Hypoxia induces HSP 70 gene expression in human hepatoma (HEP G2) cells.
Populations of cells within solid tumours are exposed to low oxygen concentrations. The mechanism by which tumour cells tolerate such hypoxia is unknown but it may parallel responses to other types of cellular stress. We investigated the effect of oxygen on steady state levels of inducible heat shock protein 70 mRNA in cultured human hepatoma cells. Northern blot analysis demonstrated that hypoxia increased HSP 70 mRNA levels within 3 hours, with a transient 12-fold increase at 6 hours compared with normoxia. We also showed that heat shock induced a 20-fold increase in HSP 70 mRNA. This data suggests that HSPs may be important in tumour progression by protecting cells from hypoxic stress.
Department of Ophthalmology, University of Manchester, UK.
B
B
Patel
A
A
Khaliq
J
J
Jarvis-Evans
M
M
Boulton
S
S
Arrol
M
M
Mackness
D
D
McLeod
D015152:Blotting, Northern; D006528:Carcinoma, Hepatocellular; D015687:Cell Hypoxia; D002460:Cell Line; D015972:Gene Expression Regulation, Neoplastic; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis*; D006801:Humans; D007700:Kinetics; D008113:Liver Neoplasms; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D013997:Time Factors; D014407:Tumor Cells, Cultured
D018840:HSP70 Heat-Shock Proteins; D012333:RNA, Messenger