Research IndicatorsGraph generated 28 February 2015 using data from PubMed using criteria.
Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic. Tag cloud generated 28 February, 2015 using data from PubMed, MeSH and CancerIndex
Specific Cancers (4)
Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.
Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).
OMIM, Johns Hopkin University
Referenced article focusing on the relationship between phenotype and genotype.
International Cancer Genome Consortium.
Summary of gene and mutations by cancer type from ICGC
Cancer Genome Anatomy Project, NCI
COSMIC, Sanger Institute
Somatic mutation information and related details
Search the Epigenomics database and view relevant gene tracks of samples.
Latest Publications: EPHB2 (cancer-related)
Although our knowledge of the biology of brain tumors has increased tremendously over the past decade, progress in treatment of these deadly diseases remains modest. Developing in vivo models that faithfully mirror human diseases is essential for the validation of new therapeutic approaches. Genetically engineered mouse models (GEMMs) provide elaborate temporally and genetically controlled systems to investigate the cellular origins of brain tumors and gene function in tumorigenesis. Furthermore, they can prove to be valuable tools for testing targeted therapies. In this review, we discuss GEMMs of brain tumors, focusing on gliomas and medulloblastomas. We describe how they provide critical insights into the molecular and cellular events involved in the initiation and maintenance of brain tumors, and illustrate their use in preclinical drug testing.
Rettew AN, Getty PJ, Greenfield EMReceptor tyrosine kinases in osteosarcoma: not just the usual suspects.
Adv Exp Med Biol. 2014; 804:47-66 [PubMed
] Related Publications
Despite aggressive surgical and chemotherapy protocols, survival rates for osteosarcoma patients have not improved over the last 30 years. Therefore, novel therapeutic agents are needed. Receptor tyrosine kinases have emerged as targets for the development of new cancer therapies since their activation leads to enhanced proliferation, survival, and metastasis. In fact, aberrant expression and activation of RTKs have been associated with the progression of many cancers. Studies from our lab using phosphoproteomic screening identified RTKs that are activated and thus may contribute to the signaling within metastatic human osteosarcoma cells. Functional genomic screening using siRNA was performed to distinguish which of the activated RTKs contribute to in vitro phenotypes associated with metastatic potential (motility, invasion, colony formation, and cell growth). The resulting RTK hits were then validated using independent validation experiments. From these results, we identified four RTKs (Axl, EphB2, FGFR2, and Ret) that have not been previously studied in osteosarcoma and provide targets for the development of novel therapeutics.
Jägle S, Rönsch K, Timme S, et al.Silencing of the EPHB3 tumor-suppressor gene in human colorectal cancer through decommissioning of a transcriptional enhancer.
Proc Natl Acad Sci U S A. 2014; 111(13):4886-91 [PubMed
] Free Access to Full Article Related Publications
The protein tyrosine kinase Ephrin type-B receptor 3 (EPHB3) counteracts tumor-cell dissemination by regulating intercellular adhesion and repulsion and acts as tumor/invasion suppressor in colorectal cancer. This protective mechanism frequently collapses at the adenoma-carcinoma transition due to EPHB3 transcriptional silencing. Here, we identify a transcriptional enhancer at the EPHB3 gene that integrates input from the intestinal stem-cell regulator achaete-scute family basic helix-loop-helix transcription factor 2 (ASCL2), Wnt/β-catenin, MAP kinase, and Notch signaling. EPHB3 enhancer activity is highly variable in colorectal carcinoma cells and precisely reflects EPHB3 expression states, suggesting that enhancer dysfunction underlies EPHB3 silencing. Interestingly, low Notch activity parallels reduced EPHB3 expression in colorectal carcinoma cell lines and poorly differentiated tumor-tissue specimens. Restoring Notch activity reestablished enhancer function and EPHB3 expression. Although essential for intestinal stem-cell maintenance and adenoma formation, Notch activity seems dispensable in colorectal carcinomas. Notch activation even promoted growth arrest and apoptosis of colorectal carcinoma cells, attenuated their self-renewal capacity in vitro, and blocked tumor growth in vivo. Higher levels of Notch activity also correlated with longer disease-free survival of colorectal cancer patients. In summary, our results uncover enhancer decommissioning as a mechanism for transcriptional silencing of the EPHB3 tumor suppressor and argue for an antitumorigenic function of Notch signaling in advanced colorectal cancer.
Morimoto T, Mitomi H, Saito T, et al.Distinct profile of HIF1α, PTCH, EphB2, or DNA repair protein expression and BRAF mutation in colorectal serrated adenoma.
J Gastroenterol Hepatol. 2014; 29(6):1192-9 [PubMed
] Related Publications
BACKGROUND AND AIMS: The serrated colorectal carcinoma (CRC) as proposed to arise from serrated adenoma (SA) is characterized by upregulation of HIF1α, suppression of PTCH or EphB2, loss of DNA repair proteins, and BRAF mutation. The aim of this study was to evaluate alterations of these candidates involved in the serrated pathway in colorectal polyps.
METHODS: We analyzed immunoreactivity of these proteins, methylation of PTCH and EphB2, and mutation of BRAF and Kras in sessile SAs (SSAs; n = 32), traditional SAs (n = 28), hyperplastic polyps (HPs; n = 24), and conventional adenomas (ADs; n = 21).
RESULTS: Increase of nuclear HIF1α expression was more frequent in SA than HP, but less frequent in SA than AD (P < 0.001). Increase of PTCH expression was not found in SSA or HP, but was evident in about half of traditional SA and all AD (P < 0.001). Decrease of EphB2 expression was more prominent in SA than HP or AD (P ≤ 0.005). Loss of hMLH1 and MGMT expression were most frequent in SSA (P < 0.001). Loss of hMSH2 showed more pronounced in SA and HP than AD (P ≤ 0.004). Methylations of PTCH and EphB2 were rare in all categories. BRAF mutation harbored frequently in SA, but not AD; only AD harbored Kras mutation.
