title: Absence of CD71 transferrin receptor characterizes human gastric adenosquamous carcinoma stem cells.
abstract: BACKGROUND
  Although the importance of cancer stem cells (CSCs) in overcoming resistance to therapy and metastasis has recently been reported, the role of CSCs in gastric cancer remains to be elucidated.
  
  
  METHODS
  MKN-1 cells were used to study markers of CSCs in gastric adenosquamous carcinoma, as these cells are suitable for determining multidifferentiation ability. Changes in expression of CD44, CD49f, CD133, and CD71 following 5-fluorouracil (5-FU) treatment were assessed.
  
  
  RESULTS
  After 5-FU treatment, only the CD71- fraction was significantly increased. Investigation of CD71 indicated that the CD71- cell fraction was present in the G1/G0 cell cycle phase and showed high resistance to the anticancer agent 5-FU. Limiting dilution and serial transplantation assays revealed the CD71- cell fraction to have higher tumorigenicity than the CD71+ cell fraction. The CD71- cell fraction showed multipotency to adenocarcinoma and squamous cell carcinoma. A three-dimensional (3D) invasion assay and immunohistochemical analysis showed CD71- cells to be highly invasive and to exist in the invasive fronts of cancer foci.
  
  
  CONCLUSIONS
  The present study suggests that use of CD71- as a marker for adenosquamous carcinoma may provide a useful model for studying CSCs.
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Osaka, Japan.
authors.forename: Masahisa
authors.initials: M
authors.lastname: Ohkuma
authors.forename: Naotsugu
authors.initials: N
authors.lastname: Haraguchi
authors.forename: Hideshi
authors.initials: H
authors.lastname: Ishii
authors.forename: Koshi
authors.initials: K
authors.lastname: Mimori
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Tanaka
authors.forename: Ho Min
authors.initials: HM
authors.lastname: Kim
authors.forename: Miho
authors.initials: M
authors.lastname: Shimomura
authors.forename: Hajime
authors.initials: H
authors.lastname: Hirose
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Yanaga
authors.forename: Masaki
authors.initials: M
authors.lastname: Mori
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015197:Carcinogenicity Tests; D018196:Carcinoma, Adenosquamous / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D019008:Drug Resistance, Neoplasm / Q000276:immunology*; D005260:Female; D005472:Fluorouracil / Q000494:pharmacology; D006801:Humans; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D009361:Neoplasm Invasiveness / Q000276:immunology; D011990:Receptors, Transferrin / Q000378:metabolism*; D013234:Stem Cells / Q000187:drug effects / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D014408:Biomarkers, Tumor; C068126:CD71 antigen; D011990:Receptors, Transferrin; D005472:Fluorouracil