Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

EphA2 is a member of the Eph family of receptor tyrosine kinases, which interact with cell-bound ligands known as ephrins. EphA2 expression was investigated by immunohistochemistry with an anti-EphA2 monoclonal antibody in 80 patients with esophageal squamous cell carcinoma (ESCC) who had undergone surgery. EphA2 overexpression was positive in 40 of the 80 patients (50%). A significant correlation was observed between EphA2 expression and regional lymph node metastasis (p=0.023), number of lymph node metastases (p=0.011) and poor degree of tumor differentiation (p=0.004). The survival rates of EphA2-positive patients were poorer than those of EphA2-negative patients (p=0.014). The 5-year survival rate of patients without EphA2 overexpression was 68%, whereas that of patients with EphA2 overexpression was 29%. EphA2 expression was also investigated in 7 ESCC cell lines (TE-1, -2, -8, -13, -15, TT and TTn) and 1 immortalized human esophageal keratinocyte cell line (CHEK-1). Western blotting revealed different levels of EphA2 expression in the 8 cell lines. EphA2 was expressed at a high level in the ESCC cell lines compared to CHEK-1. EphA2 phosphorylation was demonstrated in all cell lines. Northern blot analysis showed that EphA2 mRNA expression in TE-1 was greater than that in the other ESCC cell lines. The observation of small gaps on Western blot analysis of the ESCC cell lines suggests that there may be a mechanism for EphA2 regulation at the point of translation. In conclusion, EphA2 overexpression appears to be related to poor degree of tumor differentiation and lymph node metastasis in ESCC. Consequently, patients with EphA2 overexpression have a poorer prognosis than those without. EphA2 is a potential target to prevent ESCC cells spreading into the lymphatic drainage.
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PMID:EphA2 overexpression correlates with poor prognosis in esophageal squamous cell carcinoma. 1249 75

Cancer is a disease of aberrant signal transduction. The expression and function of intracellular signaling pathways are frequently subverted as cells progress towards a metastatic phenotype. In particular, tyrosine kinases initiate powerful signals that govern many different aspects of cell behavior. In Recent studies have demonstrated that the EphA2 receptor tyrosine kinase is frequently overexpressed and functionally altered in aggressive tumor cells, and that these changes promote metastatic character. Herein, we provide an overview of our current understanding of EphA2, with emphasis upon the differential regulation of EphA2 expression and function. We also show that differential EphA2 expression and function may provide a unique opportunity for selective therapeutic targeting of EphA2 in metastatic disease.
Clin Exp Metastasis 2003
PMID:Overexpression and functional alterations of the EphA2 tyrosine kinase in cancer. 1265 Jun 8

We have evaluated CD8+ and CD4+ T-cell responses against a new tumor-associated antigen, the receptor tyrosine kinase EphA2, which is broadly expressed in diverse cancer histologies and is frequently overexpressed in advanced stage/metastatic disease. We report herein that EphA2 is overexpressed in renal cell carcinoma (RCC) cell lines and clinical specimens of RCC, and find that the highest levels of EphA2 are consistently found in the most advanced stages of the disease. We identified and synthesized five putative HLA class I-binding and three class II-binding peptides derived from EphA2 that might serve as targets for immune reactivity. Each peptide induced specific, tumor-reactive CD8+ or CD4+T-cell responses as measured using IFN-gamma enzyme-linked immunospot assays. The EphA2 peptides elicited relatively weak responses from CD8+ T cells derived from normal healthy volunteers or from RCC patients with active disease. In marked contrast, immune reactivity to EphA2-derived epitopes was greatly enhanced in CD8+ T cells that had been isolated from patients who were rendered disease-free, after surgery. Furthermore, enzyme-linked immunospot analyses demonstrated prominent EphA2-restricted T-helper 1-type CD4+ T cell activity in patients with early stage disease, whereas T-helper 2-type and T regulatory-type responses predominated in patients with more advanced forms of RCC. These data suggest that the immune system of cancer patients actively monitors EphA2-derived epitopes, and that the magnitude and character of T-cell responses to EphA2 epitopes may convey much-needed predictive information about disease stage and outcome.
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PMID:Disease stage variation in CD4+ and CD8+ T-cell reactivity to the receptor tyrosine kinase EphA2 in patients with renal cell carcinoma. 1290 21

