title: Sublethal heat treatment promotes epithelial-mesenchymal transition and enhances the malignant potential of hepatocellular carcinoma.
abstract: Radiofrequency ablation (RFA) is a potentially curative therapy for hepatocellular carcinoma (HCC). However, incomplete RFA can induce accelerated invasive growth at the periphery. The mechanisms underlying the RFA-induced tumor promotion remain largely unexplored. Three human HCC cell lines were exposed to 45°C-55°C for 10 minutes, simulating the marginal zone of RFA treatment. At 5-12 days post-treatment cell proliferation, parameters of epithelial-mesenchymal transition (EMT), and activation of mitogen-activated protein kinases were analyzed. Livers from patients with viral hepatitis without and with HCC (n = 114) were examined to confirm the relevance of altered kinase patterns. In vivo tumorigenic potential of heat-treated versus untreated HCC cells was studied in nude mice. Heating to 55°C killed all HCC cells, whereas 65%-85% of cells survived 48°C-50°C, developing spindle-like morphology and expressing CD133, cytokeratin (CK)7, CK19, procollagen-α1(I), and Snail at day 5 after heat exposure, which returned to baseline at day 12. Heat-exposed HCC cells showed enhanced proliferation and prominent activation of p46-Shc (Src homology and collagen) and downstream extracellular signal-related kinase (Erk)1/2. In patients, Shc expression correlated with malignant potential and overall survival. Blocking Erk1/2 reduced proliferation and EMT-like changes of heat-treated HCC cells. Implantation of heat-exposed HEPG2 cells into nude mice induced significantly larger, more aggressive tumors than untreated cells.
  
  
  CONCLUSIONS
  Sublethal heat treatment skews HCC cells toward EMT and transforms them to a progenitor-like, highly proliferative cellular phenotype in vitro and in vivo, which is driven significantly by p46Shc-Erk1/2. Suboptimal RFA accelerates HCC growth and spread by transiently inducing an EMT-like, more aggressive cellular phenotype.
authors.affiliation: Division of Gastroenterology and Liver Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Yoshida
authors.forename: Miroslaw
authors.initials: M
authors.lastname: Kornek
authors.forename: Naoki
authors.initials: N
authors.lastname: Ikenaga
authors.forename: Moritz
authors.initials: M
authors.lastname: Schmelzle
authors.forename: Ryota
authors.initials: R
authors.lastname: Masuzaki
authors.forename: Eva
authors.initials: E
authors.lastname: Csizmadia
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
authors.forename: Simon C
authors.initials: SC
authors.lastname: Robson
authors.forename: Detlef
authors.initials: D
authors.lastname: Schuppan
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D049109:Cell Proliferation; D002470:Cell Survival; D058750:Epithelial-Mesenchymal Transition; D048049:Extracellular Signal-Regulated MAP Kinases / Q000502:physiology; D005260:Female; D006360:Heat-Shock Proteins / Q000096:biosynthesis; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D010766:Phosphorylation; D055765:Shc Signaling Adaptor Proteins / Q000502:physiology; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1
chemical_list: D006360:Heat-Shock Proteins; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D048049:Extracellular Signal-Regulated MAP Kinases