| Objective:To observe the reversal effect Of TP-PEI-CyD on the drug resistance of human breast cancer cell line MCF-7/Taxol,and explor its related mechanism.Methods:1.The inhibitory effects of Taxol,cisplatin and TP-PEI-CyD on growth of MCF-7 cells and MCF-7/Taxol cells were examined by CCK-8 assay and their IC50 values and the resistance index(RI)of MCF-7/Taxol cells and the low-toxic concentration that TP-PEI-CyD inhibit the growth of MCF-7/Taxol cells were calculated.2.Based on the IC50 results,MCF-7/Taxol cells were treated with a selected low-toxic concentration of TP-PEI-CyD(0.5ug/ml ? 1.5ug/ml)combined with different concentrations of Taxol(2?4?6?8?10ug/ml)andand cisplatin(1?5?10?20?30 ug/ml)detected by CCK-8 assay,and then the IC50 and reverse times were calculated.3.MCF-7/Taxol cells were treated with a low-toxic concentration of TP-PEI-CyD(0.5ug/ml ? 1.5ug/ml)and Taxol(10ug/ml)or cisplatin(10ug/ml)combined,and then the influence on cell apoptosis was detected by flow cytometry,4.MCF-7/Taxol cells were treated with a low-toxic concentration of TP-PEI-CyD(1ug/ml)and Taxol(1ug/ml)or cisplatin(2.5ug/ml)alone or combined,and then the expressions of the mRNA of MRP?LRP and GST-? was detected by RT-PCR.Results:1.CCK-8 assay results showed that,the IC50 of MCF-7 to Taxol?cisplatin ?TPL and TP-PEI-CyD was(0.23±0.02)ug/ml?(3.66±0.19)ug/ml?(0.41 ± 0.12)? g/mL ?(7.41±0.89)?g/mL respectively;the IC50 of MCF-7/Taxol to Taxol ?cisplatin?TPL and TP-PEI-CyD was(6.19±0.17)ug/ml?(23.59±0.40)ug/ml?(0.16±0.05)ug/ml ?(3.39±0.38)?g/mL respectively,they had significantly statistical difference(P<0.05).The the resistance index(RI)of MCF-7/Taxol to Taxol and cisplatin was 26.91?6.45 respectively;MCF-7/Taxol cells were treated with a low-toxic concentration(IC50<15%)of TP-PEI-CyD(0.5ug/ml?1.5ug/ml)and than Carry out the following tests.2.MCF-7/Taxol cells were treated with a low-toxic concentration of TP-PEI-CyD(0.5ug/ml)and Taxol or cisplatin combined,the result showedthat the Taxol or cisplatin IC50 of MCF-7/Taxol was decreased from(6.19±0.17)?g/mL?(23.59±0.40)?g/mL to(4.43±0.30)?g/mL?(21.65±0.54)?g/mL respectively,they had significantly statistical difference(P<0.05),and their reversal fold(RF)was 1.39?1.08 respectively;MCF-7/Taxol cells were treated with a low-toxic concentration of TP-PEI-CyD(1.5ug/ml)and Taxol or cisplatin combined,the result showed that the Taxol or cisplatin IC50 of MCF-7/Taxol was decreased from(6.19±0.17)?g/mL?(23.59±0.40)?g/mL to(3.28±0.16)?g/mL?(10.61±0.81)?g/mL respectively,they had significantly statistical difference(P<0.05),and their reversal fold(RF)was1.89 ? 2.22respectively;3.FCM results showed that the apoptosis rate of the blank group?Taxol group and cisplatin group was(7.11±0.96)%?(16.11±5.31)%?(13.42±1.69)%respectively,the apoptosis rate of the 0.5ug/ml TP-PEI-CyD group and1.5ug/ml TP-PEI-CyD was(9.96±0.62)% and(13.38±2.91)% respectively,the apoptosis rate of the Taxol combined with 0.5ug/mlTP-PEI-CyD group and the cisplatin combined with 0.5ug/mlTP-PEI-CyD was(29.13±0.43)% ?(23.14±2.30)% respectively;the apoptosis rate of the Taxol combined with1.5ug/ml TP-PEI-CyD group and the cisplatin combined with1.5ug/ml TP-PEI-CyD was(57.79±6.88)%?(54.24±5.92)% respectively;the apoptosis rate of the Taxol combined with TP-PEI-CyD was significantly lower than that in the Taxol or cisplatin group,they had significantly statisticaldifference(P<0.05).4.RT-PCR results showed that the expression of GST-??LRP and MRP in in the group of Taxol or cisplatin combined with TP-PEI-CyD were significantly lower than that in the Taxol or cisplatin group,they had significantly statistical difference(P<0.05).Conclusions: 1.TP-PEI-CyD can increase the sensitivity of human breast cancer cell line MCF-7/Taxol cells to chemotherapeutic agents,which can reverse the multidrug resistance of human breast cancer cell line MCF-7/Taxol.2.The mechanism of TP-PEI-CyD reversing multidrug resistance in human breast cancer cell line MCF-7/Taxol may be related to the down-regulation of MRP ? LRP and GST-? expressions that cause breast cancer resistant to chemotherapy. |
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