Tumor-associated angiogenesis is critical for tumor growth and metastasis and is controlled by various pro- and antiangiogenic factors. The Eph family of receptor tyrosine kinases has emerged as one of the pivotal regulators of angiogenesis. Here we report that interfering with EphA signaling resulted in a pronounced inhibition of angiogenesis in ex vivo and in vivo model systems. Administration of EphA2/Fc soluble receptors inhibited, in a dose-dependent manner, microvessel formation in rat aortic ring assay, with inhibition reaching 76% at the highest dose of 5000 ng/ml. These results were further confirmed in vivo in a porcine aortic endothelial cell-vascular endothelial growth factor (VEGF)/basic fibroblast growth factor Matrigel plug assay, in which administration of EphA2/Fc soluble receptors resulted in 81% inhibition of neovascularization. The additive effects of simultaneous inhibition of VEGF receptor 2 and EphA signaling pathways in aortic ring assay and antiangiogenic efficacy of EphA2/Fc soluble receptors against VEGF/basic fibroblast growth factor-mediated neovascularization in vivo indicated a critical and nonredundant role for EphA signaling in angiogenesis. Furthermore, in two independent experiments, we demonstrated that EphA2/Fc soluble receptors strongly (by approximately 50% versus controls) suppressed growth of ASPC-1 human pancreatic tumor s.c. xenografts. Inhibition of tumor growth was due to decreased proliferation of tumor cells. In an orthotopic pancreatic ductal adenocarcinoma model in mice, suppression of EphA signaling by i.p. administration of EphA2/Fc (30 micro g/dose, three times a week for 56 days) profoundly inhibited the growth of primary tumors and the development of peritoneal, lymphatic, and hepatic metastases. These data demonstrate a critical role of EphA signaling in tumor growth and metastasis and provide a strong rationale for targeting EphA2 receptors for anticancer therapies.
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PMID:Antiangiogenic and antitumor efficacy of EphA2 receptor antagonist. 1487 20

The aim of this study was to analyse the protein and mRNA expressions of EphA2 and EphrinA-1 in oesophageal squamous cell carcinomas and to explore their clinicopathological associations and predictive values in oesophageal squamous cell carcinoma. Tissue array and immunohistochemistry were used to assess the protein expressions of EphA2 and EphrinA-1 in tumours from 173 patients with oesophageal squamous cell carcinoma. Paraffin sections from 20 cases in which the tumours showed variable EphA2 and EphrinA-1protein expressions were used for laser capture microdissection and processed for RT-PCR detection of EphA2 and EphrinA-1 mRNA. Among the 173 oesophageal squamous cell carcinomas, 33 (19.1%) were negative, 44 (25.4%) weakly-positive, 58 (33.5%) moderately-positive and 38 (22.0%) strongly-positive for EphA2 immunostaining. For EphrinA-1 protein expression, 27 tumours (15.6%) were negative, 41 (23.7%) weakly-positive, 80 (46.2%) moderately-positive and 25 (14.5%) strongly-positive. EphA2 and EphrinA-1 were often co-localized in the same tumour areas and vascular endothelial cells. Variable amounts of EphA2 and EphrinA-1 mRNAs were observed in the 20 tumours analysed. No significant association was observed between EphA2 and EphrinA-1 protein expressions and age, tumour location, tumour size, histological differentiation or clinical stage. However, there was a significant correlation between EphA2 expression and lymph node metastases (p < 0.001). In univariate analysis, high levels of EphA2/EphrinA-1 protein expression, higher number of lymph node metastasis, higher histological grade and clinical stage were significantly associated with shorter overall survival. In Cox multivariate analysis, only EphA2, number of lymph node metastasis and clinical stage were of independent significance. We conclude that EphA2 protein expression is confirmed to be of predictive value for unfavourable survival for oesophageal cancer patients and may be a good target for oesophageal cancer therapy.
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PMID:Predictive value of EphA2 and EphrinA-1 expression in oesophageal squamous cell carcinoma. 1608 May 48

