Synergistic effects of taxotere combined with mild hyperthermia on human breast carcinoma cell line MCF-7 / 中华物理医学与康复杂志

ABSTRACT

Objective To confirm whether taxotere combined with mild hyperthermia will have synergistic effects,and to explore their joint mechanism of action.Methods Firstly the effective concentration of taxotere was determined by using MTT method to observe the effect of docetaxel on proliferation of human breast cancer cell line MCF-7.Then three samples of in vitro cultured human breast carcinoma MCF-7 cells were prepared,termed the the taxotere group,the taxotere plus mild hyperthermia group and the control group,and treated with effective concentration of taxotere exclusively or in combination with mild hyperthermia,or left without any special treatment.The taxotere plus mild hyperthermia group was subdivided into 5 subgroups according to the temperatures used (39.0 ℃,39.5 ℃,40.0 ℃,40.5 ℃,41.0 ℃) MTT assays were used to measure the proliferation and invasive capacity of the cells and their effective concentrations.Flow cytometry was used to detect cell apoptosis rates and any cell cycle changes in the control group.Western blotting was used to detect any changes in the expression of mitogen-activated protein kinases (MAPKs),Bcl-2/Bax,heat shock protein-70 (HSP-70) and P-gp.Results The taxotere with mild hyperthermia group demonstrated a significantly higher rate of apoptosis than that in the taxotere and control groups.There were also more cells in the G2/M phase observed.Combining taxotere with mild hyperthermia was found after 24 h to have significantly increased p-ERK,p-JNK,p38,HSP-70 and P-gp protein levels and to have significantly decreased Bcl-2 protein expression in contrast with the other two groups.Conclusions Combining taxotere with mild hyperthermia showed synergistic effects in vitro.It seemed to be limiting the accumulation of MCF-7 cells in the G2/M phase and activating the signal pathways of MAPKs while inhibiting the activation of Bcl-2/Bax signal pathways.Combining taxotere and mild hyperthermia can accelerate the expression of HSP70 and P-gp in MCF-7 cells.Hyperthermia might induce chemotherapy resistance.