The Possible Reverse Effect Of Mifepristone On Human Breast Cancer Drug-resistance Cell Line MCF-7/ADM

Objective:To explore the possible reverse effect of mifepristone on human breast cancer drug-resistance cell line MCF-7/ADM in vitro.Methods:1.Cell culture:Human breast cancer cell line MCF-7 was maintained in RPMI1640 medium supplemented with 10% heat-inactivated bovine serum.MCF-7/ADM was maintained in RPMI1640 medium supplemented with 10%heat-inactivated bovin serum,and 1μmol/L ADM.Both of these two cell lines were cultured in a incubator containing 5%CO₂,saturated humidity,at 37℃.2.The effect of mifepristone to MCF-7 and MCF-7/ADRMwas determined by MTT assay.The dose that made the inhibition rate of these two cell lines less than 5%was chosen as the non-cytotoxic dose.3.Different doses of ADM were used in MCF-7 and MCF-7/ADM cell lines.MTT assay was used in determining IC50 of these two cell lines.4.MCF-7 and MCF-7/ADM cell lines were treated with the non-cytotoxic dose of mifepristone and different doses of ADM.We compared IC50 of these two kinds of cells under different conditions.Results:1.5μmol/L of mifepristone made the inhibition rate of these two cells less than 5%and it had no statistical difference with the group that was not treated with mifepristone(P＞0.05).2.IC50 of ADM to MCF-7 and MCF-7/ADM cell lines were 0.42mg/L,17.21mg/L respectively.IC50 of MCF-7 was obviously less than that of MCF-7/ADM.3.After using 5μmol/L of mifepristone,IC50 of these two cells were decreased to 0.28mg/L,1.96mg/L respectively.IC50 of MCF-7/ADM was obviously decreased(P＜0.01),but that of MCF-7 was not very obvious(P＞0.05).Conclusion:1.Mifepristone can inhibit the growth of MCF-7 and MCF-7/ADM,the effects depend on the doses of mifepristone.5μmol/L of mifepristone is the non-cytotoxic dose.2.ADM can inhibit the growth of MCF-7 and MCF-7/ADM.IC50 of MCF-7 is obviously less than that of MCF-7/ADM 3.5μmol/L of mifepristone can reverse human breast cancer drug-resistance cell line MCF-7/ADM,but have no effect on MCF-7 in vitro.