Gamma ray irradiation of epithelial carcinoma cells under hypoxic conditions

We demonstrate for the first time that under hypoxic conditions, A431 epithelial carcinoma cells exhibit increased viability when exposed to low-dose γ-irradiation, indicating that radiotherapy can promote tumor cell survival when oxygen supply is limited. When assessed using iTRAQ quantitative proteomics and Western blotting, irradiated tumor cells were observed to significantly up-regulate the expression of calcium-binding proteins CALM1, CALU and RCN1, suggesting important roles for these mediators in promoting tumor cell survival during hypoxia.