The aerial parts of Saururus chinensis (SC) have been used for the treatment of
edema,
fever,
jaundice, and inflammatory diseases in Korean
folk medicine for centuries. However, the mechanism by which SC exerts these anti-tumorigenic activities in human prostate and
breast cancer cells has not yet been fully understood. In this study, we report on the
methylene chloride fraction from SC exerting cytotoxicity against prostate and
breast cancer cells in a dose-dependent manner. Specifically, SC exerted the most potent cytotoxicity in LNCaP and MCF-7 cells. SC was shown to down-regulate various angiogenetic (
VEGF), proliferative (
Cyclin D₁, anti-apoptotic (Bcl-2) gene products in these cells. SC also increased the number of
annexin V-positive apoptotic bodies and the sub-G1
DNA contents of the cell cycle undergoing apoptosis through
caspase-3 activation in both LNCaP and MCF-7 cells. We further confirmed that
caspase-3 plays an important role in SC-induced apoptosis in LNCaP and MCF-7 cells through the use of the
caspase-3 inhibitor. Moreover, we observed that SC potentiated
paclitaxel-induced apoptosis in MCF-7 cells and
sauchinone is a major active constituent of SC, which could induce apoptosis in the cells. Taken together, our data provide the evidence that SC induces apoptosis depending on
caspase-3 activation and overcomes the natural
biological resistance to
chemotherapy found in human prostate and
breast cancer cells.