infection/KS progression have been detected, but further work is required to formally establish the links between EphA2 signalling and KS oncogenesis. This review consolidates the available literature of the role of the Eph receptor family, and particularly EphA2, in tumorigenesis, with the aim to develop a better understanding of Eph signalling pathways for potential targeting in novel cancer therapies.

Expression profile of intestinal stem cell and cancer stem cell markers in gastric cancers with submucosal invasion

Cancer stem cells (CSCs) are believed to be responsible for tumor growth, invasion, and metastasis. Submucosal invasion, which greatly enhances metastasis risk, is a critical step in gastric cancer (GC) progression. To identify stem cell-related markers associated with submucosal invasion and lymph node (LN) metastasis in GCs, we investigated the expression of candidate CSC markers (CD133, CD44, and ALDH1A) and intestinal stem cell (ISC) markers (EPHB2, OLFM4, and LGR5) in early GCs that manifested submucosal invasion. We discovered that EPHB2 and LGR5 expression was frequently confined to the basal area of the lamina propria (basal pattern) in mucosal cancer, and the proportion of stem cell marker-positive cells substantially increased during submucosal invasion. CD44 expression showed a focal pattern, ALDH1A was predominantly expressed diffusely, and there was no expansion of CD44 or ALDH1A expression in the submucosal cancer cells. Unexpectedly, no CSC markers showed any associations with LN metastasis, and only loss of EPHB2 expression was associated with increased LN metastasis. Treatment of RSPO2, a niche factor, along with Wnt 3a, to GC cells led to increased EPHB2 and LGR5 mRNA levels. RNA in situ hybridization confirmed specific RSPO2 expression in the smooth muscle cells of the muscularis mucosa, suggesting that RSPO2 is responsible for the increased expression of ISC markers in GC cells at the basal areas. In summary, no stem cell markers were associated with increased LN metastasis in early GCs. Conversely, isolated EPHB2 expression was associated with lower LN metastasis. EPHB2 and LGR5 showed a basal distribution pattern along with enhanced expression in submucosal invading cells in early GCs, which was induced by a niche factor, RSPO2, from the muscularis mucosa.

Emerging Role and Therapeutic Potential of lncRNAs in Colorectal Cancer

Maintenance of the intestinal epithelium is dependent on the control of stem cell (SC) proliferation and differentiation. The fine regulation of these cellular processes requires a complex dynamic interplay between several signaling pathways, including Wnt, Notch, Hippo, EGF, Ephrin, and BMP/TGF-β. During the initiation and progression of colorectal cancer (CRC), key events, such as oncogenic mutations, influence these signaling pathways, and tilt the homeostatic balance towards proliferation and dedifferentiation. Therapeutic strategies to specifically target these deregulated signaling pathways are of particular interest. However, systemic blocking or activation of these pathways poses major risks for normal stem cell function and tissue homeostasis. Interestingly, long non-coding RNAs (lncRNAs) have recently emerged as potent regulators of key cellular processes often deregulated in cancer. Because of their exceptional tissue and tumor specificity, these regulatory RNAs represent attractive targets for cancer therapy. Here, we discuss how lncRNAs participate in the maintenance of intestinal homeostasis and how they can contribute to the deregulation of each signaling pathway in CRC. Finally, we describe currently available molecular tools to develop lncRNA-targeted cancer therapies.

RNF186 regulates EFNB1 (ephrin B1)-EPHB2-induced autophagy in the colonic epithelial cells for the maintenance of intestinal homeostasis

