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Binding of heat shock protein 70 to extracellular phosphatidylserine promotes killing of normoxic and hypoxic tumor cells.
FASEB J. 23, 2467-2477 (2009)
Hypoxia is well known to limit curability of tumors by ionizing radiation. Here, we show that hypoxia treatment of tumor cells causes coexpression of heat shock protein 70 (Hsp70) and phosphatidylserine (PS) on the cell surface. Colocalization of Hsp70 and PS, as determined by confocal microscopy, also occurs when exogenous FITC-labeled Hsp70 protein is added to normoxic and hypoxic tumor cells. Moreover, the interaction of Hsp70 with PS was demonstrated in artificial unilamellar phosphatidylcholine/ phosphatidylserine (PC/PS) liposomes at the physiological ratio of 8/2. Indeed, the Hsp70-liposome interaction gradually increased with elevating PS molar ratios (8/2 > or = 7/3 < 5/5 < 4/6 < 3/7 < 2/8). In contrast, only a weak Hsp70 interaction was detected in phosphatidylcholine/phosphatidylglycerol (PC/PG) liposomes, thus demonstrating that the interaction was not a charge-related effect. The interaction of Hsp70 with surface PS significantly reduces clonogenic cell survival in normoxic (EC(50) of Hsp70=85 microg/ml) and hypoxic (EC(50) of Hsp70=55 microg/ml) tumor cells. The radiation-induced tumor cell killing was significantly enhanced by the addition of Hsp70 protein (50 microg/ml). Since apoptosis was not significantly enhanced in normoxic and hypoxic tumor cells by the addition of Hsp70, we hypothesize that the Hsp70 protein-induced reduction in clonogenic cell survival might be through necrosis rather than apoptosis.
Impact Factor
Scopus SNIP
Web of Science
Times Cited
Times Cited
Scopus
Cited By
Cited By
Altmetric
7.049
1.610
54
74
Anmerkungen
Besondere Publikation
Auf Hompepage verbergern
Publikationstyp
Artikel: Journalartikel
Dokumenttyp
Wissenschaftlicher Artikel
Schlagwörter
nonapoptotic tumor cell death; stress proteins; ionizing radiation; cancer therapy; heat-shock proteins; natural-killer-cells; immune-response; molecular chaperones; transcription factor; mammalian-cells; stress-proteins; in-vitro; hsp70; cancer
Sprache
englisch
Veröffentlichungsjahr
2009
HGF-Berichtsjahr
0
ISSN (print) / ISBN
0892-6638
e-ISSN
1530-6860
Zeitschrift
FASEB Journal
Quellenangaben
Band: 23,
Heft: 8,
Seiten: 2467-2477
Verlag
Wiley
Verlagsort
Bethesda, Md.
Begutachtungsstatus
Peer reviewed
Institut(e)
CCG Innate Immunity in Tumor Biology (PATH-KTB)
POF Topic(s)
30504 - Mechanisms of Genetic and Environmental Influences on Health and Disease
PSP-Element(e)
G-521400-001
PubMed ID
19289606
Scopus ID
68849112162
Erfassungsdatum
2009-09-03