title: Genistein enhances insulin-like growth factor signaling pathway in human breast cancer (MCF-7) cells.
abstract: Physiological concentration of genistein, a natural isoflavonoid phytoestrogen, stimulates human breast cancer (MCF-7) cells proliferation. In this study, we hypothesize that low concentration of genistein mimics the action of 17beta-estradiol in stimulation of MCF-7 cell growth by enhancement of IGF-I signaling pathway. Genistein, at 1 microM, stimulated the growth of MCF-7 cells. Cell cycle analysis showed that 1 micro M genistein significantly increased the S phase and decreased the G0G1 phase of MCF-7 cells. The protein and mRNA expression of IGF-I receptor (IGF-IR) and insulin receptor substrate (IRS)-1, but not Src homology/collagen protein, increased in response to 1 microM genistein in a time-dependent manner. These effects could be completely abolished by cotreatment of MCF-7 cells with estrogen antagonist ICI 182780 (1 microM) and tamoxifen (0.1 microM). Our results also showed that genistein induction of IGF-IR and IRS-1 expression resulted in enhanced tyrosine phosphorylation of IGF-IR and IRS-1 on IGF-I stimulation. Taken together, these data provide the first evidence that the IGF-IR pathway is involved in the proliferative effect of low-dose genistein in MCF-7 cells.
authors.affiliation: Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong Special Administrative Region, People's Republic of China.
authors.forename: Wen-Fang
authors.initials: WF
authors.lastname: Chen
authors.forename: Man-Sau
authors.initials: MS
authors.lastname: Wong
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology; D047628:Estrogen Receptor alpha; D019833:Genistein / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D055504:Insulin Receptor Substrate Proteins; D007700:Kinetics; D009994:Osmolar Concentration; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000235:genetics / Q000378:metabolism; D011960:Receptors, Estrogen / Q000037:antagonists & inhibitors / Q000235:genetics; D055765:Shc Signaling Adaptor Proteins; D015398:Signal Transduction / Q000187:drug effects*; D013002:Somatomedins / Q000378:metabolism*; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D047628:Estrogen Receptor alpha; C526292:IRS1 protein, human; D055504:Insulin Receptor Substrate Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D011960:Receptors, Estrogen; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; D013002:Somatomedins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D004958:Estradiol; D019833:Genistein; D017526:Receptor, IGF Type 1