title: Effects of genistein and daidzein on membrane characteristics of HCT cells.
abstract: Genistein and daidzein are two major isoflavonoids in soybeans. They have received increasing attention because of their possible role in cancer prevention. In the present investigation, the human colon tumor (HCT) cell line was used to investigate the effect of isoflavonoids on cell growth with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric assay. We found that genistein and/or daidzein could inhibit growth in HCT cells. The 50% inhibitory concentrations of genistein and daidzein were 15 and 40 microM, respectively. Fluorescent polarization, quasielastic light scattering, and circular dichroism were used to study the influence of isoflavonoids on membrane characteristics of HCT cells, including membrane fluidity, density of cell surface charge, and membrane protein conformation. Membrane fluidity of HCT cells was obviously reduced by genistein, but not by daidzein. The effect of genistein was time and dose dependent. In addition, genistein and daidzein could reduce the density of cell surface charge and increase the order of membrane protein conformation. All these changes may represent one of the mechanisms of the effect of isoflavonoids on growth inhibition, differentiation promotion, and transfer interference in a tumor cell line.
authors.affiliation: Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, People's Republic of China.
authors.forename: J
authors.initials: J
authors.lastname: Yu
authors.forename: Y
authors.initials: Y
authors.lastname: Cheng
authors.forename: L
authors.initials: L
authors.lastname: Xie
authors.forename: R
authors.initials: R
authors.lastname: Zhang
mesh_terms: D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects; D003110:Colonic Neoplasms / Q000473:pathology* / Q000517:prevention & control; D004305:Dose-Response Relationship, Drug; D019833:Genistein / Q000494:pharmacology*; D006801:Humans; D007529:Isoflavones / Q000494:pharmacology*; D008560:Membrane Fluidity / Q000187:drug effects; D008565:Membrane Proteins / Q000737:chemistry / Q000187:drug effects; D011487:Protein Conformation / Q000187:drug effects; D013499:Surface Properties / Q000187:drug effects; D013997:Time Factors; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D016588:Anticarcinogenic Agents; D007529:Isoflavones; D008565:Membrane Proteins; C004742:daidzein; D019833:Genistein