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Endothelial Cell Survival (endothelial + cell_survival)
Selected AbstractsOsteoprotegerin (OPG),a potential new role in the regulation of endothelialcell phenotype and tumour angiogenesis?INTERNATIONAL JOURNAL OF CANCER, Issue 8 2006Simon S. Cross Abstract The progression of cancer depends on the establishment of a tumour blood supply, and therefore tumour angiogenesis has been identified as a major target for new anticancer agents. Recent reports have suggested that osteoprotegerin (OPG) is involved in the control of endothelial cell survival through the inhibition of the activity of tumour necrosis factor- (TNF) related apoptosis-inducing ligand (TRAIL). The role of OPG in human tumour development and angiogenesis is currently unknown. In the present study we demonstrate the ability of OPG to support endothelial cell survival, as well as the formation of cord-like structures in vitro using a matrigel tubule formation assay. Investigation of various human cancers demonstrated endothelial OPG expression in 59% of malignant tumours (n = 512), but in contrast, OPG was absent in endothelial cells associated with benign tumours and normal tissues (n = 178). In a series of 400 breast tumours, endothelial OPG expression was associated with high tumour grade and certain histological types. Our data show a clear separation in endothelial OPG expression between malignant tumours and nonmalignant tissues, supporting a potential biological role for this molecule in the development and/or maintenance of the tumour vasculature. This is the first study to report the proangiogenic effects of OPG in vitro, as well as correlating expression of OPG by tumour endothelial cells with clinicopathological data in human tumours. © 2005 Wiley-Liss, Inc. [source] Glioma cells under hypoxic conditions block the brain microvascular endothelial cell death induced by serum starvationJOURNAL OF NEUROCHEMISTRY, Issue 1 2005Yoshifumi Ueda Abstract Angiogenesis is one of essential components for the growth of neoplasms, including malignant gliomas. However, tumor vascularization is often poorly organized and marginally functional due to tumor strucutural abnormalities, inducing regional or temporal hypoxic conditions and nutritional shortages in tumor tissues. We investigated how during angiogenesis migrating endothelial cells survive in these hypoxic and reduced nutritional conditions. Human brain microvascular endothelial cells (HBMECs) underwent apoptosis and necrosis after serum withdrawal. This endothelial cell death was blocked by recombinant VEGF protein or the culture medium of U251 glioma cells exposed to hypoxia (H-CM). Hypoxic treatment increased vascular endothelial growth factor (VEGF) and tumor necrosis factor alpha (TNF-,) expression in U251 glioma cells. H-CM activated nuclear factor-,B (NF,B) protein and increased the gene expression of antiapoptotic factors including Bcl-2, Bcl-XL, survivin and X-chromosome-linked inhibitor of apoptosis protein (XIAP) in endothelial cells. The survival activity of H-CM for endothelial cells was abolished by two kinds of VEGF inhibitors {Cyclopeptidic VEGF inhibitor and a VEGF receptor tyrosine kinase inhibitor (4-[(4,-chloro-2,-fluoro) phenylamino]-6, 7-dimethoxyquinazoline)} or NF,B inhibitors (ALLN and BAY 11,7082). These VEGF inhibitors did not block the activation of NF,B induced by H-CM in endothelial cells. On the contrary, TNF-, antagonist WP9QY enhanced the survival activity of H-CM for endothelial cells and blocked NF,B activation induced by H-CM under serum-starved conditions. Taken together, our data suggest that both the secretion of VEGF from glioma cells and activation of NF,B in endothelial cells induced by TNF-, are necessary for endothelial cell survival as they increase the expression of antiapoptotic genes in endothelial cells under conditions of serum starvation. These pathways may be one of the mechanisms by which angiogenesis is maintained in glioma tissues. [source] Experimental ischaemia-reperfusion injury induces vascular endothelial growth factor expression in the rat testisANDROLOGIA, Issue 4 2009H. Hashimoto Summary Testicular torsion causes ischaemia-reperfusion (I-R) injury of testis and might lead to male infertility. Its injury initiates a pathophysiological cascade, including an activation of inflammatory cytokines and generation of nitric oxide and other reactive oxygen species. Vascular endothelial growth factor (VEGF) mediates angiogenesis and promotes endothelial cell survival. The aim of our study was to investigate the time course expression of VEGF, VEGF-receptor (R)1, VEGF-R2, nitric oxide synthases (NOS) in experimental I-R injury of rat testis. In torsion side testis, the expression of VEGF protein and mRNA significantly increased in a time-dependent manner (P < 0.001 and P < 0.001, respectively). Although the expression of VEGF-R1 mRNA was increased in a similar way (P < 0.001), VEGF-R2 mRNA expression was not detected. In immunohistochemistry, the increase in VEGF protein staining was observed in testicular vascular endothelial cells and germ cells at 24 h after reperfusion. Significant activation of inducible NOS and endothelial NOS was investigated at 12 and 24 h after reperfusion (P < 0.01 and P < 0.001, respectively). This is the first report to show the time course expression of VEGF in experimental I-R rat testis. [source] | ||||||||||