title: Identification and characterization of stemlike cells in human esophageal adenocarcinoma and normal epithelial cell lines.
abstract: OBJECTIVE
  Recent studies have suggested that human solid tumors may contain subpopulations of cancer stem cells with the capacity for self-renewal and the potential to initiate and maintain tumor growth. The aim of this study was to use human esophageal cell lines to identify and characterize putative esophageal cancer stem cell populations.
  
  
  METHODS
  To enrich stemlike cells, Het-1A (derived from immortalized normal esophageal epithelium), OE33, and JH-EsoAd1 (each derived from primary esophageal adenocarcinomas) were cultured using serum-free media to form spheres. A comprehensive analysis of parent and spheroid cells was performed by flow cytometry, Western blot analysis, immunohistochemistry and polymerase chain reaction array to study cancer stem cell-related genes, colony formation assays to assess clonogenicity, xenotransplantation to assess tumorigenicity, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays to assess chemosensitivity to 5-fluorouracil and cisplatin.
  
  
  RESULTS
  For all cell lines, clonogenicity, tumorigenicity, and chemoresistance to 5-fluorouracil and cisplatin were significantly higher than for spheroid cells compared with parent cells. Spheroids exhibited an increased frequency of cells expressing integrin α6(bri)/CD71(dim), and Achaete-scute complex homolog 2 messenger RNA and protein were also significantly overexpressed in spheroid cells compared with parent cells.
  
  
  CONCLUSIONS
  The higher clonogenicity, tumorigenicity, and drug resistance exhibited by spheroids derived from Het-1A, OE33, and JH-EsoAd1 reflects an enrichment of stemlike cell populations within each esophageal cell line. Esophageal cells enriched for integrin α6(bri)/CD71(dim) and/or overexpressing Achaete-scute complex homolog 2 would appear to represent at least a subpopulation of stemlike cells in Het-1A, OE33, and JH-EsoAd1.
authors.affiliation: University of Saskatchewan Department of Surgery, Royal University Hospital, Saskatoon, Saskatchewan, Canada.
authors.forename: Ronghua
authors.initials: R
authors.lastname: Zhao
authors.forename: Luca
authors.initials: L
authors.lastname: Quaroni
authors.forename: Alan G
authors.initials: AG
authors.lastname: Casson
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002945:Cisplatin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D004938:Esophageal Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D005434:Flow Cytometry; D005472:Fluorouracil / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D039503:Integrin alpha6 / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D008822:Mice, Transgenic; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D012333:RNA, Messenger / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D011990:Receptors, Transferrin / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018874:Spheroids, Cellular; D013997:Time Factors; D047368:Tumor Burden; D023041:Xenograft Model Antitumor Assays
chemical_list: D015703:Antigens, CD; D000970:Antineoplastic Agents; D051792:Basic Helix-Loop-Helix Proteins; D014408:Biomarkers, Tumor; D002945:Cisplatin; D005472:Fluorouracil; D039503:Integrin alpha6; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D011990:Receptors, Transferrin; C065501:ASCL2 protein, human; C068126:CD71 antigen; C116884:LGR5 protein, human