Not the presence but the synthesis of HSPS correlates with thermotolerance in a fibrosarcoma MO4 cell-line.

This study reports the induction of heat shock proteins (hsps) and thermotolerance in a MO4 cell line. An enhanced synthesis of hsp68, hsp70 and hsp90 was observed. After 6 hrs, the synthesis of hsp68 and hsp70 decreased to the control value. Hsp90 synthesis was absent after 10 hrs. However, hsps were found to be stable for longer periods of time (more than 48 hrs). A coupled study of hsps and SF demonstrated that an induction of hsps were followed by a change in the slope of the survival curve. Thermotolerance, as expressed by the observed SF after a second heating, is only present during the first 4 hrs and decayed between 4 and 8 hrs. We could not find a correlation between the presence of hsps and thermotolerance, but only between the synthesis of hsps and thermotolerance in MO4 cells.