Effect of protracted mild hyperthermia on polymerase activity in a human melanoma cell line.
Radioresistant human melanoma SkMel-3 was evaluated with its sensitivity to thermal cell killing and polymerase inactivation. Cells were heated from 40 to 45 degrees C and demonstrated no thermal tolerance development for any of the temperatures tested. In addition, at 45 degrees C the heat survival curve showed a large shoulder indicating capacity for accumulation of sublethal heat damage. Also at 45 degrees C heating polymerase beta was more sensitive than polymerase alpha + delta + epsilon. At 42 degrees C, the polymerase sensitivities were nearly the same but at the lower temperatures (41 and 40 degrees C) polymerase beta became progressively more resistant than the polymerase alpha + delta + epsilon. Thus, mild hyperthermia effects may be different than high temperature hyperthermia and may be related to polymerase alpha + delta + epsilon activity.
Raaphorst
G P
GP
Ottawa Regional Cancer Centre, Ontario, Canada.
Yang
D P
DP
Ng
C E
CE
D002470:Cell Survival; D004256:DNA Polymerase I / Q000037:antagonists & inhibitors; D004257:DNA Polymerase II / Q000037:antagonists & inhibitors; D004258:DNA Polymerase III / Q000037:antagonists & inhibitors; D006801:Humans; D006979:Hyperthermia, Induced; D008545:Melanoma / Q000201:enzymology* / Q000628:therapy*; D019384:Nucleic Acid Synthesis Inhibitors; D011836:Radiation Tolerance; D013696:Temperature; D013997:Time Factors; D014407:Tumor Cells, Cultured / Q000201:enzymology / Q000528:radiation effects
D019384:Nucleic Acid Synthesis Inhibitors; D004256:DNA Polymerase I; D004257:DNA Polymerase II; D004258:DNA Polymerase III