Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1519670 (tumor angiogenesis)
 6,052 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Eph family of receptor tyrosine kinases and their ligands, known as ephrins, play a crucial role in vascular development during embryogenesis. The function of these molecules in adult angiogenesis has not been well characterized. Here, we report that blocking Eph A class receptor activation inhibits angiogenesis in two independent tumor types, the RIP-Tag transgenic model of angiogenesis-dependent pancreatic islet cell carcinoma and the 4T1 model of metastatic mammary adenocarcinoma. Ephrin-A1 ligand was expressed in both tumor and endothelial cells, and EphA2 receptor was localized primarily in tumor-associated vascular endothelial cells. Soluble EphA2-Fc or EphA3-Fc receptors inhibited tumor angiogenesis in cutaneous window assays, and tumor growth in vivo. EphA2-Fc or EphA3-Fc treatment resulted in decreased tumor vascular density, tumor volume, and cell proliferation, but increased cell apoptosis. However, EphA2-Fc had no direct effect on tumor cell growth or apoptosis in culture, yet inhibited migration of endothelial cells in response to tumor cells, suggesting that the soluble receptor inhibited blood vessel recruitment by the tumor. These data provide the first functional evidence for Eph A class receptor regulation of pathogenic angiogenesis induced by tumors and support the function of A class Eph receptors in tumor progression.
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PMID:Soluble Eph A receptors inhibit tumor angiogenesis and progression in vivo. 1237 Aug 23

Ephrin-A1, the prototypic ligand for EphA receptor tyrosine kinases, is overexpressed in vascularized tumors relative to normal tissue. Moreover, ephrin-A1-Fc fusion proteins induce endothelial cell sprouting, migration, and assembly in vitro, and s.c. vascular remodeling in vivo. Based on these data, we hypothesized that native, membrane-bound ephrin-A1 regulates tumor angiogenesis and progression. We tested this hypothesis using a transplantable mouse mammary tumor model. Small interfering RNA-mediated ephrin-A1 knockdown in metastatic mammary tumor cells significantly diminishes lung metastasis without affecting tumor volume, invasion, intravasation, or lung colonization upon i.v. injection in vivo. Ephrin-A1 knockdown reduced tumor-induced endothelial cell migration in vitro and microvascular density in vivo. Conversely, overexpression of ephrin-A1 in nonmetastatic mammary tumor cells elevated microvascular density and vascular recruitment. Overexpression of ephrin-A1 elevated wild-type but not EphA2-deficient endothelial cell migration toward tumor cells, suggesting that activation of EphA2 on endothelial cells is one mechanism by which ephrin-A1 regulates angiogenesis. Furthermore, ephrin-A1 knockdown diminished, whereas overexpression of ephrin-A1 elevated, vascular endothelial growth factor (VEGF) levels in tumor cell-conditioned medium, suggesting that ephrin-A1-mediated modulation of the VEGF pathway is another mechanism by which membrane-tethered ephrin-A1 regulates angiogenic responses from initially distant host endothelium. These data suggest that ephrin-A1 is a proangiogenic signal, regulating VEGF expression and facilitating angiogenesis-dependent metastatic spread.
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PMID:Ephrin-A1 facilitates mammary tumor metastasis through an angiogenesis-dependent mechanism mediated by EphA receptor and vascular endothelial growth factor in mice. 1707 51

The Eph family of receptor tyrosine kinases has emerged as one of the pivotal regulators of tumor angiogenesis. EphA1, the first identified member of the Eph receptor family, has been found to be overexpressed in several types of human tumors. A recent report indicated that EphA1 was overexpressed in hepatocellular carcinoma (HCC) and that elevated expression of EphA1 can promote proliferation of HCC cells through stimulation by exogenous Ephrin-A1. To investigate the role of EphA1 in angiogenesis and progression of HCC, we down-regulated EphA1 by RNA interference (RNAi) technology, in an HCC-derived cell line with a high level of EphA1 expression. We established a stable knockdown clone named SiEphA1/Huh-7. The knockdown resulted in decreased proliferation of Huh-7 cells, as well as decreased motility and invasion capability in vitro. siRNA-based EphA1 knockdown also down-regulated the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMP)-2 and -9. Interestingly, the suppression of EphA1 expression in Huh-7 cells reduced their outgrowth when inoculated in the subcutaneous space in the flank of nude mice, presumably through angiogenesis inhibition since microvessel density was found to be inhibited.
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PMID:EphA1 receptor silencing by small interfering RNA has antiangiogenic and antitumor efficacy in hepatocellular carcinoma. 2004 22