Chalcone inhibits the proliferation of human breast cancer cell by blocking cell cycle progression and inducing apoptosis

Chalcones are discussed to represent cancer preventive food components in a human diet that is rich in fruits and vegetables. In this study, we examined chalcone (1,3-diphenyl-2-propenone) for its effect on proliferation in human breast cancer cell lines, MCF-7 and MDA-MB-231. The results showed that chalcone inhibited the proliferation of MCF-7 and MDA-MB-231 by inducing apoptosis and blocking cell cycle progression in the G2/M phase. Immunoblot assay showed that chalcone significantly decreased the expression of cyclin B1, cyclin A and Cdc2 protein, as well as increased the expression of p21 and p27 in a p53-independent manner, contributing to cell cycle arrest. An enhancement in Fas/APO-1 and its two form ligands, membrane-bound Fas ligand (mFasL) and soluble Fas ligand (sFasL), was responsible for the apoptotic effect induced by chalcone. In addition, chalcone also triggered the mitochondrial apoptotic signaling by increasing the amount of Bax and Bak and reducing the level of Bcl-2 and Bcl-XL, and subsequently activated caspase-9 in MCF-7 and MDA-MB-231 cells. Taken together, our study suggests that the blockade of cell cycle progression and initiation of cell apoptotic system may participate in the antiproliferative activity of chalcone in human breast cancer cells.