Anthocyanin-rich blackcurrant extract inhibits proliferation of the MCF10A healthy human breast epithelial cell line through induction of G0/G1 arrest and apoptosis

Blackcurrants (Ribes nigrum L., Grossulariaceae) possess a high content of anthocyanin polyphenols, which have been demonstrated to exhibit beneficial effects on health due to their antioxidant and anticarcinogenic properties. The present study investigated novel functions of anthocyanin-rich blackcurrant extracts (BCEs) in a healthy mammary epithelial cell line, MCF10A. The percentages of viable cells were 85, 75, 53 and 31% following exposure to 50, 100, 200 and 400 mu g/ml BCE, respectively. The half-maximal response concentration of BCE was 237.7 mu g/ml. Microarray and Ingenuity (R) Pathway Analysis demonstrated that BCE downregulated cell cycle signaling, including upstream genes with mitotic roles such as polo-like kinase signaling. BCE increased the number of cells in the G0/G1 phase and decreased the number of cells in the S and G2/M phases. Alkaline comet assays demonstrated that 50 and 100 mu g/ml BCE induced DNA damage in a dose-dependent manner. Cultures treated with 0, 50, and 100 mu g/ml BCE contained 4.6, 13.4 and 16.0% apoptotic cells, respectively. As compared with the untreated cultures (1.9%), the number of necrotic cells increased in the 100 mu g/ml BCE-treated cultures (from 1.9 to 4.3%) but not in the 50 mu g/ml BCE-treated cultures. Reverse transcription-quantitative polymerase chain reaction analysis demonstrated that BCE reduced mRNA expression of the genomic caretaker lysine-specific demethylas 5B (KDM5B). The results suggested that blackcurrant anthocyanins may act as cell arrest and death inducers via KDM5B downregulation in healthy breast cells.