Although genome-wide association studies have identified the gene RNF186 encoding an E3 ubiquitin-protein ligase as conferring susceptibility to ulcerative colitis, the exact function of this protein remains unclear. In the present study, we demonstrate an important role for RNF186 in macroautophagy/autophagy activation in colonic epithelial cells and intestinal homeostasis. Mechanistically, RNF186 acts as an E3 ubiquitin-protein ligase for EPHB2 and regulates the ubiquitination of EPHB2. Upon stimulation by ligand EFNB1 (ephrin B1), EPHB2 is ubiquitinated by RNF186 at Lys892, and further recruits MAP1LC3B for autophagy. Compared to control mice, rnf186^-/- and ephb2^-/- mice have a more severe phenotype in the DSS-induced colitis model, which is due to a defect in autophagy in colon epithelial cells. More importantly, treatment with ephrin-B1-Fc recombinant protein effectively relieves DSS-induced mouse colitis, which suggests that ephrin-B1-Fc may be a potential therapy for human inflammatory bowel diseases.Abbreviations: ACTB: actin beta; ATG5: autophagy related 5; ATG16L1: autophagy related 16 like 1; ATP: adenosine triphosphate; Cas9: CRISPR associated protein 9; CD: Crohn disease; CQ: chloroquine; Csf2: colony stimulating factor 2; Cxcl1: c-x-c motif chemokine ligand 1; DMSO: dimethyl sulfoxide; DSS: dextran sodium sulfate; EFNB1: ephrin B1; EPHB2: EPH receptor B2; EPHB3: EPH receptor B3; EPHB2^K788R: lysine 788 mutated to arginine in EPHB2; EPHB2^K892R: lysine 892 mutated to arginine in EPHB2; ER: endoplasmic reticulum; FITC: fluorescein isothiocyanate; GFP: green fluorescent protein; GWAS: genome-wide association studies; HRP: horseradish peroxidase; HSPA5/BiP: heat shock protein family A (Hsp70) member 5; IBD: inflammatory bowel diseases; Il1b: interleukin 1 beta; Il6: interleukin 6; IRGM:immunity related GTPase M; i.p.: intraperitoneally; IPP: inorganic pyrophosphatase; KD: knockdown; KO: knockout; MAP1LC3B: microtubule associated protein 1 light chain 3 beta; MTOR: mechanistic target of rapamycin kinase; NOD2: nucleotide binding oligomerization domain containing 2; PI3K: phosphoinositide 3-kinase; PtdIns3K: class III phosphatidylinositol 3-kinase; RNF186: ring finger protein 186; RNF186^A64T: alanine 64 mutated to threonine in RNF186; RNF186^R179X: arginine 179 mutated to X in RNF186; RPS6: ribosomal protein S6; Tnf: tumor necrosis factor; SQSTM1: sequestosome 1; Ub: ubiquitin; UBE2D2: ubiquitin conjugating enzyme E2 D2; UBE2H: ubiquitin conjugating enzyme E2 H; UBE2K: ubiquitin conjugating enzyme E2 K; UBE2N: ubiquitin conjugating enzyme E2 N; UC: ulcerative colitis; ULK1:unc-51 like autophagy activating kinase 1; WT: wild type.

Imatinib: a new chemopreventive option in adenomatous polyposis?

Patients with adenomatous polyposis, usually defined as patients with >10 adenomatous polyps in the colorectum, are at increased risk for colorectal cancer (CRC). Since surgical and endoscopic treatment do not completely eliminate the potential for future polyps or extraintestinal neoplasms, there is an unmet medical need to identify pharmacological agents to delay major surgical interventions. We present two cases of patients with adenomatous polyposis who developed chronic myelogenous leukaemia and were treated with imatinib as part of their chemotherapy. A sustained regression of the colonic polyps documented in both cases was observed after the initiation of the tyrosine kinase inhibitor. Despite the presence of potential confounders, we hypothesise the potential role of imatinib as a chemopreventive agent in patients with familial adenomatous polyposis.

APC and AXIN2 Are Promising Biomarker Candidates for the Early Detection of Adenomas and Hyperplastic Polyps

Aberrant activation of the WNT/CTNNB1 pathway is notorious in colorectal cancer (CRC). Here, we demonstrate that the expression of specific and crucial WNT signaling pathway genes is linked to disease progression in colonic adenomatous (AP) and hyperplastic (HP) polyps in an Iranian patient population. Thus, we highlight potential gene expression profiles as candidate novel biomarkers for the early detection of CRC. From a 12-month study (2016-2017), 44 biopsy samples were collected during colonoscopy from the patients with colorectal polyps and 10 healthy subjects for normalization. Clinical and demographic data were collected in all cases, and mRNA expression of APC, CTNNB1, CDH1, AXIN1, and AXIN2 genes was investigated using real-time polymerase chain reaction (PCR). CTNNB1 and CDH1 expression levels were unaltered in AP and HP subjects, whereas mRNA expression of APC was decreased in AP contrasted with HP subjects, with a significant association between APC downregulation and polyp size. Although AXIN1 showed no changes between AP and HP groups, a significant association between AXIN1 and dysplasia grade was found. Also, significant upregulation of AXIN2 in both AP and HP subjects was detected. In summary, we have shown increased expression of AXIN2 and decreased expression of APC correlating with grade of dysplasia and polyp size. Hence, AXIN2 and APC should be explored as biomarker candidates for early detection of AP and HP polyps in CRC.

