title: Anti-breast cancer potential of daidzein in rodents.
abstract: OBJECTIVE
  This study was carried out to explore anti-breast cancer potential of isoflavone daidzein or its related compounds using appropriate animal models and their anti-tumor mechanism.
  
  
  METHODS
  Daidzein or its major metabolite equol at a dose molar equivalent to tamoxifen [1.0 mg(2.7 μmol)/kg or 10 mg (27 μmol)/kg/day] was treated orally to rats bearing 7,12-dimethylbenz(a)anthracene(DMBA)-induced mammary tumors or ovariectomized athymic nude mice implanted with human MCF-7 breast cancer xenograft and an estrogen pellet. The growth of tumors was monitored for several weeks after the treatment. The cell-cycle and apoptotic stages in mammary tumors collected from rats were analyzed by flow cytometry. Immunohistochemistry analysis was also used to determine the expression of caspase-3.
  
  
  RESULTS
  Oral treatment with daidzein or equol at a human equivalent dose suppressed the growth of both DMBA-induced mammary tumors and human MCF-7 breast cancer xenografts in rodents, the inhibitory activity being superior to that of genistein or tamoxifen. Strong apoptosis induced by daidzein or equol contributes to the anti-tumor potential.
  
  
  CONCLUSIONS
  Daidzein and its metabolite equol showed the potential of inhibiting the growth of mammary tumors in rodents. Daidzein or equol could be used as a core structure to design new drugs for breast cancer therapy. Our results indicate that consumption of daidzein may protect against breast cancer.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Liu
authors.forename: Naomi
authors.initials: N
authors.lastname: Suzuki
authors.forename: Y R
authors.initials: YR
authors.lastname: Santosh Laxmi
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Shinya
authors.initials: S
authors.lastname: Shibutani
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017209:Apoptosis; D005260:Female; D006131:Growth Inhibitors / Q000627:therapeutic use*; D007529:Isoflavones / Q000627:therapeutic use*; D008325:Mammary Neoplasms, Experimental / Q000188:drug therapy* / Q000473:pathology; D051379:Mice; D051381:Rats
chemical_list: D000970:Antineoplastic Agents; D006131:Growth Inhibitors; D007529:Isoflavones; C004742:daidzein