Abstract 91: Diet-variants and immune characterization of a stage-defined, transgenic immunocompetent mouse model of HCC (ASV-B)
Authors: Tijeras-Raballand Annemilaï , Hobeika Christian , Rousseau Benoit , Hainaud Patricia , Bonnin Philippe , Rodrigues Aurélie , Ladfil Fouad , Pocard Marc , Paradis Valérie , Gramont Armand de , Raymond Eric , Dupuy Evelyne , Eveno Clarisse , Faivre Sandrine 
Published: August 2019

Background: Non-alcoholic fatty liver disease (NAFLD), especially non-alcoholic steatohepatitis (NASH) is a chronic liver disease commonly associated with hepatic fibrosis. NASH patients have an increased risk for hepatocellular carcinoma (HCC). Due to western way of life, NASH incidence is rising and is predicted to become the leading cause of HCC in the next decades. Therefore, there is an urgent need for robust animal models fully recapitulating the NASH-related HCC carcinogenesis. In this study, we develop and characterize specific diet-induced variants from our transgenic HCC mouse model, focusing on immune landscape.

Methods: To mimic NASH, ASV-B, a transgenic mouse model (C57BL/6J) that spontaneously develops a reproducible stage-defined HCC (hyperplasia at week(W)8, nodular stage at W12, and diffuse carcinoma at W16-20) was exposed to 5 different diets. Ten ASV-B and 5 control mice were fed as follows: classic diet as control (yellow), or a high-fat diet (blue), a diet enriched with saturated fatty acids + 1.25% cholesterol (green), a diet containing 22% of vegetal oil + 0.2% cholesterol (orange), and a 1.25% cholesterol diet containing 21% of milkfat (red). All mice fed with special diets also received 30% fructose in the drink water. RNA was extracted from frozen livers at W20 for 40 immune markers analysis using qRT-PCR (LightCycler, Roche). Immune populations were assessed using automated immunohistochemistry (IHC) (Bond Max, Leica).

Results: ASV-B model shows an increase in liver volume and angiogenesis, ASV-B livers harboring marked arterialization and capillarization as compared to control. Assessing immune markers on 7 evaluable tumor specimens, we observed an increase in CD8, Foxp3, INOS, CD11b, PD-1, PD-L1, IL1β, IFN-γ, TNF-α, IL17A and IL17F mRNA expression, as frequently observed in human inflammatory HCC. In addition, IHC staining showed intratumoral infiltration of lymphocytes (CD8+) and macrophages (F4/80+, a well-characterized and extensively referenced mouse macrophage marker). ASV-B mice receiving yellow, blue, and green regimens showed similar liver volumes and weight. By macroscopic analysis, we observed increased liver steatosis, and fibrosis in the red and orange regimen compared to others. Moreover, we observed a 40% mortality rate in the orange regimen, and a 20% mortality rate in the blue and the green regimens. At the conference, we will show the morphologic changes of the livers using HPS staining and the immune landscape in the livers of the diet-variants.

Conclusion: ASV-B transgenic mouse model mimics several characteristics of human HCC developing on healthy liver including inflammatory reaction and immune cell infiltration. In the ASV-B model, we have been able to develop specific-diets variants aiming at mimicking NASH that could be used for drug testing.

Citation Format: Annemilaï Tijeras-Raballand, Christian Hobeika, Benoit Rousseau, Patricia Hainaud, Philippe Bonnin, Aurélie Rodrigues, Fouad Ladfil, Marc Pocard, Valérie Paradis, Armand de Gramont, Eric Raymond, Evelyne Dupuy, Clarisse Eveno, Sandrine Faivre. Diet-variants and immune characterization of a stage-defined, transgenic immunocompetent mouse model of HCC (ASV-B) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 91.