mTOR Signaling Combined with Cancer Stem Cell Markers as a Survival Predictor in Stage II Colorectal Cancer

PURPOSE

Wnt and mammalian target of rapamycin (mTOR) are major molecular signaling pathways associated with the development and progression of tumor, as well as the maintenance and proliferation of cancer stem cells (CSCs), in colorectal cancer (CRC). Identifying patients at risk of poor prognosis is important to determining whether to add adjuvant treatment in stage II CRC and thus improve survival. In the present study, we evaluated the prognostic value of Wnt, mTOR, and CSC markers as survival predictors in stage II CRC.

MATERIALS AND METHODS

We identified 148 cases of stage II CRC and acquired their tumor tissue. Tissue microarrays for immunohistochemical staining were constructed, and the expressions of CD166, CD44, EphB2, β-catenin, pS6 were evaluated using immunohistochemical staining.

RESULTS

The expressions of CD166 (p=0.045) and pS6 (p=0.045) and co-expression of pS6/CD166 (p=0.005), pS6/CD44 (p=0.042), and pS6/CD44/CD166 (p=0.013) were negatively correlated with cancer-specific survival. Cox proportional hazard analysis showed the combination of CD166/pS6 [hazard ratio, 9.42; 95% confidence interval, 2.36-37.59; p=0.002] to be the most significant predictor related with decreased cancer-specific survival. In addition, co-expression of CD44/CD166 (p=0.017), CD166/β-catenin (p=0.036), CD44/β-catenin (p=0.001), and CD44/CD166/β-catenin (p=0.001) were significant factors associated with liver metastasis.

CONCLUSION

Specific combinations of CSC markers and β-catenin/mTOR signaling could be a significant predictor of poor survival in stage II CRC.

TAGAP instructs Th17 differentiation by bridging Dectin activation to EPHB2 signaling in innate antifungal response

The TAGAP gene locus has been linked to several infectious diseases or autoimmune diseases, including candidemia and multiple sclerosis. While previous studies have described a role of TAGAP in T cells, much less is known about its function in other cell types. Here we report that TAGAP is required for Dectin-induced anti-fungal signaling and proinflammatory cytokine production in myeloid cells. Following stimulation with Dectin ligands, TAGAP is phosphorylated by EPHB2 at tyrosine 310, which bridges proximal Dectin-induced EPHB2 activity to downstream CARD9-mediated signaling pathways. During Candida albicans infection, mice lacking TAGAP mount defective immune responses, impaired Th17 cell differentiation, and higher fungal burden. Similarly, in experimental autoimmune encephalomyelitis model of multiple sclerosis, TAGAP deficient mice develop significantly attenuated disease. In summary, we report that TAGAP plays an important role in linking Dectin-induced signaling to the promotion of effective T helper cell immune responses, during both anti-fungal host defense and autoimmunity.

TAGAP gene variants are linked to human autoimmunity. Here the authors identify TAGAP as a Dectin-1 and EphB2-binding protein mediating antifungal innate immune signaling and cytokine production, and demonstrate TAGAP in non-T cells promotes Th17 response in mouse models of infection and autoimmunity.

Evaluation of the Anti-Tumor Activity of Small Molecules Targeting Eph/Ephrins in APC min/J Mice

The Eph receptors are the largest receptors tyrosine kinases (RTKs) family in humans and together with ephrin ligands constitute a complex cellular communication system often dysregulated in many tumors. The role of the Eph-ephrin system in colorectal cancer (CRC) has been investigated and different expression of Eph receptors have been associated with tumor development and progression. In light of this evidence, we investigated if a pharmacological approach aimed at inhibiting Eph/ephrin interaction through small molecules could prevent tumor growth in APC ^min/J mice. The 8-week treatment with the Eph-ephrin antagonist UniPR129 significantly reduced the number of adenomas in the ileum and decreased the diameter of adenomas in the same region. Overall our data suggested as UniPR129 could be able to slow down the tumor development in APC ^min/J mice. These results further confirm literature data about Eph kinases as a new valuable target in the intestinal cancer and for the first time showed the feasibility of the Eph-ephrin inhibition as a useful pharmacological approach against the intestinal tumorigenesis. In conclusion this work paves the way for further studies with Eph-ephrin inhibitors in order to confirm the Eph antagonism as innovative pharmacological approach with preventive benefit in the intestinal tumor development.

