Preliminary Study Of Reversal Effect Of Mifepristone On Breast Cancer Drug-resistance Cell Line (MCF-7/ADR)

Objective:In this dissertation, the chemotherapy drug susceptibility to Human breast cancer cell line MCF-7 and Human breast cancer drug-resistance cell line MCF-7/ADR as research models。To explore the possible reverse effect of mifepristone on human breast cancer drug-resistance cell line MCF-7/ADR.Methods:Human breast cancer MCF-7 cells and adriamycin-resistant MCF-7/ADR cells were cultured and passaged. Cells of logarithmic growth phase were adopted. Experimental groups:MCF-7 group, MCF-7/ADR group, MCF-7+MIF group and MCF-7/ADR+MIF group. Flow cytometry was used to detect the cell-membrane P-gp expression, the intracellular adriamycin (ADR) accumulation and cell cycle distribution in these MDR cells with or without mifepristone.Results:1,The P-gp expression on MCF-7/ADR cell membranes was (64.77±3.21)% before treated with MIF, and the P-gp expression on MCF-7 cell membranes was (38.22±1.76)%,the former was significantly higher than the latter,P<0.01;After using MIF for 72 hours,the P-gp expression on MCF-7/ADR cell membranes was (23.21±1.80)%, the P-gp expression on MCF-7 cell membranes was (19.37±2.37)%,Both significantly lower than that without MIF,P<0.05;However,no statistical differences were found between MCF-7/ADR cells and MCF-7 cells,p>0.05.2,When treated with 5μmol/L ADR, the intracellular fluorescence desity of ADR in MCF-7/ADR cells was (47.13±4.11)%, the intracellular fluorescence desity of ADR in MCF-7 cells was (60.24±2.61)%,The former was significantly lower than the latter,P <0.05;Treated with 5μmol/L ADR in combination with 10μmol/L MIF, the intracellular fluorescence desity of ADR in MCF-7/ADR and MCF-7 cells were (82.72±2.42)% and (88.63±2.75)% respectively, both higher than that without MIF,P<0.01; There were no statistical differences between MCF-7/ADR cells and MCF-7 cells,p>0.05.3,Before treated with MIF, the G0/G1 ratio of MCF-7/ADR cells was (77.21±3.10)%,the G0/G1 ratio of MCF-7 cells was (59.05±2.16)%, The former was significantly higher than the latter,P<0.05;the S ratio were just the opposite,the S ratio of MCF-7/ADR cells was obviously less than that of MCF-7 cells,P<0.05; when treated with 10μmol/L MIF, the growth of MCF-7 cells was inhibited, the G0/G1 ratio was(75.28±2.53)%, But compared with before, the G0/G1 ratio was obviously increased,P <0.05;the S ratio of MCF-7 cells was obviously less than that without MIF,P<0.05; the G0/G1 and S ratio of MCF-7/ADR cells were(80.13±2.72)% and (13.52±1.03)% respectively, both no statistical differences than that without MIF,P>0.05,while the growth inhibition of MCF-7/ADR cells was not so obvious;There were no statistical differences between two kinds of cells,p>0.05;For all groups, the G2/M ratio had no statistical differences with or without MIF,p>0.05.Conclusion:1,MIF can reverse drug resistance of human breast cancer MCF-7/ADR cells through decreasing P-gp expression and increasing the intracellular accumulation of adriamycin(ADR).2,P-gp mediated efflux of intracellular drug may be the main reason of drug resistance in human breast cancer cell line MCF-7/ADR.3,10μmol/L mifepristone had no distinct influence on cell cycle of human breast cancer drug-resistant MCF-7/ADR cells.