Inducing apoptosis effect of caffeic acid 3,4-dihydroxy-phenethyl ester on the breast cancer cells

To explore the antitumor effect of caffeic acid 3,4-dihydroxy-phenethyl ester (CADPE) on the breast cancer cell lines and illuminate the related mechanism. After treatment with different concentrations of CADPE for 24, 48, and 72 h, cell proliferation ability of the breast cancer cell lines MDA-MB-231 and MDA-MB-435 was analyzed by the MTT. Changes of the cell cycles were evaluated by PI staining. Cell apoptosis was examined by flow cytometry after Annexin V/7AAD double staining. Nuclear morphologic changes were observed under the inverted fluorescence microscope after staining with Hoechst 33342. Mitochondrial membrane potential and reactive oxygen species (ROS) level were estimated by JC-1 and DCFH-DA staining. In addition, the expression level of mitochondrial signaling pathway proteins Bcl-2, Bax, and caspase-3 were evaluated by Western blot. CADPE has the distinct cytotoxic effect to the breast cancer cells, and the effect is dose dependent. It did not change the cell cycles but induced the cell apoptosis of the breast cancer cells. At the same time, after CADPE treatment, the expression levels of caspase-3 and Bax in the breast cancer cells were upregulated and Bcl-2 expression was declined. The ROS level in the breast cancer cells was enhanced, and mitochondrial membrane potential of the cells was downregulated. CADPE has the antitumor functions. It can induce the cell apoptosis through downregulating Bcl-2 expression, enhancing Bax and caspase-3 expression levels, upregulating ROS level and reducing the mitochondrial membrane potential of the breast cancer cells to trigger the mitochondrial signal pathway.