Linked Life Data

12052835

Source:http://linkedlifedata.com/resource/pubmed/id/12052835

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
33
pubmed:dateCreated
2002-8-12
pubmed:abstractText
HIF-1 alpha is a normally labile proangiogenic transcription factor that is stabilized and activated in hypoxia. Although the von Hippel Lindau (VHL) gene product, the ubiquitin ligase responsible for regulating HIF-1 alpha protein levels, efficiently targets HIF-1 alpha for rapid proteasome-dependent degradation under normoxia, HIF-1 alpha is resistant to the destabilizing effects of VHL under hypoxia. HIF-1 alpha also associates with the molecular chaperone Hsp90. To examine the role of Hsp90 in HIF-1 alpha function, we used renal carcinoma cell (RCC) lines that lack functional VHL and express stable HIF-1 alpha protein under normoxia. Geldanamycin (GA), an Hsp90 antagonist, promoted efficient ubiquitination and proteasome-mediated degradation of HIF-1 alpha in RCC in both normoxia and hypoxia. Furthermore, HIF-1 alpha point mutations that block VHL association did not protect HIF-1 alpha from GA-induced destabilization. Hsp90 antagonists also inhibited HIF-1 alpha transcriptional activity and dramatically reduced both hypoxia-induced accumulation of VEGF mRNA and hypoxia-dependent angiogenic activity. These findings demonstrate that disruption of Hsp90 function 1) promotes HIF-1 alpha degradation via a novel, oxygen-independent E3 ubiquitin ligase and 2) diminishes HIF-1 alpha transcriptional activity. Existence of an Hsp90-dependent pathway for elimination of HIF-1 alpha predicts that Hsp90 antagonists may be hypoxic cell sensitizers and possess antiangiogenic activity in vivo, thus extending the utility of these drugs as therapeutic anticancer agents.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
277
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
29936-44
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Hsp90 regulates a von Hippel Lindau-independent hypoxia-inducible factor-1 alpha-degradative pathway.
pubmed:affiliation
Cell and Cancer Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Rockville, Maryland 20850, USA.
pubmed:publicationType
Journal Article