Linked Life Data

10215998

Source:http://linkedlifedata.com/resource/pubmed/id/10215998

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1999-7-7
pubmed:abstractText
Vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) is a mitogen and chemotactic factor for endothelial cells in vitro and an angiogenesis and vascular permeability factor in vivo. Due to its properties, VEGF is a candidate for both angiogenesis and vascular permeability/oedema induction which typically occur in glioblastomas. In this study we test the hypothesis that the antioedema effect of dexamethasone is mediated by downregulation of VEGF or VEGF receptor expression. VEGF mRNA and protein levels of two rat glioma cells lines, C6 and GS-9L, were determined after incubation with dexamethasone under normoxic and hypoxic conditions. In normoxic C6 and GS9L cells, we observed 50-60% downregulation of VEGF mRNA by dexamethasone (P=0.015 and P=0. 01, respectively). This effect was dependent on glucocorticoid-receptor (GR) function. The inhibitory effect of dexamethasone on VEGF gene expression by tumour cells was markedly reduced by hypoxia which suggests that the upregulation of VEGF driven by hypoxia overcomes the effect of the dexamethasone. Dexamethasone did not alter VEGFR-2 mRNA levels in human umbilical endothelial cells. In a subcutaneous glioma tumour model, we observed only a 15% decrease in VEGF mRNA expression in dexamethasone treated animals (n = 12) compared with controls animals (P = 0.24). We conclude that dexamethasone may decrease brain tumour-associated oedema by reduction of VEGF expression in tumour cells. However, the highly reduced activity on hypoxic tumour cells suggests that dexamethasone efficacy may be limited by hypoxia in rapidly growing tumours.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0305-1846
pubmed:author
pubmed:issnType
Print
pubmed:volume
25
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
104-12
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:10215998-Animals, pubmed-meshheading:10215998-Cell Hypoxia, pubmed-meshheading:10215998-Cell Line, pubmed-meshheading:10215998-Dexamethasone, pubmed-meshheading:10215998-Down-Regulation, pubmed-meshheading:10215998-Endothelial Growth Factors, pubmed-meshheading:10215998-Endothelium, Vascular, pubmed-meshheading:10215998-Estradiol, pubmed-meshheading:10215998-Glioma, pubmed-meshheading:10215998-Glucocorticoids, pubmed-meshheading:10215998-Humans, pubmed-meshheading:10215998-Lymphokines, pubmed-meshheading:10215998-Progesterone, pubmed-meshheading:10215998-RNA, Messenger, pubmed-meshheading:10215998-Rats, pubmed-meshheading:10215998-Tumor Cells, Cultured, pubmed-meshheading:10215998-Umbilical Veins, pubmed-meshheading:10215998-Vascular Endothelial Growth Factor A, pubmed-meshheading:10215998-Vascular Endothelial Growth Factors
pubmed:year
1999
pubmed:articleTitle
Differential downregulation of vascular endothelial growth factor by dexamethasone in normoxic and hypoxic rat glioma cells.
pubmed:affiliation
Department of Neuropathology, Freiburg University Medical School, Germany.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't