title: Toll-like receptor 3 expressing tumor parenchyma and infiltrating natural killer cells in hepatocellular carcinoma patients.
abstract: BACKGROUND
  Hepatocellular carcinoma (HCC) is a highly aggressive cancer that is linked to chronically dysregulated liver inflammation. However, appropriate immune responses can control HCC progression. Here we investigated the role and underlying mechanism of toll-like receptor 3 (TLR3) in HCC.
  
  
  METHODS
  HCC cell death, and natural killer (NK) cell activation and cytotoxicity were assessed in vitro after treatment with the TLR3 ligand poly(I:C). The effect of TLR3 on the tumor parenchyma and infiltrating immune cells was investigated in a spontaneous liver tumor mouse model and a transplanted tumor mouse model (n = 3-9 mice per group). Immunohistochemistry and quantitative polymerase chain reaction were used to analyze tumor samples from 172 HCC patients. Paired t-tests and analysis of variance tests were used to calculate P-values. The relationship between TLR3 expression and survival was determined by the Kaplan-Meier univariate survival analysis and a log-rank test. All statistical tests were two-sided.
  
  
  RESULTS
  TLR3 activation increased cell death in the TLR3(+) SNU182 HCC cell line (30.5% vs 8.5%, P = .03) and promoted NK-cell activation (32.6% vs 19.4%, P < .001) and cytotoxicity (relative fourfold increase, P = .03) in vitro. In vivo, poly(I:C) treatment increased intratumoral chemokine expression, NK-cell activation and tumor infiltration, and proliferation of tumor-infiltrating T and NK cells. Proliferation of tumor parenchyma cells was decreased. Also, expression of chemokines or treatment with poly(I:C) decreased tumor growth. TLR3 expression in patient samples correlated with NK-cell activation, NK- and T-cell tumor infiltration, and inversely correlated with tumor parenchyma cell viability. TLR3 expression was also associated with longer survival in HCC patients (hazard ratio of survival = 2.1, 95% confidence interval = 1.3 to 3.4, P = .002).
  
  
  CONCLUSIONS
  TLR3 is an important modulator of HCC progression and is a potential target for novel immunotherapy.
authors.affiliation: Singapore Immunology Network SIgN, Agency for Science, Technology and Research A*STAR, 8A Biomedical Grove, Immunos, Biopolis, Singapore 138648, Singapore.
authors.forename: Valerie
authors.initials: V
authors.lastname: Chew
authors.forename: Charlene
authors.initials: C
authors.lastname: Tow
authors.forename: Caleb
authors.initials: C
authors.lastname: Huang
authors.forename: Emilie
authors.initials: E
authors.lastname: Bard-Chapeau
authors.forename: Neal G
authors.initials: NG
authors.lastname: Copeland
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Jenkins
authors.forename: Achim
authors.initials: A
authors.lastname: Weber
authors.forename: Kiat Hon
authors.initials: KH
authors.lastname: Lim
authors.forename: Han Chong
authors.initials: HC
authors.lastname: Toh
authors.forename: Mathias
authors.initials: M
authors.lastname: Heikenwalder
authors.forename: Irene Oi-Lin
authors.initials: IO
authors.lastname: Ng
authors.forename: Alessandra
authors.initials: A
authors.lastname: Nardin
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Abastado
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004195:Disease Models, Animal; D005260:Female; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D008113:Liver Neoplasms / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008875:Middle Aged; D009368:Neoplasm Transplantation; D016133:Polymerase Chain Reaction; D051196:Toll-Like Receptor 3 / Q000276:immunology* / Q000378:metabolism
chemical_list: C495344:TLR3 protein, human; D051196:Toll-Like Receptor 3