Accumulation of cell cycle regulatory proteins, p21 and p27, induced after hyperthermia in human glioma cells.

It was investigated whether there was a relationship between p53 p21 and p27 induction pathways in the cellular response of glioma cells to hyperthermia. Two glioma cell lines were employed. A-172 cells had the wild-type of p53, and U251 cells had the mutant-type of p53. An adenovirus harbouring wild-type p53 was also used for the overexpression. The protein induction by hyperthermia was monitored by Western blot analysis. In U251 cells, the expression of wild-type p53 and hyperthermia had an additional cytotoxic effect, but did not affect A-172 cells. Significant p21 accumulation by hyperthermia was recognized in A-172 cells, and was also recognized in p53-transduced U251 cells. On the other hand, the accumulation of p27 by hyperthermia was not seen in A-172 or U251 cells, and the exogenous expression of p53 did not affect the accumulation of p27 by hyperthermia in U251 cells. These findings suggest that the p53 p21 pathway is involved in the signal transduction after hyperthermia, rather than the p27 pa...