Temperature-dependency of the expression of heat shock proteins in rat hepatoma cells with a different degree of heat sensitivity

Abstract

Of two rat hepatoma cell lines, Reuber H35 and HTC, with a different degree of differentiation and heat sensitivity, treated at 41–44°C for various periods of time, the expression of thermotolerance, recovery of protein synthesis and rate of hsp synthesis were studied in relation to heat-induced cell killing. The temperature dependency of the induction of thermotolerance, either chronic or acute, was different between the cell lines; tolerance of H35 cells being induced at lower temperature than that of HTC cells. Induction of thermotolerance was related to survival decrement and the correlation was similar for both cell lines. Protein syntheses of H35 and HTC cells are equally sensitive for incubation at increased temperature, but recovery of protein synthesis after heat treatment was slightly different between the cell lines; H35 being more delayed than HTC. A strong but different correlation between total amount of protein synthesized after heat treatment and cell survival was found for the two cell lines. The increased heat sensitivity of H35 cells parallels the increased capacity of selective hsp synthesis as compared with that of HTC cells.

Key Words:

• Hyperthermia
• thermotolerance
• heat shock proteins
• hepatoma cells
• differentiation