Expression Profile and Prognostic Significance of EPHB3 in Colorectal Cancer

The protein tyrosine kinase Ephrin type-B receptor 3 (EPHB3) is expressed in cells at the base of intestinal crypts, acting as a cellular guide in the maintenance of intestinal crypt architecture. We aimed to investigate the expression profile of EPHB3 in colorectal precancerous lesions and colorectal cancers (CRCs), and assess its prognostic value. EPHB3 expression was higher in CRCs than in normal mucosa and was associated with the intestinal stem cell markers EPHB2, OLFM4, LRIG1, and a proposed cancer stem cell marker, CD44. Enhanced EPHB3 expression significantly declined during the transformation from adenoma to carcinoma and as the tumor invaded into deeper tissue layers. Namely, a substantial reduction of EPHB3 expression was observed in the budding cancer cells at the invasive tumor fronts, which was more extensive than E-cadherin downregulation. In an azoxymethane/dextran sulfate sodium-induced, colitis-associated, CRC model, EPHB3 expression increased along with tumor development. In a large cohort of CRC patients, EPHB3 positivity was observed in 24% of 610 CRCs and was negatively correlated with tumor differentiation, lympho-vascular invasion, and tumor, node, and metastasis stages. EPHB3 was positively associated with microsatellite instability but was associated with neither CpG island methylation, nor with KRAS and BRAF mutations. Notably, EPHB3 positivity was associated with better clinical outcomes, although it was not an independent prognostic marker. Overexpression of EPHB3 in the colon cancer cell line, DLD1, led to decreased cell growth and migration and reduced mitogen-activated protein kinase signaling. Taken together, our data demonstrate the suppressive role of EPHB3 in CRC progression.

Mouse models of colorectal cancer: Past, present and future perspectives

Colorectal cancer (CRC) is the third most common diagnosed malignancy among both sexes in the United States as well as in the European Union. While the incidence and mortality rates in western, high developed countries are declining, reflecting the success of screening programs and improved treatment regimen, a rise of the overall global CRC burden can be observed due to lifestyle changes paralleling an increasing human development index. Despite a growing insight into the biology of CRC and many therapeutic improvements in the recent decades, preclinical in vivo models are still indispensable for the development of new treatment approaches. Since the development of carcinogen-induced rodent models for CRC more than 80 years ago, a plethora of animal models has been established to study colon cancer biology. Despite tenuous invasiveness and metastatic behavior, these models are useful for chemoprevention studies and to evaluate colitis-related carcinogenesis. Genetically engineered mouse models (GEMM) mirror the pathogenesis of sporadic as well as inherited CRC depending on the specific molecular pathways activated or inhibited. Although the vast majority of CRC GEMM lack invasiveness, metastasis and tumor heterogeneity, they still have proven useful for examination of the tumor microenvironment as well as systemic immune responses; thus, supporting development of new therapeutic avenues. Induction of metastatic disease by orthotopic injection of CRC cell lines is possible, but the so generated models lack genetic diversity and the number of suited cell lines is very limited. Patient-derived xenografts, in contrast, maintain the pathological and molecular characteristics of the individual patient's CRC after subcutaneous implantation into immunodeficient mice and are therefore most reliable for preclinical drug development - even in comparison to GEMM or cell line-based analyses. However, subcutaneous patient-derived xenograft models are less suitable for studying most aspects of the tumor microenvironment and anti-tumoral immune responses. The authors review the distinct mouse models of CRC with an emphasis on their clinical relevance and shed light on the latest developments in the field of preclinical CRC models.

