[Mechanisms of yanshu injection for overcoming multidrug resistance in breast carcinoma MCF-7 cells: an experimental research].

Objective: To investigate the mechanism of Yanshu Injection (YI) for overcoming multidrug resistance in breast carcinoma MCF-7 cells.

Methods: Human breast carcinoma MCF-7 cells and doxorubicin-resistant MCF-7/DOX cells were treated with YI. Its inhibition on the cell proliferation was detected by MTT assay. The fluorescence intensity of doxorubicin was detected by flow cytometry. The expression of apoptosis related protein and P-glycoprotein were examined by immunoblotting after treated by YI.

Results: The inhibitory action of YI on MCF-7/DOX cells was similar to that of MCF-7 cells, indicating no cross resistance (P > 0.05). 1/16 YI could obviously induce the apoptosis of MCF-7 cells and DOX cells. 1/256 YI +5 nmol/L doxorubicin and 1/128 YI +5 nmol/L doxorubicin could reduce the survival rate of MCF-7/ DOX resistant cells from 86.8% to 74.6% (P < 0.05) and 71.6% (P < 0.01) respectively, showing obvious synergistic effect. Besides, the accumulation of doxorubicin was increased after treated by YI in the MCF-7/ DOX cells. Results of immunoblotting indicated that reduction of P-glycoprotein expression was detected in MCF-7/DOX cells after exposure to YI.

Conclusion: YI could overcome the multidrug resistance in breast carcinoma MCF-7 cells possibly through reducing the expression of P-glycoprotein.