In vitro response of human glioblastoma and canine glioma cells to hyperthermia, radiation, and chemotherapy.

Little is known about the sensitivity of human glioblastoma cells to hyperthermia alone and in combination with other therapies. We carried out in vitro cell survival studies on the human glioblastoma cell line U-87MG and our model canine glioma canine brain tumor (CBT) cells after multimodality treatment. Ionizing radiation was administered to flasks of cells in logarithmic growth at 500 rads (5 Gy) with consecutive treatment by hyperthermia, 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU), or cisplatin. Cells were treated with single doses of BCNU at 5 microM with sequentially added radiation or hyperthermia and at 1 to 2 micrograms/ml of cisplatin with hyperthermia. Hyperthermia was administered in a precision controlled water bath at 44 degrees C for 30 minutes in combination with chemotherapy or radiation. In general, the sensitivity of U-87MG and CBT cells was similar for all test regimens. For example, colony formation efficiency decreased by 64% in CBT cells and by 64.4% in U-87MG cells after hyperthermia alone at 44 degrees C for 60 minutes. All combinations of BCNU, hyperthermia, and radiation administered in vitro produced enhanced cell killing, but the effects of multiple modalities were generally additive in both cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)