CONCLUSIONS: This work provides evidence of similarity of HIF1α, EphB2 or DNA repair proteins expression, and BRAF mutation in serrated CRCs and their precursors, especially SSA, compared with AD and HP.
Gao Q, Liu W, Cai J, et al.EphB2 promotes cervical cancer progression by inducing epithelial-mesenchymal transition.
Hum Pathol. 2014; 45(2):372-81 [PubMed
] Related Publications
EphB2, a receptor tyrosine kinase for ephrin ligands, is overexpressed in various cancers and plays an important role in tumor progression. However, the expression and functions of EphB2 in cervical cancer remain unknown. In this study, we performed immunohistochemistry in clinical cervical specimens and found that EphB2 was overexpressed in the cervical cancer specimens, and its expression correlated with cancer progression. The percentage of EphB2-positive cells increased gradually from 28% in the normal cervix to 40% in high-grade squamous intraepithelial lesions, and ultimately to 69.8% in squamous cell carcinomas (P < .05). We overexpressed EphB2 in HeLa cells and silenced EphB2 in cervical cancer (C33A) cells, which expressed low and high levels of EphB2, respectively. Exogenous EphB2 promoted cell migration, invasion, and an epithelial-mesenchymal transition (EMT) signature, which is a complex process that occurs during organogenesis and cancer metastasis, whereas EphB2 silencing had the opposite effect (P < .05). Furthermore, HeLa cells with exogenous EphB2 exhibited a stem cell-like state that promoted tumorsphere formation in vitro and exhibited tumorigenesis potential in vivo (P < .05), whereas EphB2 silencing in C33A cells inhibited these stem cell properties (P < .05). In addition, we investigated the intracellular signaling pathways in cervical cancer and found that R-Ras expression correlated positively with EphB2 in clinical samples, and its activity was regulated by EphB2 in cervical cancer. These findings demonstrate that EphB2 plays an important role in cervical cancer progression by orchestrating an EMT program through R-Ras activation.
Targeted therapeutic approaches have seen tremendous advances in the last decade, for good reason. Specifically intervening with a disease-causing gene can revert the deleterious phenotype while eliminating the toxicity often associated with broad-spectrum agents. Unfortunately, because these selective agents hit one target in a single location, acquired resistance is often high. An arguably better treatment approach includes coupling multiple targeted agents or using an agent that hits an individual target in several independent locations and/or alters multiple relevant targets in the disease-causing pathway(s), precisely the approach taken by Nishimura and colleagues in their recent report aimed at identifying a better treatment option for ovarian cancer.
Aberrant regulation of the Wnt/β-catenin pathway has an important role during the onset and progression of colorectal cancer, with over 90% of cases of sporadic colon cancer featuring mutations in APC or β-catenin. However, it has remained a point of controversy whether these mutations are sufficient to activate the pathway or require additional upstream signals. Here we show that colorectal tumours express elevated levels of Wnt3 and Evi/Wls/GPR177. We found that in colon cancer cells, even in the presence of mutations in APC or β-catenin, downstream signalling remains responsive to Wnt ligands and receptor proximal signalling. Furthermore, we demonstrate that truncated APC proteins bind β-catenin and key components of the destruction complex. These results indicate that cells with mutations in APC or β-catenin depend on Wnt ligands and their secretion for a sufficient level of β-catenin signalling, which potentially opens new avenues for therapeutic interventions by targeting Wnt secretion via Evi/Wls.
Increased microRNA-10b (miR-10b) expression in the cancer cells in pancreatic ductal adenocarcinoma (PDAC) is a marker of disease aggressiveness. In the present study, we determined that plasma miR-10b levels are significantly increased in PDAC patients by comparison with normal controls. By gene profiling, we identified potential targets downregulated by miR-10b, including Tat-interacting protein 30 (TIP30). Immunoblotting and luciferase reporter assays confirmed that TIP30 was a direct miR-10b target. Downregulation of TIP30 by miR-10b or siRNA-mediated silencing of TIP30 enhanced epidermal growth factor (EGF)-dependent invasion. The actions of miR-10b were abrogated by expressing a modified TIP30 cDNA resistant to miR-10b. EGF-induced EGF receptor (EGFR) tyrosine phosphorylation and extracellular signal-regulated kinase phosphorylation were enhanced by miR-10b, and these effects were mimicked by TIP30 silencing. The actions of EGF in the presence of miR-10b were blocked by EGFR kinase inhibition with erlotinib and by dual inhibition of PI3K (phosphatidylinositol 3'-kinase) and MEK. Moreover, miR-10b, EGF and transforming growth factor-beta (TGF-β) combined to markedly increase cell invasion, and this effect was blocked by the combination of erlotinib and SB505124, a type I TGF-β receptor inhibitor. miR-10b also enhanced the stimulatory effects of EGF and TGF-β on cell migration and epithelial-mesenchymal transition (EMT) and decreased the expression of RAP2A, EPHB2, KLF4 and NF1. Moreover, miR-10b overexpression accelerated pancreatic cancer cell (PCC) proliferation and tumor growth in an orthotopic model. Thus, plasma miR-10b levels may serve as a diagnostic marker in PDAC, whereas intra-tumoral miR-10b promotes PCC proliferation and invasion by suppressing TIP30, which enhances EGFR signaling, facilitates EGF-TGF-β cross-talk and enhances the expression of EMT-promoting genes, whereas decreasing the expression of several metastasis-suppressing genes. Therefore, therapeutic targeting of miR-10b in PDAC may interrupt growth-promoting deleterious EGF-TGF-β interactions and antagonize the metastatic process at various levels.
