Abstract
The p53 tumor suppressor protein functions as a critical component of genotoxic stress response by regulating the gene expression of effectors that control the fate of a cell following DNA damage. In fact, wild-type p53 cells were more sensitive to low-linear energy transfer (LET) radiations than mutated p53 and p53-null cells, because low LET radiations induce p53-dependent apoptosis. In contrast to low LET radiation, high LET radiations such as heavy-ion particles have several potential advantages which are an excellent dose distribution, a higher relative biological effectiveness, a reduction in the oxygen enhancement ratio, less variation in cell cycle-related radiosensitivity, and the existence of less efficient repair of cellular radiation injury. In addition, we have demonstrated that high-LET radiations can have highly lethal effect on radio-resistant tumors, and can induce apoptosis in cancer cells nevertheless of p53 gene status so called as a p53-independent manner. Therefore, we suggested that high LET heavy-ion beams provide an effective tool for any types of p53-pacients. In addition, we proposed that the elucidation of the p53-independent apoptosis-related genes might provide new insights into cancer therapies.
