Anthocyanin­rich 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 prope-rties. The present study investigated novel functions of anthocyanin­rich 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 µg/ml BCE, respectively. The half­maximal response concentration of BCE was 237.7 µg/ml. Microarray and Ingenuity® Pathway Analysis demonstrated that BCE downregulated cell cycle signaling, including upstream genes with mitotic roles such as polo­like 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 µg/ml BCE induced DNA damage in a dose­dependent manner. Cultures treated with 0, 50, and 100 µg/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 µg/ml BCE­treated cultures (from 1.9 to 4.3%) but not in the 50 µg/ml BCE­treated cultures. Reverse transcription­quantitative polymerase chain reaction analysis demonstrated that BCE reduced mRNA expression of the genomic caretaker lysine­specific demethylas  5B (KDM5B). The results suggested that blackcurrant anthocyanins may act as cell arrest and death inducers via KDM5B downregulation in healthy breast cells.

Phytoestrogenic activity of blackcurrant (Ribes nigrum) anthocyanins is mediated through estrogen receptor alpha.

SCOPE: Blackcurrants (Ribes nigrum L., Grossulariaceae) contain high amounts of anthocyanin polyphenols, which have antioxidant and anti-carcinogenic health benefits. This study analyzed the potential phytoestrogenic effects of blackcurrant extract (BCE) in breast cancer (MCF-7) and human endometrial cancer (Ishikawa) cell lines that over-express estrogen receptor alpha (ERα), as well as in immature female rats. METHODS AND RESULTS: Microarray analysis and Ingenuity® Pathway Analysis showed that BCE activated the ERα pathway, whereas quantitative-PCR confirmed that BCE and four types of anthocyanins up-regulated genes downstream of ERα. BCE (0.1-1.0 µg/mL) and anthocyanins (0.1-10 µM) induced MCF-7 cell proliferation; however, this effect was blocked by ER antagonist fulvestrant. Flow cytometry showed that anthocyanins reduced and increased the number of MCF-7 cells in the G0/G1 and G2/M phases, respectively. Anthocyanins stimulated ERα transcriptional activity in human ERα reporter assays and induced alkaline phosphatase activity in Ishikawa cells. Competition assays and in silico analysis indicated that anthocyanins bind to ERα. Finally, BCE focally induced stratification of columnar epithelial cells in the rat uterus and increased cytoplasmic mucin levels in these cells. CONCLUSION: These results suggest that blackcurrant anthocyanins act as phytoestrogens in vitro and in vivo.