UNLABELLED: Development of improved RNA interference-based strategies is of utmost clinical importance. Although siRNA-mediated silencing of EphA2, an ovarian cancer oncogene, results in reduction of tumor growth, we present evidence that additional inhibition of EphA2 by a microRNA (miRNA) further "boosts" its antitumor effects. We identified miR-520d-3p as a tumor suppressor upstream of EphA2, whose expression correlated with favorable outcomes in two independent patient cohorts comprising 647 patients. Restoration of miR-520d-3p prominently decreased EphA2 protein levels, and suppressed tumor growth and migration/invasion both in vitro and in vivo. Dual inhibition of EphA2 in vivo using 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) nanoliposomes loaded with miR-520d-3p and EphA2 siRNA showed synergistic antitumor efficiency and greater therapeutic efficacy than either monotherapy alone. This synergy is at least in part due to miR-520d-3p targeting EphB2, another Eph receptor. Our data emphasize the feasibility of combined miRNA-siRNA therapy, and will have broad implications for innovative gene silencing therapies for cancer and other diseases.
SIGNIFICANCE: This study addresses a new concept of RNA inhibition therapy by combining miRNA and siRNA in nanoliposomal particles to target oncogenic pathways altered in ovarian cancer. Combined targeting of the Eph pathway using EphA2-targeting siRNA and the tumor suppressor miR-520d-3p exhibits remarkable therapeutic synergy and enhanced tumor suppression in vitro and in vivo compared with either monotherapy alone.
Lin L, Chen X, Peng X, et al.MicroRNA-128 promotes cell-cell adhesion in U87 glioma cells via regulation of EphB2.
Oncol Rep. 2013; 30(3):1239-48 [PubMed
] Related Publications
MicroRNAs (miRNAs) are small, non-coding RNAs which regulate gene expression at the post-transcriptional level. Abnormal expression of miRNAs occurs frequently in human tumors. Despite the fact that reduced expression of miR-128 has been observed in glioma tissues and cells, the role of miR-128 in tumors has not been fully characterized. In the present study, cell adhesion assays indicated that overexpression of miR-128 can promote cell-cell adhesion. Target site prediction algorithms indicated that miR-128 binds the 3'-untranslated regions of erythropoietin-producing hepatocellular receptor (Eph)B1 and EphB2 mRNAs. Luciferase reporter assays confirmed that miR-128 binds and regulates EphB1 and EphB2 mRNAs. Overexpression of EphB2 reduced the ability of miR-128 to promote cell-cell adhesion. The wound-healing assay indicated that miR-128 significantly inhibited cell migration via EphB2. This study revealed the novel functions of miR-128 in cell-cell adhesion and cell migration in glioma cells through the regulation of EphB2, and identified EphB1 and EphB2 as novel miR-128 targets.
Chen Q, Chen L, Zhao R, et al.Microarray analyses reveal liver metastasis-related genes in metastatic colorectal cancer cell model.
J Cancer Res Clin Oncol. 2013; 139(7):1169-78 [PubMed
] Related Publications
PURPOSE: To study the molecular mechanisms of colorectal cancer liver metastasis.
METHODS: Cecal wall implantation was performed in nude mice to subclone a highly liver metastatic human colorectal cancer clone (SW1116-M) from SW1116. In vivo and in vitro assays were adopted to confirm the proliferation and metastasis potential. The human tumor metastasis PCR microarrays were used to analyze the differential gene expressions. The results were confirmed further by real-time quantitative PCR.
RESULTS: SW1116-M and SW1116-S5, two human colon cancer cell clones with different metastatic potential, were subcloned from SW1116. In SW1116-M, in vitro invasion, migration and in vivo metastatic potential were higher, and in vitro proliferation rate was lower than SW1116-S5. In tumor metastasis PCR microarray, 24 genes related to cell invading, adhesion, cellular growth and differentiation were found with a twofold difference between SW1116-S5 and SW1116-M. Sixteen of these, including E-cadherins, MTSS1, TRAIL and TRPM1, were up-regulated; eight genes including cathepsin L, EphB2, HGF, MET, MCAM and RORβ were down-regulated.
CONCLUSIONS: We have established a highly liver metastatic clone. The subsequent metastasis PCR microarray analysis identified a procedure of cellular differentiation and mesenchymal to epithelial transition (MET) in liver metastasis. The colonization to from macrometastasis is not a switch from cell cycle arrest but a result of cell differentiation and MET.
Molinský J, Klánová M, Maswabi B, et al.In vivo growth of mantle cell lymphoma xenografts in immunodeficient mice is positively regulated by VEGF and associated with significant up-regulation of CD31/PECAM1.
Folia Biol (Praha). 2013; 59(1):26-31 [PubMed
] Related Publications
Mantle cell lymphoma (MCL) is an aggressive lymphoma subtype with dismal prognosis. New treatments are needed to improve outcome of relapsed/ refractory disease. Recently, several drugs targeting at least partially the process of angiogenesis have been successfully tested in the therapy of MCL. Molecular mechanisms that regulate MCL-induced angiogenesis and that might represent potential new druggable targets remain, however, incompletely understood. We established two mouse models of human MCL by subcutaneous xenotransplantation of JEKO-1 and HBL-2 cell lines into immunodeficient mice. Histological analyses of xenografts confirmed their neovascularization. The growth of xenografts was significantly suppressed by single-agent therapy with bevacizumab, monoclonal antibody targeting vascular endothelial growth factor (VEGF). Subsequently, we analysed expression of 94 angiogenesis related genes in ex vivo isolated JEKO-1 and HBL-2 cells compared to in vitro growing cells using TaqMan low-density arrays. The most up-regulated genes in both JEKO-1 and HBL-2 xenografts were genes encoding platelet/endothelial cell-adhesion molecule (CD31/PECAM1), VEGF receptor 1 (FLT1), hepatocyte growth factor (HGF), angiogenin (ANG) and transcription factor PROX1. The most downregulated genes in both JEKO-1 and HBL-2 xenografts were midkine (MDK) and ephrine B2 (EPHB2). In summary, our results demonstrate an important role of angiogenesis in the biology of MCL and provide preclinical evidence of potent anti-MCL activity of bevacizumab. In addition, gene expression profiling of 94 angiogenesis-related targets revealed several in vivo up-regulated and down-regulated transcripts. The most differentially expressed target in both MCL tumours was CD31/PECAM1. Whether any of these molecules might represent a potential druggable target in MCL patients remains to be elucidated.
