RESUMEN
Aim To explore the relationship between Snail and P-gp in breast cancer cell,and to reveal the effect of epithelial-mesenchymal transformation(EMT)on the multidrug-resistance(MDR)of breast cancer cell.Methods The eukaryotic expression vector pCDNA3.1-Snail was constructed, and then transfected into human breast cancer cell line MCF-7 to constuct MCF-7/Snail.Both cell lines MCF-7 and MCF-7/Snail were induced by adriamycin(ADM).Cell cytotoxicity assay and ADM efflux assay were used to measure the ability of drug resistance.The positive rate of P-gp of the two cell lines was detected by flow cytometry;the mRNA of MDR1 and Snail was evaluated by real-time PCR.Results MCF-7,the expression of MDR1 mRNA and Snail mRNA in MCF-7/Snail cell lines significantly increased;the expression of P-gp was increased too;the RR increased to 109.2;fluorescence intensity intracellular was reduced to 7.1.Conclusion After transfected the eukaryotic expression vector,the capacity of MCF-7/Snail strongly increases compared with that of MCF-7.