Enhancement of thermal cell killing by methylglyoxal bis(guanylhydrazone) in Chinese hamster V-79 cells.

Abstract

Using the method of colony formation, the modifying effect of methylglyoxal bis(guanylhydrazone) (MGBG) was examined on 44 degrees hyperthermia- and/or radiation-induced cell killing and on thermotolerance development after 44 degrees exposure in Chinese hamster V-79 cells. After exposure to MGBG (10 microM) for more than 6 hr, cells became more sensitive to 44 degrees hyperthermia. When an interval at 37 degrees (up to 24 hr) was interposed between MGBG and hyperthermic treatments, cell survival was not significantly increased, as compared with that for MGBG immediately followed by 44 degrees. Cells treated with MGBG remained more thermosensitive, even after a 24 hr interval. On the other hand, when cells were exposed to split dose 44 degrees hyperthermia in the presence of MGBG during an interval of 6 hr at 37 degrees, the development of thermotolerance was not inhibited. After the combined treatments of MGBG followed by X-ray irradiation and hyperthermia, cell survival was markedly decreased, as compared with that in the case of X-ray irradiation alone or in combination with hyperthermia.