Figure 1.

SSD induces apoptosis. MDA-MB-231 cells were exposed to SSD for 24 h and (A) cell viability was examined using an MTT assay (n=3) and (B) the percentage of apoptotic cells was determined by flow cytometry (n=3). (C) Quantitative analysis of the apoptotic rate from data presented in part B. (D) MDA-MB-231 cells were exposed to SSD for 24 h and the expression levels of c-caspase-3 and c-PARP were detected by western blotting (n=3). (E) Semi-quantitative analysis of the expression levels presented in part D. All data are presented as the mean ± SD. *P<0.05, **P<0.01 vs. 0 µM. SSD, saikosaponin D; c-, cleaved; IC₅₀, half maximal inhibitory concentration; PI, propidium iodide; PARP, poly (ADP-ribose) polymerase.