Sublethal heat treatment promotes epithelial-mesenchymal transition and enhances the malignant potential of hepatocellular carcinoma.

Abstract

UNLABELLED:

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: Shuhei Yoshida, Miroslaw Kornek, Naoki Ikenaga, Moritz Schmelzle, Ryota Masuzaki, Eva Csizmadia, Yan Wu, Simon C Robson, Detlef Schuppan
• Journal: Hepatology (Baltimore, Md.) (Hepatology) Vol. 58 Issue 5 Pg. 1667-80 (Nov 2013) ISSN: 1527-3350 [Electronic] United States
• PMID: 23729316 (Publication Type: Journal Article)
• Copyright: © 2013 by the American Association for the Study of Liver Diseases.

Chemical References

• Heat-Shock Proteins
• SHC1 protein, human
• Shc Signaling Adaptor Proteins
• Src Homology 2 Domain-Containing, Transforming Protein 1
• Extracellular Signal-Regulated MAP Kinases

Topics

• Adult
• Aged
• Animals
• Carcinoma, Hepatocellular (pathology, surgery)
• Catheter Ablation (methods)
• Cell Proliferation
• Cell Survival
• Epithelial-Mesenchymal Transition
• Extracellular Signal-Regulated MAP Kinases (physiology)
• Female
• Heat-Shock Proteins (biosynthesis)
• Hep G2 Cells
• Humans
• Liver Neoplasms (pathology, surgery)
• Male
• Mice
• Mice, Inbred BALB C
• Middle Aged
• Phosphorylation
• Shc Signaling Adaptor Proteins (physiology)
• Src Homology 2 Domain-Containing, Transforming Protein 1