Objective: To investigate the anti-proliferation and apoptosis effects of aloe emodin (AE) alone and in combination with cisplatin (AE-CP) on breast cancer cell MDA-MB-231. Method: MDA-MB-231 cells were treated for 48 h with 5

10

20

30

40

50 μmol·L-1 AE

2

4

8

12

24

36 μmol·L-1 CP or various concentrations of AE-CP. Cell proliferation was detected by MTT. Apoptosis and cell cycle were detected by Annexin V FITC/PI double-staining and flow cytometer. The protein levels of Bax

Bcl-2 and Bcl-xL were analyzed by Western blot. Result: AE alone significantly inhibited cell proliferation

with an IC50 of 22.21 μmol·L-1. IC50 decreased to 9.51 μmol·L-1 when it was used in combination with CP. The combination index CI50<1

indicating a synergic effect. AE alone arrested cell cycle in G1 phase and induced apoptosis. The arrest was accentuated when CP was given simultaneously

accompanied by a marked increment of apoptosis rate. AE-CP significantly inhibited the protein levels of Bcl-2 and Bcl-xL

but increased Bax. Conclusion: AE could inhibit the cell proliferation of MDA-MB-231

arrest the cell cycle in G1 phase

and induce apoptosis by increasing apoptosis proteins and decreasing anti-apoptosis proteins. AE shows a synergic effect of apoptosis when combined with CP.