Enhancement of sensitivity to hyperthermia by lonidamine in human cancer cells

Human glioma (87MG) and squamous cell carcinoma of the head and neck UMSCC-1 were shown to be sensitized to hyperthermia by Lonidamine treatment before and during hyperthermia. The degree of thermal sensitization increased with increasing heating times and temperatures. In addition, the thermal sensitization by Lonidamine as well as cellular thermal sensitivity were dependent on pH and increased with the more acidic pH. Even though plateau phase cells were more thermally resistant than exponentially growing cells, Lonidamine treatment caused thermal sensitization under both conditions. These data show that Lonidamine may hold potential to enhance the effectiveness of hyperthermia in cancer treatment and that especially in tumours with low pH an enhanced therapeutic gain may be achieved.