Effects of low dose radiation on cytokine-induced killer cells on breast cancer cell lines

Objective: To observe the effects of low dose radiation on cytokine-induced killer cells on breast cancer cell lines and explore the possible mechanism. Methods: Peripheral blood mononuelear cells (PBMC) were separated from healthy human peripheral white blood cells. DCs and CIK cells were prepared from human PBMCs with different cytokines. CIK cells were cocultured with autologous DCs for 7 days at a ratio of 1 : 5 to get immunologic effector DC-CIK cells. DC-CIK and CIK cells were irradiated by X-rays at different doses of 40, 80, 120 mGy, then their phenotypes were analyzed by flow cytometry and their cytotoxic effects on breast cancer cell lines were detected by CCK-8 assay. Results: Compared with CIK group, DC-CIK group enhanced the cytotoxicity in breast cancer cells at different ratios (t = 3.63, 5.62, 8.21, 5.49, P < 0.05). Compared with CIK 0 mGy group, low dose irradiated CIK cells induced a higher cytotoxicity to MCF-7 and SK-BR-3 breast cancer cells. But there was no significant difference between DC-CIK 0 mGy group and low dose irradiated DC-CIK cells. Conclusions: Low dose radiation has synergistic effect with CIK cells on killing breast cancer. (authors)