Phenotypic similarities have long been recognized between subpopulations of glioma and neural stem cells. Many of these similar properties, including the robust abilities to self-renew, migrate, and invade, are hallmarks of glioma cells that render them extremely aggressive. However, the molecular mechanisms underlying this character, particularly in glioma stem-like cells that drive this disease, remain poorly understood. Here, we report the results of a differential miRNA expression screen that compared glioma and neural stem cells, where we found that miR-204 was markedly downregulated in both types of cells. Mechanistic investigations revealed that miR-204 simultaneously suppressed self-renewal, stem cell-associated phenotype, and migration of glioma cells by targeting the stemness-governing transcriptional factor SOX4 and the migration-promoting receptor EphB2. Restoring miR-204 expression in glioma cells suppressed tumorigenesis and invasiveness in vivo and increased overall host survival. Further evaluation revealed that the miR-204 promoter was hypermethylated and that attenuating promoter methylation was sufficient to upregulate miR-204 in glioma cells. Together, our findings reveal miR-204 as a pivotal regulator of the development of stem cell-like phenotypes and cell motility in malignant glioma cells.
BACKGROUND: Biological entities do not perform in isolation, and often, it is the nature and degree of interactions among numerous biological entities which ultimately determines any final outcome. Hence, experimental data on any single biological entity can be of limited value when considered only in isolation. To address this, we propose that augmenting individual entity data with the literature will not only better define the entity's own significance but also uncover relationships with novel biological entities.To test this notion, we developed a comprehensive text mining and computational methodology that focused on discovering new targets of one class of molecular entities, transcription factors (TF), within one particular disease, colorectal cancer (CRC).
METHODS: We used 39 molecular entities known to be associated with CRC along with six colorectal cancer terms as the bait list, or list of search terms, for mining the biomedical literature to identify CRC-specific genes and proteins. Using the literature-mined data, we constructed a global TF interaction network for CRC. We then developed a multi-level, multi-parametric methodology to identify TFs to CRC.
RESULTS: The small bait list, when augmented with literature-mined data, identified a large number of biological entities associated with CRC. The relative importance of these TF and their associated modules was identified using functional and topological features. Additional validation of these highly-ranked TF using the literature strengthened our findings. Some of the novel TF that we identified were: SLUG, RUNX1, IRF1, HIF1A, ATF-2, ABL1, ELK-1 and GATA-1. Some of these TFs are associated with functional modules in known pathways of CRC, including the Beta-catenin/development, immune response, transcription, and DNA damage pathways.
CONCLUSIONS: Our methodology of using text mining data and a multi-level, multi-parameter scoring technique was able to identify both known and novel TF that have roles in CRC. Starting with just one TF (SMAD3) in the bait list, the literature mining process identified an additional 116 CRC-associated TFs. Our network-based analysis showed that these TFs all belonged to any of 13 major functional groups that are known to play important roles in CRC. Among these identified TFs, we obtained a novel six-node module consisting of ATF2-P53-JNK1-ELK1-EPHB2-HIF1A, from which the novel JNK1-ELK1 association could potentially be a significant marker for CRC.
Eph/ephrin signaling has been implicated in various types of key cancer-enhancing processes, like migration, proliferation, and angiogenesis. In medulloblastoma, invading tumor cells characteristically lead to early recurrence and a decreased prognosis. Based on kinase-activity profiling data published recently, we hypothesized a key role for the Eph/ephrin signaling system in medulloblastoma invasion. In primary medulloblastoma samples, a significantly higher expression of EphB2 and the ligand ephrin-B1 was observed compared with normal cerebellum. Furthermore, medulloblastoma cell lines showed high expression of EphA2, EphB2, and EphB4. Stimulation of medulloblastoma cells with ephrin-B1 resulted in a marked decrease in in vitro cell adhesion and an increase in the invasion capacity of cells expressing high levels of EphB2. The cell lines that showed an ephrin-B1-induced phenotype possessed increased levels of phosphorylated EphB2 and, to a lesser extent, EphB4 after stimulation. Knockdown of EphB2 expression by short hairpin RNA completely abolished ephrin ligand-induced effects on adhesion and migration. Analysis of signal transduction identified p38, Erk, and mTOR as downstream signaling mediators potentially inducing the ephrin-B1 phenotype. In conclusion, the observed deregulation of Eph/ephrin expression in medulloblastoma enhances the invasive phenotype, suggesting a potential role in local tumor cell invasion and the formation of metastases.
Motaln H, Gruden K, Hren M, et al.Human mesenchymal stem cells exploit the immune response mediating chemokines to impact the phenotype of glioblastoma.
Cell Transplant. 2012; 21(7):1529-45 [PubMed
] Related Publications
In contrast to the application of human mesenchymal stem cells (hMSCs) in regenerative medicine, only a limited number of studies are addressing their use in anticancer therapy. As the latter may represent a new hope to improve the survival of patients with glioblastoma multiformae (GBM), the most common and malignant form of the brain tumors, we aimed to investigate the interactions of hMSCs and GBM cells under in vitro conditions. Four hMSC clones and three different GBM cell lines were used to study their mutual paracrine interactions in cocultures compared to their monocultures, where cells were grown under the same experimental conditions. The effects on cell growth, proliferation, and invasion in Matrigel were quantified. Further, bioinformatics tools were used to relate these results to the data obtained from cytokine macroarrays and cDNA microarrays that revealed proteins and genes significantly involved in cellular cross-talk. We showed that hMSCs are responsible for the impairment of GBM cell invasion and growth, possibly via induction of their senescence. On the other hand, GBM cells inversely affected some of these characteristics in hMSCs. We found CCL2/MCP-1 to be the most significantly regulated chemokine during hMSC and U87-MG paracrine signaling in addition to several chemokines that may account for changed cocultured cells' phenotype by affecting genes associated with proliferation (Pmepa-1, NF-κB, IL-6, IL-1b), invasion (EphB2, Sod2, Pcdh18, Col7A1, Gja1, Mmp1/2), and senescence (Kiaa1199, SerpinB2). As we functionally confirmed the role of CCL2/MCP-1 in GBM cell invasion we thereby propose a novel mechanism of CCL2/MCP-1 antimigratory effects on GBM cells, distinct from its immunomodulatory role. Significant alterations of GBM phenotype in the presence of hMSCs should encourage the studies on the naive hMSC use for GBM treatment.