Stem Cell Signaling Pathways in the Small Intestine

The ability of stem cells to divide and differentiate is necessary for tissue repair and homeostasis. Appropriate spatial and temporal mechanisms are needed. Local intercellular signaling increases expression of specific genes that mediate and maintain differentiation. Diffusible signaling molecules provide concentration-dependent induction of specific patterns of cell types or regions. Differentiation of adjacent cells, on the other hand, requires cell–cell contact and subsequent signaling. These two types of signals work together to allow stem cells to provide what organisms require. The ability to grow organoids has increased our understanding of the cellular and molecular features of small “niches” that modulate stem cell function in various organs, including the small intestine.

Expression levels of EPHB4, EFNB2 and caspase-8 are associated with clinicopathological features and progression of esophageal squamous cell cancer

The upregulation of EPH receptor B4 (EPHB4) results in a survival advantage for tumor cells via the inhibition of the casapse-8-mediated apoptotic pathway, which begins from the cell membrane. The present study investigated the expression patterns of EPHB4, ephrin B2 (EFNB2) and caspase-8 in patients with esophageal squamous cell carcinoma (ESCC). The association between the expression patterns and certain clinicopathological characteristics of the patients was also determined. mRNA levels of EPHB4, EFNB2 and caspase-8 in paired primary ESCC samples and adjacent esophageal tissues collected from 96 patients with ESCC were quantified using quantitative PCR. Upregulation of EPHB4 and EFNB2 mRNA expression, and downregulation of caspase-8 mRNA were detected in ESCC samples compared with that in the adjacent esophageal tissues. The expression levels of EPHB4 and EFNB2 were positively correlated with each other, whereas the mRNA levels of both EPHB4 and EFNB2 exhibited a negative correlation with that of caspase-8. The mRNA levels of both EPHB4 and EFNB2 demonstrated a significant positive association with certain clinicopathological features of patients with ESCC, including family history, tumor size, metastasis and stage. Conversely, a negative association was revealed between the expression level of caspase-8 and clinicopathological features of patients with ESCC. Moreover, mRNA expression levels of EPHB4 and EFNB2 were negatively associated with survival times of patients with ESCC, whereas the level of caspase-8 was positively associated with patient outcome. The results from the present study suggested that EPHB4, EFNB2 and caspase-8 may be implicated in the tumorigenesis and progression of ESCC, and that consequently, they may serve as useful prognostic markers, as well as potential therapeutic targets.

Identification of Eph receptor signaling as a regulator of autophagy and a therapeutic target in colorectal carcinoma

Advanced colorectal carcinoma is currently incurable, and new therapies are urgently needed. We report that phosphotyrosine‐dependent Eph receptor signaling sustains colorectal carcinoma cell survival, thereby uncovering a survival pathway active in colorectal carcinoma cells. We find that genetic and biochemical inhibition of Eph tyrosine kinase activity or depletion of the Eph ligand EphrinB2 reproducibly induces colorectal carcinoma cell death by autophagy. Spautin and 3‐methyladenine, inhibitors of early steps in the autophagic pathway, significantly reduce autophagy‐mediated cell death that follows inhibition of phosphotyrosine‐dependent Eph signaling in colorectal cancer cells. A small‐molecule inhibitor of the Eph kinase, NVP‐BHG712 or its regioisomer NVP‐Iso, reduces human colorectal cancer cell growth in vitro and tumor growth in mice. Colorectal cancers express the EphrinB ligand and its Eph receptors at significantly higher levels than numerous other cancer types, supporting Eph signaling inhibition as a potential new strategy for the broad treatment of colorectal carcinoma.

Functional Prediction of Candidate MicroRNAs for CRC Management Using in Silico Approach

Approximately 30–50% of malignant growths can be prevented by avoiding risk factors and implementing evidence-based strategies. Colorectal cancer (CRC) accounted for the second most common cancer and the third most common cause of cancer death worldwide. This cancer subtype can be reduced by early detection and patients’ management. In this study, the functional roles of the identified microRNAs were determined using an in silico pipeline. Five microRNAs identified using an in silico approach alongside their seven target genes from our previous study were used as datasets in this study. Furthermore, the secondary structure and the thermodynamic energies of the microRNAs were revealed by Mfold algorithm. The triplex binding ability of the oligonucleotide with the target promoters were analyzed by Trident. Finally, evolutionary stage-specific somatic events and co-expression analysis of the target genes in CRC were analyzed by SEECancer and GeneMANIA plugin in Cytoscape. Four of the five microRNAs have the potential to form more than one secondary structure. The ranges of the observed/expected ratio of CpG dinucleotides of these genes range from 0.60 to 1.22. Three of the candidate microRNA were capable of forming multiple triplexes along with three of the target mRNAs. Four of the total targets were involved in either early or metastatic stage-specific events while three other genes were either a product of antecedent or subsequent events of the four genes implicated in CRC. The secondary structure of the candidate microRNAs can be used to explain the different degrees of genetic regulation in CRC due to their conformational role to modulate target interaction. Furthermore, due to the regulation of important genes in the CRC pathway and the enrichment of the microRNA with triplex binding sites, they may be a useful diagnostic biomarker for the disease subtype.

