ABSTRACT
Objective: To investigate hyperthermia enhanced expression of heat shock protein70 (HSP70) in breast cancer drug sensitive cell line MCF7 and multi-drug resistant (MDR) cell line MCF7/ADR, so as to increase cytotoxic activity of immunologic effector cells against the target cells, and to provide an experimental basis for cell immunotherapy based on hyperthermia. Methods: The immunological effector cells were induced and expanded by cytokines. Breast cancer cell lines MCF7 and MCF7/ADR were treated at 42 ℃ for an hour. Then after being incubated for additional 4 hours, 24 hours and 48 hours, the cells were digested. Flow cytometry (FCM) was used to detect the expression of HSP70 on the target cells. MTT assay was employed to evaluate cell proliferation and the cytotoxic activity of immunologic effector cells against target cells. Results: The expressions of HSP70 in both the target cells had significant difference. The expression of HSP70 in MCF7/ADR cells was higher than in MCF7 cells before hyperthermia. After hyperthermia the expression of HSP70 increased by 6 folds in MCF7/ADR cells, and 22 folds in MCF7 cells and was higher than in MCF7/ADR cells at hour 4. The proliferation inhibition fraction of hyperthermia against MCF7 was significantly lower than that of MCF7/ADR. The cytotoxic activity of immunologic effector cells against MCF7 cells was lower than against MCF7/ADR cells before hyperthermia. After hyperthermia the cytotoxic activity of immunologic effector cells against MCF7 cells rose by 86.23%, and was higher than against MCF7/ADR cells (rose by 30.32%). Conclusion: The expression of HSP70 in breast cancer drug sensitive cell line MCF7 and MDR cell line MCF7/ADR were enhanced significantly by hyperthermia. Cytotoxic activity of immunologic effector cells against both the target cells were increased by hyperthermia. The differential expressions of HSP70 in breast cancer drug sensitive cell line MCF7 and MDR cell line MCF7/ADR affect the cytotoxic activity of immunologic effector cells.