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 μg/ml) or peplomycin (PEP) (1.0 μg/ml) on surviving fractions of human maxillary carcinoma IMC-2 cells. Either CDDP or PEP enhanced the 44°C thermosensitivity of thermotolerant cells after heating at 42°C for 2 hours. The development of thermo-tolerance at 42°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°C step-up heating, the 44°C thermosensitivity of thermotolerant cells after heating at 42°C with PEP for 2 hours was enhanced similarly to that at 44°C with PEP. Heating at 42°C combined with either of the two drugs showed a marked interactive effect.