Wogonin induces apoptosis and down-regulates survivin in human breast cancer MCF-7 cells by modulating PI3K-AKT pathway

Wogonin, one of flavonoid compounds isolated from Chinese herbal plants Scutellaria baicalensis Georgi, has been recognized as a potent anti-cancer agent acting through control of growth, differentiation and apoptosis. However, the underlying molecular mechanism of its anti-cancer activity remains to be further elucidated. In this study, we investigated the potential role of wogonin in the induced-apoptosis of human breast cancer cells MCF-7. Wogonin was found to inhibit the proliferation of MCF-7 in a concentration and time-dependent manner, notably wogonin could induce G1 phase arrest of MCF-7 cells. Wogonin-induced apoptosis was accompanied by a significant decrease of the Bcl-2 and survivin and increase of Bax and p53. Wogonin also increased active apoptosis forms of caspases-3, -8, -9 significantly. Z-DEVD-fmk, a specific caspase-3 inhibitor, significantly inhibited wogonin-induced cell apoptosis. Wogonin also suppressed the phosphorylation of PI3K/Akt and induced phosphorylation of ERK. PD98059, a specific ERK inhibitor, significantly blocked wogonin-induced apoptosis. On the other hand, LY294002, a specific PI3K inhibitor, significantly increased wogonin-induced cell apoptosis. Further study indicated that LY294002 not only down-regulated the expression of survivin alone, but also enhanced the inhibition of survivin expression combined with wogonin. In conclusion, the pro-apoptotic effect of wogonin is mediated through the activation of ERK and the activation of caspases, and is correlated with the block of the PI3K/Akt/survivin signal pathways in MCF-7 cells.