TLR4-dependent tumor-initiating stem cell-like cells (TICs) in alcohol-associated hepatocellular carcinogenesis

Adv Exp Med Biol. 2015:815:131-44. doi: 10.1007/978-3-319-09614-8_8.

Abstract

Alcohol abuse predisposes individuals to the development of hepatocellular carcinoma (HCC) and synergistically heightens the HCC risk in patients infected with hepatitis C virus (HCV). The mechanisms of this synergism have been elusive until our recent demonstration of the obligatory role of ectopically expressed TLR4 in liver tumorigenesis in alcohol-fed HCV Ns5a or Core transgenic mice. CD133+/CD49f+ tumor-initiating stem cell-like cells (TICs) isolated from these models are tumorigenic in a manner dependent on TLR4 and NANOG. TICs' tumor-initiating activity and chemoresistance are causally associated with inhibition of TGF-β tumor suppressor pathway due to NANOG-mediated expression of IGF2BP3 and YAP1. TLR4/NANOG activation causes p53 degradation via phosphorylation of the protective protein NUMB and its dissociation from p53 by the oncoprotein TBC1D15. Nutrient deprivation reduces overexpressed TBC1D15 in TICs via autophagy-mediated degradation, suggesting a possible role of this oncoprotein in linking metabolic reprogramming and self-renewal.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Animals
  • Carcinogenesis
  • Carcinoma, Hepatocellular / chemically induced*
  • Ethanol / toxicity*
  • GTPase-Activating Proteins / physiology
  • Humans
  • Liver Neoplasms / chemically induced*
  • Mice
  • Neoplastic Stem Cells / physiology*
  • Proto-Oncogenes
  • Toll-Like Receptor 4 / physiology*
  • Transforming Growth Factor beta / physiology

Substances

  • GTPase-Activating Proteins
  • TBC1D15 protein, human
  • Toll-Like Receptor 4
  • Transforming Growth Factor beta
  • Ethanol