We discovered that miR-27b controls 2 critical vascular functions: it turns the angiogenic switch on by promoting endothelial tip cell fate and sprouting and it promotes venous differentiation. We have identified its targets, a Notch ligand Delta-like ligand 4 (Dll4) and Sprouty homologue 2 (Spry2). miR-27b knockdown in zebrafish and mouse tissues severely impaired vessel sprouting and filopodia formation. Moreover, miR-27b was necessary for the formation of the first embryonic vein in fish and controlled the expression of arterial and venous markers in human endothelium, including Ephrin B2 (EphB2), EphB4, FMS-related tyrosine kinase 1 (Flt1), and Flt4. In zebrafish, Dll4 inhibition caused increased sprouting and longer intersegmental vessels and exacerbated tip cell migration. Blocking Spry2 caused premature vessel branching. In contrast, Spry2 overexpression eliminated the tip cell branching in the intersegmental vessels. Blockade of Dll4 and Spry2 disrupted arterial specification and augmented the expression of venous markers. Blocking either Spry2 or Dll4 rescued the miR-27b knockdown phenotype in zebrafish and in mouse vascular explants, pointing to essential roles of these targets downstream of miR-27b. Our study identifies critical role of miR-27b in the control of endothelial tip cell fate, branching, and venous specification and determines Spry2 and Dll4 as its essential targets.
Adjakly M, Bosviel R, Rabiau N, et al.DNA methylation and soy phytoestrogens: quantitative study in DU-145 and PC-3 human prostate cancer cell lines.
Epigenomics. 2011; 3(6):795-803 [PubMed
] Related Publications
AIM: DNA hypermethylation is an epigenetic mechanism which induces silencing of tumor-suppressor genes in prostate cancer. Many studies have reported that specific components of food plants like soy phytoestrogens may have protective effects against prostate carcinogenesis or progression. Genistein and daidzein, the major phytoestrogens, have been reported to have the ability to reverse DNA hypermethylation in cancer cell lines. The aim of this study was to investigate the potential demethylating effects of these two soy compounds on BRCA1, GSTP1, EPHB2 and BRCA2 promoter genes.
METHODS & MATERIALS: Prostate cell lines DU-145 and PC-3 were treated with genistein 40 µM, daidzein 110 µM, budesonide (methylating agent) 2 µM and 5-azacytidine (demethylating agent) 2 µM. In these two human prostate cancer cell lines we performed methylation quantification by using Methyl Profiler DNA methylation analysis. This technique is based on a methylation-specific digestion followed by quantitative PCR. We analyzed the corresponding protein expression by western blotting.
RESULTS: Soy phytoestrogens induced a demethylation of all promoter regions studied except for BRCA2, which is not methylated in control cell lines. An increase in their protein expression was also demonstrated by western blot analysis and corroborated the potential demethylating effect of soy phytoestrogens.
CONCLUSION: This study showed that the soy phytoestrogens, genistein and daidzein, induce a decrease of methylation of BRCA1, GSTP1 and EPHB2 promoters. Therefore, soy phytoestrogens may have a protective effect on prostate cancer. However, more studies are needed in order to understand the mechanism by which genistein and daidzein have an inhibiting action on DNA methylation.
Herath NI, Spanevello MD, Doecke JD, et al.Complex expression patterns of Eph receptor tyrosine kinases and their ephrin ligands in colorectal carcinogenesis.
Eur J Cancer. 2012; 48(5):753-62 [PubMed
] Related Publications
Aberrant expression of Eph and ephrin proteins in human cancers is extensively documented. However, data are frequently limited to one gene and therefore incomplete and in some instances conflicting. We analysed expression of all Eph and ephrin genes in colorectal cancer (CRC) cell lines and 153 clinical specimens, providing for the first time a comprehensive analysis of this system in CRC. Eph/ephrin mRNA expression was assessed by quantitative real-time PCR and correlated with protein expression (flow cytometry, Western blotting and immunocytochemistry). These data show that EphA1, EphA2, EphB2 and EphB4 were significantly over expressed in CRC. In all cases, at least one Eph gene was found in normal colon (EphA1, EphA2, EphB2, EphB4), where expression was observed at high levels in most CRCs. However, other Eph gene expression was lost in individual CRCs compared to the corresponding normal, EphA7 being a striking example. Loss of expression was more common in advanced disease and thus correlated with poor survival. This is consistent with the redundant functionality of Eph receptors, such that expression of a single Eph gene is sufficient for effector function. Overall, the data suggest a progressive loss of expression of individual Eph genes suggesting that individual CRCs need to be phenotyped to determine which Eph genes are highly expressed. Targeted therapies could then be selected from a group of specific antibodies, such as those developed for EphA1.
Fox BP, Kandpal RPA paradigm shift in EPH receptor interaction: biological relevance of EPHB6 interaction with EPHA2 and EPHB2 in breast carcinoma cell lines.
