Analysis Of RANKL/RANK Signaling Pathway Mediated The Drug-resistance To Adriamycin Of Breast Cancer MCF-7 Cells

Objective To investigate the effect of RANKL/RANK(the receptor activator of nuclear factor ?B ligand / receptor activator of nuclear factor ?B,RANKL/RANK)signaling pathway on the drug resistance in breast cancer cells,and analysis its potential mechanism.Method Human breast cancer cell lines MCF-7 and adriamycin-resistant human breast cancer cell line MCF7/ADR were cultured.Expression levels of RANK in MCF-7 and MCF7/ADR cells were detected by Immunofluorescence and Western blot.Two kinds of cells were pre-treated with RANKL and RANKL inhibitor osteoprotegerin(OPG)respectively,Protein levels of RANK and breast cancer stem cell associated ALDH1 were detected by Western blot.The drug resistance to adriamycin of MCF-7,pre-treated with RANKL and OPG,were detected by CCK-8(Cell Counting Kit 8),and the results were calculated by cell survival rate(%).Result Immunofluorescence and Western blot showed that the expression of RANK protein in MCF7/ADR were significantly increased(P<0.05),and in the same concentration of RANKL,the protein level of ALDH1 in MCF7/ADR was obviously higher than MCF-7(P<0.05).With the increase of the concentration of RANKL(0,50,100ng�m L-1),the expression of two kinds of cell were gradually increased(P<0.05).The protein levels of ALDH1 in MCF-7 which pre-treated with RANKL 100ng�mL-1 and OPG 500ng�m L-1 were significantly lower than the RANKL 100ng�mL-1group(P<0.05).In CCK-8 trials,when Adriamycin were from 2.5?mol�L-1 to 5?mol�L-1,with the increase of the concentration of RANKL,the cell survival rate of MCF-7 was obviously dose-dependent,and there was a gradual increasing trend.However OPG can reverse the phenomenon(P>0.05).Conclusion RANKL/RANK signaling pathway may have participation in drug resistance in breast cancer.It may have promoting effect on the process of drug resistance by maintaining stem cells population.