Treatment of human clonogenic tumor cells and bone marrow progenitor cells with bleomycin and peplomycin under 40.5 degrees C hyperthermia in vitro.

Tumor cells derived from 13 different individual human tumors were plated in a colony forming monolayer assay. The effect of bleomycin and peplomycin on colony formation was assessed in normothermic conditions and after a hyperthermic treatment at 40.5 degrees C for 2 h at the beginning of the culture. In three out of the 13 tumor samples (two colon carcinomas, one malignant melanoma), hyperthermic incubation resulted in a thermal enhancement of the effects of bleomycin and peplomycin. In addition, human bone marrow progenitor cells (CFU-C) were subjected to the same procedure. Peplomycin proved to be less toxic to CFU-C than bleomycin. In samples from eight different donors, homogeneous dose-response curves were observed. There was no difference between normo- and hyperthermic incubation.