[The effect of hyperthermia and antitumor drugs on brain tumor cell lines]

The effects of heat and antitumor drugs on malignant brain tumor cell lines were studied. A human glioblastoma cell line (SKMG1) and rat malignant brain tumor cell lines (T9, EB 679 and TR 481) were used in this experiment. Five different modalities of treatment with heat and drugs were used as follows: (Group 1) exposure to heat alone at 42 degrees C for one hour; (Group 2) exposure to antitumor drug alone for one hour (ACNU 2.5 or 5 micrograms/ml, ACR 0.02 micrograms/ml and CDDP 1 microgram/ml); (Group 3) simultaneous exposure to heat at 42 degrees C and drug for one hour; (Group 4) heat at 42 degrees C given first for one hour, followed by one hour exposure to drug one hour later ("preheating"); (Group 5) drug given first for one hour, followed by one hour exposure to heat at 42 degrees C one hour later ("postheating"). After each treatment, the inhibition rate at 4 days was evaluated and compared for each group. A synergistic effect was observed in Group 3. For example, when T9 cells were exposed to ACNU and to heat at 42 degrees C at the same time for one hour, inhibition rate was 78%, while the rates for Group 1 and Group 2 were 7% and 21%, respectively. The cytotoxicity of simultaneous treatment with antitumor drugs (ACNU, ACR and CDDP) and hyperthermia at 42 degrees C was apparently superior to that of other treatment modalities.