title: CD44s signals the acquisition of the mesenchymal phenotype required for anchorage-independent cell survival in hepatocellular carcinoma.
abstract: BACKGROUND
  Circulating tumour cells (CTCs) have an important role in metastatic processes, but details of their basic characteristics remain elusive. We hypothesised that CD44-expressing CTCs show a mesenchymal phenotype and high potential for survival in hepatocellular carcinoma (HCC).
  
  
  METHODS
  Circulating CD44(+)CD90(+) cells, previously shown to be tumour-initiating cells, were sorted from human blood and their genetic characteristics were compared with those of tumour cells from primary tissues. The mechanism underlying the high survival potential of CD44-expressing cells in the circulatory system was investigated in vitro.
  
  
  RESULTS
  CD44(+)CD90(+) cells in the blood acquired epithelial-mesenchymal transition, and CD44 expression remarkably increased from the tissue to the blood. In Li7 and HLE cells, the CD44(high) population showed higher anoikis resistance and sphere-forming ability than did the CD44(low) population. This difference was found to be attributed to the upregulation of Twist1 and Akt signal in the CD44(high) population. Twist1 knockdown showed remarkable reduction in anoikis resistance, sphere formation, and Akt signal in HLE cells. In addition, mesenchymal markers and CD44s expression were downregulated in the Twist1 knockdown.
  
  
  CONCLUSIONS
  CD44s symbolises the acquisition of a mesenchymal phenotype regulating anchorage-independent capacity. CD44s-expressing tumour cells in peripheral blood are clinically important therapeutic targets in HCC.
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Okabe
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ishimoto
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Mima
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nakagawa
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Hayashi
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kuroki
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Imai
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nitta
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Saito
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: D
authors.initials: D
authors.lastname: Hashimoto
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Chikamoto
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ishiko
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Division of Gene Regulation, Institute for Advanced Medical Research, School of Medicine, Keio University, Minato, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Nagano
authors.affiliation: 1] Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan [2] Department of Multidisciplinary Treatment for Gastroenterological Cancer, Kumamoto University Hospital, Kumamoto 860-8556, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Beppu
authors.affiliation: Division of Gene Regulation, Institute for Advanced Medical Research, School of Medicine, Keio University, Minato, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Saya
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Baba
mesh_terms: D023102:Anoikis / Q000235:genetics; D017209:Apoptosis; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement; D002470:Cell Survival; D015536:Down-Regulation; D058750:Epithelial-Mesenchymal Transition; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics / Q000378:metabolism*; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology*; D008648:Mesoderm / Q000166:cytology; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics*; D051057:Proto-Oncogene Proteins c-akt / Q000096:biosynthesis; D034622:RNA Interference; D034741:RNA, Small Interfering; D018800:Thy-1 Antigens / Q000378:metabolism; D051879:Twist-Related Protein 1 / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D018960:Hyaluronan Receptors; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; C103173:TWIST1 protein, human; D018800:Thy-1 Antigens; D051879:Twist-Related Protein 1; D051057:Proto-Oncogene Proteins c-akt