EphA2 is a transmembrane receptor tyrosine kinase that functions in the regulation of cell growth, survival, angiogenesis, and migration and EphA2 targeting has been proposed as a novel therapeutic strategy for neoplasms that overexpress this protein. EphA2 overexpression has been correlated with increased invasive and metastatic ability in pancreatic cancer cell lines. However, the patterns of EphA2 expression in human pancreatic cancers and associated metastases is unknown, as are the genetics of EphA2 in this tumor type. We collected clinicopathologic data and paraffin-embedded materials from 98 patients with primary and/or metastatic pancreatic cancer and performed immunohistochemical labeling for EphA2 protein. EphA2 protein immunolabeling was found in 207 of 219 samples (95%). The expression was predominantly cytoplasmic, although predominant membranous staining was observed in a minority of cases. When evaluated specifically for labeling intensity, primary and metastatic carcinomas were more strongly positive compared to benign ducts and PanIN lesions (P < 0.00001 and P < 0.01, respectively) and poorly differentiated carcinomas were more strongly positive for EphA2 than well and moderately differentiated tumors (P < 0.005). When primary carcinomas without metastatic disease were specifically compared to carcinomas with associated metastatic disease, the advanced carcinomas showed relatively less strong positive labeling for EphA2 (P < 0.008). Moreover, decreased EphA2 labeling was more commonly found in liver (P < 0.002), lung (P < 0.004) or peritoneal metastases (P < 0.01) as compared to distant lymph node metastases (P < 0.01). Genetic sequencing of the tyrosine kinase domain of EPHA2 in 22 samples of xenograft enriched pancreatic cancer did not reveal any inactivating mutations. However, EPHA2 amplification was found in 1 of 33 pancreatic cancers corresponding to a lymph node metastasis, indicating EPHA2 genomic amplification may underlie EphA2 overexpression in a minority of patients. Our data confirms that EphA2 is overexpressed in pancreatic cancer, but suggests a relative loss of EphA2 in co-existent pancreatic cancer metastases as well as a role for EPHA2 in organ specific metastasis.
Clin Exp Metastasis 2006
PMID:Patterns of EphA2 protein expression in primary and metastatic pancreatic carcinoma and correlation with genetic status. 1714 15

Magnetic cobalt spinel ferrite nanoparticles coated with biocompatible polygalacturonic acid were functionalized with ligands specific for targeting expressed EphA2 receptors on ovarian cancer cells. By using such magnetic nanoparticle-peptide conjugates, targeting and extraction of malignant cells were achieved with a magnetic field. Targeting ovarian cancer cells with receptor specific peptide-modified magnetic nanoparticles resulted in cell capture from a flow stream in vitro and from the peritoneal cavity of mice in vivo. Successful removal of metastatic cancer cells from the abdominal cavity and circulation using magnetic nanoparticle conjugates indicate the feasibility of a dialysis-like treatment and may improve long-term survival rates of ovarian cancer patients. This approach can be applied for fighting other cancers, such as leukemia, once the receptors on malignant cells are identified and the efficacy of targeting ligands is established.
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PMID:Magnetic nanoparticle-peptide conjugates for in vitro and in vivo targeting and extraction of cancer cells. 1861 Oct 5