Epithelial NOTCH Signaling Rewires the Tumor Microenvironment of Colorectal Cancer to Drive Poor-Prognosis Subtypes and Metastasis

The metastatic process of colorectal cancer (CRC) is not fully understood and effective therapies are lacking. We show that activation of NOTCH1 signaling in the murine intestinal epithelium leads to highly penetrant metastasis (100% metastasis; with >80% liver metastases) in KrasG12D-driven serrated cancer. Transcriptional profiling reveals that epithelial NOTCH1 signaling creates a tumor microenvironment (TME) reminiscent of poorly prognostic human CRC subtypes (CMS4 and CRIS-B), and drives metastasis through transforming growth factor (TGF) β-dependent neutrophil recruitment. Importantly, inhibition of this recruitment with clinically relevant therapeutic agents blocks metastasis. We propose that NOTCH1 signaling is key to CRC progression and should be exploited clinically.

β-Catenin Controls the Electrophysiologic Properties of Skeletal Muscle Cells by Regulating the α2 Isoform of Na+/K+-ATPase

β-Catenin is a key component of the canonical Wnt signaling pathway. It has been shown to have an important role in formation of the neuromuscular junction. Our previous studies showed that in the absence of β-catenin, the resting membrane potential (RMP) is depolarized in muscle cells and expression of the α2 subunit of sodium/potassium adenosine triphosphatase (α2NKA) is reduced. To understand the underlying mechanisms, we investigated the electrophysiologic properties of a primary cell line derived from mouse myoblasts (C2C12 cells) that were transfected with small-interfering RNAs and over-expressed plasmids targeting β-catenin. We found that the RMP was depolarized in β-catenin knocked-down C2C12 cells and was unchanged in β-catenin over-expressed muscle cells. An action potential (AP) was not released by knockdown or over-expression of β-catenin. α2NKA expression was reduced by β-catenin knockdown, and increased by β-catenin over-expression. We showed that β-catenin could interact physically with α2NKA (but not with α1NKA) in muscle cells. NKA activity and α2NKA content in the cell membranes of skeletal muscle cells were modulated positively by β-catenin. These results suggested that β-catenin (at least in part) regulates the RMP and AP in muscle cells, and does so by regulating α2NKA.

Long noncoding RNA SNHG14 facilitates colorectal cancer metastasis through targeting EZH2-regulated EPHA7

Accumulating evidence suggested the participation of long noncoding RNAs (lncRNAs) in regulating various biological processes so as to affecting cancer progression. However, the functional role of most lncRNAs in colorectal carcer (CRC) is still largely covered. In the present study, we disclosed SNHG14 as a carcinogene in CRC development, as it was low-expressed in normal colon tissues but markedly upregulated in CRC cell lines. Besides, SNHG14 contributed to CRC cell proliferation, motility and EMT in vitro, and inhibition of it confined CRC tumor growth and liver metastasis in vivo. Next, the mechanistic investigations confirmed that SNHG14-promoted CRC progression was mediated by EPHA7, which was negatively regulated by SNHG14 in CRC via an EZH2-dependent way. Importantly, EZH2 was proved as a transcription factor of EPHA7 and functioned as a repressor in EPHA7 transcription by enhancing methylation on EPHA7 promoter. Meanwhile, SNHG14 increased EZH2 expression in CRC via stabilizing its mRNA by interacting with FUS, and via freeing its mRNA from miR-186-5p-induced silence. All in all, our observations demonstrated that SNHG14 serves as a facilitator in CRC through targeting EZH2-repressed EPHA7 by enhancing EZH2 via recruiting FUS and absorbing miR-186-5p, indicating a promising new road for CRC diagnosis and treatment.