HEAT-INDUCED APOPTOSIS IN HUMAN GLIOBLASTOMA CELL-LINE A172

OBJECTIVE: Hyperthermia has been clinically applied to some types of b rain tumors. However, the detailed mechanisms of this growth inhibitio n are not clear. The effect of mild hyperthermia on cultured human gli oblastoma cell line, A172, was studied. METHODS: A172 cells were heat treated (43-44.5 degrees C) for 1 hour in the growing phase. Cell viab ility was assessed by trypan blue dye exclusion assay. The presence of apoptosis was determined by the morphological changes observed using phase contrast microscopy and nuclear changes observed using HOECHST 3 3342 stain. For the evaluation of cellular deoxyribonucleic acid fragm entation, the TUNEL method was used. The expression of p53 and bar pro teins was evaluated by Western blot, and the bar messenger ribonucleic acid was detected by Northern blot. RESULTS: Heat treatment induced c ell death in time- and temperature-dependent manners. The nuclear stai ning with HOECHST 33342 demonstrated morphological changes consistent with apoptosis. The TUNEL stain also demonstrated damages in the deoxy ribonucleic acid. These morphological changes were accompanied by the accumulation of p53 protein, bar protein, and messenger ribonucleic ac id. CONCLUSION: These results indicate that mild hyperthermia induces apoptosis in A172 glioblastoma cells.