The greatest health threat from malignant melanoma is death due to metastatic disease. Consequently, the identification of markers predictive of metastatic disease is essential for identifying new therapeutic targets. EphA2, a protein tyrosine kinase receptor commonly expressed in epithelial cells, has been found to be overexpressed and constitutively active in melanoma tumor cells having a metastatic phenotype as characterized by increased invasion, proliferation and vasculogenic mimicry (VM). Based on this observation, we hypothesized that increased expression of EphA2 by melanoma tumor cells could promote these characteristics of a metastatic phenotype in addition to promoting tumorigenicity as a whole. We analyzed a panel of human melanoma tumor cell lines derived from patient tissues classified as primary (either radial growth phase or vertical growth phase) and/or metastatic for the expression of EphA2 and found a correlation between increased EphA2 expression and metastatic potential. Experiments using the most metastatic of the human melanoma cell lines demonstrated that downregulation of EphA2 results in a significant decrease in invasion, proliferation, clonogenicity and VM in vitro, in addition to suppressed tumorigenicity in an orthotopic mouse model. Lastly, utilization of a human phospho-kinase array revealed increased phosphorylation of several different protein kinases involved in mediating various aspects of cellular proliferation. To the best of our knowledge these results provide the first direct in vivo evidence demonstrating a role for EphA2 in promoting melanoma tumorigenicity and suggest EphA2 as a significant molecular target for the therapeutic intervention of malignant melanoma.
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PMID:EphA2 as a promoter of melanoma tumorigenicity. 1922 60

Eph tyrosine kinases instruct cell for a repulsive behavior, regulating cell shape, adhesion, and motility. Beside its role during embryogenesis, neurogenesis, and angiogenesis, EphA2 kinase is frequently up-regulated in tumor cells of different histotypes, including prostate, breast, colon, and lung carcinoma, as well as melanoma. Although a function in both tumor onset and metastasis has been proposed, the role played by EphA2 is still debated. Here, we showed that EphA2 reexpression in B16 murine melanoma cells, which use a defined mesenchymal invasion strategy, converts their migration style from mesenchymal to amoeboid-like, conferring a plasticity in tumor cell invasiveness. Indeed, in response to reexpression and activation of EphA2, melanoma cells activate a nonproteolytic invasive program that proceeds through the activation of cytoskeleton motility, the retraction of cell protrusions, a Rho-mediated rounding of the cell body, and squeezing among three-dimensional matrix, giving rise to successful lung and peritoneal lymph node metastases. Our results suggest that, among the redundant mechanisms operating in tumor cells to penetrate the anatomic barriers of host tissues, EphA2 plays a pivotal role in the adaptive switch in migration pattern and mechanism, defining and distinguishing tumor cell invasion strategies. Thus, targeting EphA2 might represent a future approach for the therapy of cancer dissemination.
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PMID:EphA2 reexpression prompts invasion of melanoma cells shifting from mesenchymal to amoeboid-like motility style. 1924 30

Ligand-activated Eph tyrosine kinases regulate cellular repulsion, morphology, adhesion, and motility. EphA2 kinase is frequently up-regulated in several different types of cancers, including prostate, breast, colon, and lung carcinomas, as well as in melanoma. The existing data do not clarify whether EphA2 receptor phosphorylation or its simple overexpression, which likely leads to Eph kinase-independent responses, plays a role in the progression of malignant prostate cancer. In this study, we address the role of EphA2 tyrosine phosphorylation in prostate carcinoma cell adhesion, motility, invasion, and formation of metastases. Tumor cells expressing kinase-deficient EphA2 mutants, as well as an EphA2 variant lacking the cytoplasmic domain, are defective in ephrinA1-mediated cell rounding, retraction fiber formation, de-adhesion from the extracellular matrix, RhoA and Rac1 GTPase regulation, three-dimensional matrix invasion, and in vivo metastasis, suggesting a key role for EphA2 kinase activity. Nevertheless, EphA2 regulation of cell motility and invasion, as well as the formation of bone and visceral tumor colonies, reveals a component of both EphA2 kinase-dependent and -independent features. These results uncover a differential requirement for EphA2 kinase activity in the regulation of prostate carcinoma metastasis outcome, suggesting that although the kinase activity of EphA2 is required for the regulation of cell adhesion and cytoskeletal rearrangement, some distinct kinase-dependent and -independent pathways likely cooperate to drive cancer cell migration, invasion, and metastasis outcome.
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PMID:Kinase-dependent and -independent roles of EphA2 in the regulation of prostate cancer invasion and metastasis. 1926 6


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