title: Phytoestrogenic activity of blackcurrant (Ribes nigrum) anthocyanins is mediated through estrogen receptor alpha.
abstract: METHODS
  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.
  
  
  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.
  
  
  CONCLUSIONS
  These results suggest that blackcurrant anthocyanins act as phytoestrogens in vitro and in vivo.
authors.affiliation: Department of Biomedical Sciences, Hirosaki University Graduate School of Health Sciences, Hirosaki, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Nanashima
authors.affiliation: Department of Pathologic Analysis, Hirosaki University Graduate School of Health Sciences, Hirosaki, Japan.
authors.forename: Kayo
authors.initials: K
authors.lastname: Horie
authors.affiliation: Department of Health Promotion, Hirosaki University Graduate School of Health Sciences, Hirosaki, Japan.
authors.forename: Toshiko
authors.initials: T
authors.lastname: Tomisawa
authors.affiliation: Department of Biomedical Sciences, Hirosaki University Graduate School of Health Sciences, Hirosaki, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Chiba
authors.affiliation: Department of Biomedical Sciences, Hirosaki University Graduate School of Health Sciences, Hirosaki, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Nakano
authors.affiliation: Department of Disability and Health, Hirosaki University Graduate School of Health Sciences, Hirosaki, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Fujita
authors.affiliation: Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Japan.
authors.forename: Hayato
authors.initials: H
authors.lastname: Maeda
authors.affiliation: Department of Pathologic Analysis, Hirosaki University Graduate School of Health Sciences, Hirosaki, Japan.
authors.forename: Maiko
authors.initials: M
authors.lastname: Kitajima
authors.affiliation: Department of Disability and Health, Hirosaki University Graduate School of Health Sciences, Hirosaki, Japan.
authors.forename: Shizuka
authors.initials: S
authors.lastname: Takamagi
authors.affiliation: Center for Joint Research, Hirosaki University, Hirosaki, Japan.
authors.forename: Daishi
authors.initials: D
authors.lastname: Uchiyama
authors.affiliation: Department of Pathologic Analysis, Hirosaki University Graduate School of Health Sciences, Hirosaki, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Watanabe
authors.affiliation: Department of Biomedical Sciences, Hirosaki University Graduate School of Health Sciences, Hirosaki, Japan.
authors.forename: Toshiya
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Faculty of Education, Hirosaki University, Hirosaki, Japan.
authors.forename: Yoji
authors.initials: Y
authors.lastname: Kato
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D000872:Anthocyanins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D001667:Binding, Competitive; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D016889:Endometrial Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D047629:Estrogen Receptor beta / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D061986:MCF-7 Cells / Q000187:drug effects; D062105:Molecular Docking Simulation; D048789:Phytoestrogens / Q000494:pharmacology*; D017207:Rats, Sprague-Dawley; D031965:Ribes / Q000737:chemistry*
chemical_list: D000872:Anthocyanins; D047629:Estrogen Receptor beta; D048789:Phytoestrogens; D000469:Alkaline Phosphatase
keywords: Anthocyanin; Blackcurrant; Estrogenic activity; Phytoestrogen; Uterotrophic assay