Marc Bonnin1, Nadim Fares1, Barbara Testoni1, Yann Estornes1, Kathrin Weber1, Béatrice Vanbervliet1, Lydie Lefrançois1, Amandine Garcia1, Alain Kfoury1, Floriane Pez1, Isabelle Coste1, Pierre Saintigny2, Alain Viari3, Kévin Lang1, Baptiste Guey1, Valérie Hervieu4, Brigitte Bancel4, Birke Bartoch1, David Durantel1, Toufic Renno1, Philippe Merle5, Serge Lebecque6. 1. INSERM, U1052, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL1), CNRS UMR_5286, Centre Léon Bérard, Lyon, France. 2. INSERM, U1052, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL1), CNRS UMR_5286, Centre Léon Bérard, Lyon, France; Department of Translational Research and Innovation and Department of Medicine, Centre Léon Bérard, Lyon, France. 3. Synergie Lyon Cancer, Plateforme de Bioinformatique 'Gilles Thomas' Centre Léon Bérard, Lyon, France. 4. Service d'Anatomopathologie, Groupement Hospitalier Est, Hospices Civils de Lyon, Lyon, France. 5. INSERM, U1052, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL1), CNRS UMR_5286, Centre Léon Bérard, Lyon, France; Groupement Hospitalier Lyon Nord, Hepatology Unit, Lyon, France. Electronic address: philippe.merle@inserm.fr. 6. INSERM, U1052, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL1), CNRS UMR_5286, Centre Léon Bérard, Lyon, France; Hospices Civils de Lyon, Laboratoire d'Anatomie et Cytologie Pathologiques, Centre Hospitalier Lyon Sud, Pierre Bénite, France. Electronic address: serge.lebecque@univ-lyon1.fr.
Abstract
BACKGROUND & AIMS: Low levels of toll-like receptor 3 (TLR3) in patients with hepatocellular carcinoma (HCC) are associated with poor prognosis, primarily owing to the loss of inflammatory signaling and subsequent lack of immune cell recruitment to the liver. Herein, we explore the role of TLR3-triggered apoptosis in HCC cells. METHODS: Quantitative reverse transcription PCR, western blotting, immunohistochemistry and comparative genomic hybridization were used to analyze human and mouse HCC cell lines, as well as surgically resected primary human HCCs, and to study the impact of TLR3 expression on patient outcomes. Functional analyses were performed in HCC cells, following the restoration of TLR3 by lentiviral transduction. The role of TLR3-triggered apoptosis in HCC was analyzed in vivo in a transgenic mouse model of HCC. RESULTS: Lower expression of TLR3 in tumor compared to non-tumor matched tissue was observed at both mRNA and protein levels in primary HCC, and was predictive of shorter recurrence-free survival after surgical resection in both univariate (hazard ratio [HR] 1.79; 95% CI 1.04-3.06; p = 0.03) and multivariate analyses (HR 1.73; CI 1.01-2.97; p = 0.04). Immunohistochemistry confirmed frequent downregulation of TLR3 in human and mouse primary HCC cells. None of the 6 human HCC cell lines analyzed expressed TLR3, and ectopic expression of TLR3 following lentiviral transduction not only restored the inflammatory response but also sensitized cells to TLR3-triggered apoptosis. Lastly, in the transgenic mouse model of HCC, absence of TLR3 expression was accompanied by a lower rate of preneoplastic hepatocyte apoptosis and accelerated hepatocarcinogenesis without altering the tumor immune infiltrate. CONCLUSION: Downregulation of TLR3 protects transforming hepatocytes from direct TLR3-triggered apoptosis, thereby contributing to hepatocarcinogenesis and poor patient outcome. LAY SUMMARY: Hepatocellular carcinoma (HCC) is a heterogeneous disease associated with a poor prognosis. In patients with HCC, TLR3 downregulation is associated with reduced survival. Herein, we show that the absence of TLR3 is associated with a lower rate of apoptosis, and subsequently more rapid hepatocarcinogenesis, without any change to the immune infiltrate in the liver. Therefore, the poor prognosis associated with low TLR3 expression in HCC is likely linked to tumors ability to escape apoptosis. TLR3 may become a promising therapeutic target in TLR3-positive HCC.
BACKGROUND & AIMS: Low levels of toll-like receptor 3 (TLR3) in patients with hepatocellular carcinoma (HCC) are associated with poor prognosis, primarily owing to the loss of inflammatory signaling and subsequent lack of immune cell recruitment to the liver. Herein, we explore the role of TLR3-triggered apoptosis in HCC cells. METHODS: Quantitative reverse transcription PCR, western blotting, immunohistochemistry and comparative genomic hybridization were used to analyze human and mouseHCC cell lines, as well as surgically resected primary human HCCs, and to study the impact of TLR3 expression on patient outcomes. Functional analyses were performed in HCC cells, following the restoration of TLR3 by lentiviral transduction. The role of TLR3-triggered apoptosis in HCC was analyzed in vivo in a transgenic mouse model of HCC. RESULTS: Lower expression of TLR3 in tumor compared to non-tumor matched tissue was observed at both mRNA and protein levels in primary HCC, and was predictive of shorter recurrence-free survival after surgical resection in both univariate (hazard ratio [HR] 1.79; 95% CI 1.04-3.06; p = 0.03) and multivariate analyses (HR 1.73; CI 1.01-2.97; p = 0.04). Immunohistochemistry confirmed frequent downregulation of TLR3 in human and mouse primary HCC cells. None of the 6 humanHCC cell lines analyzed expressed TLR3, and ectopic expression of TLR3 following lentiviral transduction not only restored the inflammatory response but also sensitized cells to TLR3-triggered apoptosis. Lastly, in the transgenic mouse model of HCC, absence of TLR3 expression was accompanied by a lower rate of preneoplastic hepatocyte apoptosis and accelerated hepatocarcinogenesis without altering the tumor immune infiltrate. CONCLUSION: Downregulation of TLR3 protects transforming hepatocytes from direct TLR3-triggered apoptosis, thereby contributing to hepatocarcinogenesis and poor patient outcome. LAY SUMMARY:Hepatocellular carcinoma (HCC) is a heterogeneous disease associated with a poor prognosis. In patients with HCC, TLR3 downregulation is associated with reduced survival. Herein, we show that the absence of TLR3 is associated with a lower rate of apoptosis, and subsequently more rapid hepatocarcinogenesis, without any change to the immune infiltrate in the liver. Therefore, the poor prognosis associated with low TLR3 expression in HCC is likely linked to tumors ability to escape apoptosis. TLR3 may become a promising therapeutic target in TLR3-positive HCC.
Authors: Ryan A Hlady; Xia Zhao; Louis Y El Khoury; Aesis Luna; Kien Pham; Qunfeng Wu; Jeong-Heon Lee; Nikolaos T Pyrsopoulos; Chen Liu; Keith D Robertson Journal: Hepatology Date: 2021-12-15 Impact factor: 17.298