Securin has been shown to regulate
genomic stability; nevertheless, the role of
securin on the cytotoxicity after radiation is still unclear. Exposure to 1-10 Gy X-ray radiation induced cell death in RKO
colorectal cancer cells. The
protein levels of
securin, p53, and p21 were elevated by radiation. The
proteins of phosphorylation of p53 at serine-15, which located on the nuclei of
cancer cells, were highly induced by radiation. However, radiation increased
securin proteins, which located on both of nuclei and cytoplasma in RKO cells. The p53-wild type
colorectal cancer cells were more susceptible on cytotoxicity than the p53-mutant cells following exposure to radiation. Besides, the existence of
securin in
colorectal cancer cells induced higher apoptosis than the
securin-null after radiation.
Securin proteins were elevated by radiation in the p53-wild type and -mutant cells; furthermore, radiation raised the p53
protein expression in both the
securin-wild type and -null cells. As a whole, these findings suggest that the existence of
securin promotes apoptosis via a p53-indpendent pathway after radiation in human
colorectal cancer cells.