Accumulation of mutant p53 and hsp72 by heat treatment, and their association in a human glioblastoma cell line

Abstract

The cellular content of mutant p53 and hsp72 proteins following γ-ray irradiation, UV irradiation, and heat treatment was studied in A-7 cells, a human glioblastoma cell line. A-7 was found to contain a mutant p53 gene in which the arginine codon at position 175 was substituted by a histidine codon. Although the p53 gene was mutant, the phenotype of the p53 protein appeared wild-type since the cellular content of the p53 protein was limited under normal culturing conditions. The quantity of mutant p53 and hsp72 proteins in A-7 was increased by heat treatment as well as γ-ray and UV irradiation. Furthermore, the mutant p53 protein was coimmunoprecipitated with anti-hsp72/hsc 73 antibody. Additionally, hsp 72 and hsc 73 were coimmunoprecipitated with anti-p53 antibody. These results suggest that in A-7, p53 protein accumulation may be caused as a result of response to stressors, such as γ-ray, UV and heat and that mutant p53 protein and hsp 72/hsc 73 may manage biological functions cooperatively after γ-ray, UV and also heat treatments.

Key Words:

• p53
• heat shock protein
• hyperthermia