Immunotherapy with dendritic cells and cytokine-induced killer cells for MDA-MB-231 breast cancer stem cells in nude mice.

OBJECTIVE To compare the effects and safety of immunotherapy using different methods to load DC-CIK cells for MDA-MB-231 breast cancer stem cells. METHODS A breast cancer model was established in BALB/c nude mice using breast cancer stem cells. All mice were randomly divided into six groups, and each group had three nude mice: the blank control group, the DC-CIK group (group D), the MDA-MB-231 CSC whole-cell lysate DC-CIK group (group L-D), the MDA-MB-231 CSC RNA DC-CIK group (group R-D), the THP DC-CIK group (group T-D) and group THP. Nude mice in groups D, L-D, R-D and T-D were injected with CSCs; 4 days later, the mice were inoculated with 1 × 10(6) DC-CIK cells via the tail vein. This injection was repeated 2 times a week for three weeks. The mice in groups THP and T-D were injected with a 5 mg/Kg dose of THP chemotherapeutic agents via the tail vein the day before DC-CIK injection, which was repeated one time a week for three weeks. Nude mice in the blank control group were injected with normal saline. The weights and sizes of the tumors were measured after the mice were euthanized. The expression of c-Myc, a key proto-oncogene associated with the Akt signaling pathway, was detected with RT-PCR. RESULTS The tumor growth rates in each group were as follows: group L-D < group R-D < group D < group T-D < blank control group < group THP. The nude mice in groups L-D, R-D and D were normal, active and had a healthy appetite. The mice in groups T-D and THP were lethargic, less active and showed loss of appetite, and their caudal vein was easy to stimulate. The mice in the blank control group were sacrificed during the third week or when their tumors developed ulceration. Compared with the blank control group, c-Myc gene expression was reduced in the tumors of the five experimental groups. CONCLUSION The results showed that DC-CIK cells stimulated by different methods were highly effect against MDA-MB-231 breast cancer stem cells in nude mice in all groups, especially in group L-D. DC-CIK immunotherapy may provide a new strategy for the clinical treatment of breast cancer.