Cancer Genomics Proteomics. 2011 Jul-Aug; 8(4):185-93 [PubMed
] Related Publications
EPH receptors are the largest known family of receptor tyrosine kinases characterized in humans. These proteins are involved in axon guidance, tissue organization, synaptic plasticity, vascular development and the progression of various diseases including cancer. The varied biological effects of EPH receptors are mediated in part by the expression of these proteins and their intracellular binding proteins. The ability of EPH molecules to form heterodimers within their own class has been suggested, although not exhaustively characterized. We have clarified this phenomenon by showing that EPHB6, a kinase-deficient receptor, can interact with EPHB2 in mammalian cells, and more significantly EPHB6 interacts with EPHA2. However, EPHB6 does not interact with another kinase-deficient receptor, EPHA10. The interaction between EPHB6 and EPHA2 is the first demonstration of an A-type receptor interacting with a B-type receptor. Furthermore, we correlated relative expression of EPHB6, EPHB2 and EPHA2 with non-invasive and invasive phenotypes of breast tumor cell lines. Our results indicate that tumor invasiveness-suppressing activity of EPHB6 is mediated by its ability to sequester other kinase-sufficient and oncogenic EPH receptors. These observations suggest that cellular phenotypes may, in part, be attributed to a combinatorial expression of EPH receptors and heteromeric interactions among the same class, as well as between two classes, of EPH receptors. Our results also suggest that EPHA10 may transduce signals by interacting with other kinase-sufficient receptors in a similar manner.
Zlobec I, Bihl M, Foerster A, et al.Comprehensive analysis of CpG island methylator phenotype (CIMP)-high, -low, and -negative colorectal cancers based on protein marker expression and molecular features.
J Pathol. 2011; 225(3):336-43 [PubMed
] Related Publications
CpG island methylator phenotype (CIMP) is being investigated for its role in the molecular and prognostic classification of colorectal cancer patients but is also emerging as a factor with the potential to influence clinical decision-making. We report a comprehensive analysis of clinico-pathological and molecular features (KRAS, BRAF and microsatellite instability, MSI) as well as of selected tumour- and host-related protein markers characterizing CIMP-high (CIMP-H), -low, and -negative colorectal cancers. Immunohistochemical analysis for 48 protein markers and molecular analysis of CIMP (CIMP-H: ≥ 4/5 methylated genes), MSI (MSI-H: ≥ 2 instable genes), KRAS, and BRAF were performed on 337 colorectal cancers. Simple and multiple regression analysis and receiver operating characteristic (ROC) curve analysis were performed. CIMP-H was found in 24 cases (7.1%) and linked (p < 0.0001) to more proximal tumour location, BRAF mutation, MSI-H, MGMT methylation (p = 0.022), advanced pT classification (p = 0.03), mucinous histology (p = 0.069), and less frequent KRAS mutation (p = 0.067) compared to CIMP-low or -negative cases. Of the 48 protein markers, decreased levels of RKIP (p = 0.0056), EphB2 (p = 0.0045), CK20 (p = 0.002), and Cdx2 (p < 0.0001) and increased numbers of CD8+ intra-epithelial lymphocytes (p < 0.0001) were related to CIMP-H, independently of MSI status. In addition to the expected clinico-pathological and molecular associations, CIMP-H colorectal cancers are characterized by a loss of protein markers associated with differentiation, and metastasis suppression, and have increased CD8+ T-lymphocytes regardless of MSI status. In particular, Cdx2 loss seems to strongly predict CIMP-H in both microsatellite-stable (MSS) and MSI-H colorectal cancers. Cdx2 is proposed as a surrogate marker for CIMP-H.
Wang D, Peregrina K, Dhima E, et al.Paneth cell marker expression in intestinal villi and colon crypts characterizes dietary induced risk for mouse sporadic intestinal cancer.
Proc Natl Acad Sci U S A. 2011; 108(25):10272-7 [PubMed
] Free Access to Full Article Related Publications
Nutritional and genetic risk factors for intestinal tumors are additive on mouse tumor phenotype, establishing that diet and genetic factors impact risk by distinct combinatorial mechanisms. In a mouse model of dietary-induced sporadic small and large intestinal cancer in WT mice in which tumor etiology, lag, incidence, and frequency reflect >90% of intestinal cancer in Western societies, dietary-induced risk altered gene expression profiles predominantly in villus cells of the histologically normal mucosa, in contrast to targeting of crypt cells by inheritance of an Apc(1638N) allele or homozygous inactivation of p21(Waf1/cip1), and profiles induced by each risk factor were distinct at the gene or functional group level. The dietary-induced changes in villus cells encompassed ectopic expression of Paneth cell markers (a lineage normally confined to the bottom of small intestinal crypts), elevated expression of the Wnt receptor Fzd5 and of EphB2 (genes necessary for Paneth cell differentiation and localization to the crypt bottom), and increased Wnt signaling in villus cells. Ectopic elevation of these markers was also present in the colon crypts, which are also sites of sporadic tumors in the nutritional model. Elevating dietary vitamin D(3) and calcium, which prevents tumor development, abrogated these changes in the villus and colon cells. Thus, common intestinal cancer driven by diet involves mechanisms of tumor development distinct from those mechanisms that cause tumors induced by the rare inheritance of a mutant adenomatous polyposis coli (Apc) allele. This is fundamental for understanding how common sporadic tumors arise and in evaluating relative risk in the population.
The EphB2 gene has been implicated as a tumor suppressor gene somatically altered in both prostate cancer (PC) and colorectal cancer. We have previously shown an association between an EphB2 germline nonsense variant and risk of familial prostate cancer among African American Men (AAM). Here we set out to test the hypothesis that common variation within the EphB2 locus is associated with increased risk of sporadic PC in AAM. We genotyped a set of 341 single nucleotide polymorphisms (SNPs) encompassing the EphB2 locus, including known and novel coding and noncoding variants, in 490 AA sporadic PC cases and 567 matched controls. Single marker-based logistical regression analyses revealed seven EphB2 SNPs showing statistically significant association with prostate cancer risk in our population. The most significant association was achieved for a novel synonymous coding SNP, TGen-624, (Odds Ratio (OR) = 0.22; 95% Confidence Interval (CI) 0.08-0.66, p = 1×10(-5)). Two other SNPs also show significant associations toward a protective effect rs10465543 and rs12090415 (p = 1×10(-4)), OR = 0.49 and 0.7, respectively. Two additional SNPs revealed trends towards an increase in risk of prostate cancer, rs4612601 and rs4263970 (p = 0.001), OR = 1.35 and 1.31, respectively. Furthermore, haplotype analysis revealed low levels of linkage disequilibrium within the region, with two blocks being associated with prostate cancer risk among our population. These data suggest that genetic variation at the EphB2 locus may increase risk of sporadic PC among AAM.
