Dryofragin, a Phloroglucinol Derivative, Induces Apoptosis in Human Breast Cancer MCF-7 Cells Through ROS-mediated Mitochondrial Pathway

Dryofragin is a phloroglucinol derivative extracted from Dryopteris fragrans (L.) Schott. In this study, the anticancer activity of dryofragin on human breast cancer MCF-7 cells was investigated. Dryofragin inhibited the growth of MCF-7 cells in a time and concentration-dependent manner. The cell viability was measured using MTT assay. After treatment with dryofragin for 72, 48 and 24 h, the IC₅₀ values were 27.26, 37.51 and 76.10 μM, respectively. Further analyses of DNA fragmentation and Annexin V-PI double-labeling indicated an induction of apoptosis. Dryofragin-treatment MCF-7 cells had a significantly accumulation of reactive oxygen species (ROS), as well as an increased percentage of cells with mitochondrial membrane potential (MMP) disruption. These phenomena were blocked by pretreatment for 2 h of MCF-7 cells with the antioxidant compound N-acetyl-L-cysteine (NAC, 5 mM). These results speak for the involvement of a ROS-mediated mitochondria-dependent pathway in dryofragin-induced apoptosis. Western blot results showed that dryofragin inhibited Bcl-2 and induced Bax expression which led to an activation of caspases-9 and -3 in the cytosol, and further cleavage of poly ADP-ribose polymerase (PARP) in the nucleus, then induced cell apoptosis. In conclusion, the present study provides evidence that dryofragin induces apoptosis in human breast cancer MCF-7 cells through a ROS-mediated mitochondrial pathway.