Effects of cyclopamine on the biological characteristics of human breast cancer MCF-7 cell line and its mechanism.

PURPOSE: To observe the effects of cyclopamine on the biological characteristics of human breast cancer MCF-7 cell line and explore its mechanism. MATERIALS AND METHODS: After human breast cancer MCF-7 cells were treated with different-concentration cyclopamine for different periods, MTT assay was used to detect the inhibitory effect of cyclopamine on MCF-7 cell proliferation, flow cytometry was used to determine the distribution of MCF-7 cell cycle and the effect of cyclopamine on MCF-7 apoptosis, and Western blot was used to measure the protein levels of cyclins D1 and p21 in MCF-7 cells. RESULTS: In certain range, MCF-7 cell proliferation was inhibited by cyclopamine in a dose- and time-dependent manner, and the optimal inhibiting concentration was ten µmol/L and the optimal action time at 48 hours. With the time prolongation of cyclopamine action, the cells in G0/G1 phase were significantly increased, but the cells in S phase were significantly decreased (compared with blank control group, allp < 0.05). With the time prolongation of cyclopamine action, apoptosis rate of MCF-7 cells was also significantly increased (compared with blank control group, allp < 0.05). The level of cyclin D1 of MCF-7 cells was decreased, but cyclin p21 was increased (compared with blank control group, all p < 0.05). CONCLUSION: Cyclopamine inhibits MCF-7 cell proliferation via arresting MCF-7 cell transformation from G1 phase to S phase. This may be associated with the expressions of Hedgehog (Hh) signaling pathway-related cyclins.