Therapies directed against receptor tyrosine kinases are effective in many cancer subtypes, including lung and breast cancer. We used a phosphoproteomic platform to identify active receptor tyrosine kinases that might represent therapeutic targets in a panel of 25 melanoma cell strains. We detected activated receptors including TYRO3, AXL, MERTK, EPHB2, MET, IGF1R, EGFR, KIT, HER3, and HER4. Statistical analysis of receptor tyrosine kinase activation as well as ligand and receptor expression indicates that some receptors, such as FGFR3, may be activated via autocrine circuits. Short hairpin RNA knockdown targeting three of the active kinases identified in the screen, AXL, HER3, and IGF1R, inhibited the proliferation of melanoma cells and knockdown of active AXL also reduced melanoma cell migration. The changes in cellular phenotype observed on AXL knockdown seem to be modulated via the STAT3 signaling pathway, whereas the IGF1R-dependent alterations seem to be regulated by the AKT signaling pathway. Ultimately, this study identifies several novel targets for therapeutic intervention in melanoma.
Tanabe H, Kuribayashi K, Tsuji N, et al.Sesamin induces autophagy in colon cancer cells by reducing tyrosine phosphorylation of EphA1 and EphB2.
Int J Oncol. 2011; 39(1):33-40 [PubMed
] Related Publications
Receptor tyrosine kinase EphB2 and autophagic machinery are known as tumor suppressors; however, the connection remains to be elucidated. Here, we show the link between EphB2 and autophagy. Sesamin, a major lignan in sesame oil, induced autophagy in the human colon cancer cell lines HT29 and LS180, as shown by electron microscopy, as well as Western blotting and immunofluorescence imaging using an anti-LC3 antibody. Receptor tyrosine kinase array analysis revealed that sesamin treatment increased the levels of unphosphorylated -EphA1 and -EphB2 in HT29 cells. Silencing of EphA1 and EphB2 blocked sesamin-induced autophagy as well as sesamin-induced loss of cell viability. These results show that EphA1 and EphB2 play a critical role in this process. The present study reveals a novel function for EphA1 and EphB2 in the induction of autophagy, suggesting a tumor suppressor role for these proteins in colorectal cancer.
Merlos-Suárez A, Barriga FM, Jung P, et al.The intestinal stem cell signature identifies colorectal cancer stem cells and predicts disease relapse.
Cell Stem Cell. 2011; 8(5):511-24 [PubMed
] Related Publications
A frequent complication in colorectal cancer (CRC) is regeneration of the tumor after therapy. Here, we report that a gene signature specific for adult intestinal stem cells (ISCs) predicts disease relapse in CRC patients. ISCs are marked by high expression of the EphB2 receptor, which becomes gradually silenced as cells differentiate. Using EphB2 and the ISC marker Lgr5, we have FACS-purified and profiled mouse ISCs, crypt proliferative progenitors, and late transient amplifying cells to define a gene program specific for normal ISCs. Furthermore, we discovered that ISC-specific genes identify a stem-like cell population positioned at the bottom of tumor structures reminiscent of crypts. EphB2 sorted ISC-like tumor cells display robust tumor-initiating capacity in immunodeficient mice as well as long-term self-renewal potential. Taken together, our data suggest that the ISC program defines a cancer stem cell niche within colorectal tumors and plays a central role in CRC relapse.
Rönsch K, Jäger M, Schöpflin A, et al.Class I and III HDACs and loss of active chromatin features contribute to epigenetic silencing of CDX1 and EPHB tumor suppressor genes in colorectal cancer.
Epigenetics. 2011; 6(5):610-22 [PubMed
] Related Publications
Aberrant Wnt/β-catenin signaling is a driving force during initiation and progression of colorectal cancer. Yet, the Wnt/β-catenin targets CDX1, EPHB2, EPHB3 and EPHB4 (EPHB2-4) act as tumor suppressors in intestinal epithelial cells and frequently appear to be transcriptionally silenced in carcinomas. The molecular mechanisms which underlie the apparent loss of expression of a subset of Wnt/β-catenin targets in a background of persistent pathway activity are largely unknown. To gain insight into this, we quantified expression of CDX1 and EPHB2-4 in human tissue specimens of case-matched colorectal normal mucosa, adenoma and invasive carcinoma. In particular EPHB2-4 display biphasic, albeit not strictly coincident, expression profiles with elevated levels in adenomas and decreased transcription in approximately 30% of the corresponding carcinomas. Consistent with their divergent and variable expression we observed considerable heterogeneity among the epigenetic landscapes at CDX1 and EPHB2-4 in a model of colorectal carcinoma cell lines. Unlike the inactive CDX1 locus, EPHB2-4 maintain DNA hypomethylation of their promoter regions in the silent state. A strong reduction of active histone modifications consistently parallels reduced expression of CDX1 and EPHB3 and to some extent of EPHB2. Accordingly, treatment with inhibitors for DNA methyltransferases (DNMTs) and histone deacetylases (HDACs) restored CDX1 and EPHB2-4 expression depending upon epigenetic features at their promoters but also upon cellular background. Overall our findings show that downregulation of CDX1 and EphB receptor genes occurs independently and that different branches of epigenetic control systems including class I and III HDACs contribute to epigenetic silencing of Wnt/β-catenin targets during colorectal tumorigenesis.
