Modification of tumor cell sensitivity to antineoplastic agents lonidamine and bouvardin (NSC 259968) at elevated...

Lymphocytic leukemia P388 and Sarcoma-180 cells were exposed to various concentrations (0.01 mM to 0.04 mM) of lonidamine at 37 degrees C and 43 degrees C for 30 min and 60 min in vitro. Similarly combined effect of lonidamine and bouvardin on these tumor cells was also assessed at 37 degrees C and 43 degrees C. The effect was evaluated by comparing the rate of 3H-thymidine incorporation in treated cells to that of control cells. It was observed that at 37 degrees C lonidamine did not exert cytotoxic effect on P388 cells at prescribed time interval. Sarcoma-180 cells, however, showed significant sensitivity to the drug at 37 degrees C. Lonidamine exhibited greater cytotoxicity at 43 degrees C towards both P388 and Sarcoma-180 cells at 30 and 60 min exposure. Lonidamine also enhanced cytotoxicity of bouvardin in P388 and reversed the natural resistance of Sarcoma-180 cells to bouvardin at 37 degrees C.