Effect of pH on quercetin-induced suppression of heat shock gene expression and thermotolerance development in HT-29 cells.
When cells were heated for 15 min at 45 degrees C, they became thermotolerant to a second heat exposure at 45 degrees C. Thermotolerance developed rapidly, reached its maximum 6 hr after heat shock, and then gradually decayed. The development of thermotolerance was partially suppressed by treatment with various concentrations of quercetin (0.05-0.2 mM) at pH 7.4 after the initial heat treatment. In contrast, the drug markedly inhibited thermotolerance development at pH 6.5. Furthermore, a combination of low pH and quercetin treatment distinctively altered the expression of HSP70 gene compared with that of HSP28 or HSP90 gene. These results demonstrate a good correlation between the amount of HSP70 gene expression and development of thermotolerance.
Lee
Y J
YJ
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan 48073.
Curetty
L
L
Hou
Z Z
ZZ
Kim
S H
SH
Kim
J H
JH
Corry
P M
PM
D015152:Blotting, Northern; D002460:Cell Line; D003110:Colonic Neoplasms; D015342:DNA Probes; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression / Q000187:drug effects; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics*; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011794:Quercetin / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013696:Temperature
D015342:DNA Probes; D006360:Heat-Shock Proteins; D012333:RNA, Messenger; D011794:Quercetin