The protective effect of mild hyperthermia against UV-mimetic agent 4-nitroquinoline-1-oxide (4NQO) in human colon cells.

Hyperthermia-induced cellular response has been widely investigated for understanding cell physiology in stressful conditions as well as for therapeutic application using heat shock. In this study, the protective effect of mild hyperthermia-induced cellular response was investigated in RKO human colon cell lines, which harbor wild-type p53. Our data showed that the accumulation of p53 protein was induced without DNA damage in response to mild hyperthermia. Interestingly, the sub-lethal of heat shock at 40 degrees C for 30 minutes in RKO cells showed the protective effect against UV mimetic agent 4-nitroquinoline-1-oxide (4NQO) with the decrease in mitotic index, although other papers had shown the induction of apoptosis in RKO cells under the higher dose of heat stress. Thus, we suggest that the protective effect of sub-lethal heat shock might be applicable for a novel preventive approach to clinical applications of mild hyperthermia.