title: Genistein inhibits cell invasion and motility by inducing cell differentiation in murine osteosarcoma cell line LM8.
abstract: BACKGROUND
  One of the problems associated with osteosarcoma is the frequent formation of micrometastases in the lung prior to diagnosis because the development of metastatic lesions often causes a fatal outcome. Therefore, the prevention of pulmonary metastases during the early stage of tumor development is critical for the improvement of the prognosis of osteosarcoma patients. In Japan, soy is consumed in a wide variety of forms, such as miso soup and soy sauce. The purpose of this study is to investigate the effect of genistein, an isoflavone found in soy, on the invasive and motile potential of osteosarcoma cells.
  
  
  METHODS
  LM8 cells were treated for 3 days with various concentrations of genistein. The effect of genistein on cell proliferation was determined by DNA measurement in the cultures and 5-bromo-2'-deoxyuridine (BrdU) incorporation study. The assays of cell invasion and motility were performed using the cell culture inserts with either matrigel-coated membranes or uncoated membranes in the invasion chambers. The expression and secretion of MMP-2 were determined by immunohistochemistry and gelatin zymography. The subcellular localization and cellular level of β-catenin were determined by immunofluorescence and Western blot. For examining cell morphology, the ethanol-fixed cells were stained with hematoxylin-eosin (H&E). The expression of osteocalcin mRNA was determined by reverse transcription-polymerase chain reaction (RT-PCR).
  
  
  RESULTS
  Genistein dose-dependently inhibits cell proliferation. Genistein-treated cells were less invasive and less motile than untreated cells. The expression and secretion of MMP-2 were lower in the genistein-treated cultures than in the untreated cultures. β-Catenin in untreated cells was located in the cytoplasm and/or nucleus, while in genistein-treated cells it was translocated near to the plasma membrane. The level of β-catenin was higher in genistein-treated cells than in untreated cells. Treatment of LM8 cells with genistein induced morphological changes, markedly decreased the formation of multilayer masses of cells, and markedly increased the expression of osteocalcin mRNA.
  
  
  CONCLUSIONS
  Genistein decreased invasive and motile potential by inducing cell differentiation in LM8 cells. Genistein may be useful as an anti-metastatic drug for osteosarcoma through its differentiation-inducing effects.
authors.affiliation: Department of Medical Technology, Faculty of Health Sciences, Ehime Prefectural University of Health Sciences, Takooda, Tobe-cho, Iyo-gun, Ehime, 791-2101, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nakamura
authors.forename: Junichi
authors.initials: J
authors.lastname: Aizawa
authors.forename: Kenshi
authors.initials: K
authors.lastname: Sakayama
authors.forename: Teruki
authors.initials: T
authors.lastname: Kidani
authors.forename: Tomoyo
authors.initials: T
authors.lastname: Takata
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Norimatsu
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Miura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Masuno
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000633:toxicity*; D002454:Cell Differentiation / Q000187:drug effects*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D019833:Genistein / Q000633:toxicity*; D007150:Immunohistochemistry; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D051379:Mice; D015675:Osteocalcin / Q000235:genetics / Q000378:metabolism; D012516:Osteosarcoma / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
chemical_list: D016588:Anticarcinogenic Agents; D012333:RNA, Messenger; D051176:beta Catenin; D015675:Osteocalcin; D019833:Genistein; D020778:Matrix Metalloproteinase 2