Effects Of Aloe Emodin On Cell Proliferation And Telomerase Expression In Breast Cancer Cell Line MDA-MB231

Objective: To investigate the anti-proliferation and hTERT expression effects of aloe emodin(AE)alone and in combination with cisplatin(AE-CDDP)on breast cancer cell MDA-MB-231.Determine whether there was any synergistic effects between the two agents.To study the effects of AE on the expression of the subunit of telomerase hTERT and its regulatory factors c-Myc,WT1 and E2F1 in breast cancer cell line MDA-MB231.Explore its possible mechanism of action.Methods:1.The cells in logarithmic growth phase were collected and cultured for 24 h,and then they were divided into several groups including AE-treated groups(containing 5,10,20,30,40 and 50 μmol·L-1 of AE in the cultural medium),negative control group(only containing medium and cells),reagent group(containing 0.1% DMSO and cells)and the blank group(no cells).The proliferation of cells in different concentrations of AE was measure by MTT method.The proliferation of the cells that were treated by 30 μmol·L-1 of AE and by different time(24 h,48 h,60 h and 72 h)was also measured.2.The cells were first treated by 2 μmol·L-1,4 μmol·L-1,6 μmol·L-1,8 μmol·L-1,12 μmol·L-1 and 24 μmol·L-1 of cisplatin alone or in combination with 5 μmol·L-1,10 μmol·L-1,20 μmol·L-1,30 μmol·L-1,40 μmol·L-1,50 μmol·L-1 of aloe emodin for 48 h,and then the proliferation of the cells was detected by MTT.3.The protein level of hTERT,c-Myc,WT1 and E2F1 in the cells that were treated by 0 μmol·L-1(control group),10 μmol·L-1,30 μmol·L-1 and 50 μmol·L-1 of AE for 48 h was estimated by the method of Western blot.4.The protein levels of hTERT,c-Myc,WT1 and E2F1 in the cells that were treated by 30 of AE and by different time were also estimated.5.The protein level of hTERT was analyzed by 10 μmol·L-1 of AE and combined with 12 μmol·L-1CDDP by Western blot.Results:1.MTT analysis showed that the compared with the control group,AE significantly inhibited the proliferation of MDA-MB231 cells cultured in vitro and the inhibitory effect increased with the AE concentration.The valued of IC50 was 22.21 μmol·L-1.Under the same concentration of AE,the inhibition of cell proliferation was significantly enhanced with time.2.MTT analysis showed that the half proliferative inhibition value(IC50)was 11.05 μmol·L-1 when treated by CDDP alone,while the IC50 value was decreased to 9.51 μmol·L-1 when treated in combination with aloe emodin.The combination index CI50 was <1.The results indicated that after combination,aloe emodin could improve the sensitivity of breast cancer MDA-MB231 cells to cisplatin,indicating the enhanced sensitivity to chemotherapy of the cells when treated by aloe emodin.Aloe emodin may have synergistic effect with cisplatin.3.The results of Western blot showed that aloe emodin increased the expression of WT1 but inhibited the expression of h-TERT and telomerase regulatory factor c-Myc.The inhibition effect and drug concentration were positively correlated.The lower concentrations of AE promoted expression of regulatory faction E2F2,while the higher concentrations inhibited the expression.4.The results of Western blot showed that aloe emodin decreased the expression of hTERT and c-Myc as well as increased the expression of WT1 and E2F1 by a time depend manner.5.The Western blot showed that aloe emodin could enhance the proliferative inhibition of cisplatin on h TERT expression.Conclusion:1.Aloe emodin inhibits the growth of MDA-MB231 cells.The proliferative inhibition increases with the increasing of aloe emodin concentration and treating time,in a dose-and-time-dependent manner.The combination of aloe emodin and CDDP can inhibit the proliferation of breast cancer MDA-MB231 cells and the protein expression of telomerase subunit hTERT,indicating a synergistic effect.2.Aloe emodin inhibited the protein expression of telomerase subunit hTERT by decreasing the expression of positive regulatory factor c-Myc and increasing the expression of its negative regulatory factor.