Combined effect of diethyldithiocarbamate (DDC) and modest hyperthermia on Chinese hamster (V79) cell survival and DNA strand break repair following photon irradiation.
Previous studies from our institution have shown that 10(-4) M DDC enhances the effects of radiation and of hyperthermia treatment at 43 degrees C on the killing of Chinese hamster (DON) cells. We herein report studies on the combined effect seen at more modest temperatures (41 degrees C) which can be achieved in humans by whole body heating without the need for general anesthesia. Treatment of V79 cells with DDC for 60 minutes at 37 degrees C or 41 degrees C had minimal toxicity at concentrations up to 5 X 10(-5) M. When cells were irradiated with single doses up to 1000 rad (137Cs, 350 rad/min), pre-incubation with 10(-4) M DDC had no effect on cell survival at 37 degrees C, but markedly decreased survival at 41 degrees C (D37 = 475 rad without DDC, 270 rad with DDC). The mechanism of this increased cell killing is not known. We observed, however, that there is no repair of DNA single strand breaks in DNA from irradiated V79 cells previously held at 41 degrees C in the presence of 10(-4) M DDC. Without DDC, repair of SSB was similar at 37 degrees C and 41 degrees C.
D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects*; D006224:Cricetinae; D003412:Cricetulus; D004260:DNA Repair / Q000187:drug effects; D004050:Ditiocarb / Q000494:pharmacology*; D004307:Dose-Response Relationship, Radiation; D006979:Hyperthermia, Induced; D011837:Radiation-Protective Agents / Q000494:pharmacology; D013859:Thiocarbamates / Q000494:pharmacology*; D013997:Time Factors
D011837:Radiation-Protective Agents; D013859:Thiocarbamates; D004050:Ditiocarb