Identification of genes responsive to mild hyperthermia in human leukemia U937 cells

The rationale underlying hyperthermia is the fact that temperatures over 42.5C are highly cytotoxic to tumor cells. On the other hand, although mild hyperthermia at a range from 39 to 41C alone did not induce cytotoxicity in tumor cells, mild hyperthermia is reported to show a synergism with radiotherapy and anti-cancer drugs. Here, the effects of mild hyperthermia (41C for 30 min) on the gene expression in human lymphoma U937 cells were investigated using by an Affymetrix GeneChip system. Although the cells treated with the mild hyperthermia did not induce apoptosis, a significant increase in protein levels of heat shock proteins, Hsp40 and Hsp70, was observed following activation of heat shock factor-1. At 3 h post-treatment, 938 probe sets that were differentially expressed by >1.5-fold were identified.

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Tabuchi Y, Takasaki I, Wada S, Zhao QL, Hori T, Nomura T, Ohtsuka K, Kondo T