Chetcuti A, Aktas S, Mackie N, et al.Expression profiling reveals MSX1 and EphB2 expression correlates with the invasion capacity of Wilms tumors.
Pediatr Blood Cancer. 2011; 57(6):950-7 [PubMed
] Related Publications
BACKGROUND: Wilms tumor is the most common pediatric renal malignancy, but the parameters that are important to its invasion capacity are poorly understood. The aim of this study was to identify new proteins associated with the invasion capacity of Wilms tumor.
PROCEDURE: Gene expression profiles for 15 primary Wilms tumor samples were determined by Affymetrix Genechip® Human Genome Ul33A microarray analysis. The gene expression profiles for selected genes was further confirmed by quantitative RT-PCR analysis. Immunohistochemical analysis was performed on 25 Wilms tumor cases to confirm expression for Bcl2A1, EphB2, MSX1, and RIN1.
RESULTS: Using microarray analysis 14 genes showed differential expression (P < 0.05) comparing stage 1 non-invasive Wilms tumor to stages 2-4 invasive Wilms tumor. The differential expression for Bcl2A1, EphB2, MSX1, and RIN1 was confirmed by quantitative RT-PCR. MSX1 protein was statistically significantly lower in stages 2-4 invasive Wilms tumor cases compared to stage 1 non-invasive cases (P = 0.013). EphB2 protein was higher in stages 2-4 Wilms tumor cases compared to stage 1 cases (P = 0.006). There was no statistically significant difference between stages 1 and 2-4 Wilms tumor for Bcl2A1 (P = 0.230) or RIN1 (P = 0.969) at the protein level.
CONCLUSION: Our results indicate that MSX1 may be associated with the invasion capacity of Wilms tumors. RIN1 is a downstream effector of RAS and Bcl2A1 functions as an anti-apoptotic protein. EphB2 is an ephrin receptor and is up-regulated in invasive tumors but its role needs to be confirmed in further cases of Wilms tumors.
Hua YQ, Ouyang HQ, Chen Z, et al.Promoted cancer growth by stimulating cell proliferation and decreasing apoptosis using a lentivirus-based EphB2 RNAi in pancreatic carcinoma CFPAC-1 cells.
Biomed Pharmacother. 2011; 65(2):123-31 [PubMed
] Related Publications
Several studies have reported the change of EphB2 in a variety of carcinomas and suggested a functional relation between EphB2 and tumor progression. However, its role in human pancreatic carcinoma has not been described. The aim of this study was to evaluate the significance of EphB2 in human pancreatic carcinoma CFPAC-1 cells. A lentivirus-based RNA interference (RNAi) vector was designed, synthesized and transfected into CFPAC-1 cells to inhibit EphB2 expression. WST-8 based Colorimetric Assay Cell Counting kit 8 (CCK-8) in vitro and xenograft transplantation model in nude mice was used to evaluate cell proliferation and growth respectively. Cell-cycle and apoptosis were analyzed by flow cytometry (FCM). RT-PCR and Western blot were used to assess mRNA expression and protein levels. EphB2 expression was significantly suppressed both in mRNA and protein levels using the lentivirus-based EphB2 RNAi in CFPAC-1 cells (P<0.01, P<0.01). Silencing EphB2 stimulated cell growth in vitro (P<0.05) and proliferation in vivo (P<0.01) versus Control RNAi. EphB2 RNAi significantly increased S phase cells from 18.15 to 27.18% (P<0.05), and significantly decreased G1 phase cells from 72.93 to 57.61% compared with Control RNAi (P<0.05). In addition, decreased apoptosis was observed in CFPAC-1 EphB2 RNAi cells compared with Control RNAi cells (P<0.01). The apoptosis rate was 1.63% and 7.44%, respectively. Silencing EphB2 increased CyclinD1, cyclindependent kinase 6 (CDK6) and Bcl-2 expression in both mRNA and protein levels compared with Control RNAi. A lentivirus-based EphB2 RNAi efficiently inhibited EphB2 gene and its protein expression. Silencing EphB2 stimulated pancreatic carcinoma growth by increasing cell proliferation through G1/S phase breakthrough, which relied on a CyclinD1/CDK6 cell-cycle regulated signal. Similarly, EphB2 inhibition also reduced CFPAC-1 cells apoptosis by up-regulating Bcl-2 expression. Thus, at least in the context of pancreatic carcinoma CFPAC-1 cells, EphB2 plays a tumor suppressor role in cell proliferation and apoptosis.
Vidaurreta M, Rafael S, Veganzones S, et al.Influence of A9 region mutation in EphB2 gene in the prognosis of patients with colorectal adenocarcinoma.
Ann Surg Oncol. 2011; 18(5):1501-5 [PubMed
] Related Publications
BACKGROUND: EphB2 is a transmembrane glycoprotein implicated in the regulation of cell growth, differentiation, and motility. It has been proposed as a tumor suppressor gene, and the role of EphB2 protein in tumorogenesis has been demonstrated. The aim of this study was to test the influence of mutation of A9 region in EphB2 gene in the prognosis of patients with sporadic CCR.
MATERIALS AND METHODS: A total of 473 patients with colorectal cancer were included. A9 region in exon 17 of EphB2 was amplified using specific primer and analyzed using Genescan. All mutations were confirmed by direct sequencing.
RESULTS: EphB2 mutation was detected in 13 of the 473 patients (2.7%). Mutation of EphB2 showed association with tumor site, 12 of 13 mutations were proximal tumors (P < 0.001). EphB2 mutation confers better prognosis in the adenocarcinoma group; 100% of patients carrying the mutation survived and were disease free after 72 months (P = 0.02 and 0.03, respectively).
CONCLUSIONS: Despite the low frequency of EphB2 gene, we got promising results. It would be very interesting to increase the population size to verify our results. If these findings are confirmed, EphB2 could help discriminate patients with adenocarcinoma with different prognosis and to improve the election of the most suitable treatment in each case.