[Alterations in cytokinetics and heat shock protein (70 kDa) expression of glial cell by hyperthermia]

Expression of major heat shock and stress-induced protein, HSP70, is known to be under complex regulation in tumor cells. In this study, we investigated the alternations of cytokinetics and HSP70 expression by hyperthermia in the in vitro experimental systems, using two rat glioma cell lines, two human glioblastoma cell lines and rat glioblast cells. For hyperthermal treatment the flasks were placed in water baths warmed up at 41 -45 degrees C for 15 min. To determine the effect of hyperthermia on the cell cycle progression, the changes in the DNA distribution of the cell population were studied by flow cytometry (FCM). The levels of HSP70 protein were determined by immunoblot analysis. The relationship between cell cycle and HSP70 expression was investigated by FCM using PI and FITC-labelled HSP70 double staining technique. These results were as follows: 1) Compared with the control, hyperthermic treatment at 42 degrees C or 44 degrees C caused both 354A and T98G cells to accumulate in S phase 18 hours after treatment and G2/M phase after 6-18 hours. 2) Hyperthermic treatment at 42 degrees C caused C6 cells to accumulate in S phase 6 hours after treatment, whereas heat treatment at 44 degrees C caused C6 cells to accumulate in S phase after 18 hours and G2/M phase after 6 hours. 3) A172 cells were accumulated only in G2/M phase by hyperthermia. 4) Glioblast cells did not show the alterations of cytokinetics by heat treatment remarkably. 5) HSP70 protein synthesis were enhanced under hyperthermic conditions in all type of cells, whether primary glioblast or permanent glioma cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)