Hyperthermia induces apoptosis in malignant fibrous histiocytoma cellsin vitro

Abstract

The effect of mild hyperthermia on a cultured rat malignant fibrous histiocytoma (MFH) cell line, MFH-2NR, was investigated. MFH cells in log-phase (growing phase) were heated at 41°–44°C for 1 hr. Hyperthermic treatment at 41°C did not substantially affect cell proliferation and treatment at 44°C caused necrosis. After hyperthermic treatment at 42° or 43°C, proliferation of MFH cells was arrested and morphological changes characteristic of apoptosis, cell shrinkage accompanying apoptotic bodies and chromatin condensation, became apparent. Hyperthermia-induced apoptosis was further confirmed by terminal deoxynucleotidyl transferase staining and a ladder pattern on agarose gel electrophoresis. Flow cytometric analysis indicated that the population in the G1 phase of the cell cycle significantly decreased with a concomitant increase in apoptotic cells, indicating that apoptosis might occur mainly in the G1 phase population. © 1996 Wiley-Liss, Inc.