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Diosgenin, a steroidal saponin present in fenugreek, has been reported with many pharmaceutical effects related to anti-cancer and anti-inflammation properties. To elucidate the mechanism of its anti-proliferative capacity, we investigate its effects on cell cycle arrest and apoptosis in human breast cancer Hs578T cells. We observed that diosgenin exerted a dose- and time-dependent inhibitory effect on the viability of Hs578T cell by the MTT assay. Compared with control group, when cells were treated with diosgenin at concentration higher than 25 uM for 48 hrs, the percentage of G2/M fractions was decreased and that of subG1 phase cells was increased (P<0.05) via flow cytometric analysis with PI staining, responding to show the increasing expressions of Chk1, and inversely reducing expressions of Cdc25c and cyclin B. In addition, protein expressions of cytochrome c, caspases 9 and 3 were increased, whereas antiapoptotic Bcl-2 was decreased in Hs578T cells treated with diosgenin, representing a dose-dependent manner. Furthermore, a dramatic increasing of apoptosis was more predominant by the presence of DNA ladder, which was followed by the mitochondrial membrane potential (MMP) depolarization in those cells exposed to diosgenin. In conclusion, diosgenin possesses an anti-cancer effect, inhibiting Hs578T cell proliferation via cell cycle G2/M arrest and subjecting to apoptosis with disruption of MMP and diosgenin may, therefore, be available in the clinical treatment of breast carcinoma.

98th AACR Annual Meeting-- Apr 14-18, 2007; Los Angeles, CA