Linked Life Data

17178869

Source:http://linkedlifedata.com/resource/pubmed/id/17178869

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
24
pubmed:dateCreated
2006-12-20
pubmed:abstractText
Hypoxia is a common feature in tumors associated with an increased resistance of tumor cells to therapies. In addition to O(2) diffusion-limited hypoxia, another form of tumor hypoxia characterized by fluctuating changes in pO(2) within the disorganized tumor vascular network is described. Here, we postulated that this form of intermittent hypoxia promotes endothelial cell survival, thereby extending the concept of hypoxia-driven resistance to the tumor vasculature. We found that endothelial cell exposure to cycles of hypoxia reoxygenation not only rendered them resistant to proapoptotic stresses, including serum deprivation and radiotherapy, but also increased their capacity to migrate and organize in tubes. By contrast, prolonged hypoxia failed to exert protective effects and even seemed deleterious when combined with radiotherapy. The use of hypoxia-inducible factor-1alpha (HIF-1alpha)-targeting small interfering RNA led us to document that the accumulation of HIF-1alpha during intermittent hypoxia accounted for the higher resistance of endothelial cells. We also used an in vivo approach to enforce intermittent hypoxia in tumor-bearing mice and found that it was associated with less radiation-induced apoptosis within both the vascular and the tumor cell compartments (versus normoxia or prolonged hypoxia). Radioresistance was further ascertained by an increased rate of tumor regrowth in irradiated mice preexposed to intermittent hypoxia and confirmed in vitro using distinctly radiosensitive tumor cell lines. In conclusion, we have documented that intermittent hypoxia may condition endothelial cells and tumor cells in such a way that they are more resistant to apoptosis and more prone to participate in tumor progression. Our observations also underscore the potential of drugs targeting HIF-1alpha to resensitize the tumor vasculature to anticancer treatments.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0008-5472
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
66
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11736-44
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Preconditioning of the tumor vasculature and tumor cells by intermittent hypoxia: implications for anticancer therapies.
pubmed:affiliation
Unit of Pharmacology and Therapeutics (FATH 5349), Université Catholique de Louvain, B-1200 Brussels, Belgium.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't