In vitro effects of hyperthermia combined with cisplatin or peplomycin on the human maxillary carcinoma cell line IMC-2.

ABSTRACT

We examined the interactive effects of hyperthermia combined with cisplatin (CDDP) (0.5 micrograms/ml) or peplomycin (PEP) (1.0 microgram/ml) on surviving fractions of human maxillary carcinoma IMC-2 cells. Either CDDP or PEP enhanced the 44 degree C thermosensitivity of thermotolerant cells after heating at 42 degrees C for 2 hours. The development of thermotolerance at 42 degrees C with either of the two drugs for 2 hours was not inhibited by CDDP, but it was partially inhibited by PEP. Moreover, for PEP throughout the entire period of 42-44 degrees C step-up heating, the 44 degree C thermosensitivity of thermotolerant cells after heating at 42 degrees C with PEP for 2 hours was enhanced similarly to that at 44 degrees C with PEP. Heating at 42 degrees C combined with either of the two drugs showed a marked interactive effect.