Key features of the environment promoting liver cancer in the absence of cirrhosis

Marco Y.w Zaki ,Ahmed Khairallah Mahdi,Gillian Patman ,João Maurício ,Charlotte V Cox ,Derek A Mann ,Erik Ramon‐Gil ,Misti Mccain ,Quentin M Anstee ,Fiona Oakley,Anna Whitehead,John Lunec,Olivier Govaere,Caroline Wilson,Robyn Watson,Sameh Abou-Beih,Jack Leslie,Dina Tiniakos,Despina Televantou,Sirintra Nakjang,Ruchi Shukla,Helen L Reeves

doi:10.1038/s41598-021-96076-2

Abstract

The prevalence of obesity and non-alcoholic fatty liver disease (NAFLD) associated hepatocellular carcinoma (HCC) is rising, even in the absence of cirrhosis. We aimed to develop a murine model that would facilitate further understanding of NAFLD-HCC pathogenesis. A total of 144 C3H/He mice were fed either control or American lifestyle (ALIOS) diet, with or without interventions, for up to 48 weeks of age. Gross, liver histology, immunohistochemistry (IHC) and RNA-sequencing data were interpreted alongside human datasets. The ALIOS diet promoted obesity, elevated liver weight, impaired glucose tolerance, non-alcoholic fatty liver disease (NAFLD) and spontaneous HCC. Liver weight, fasting blood glucose, steatosis, lobular inflammation and lipogranulomas were associated with development of HCC, as were markers of hepatocyte proliferation and DNA damage. An antioxidant diminished cellular injury, fibrosis and DNA damage, but not lobular inflammation, lipogranulomas, proliferation and HCC development. An acquired CD44 phenotype in macrophages was associated with type 2 diabetes and NAFLD-HCC. In this diet induced NASH and HCC (DINAH) model, key features of obesity associated NAFLD-HCC have been reproduced, highlighting roles for hepatic steatosis and proliferation, with the acquisition of lobular inflammation and CD44 positive macrophages in the development of HCC—even in the absence of progressive injury and fibrosis.

Highlights

Fat diet alone is insufficient to cause cancers and is given in combination with additional means of promoting oxidative stress/fibrosis or carcinogens[9,10]
Activation of the Ras/Raf/MEK/ERK pathway is common in murine hepatocarcinogenesis regardless of the strain, with the liability of C3H/He attributed to an enhanced acquisition of spontaneous or induced Ha-ras oncogene mutation[19]
Neither dietary group developed diabetes, as defined by a glucose tolerance test (GTT) performed at 48 weeks compared to 8 weeks, but both dietary groups had elevated glucose levels at 2 hours, in keeping with age related impaired glucose tolerance (F1D)

Summary

Introduction

Fat diet alone is insufficient to cause cancers and is given in combination with additional means of promoting oxidative stress/fibrosis or carcinogens[9,10] These approaches all have value, with the use of C57Bl/6 mice a significant asset lending itself to subsequent genetic manipulation. While there are major advantages using C57Bl/6 mice, they do not develop the metabolic syndrome with age, even if they are fed an obesigenic diet While these models are undoubtedly valuable for studying hepatocarcinogenesis in the presence of the injuries created, they do not necessarily capture the multifactorial processes underlying obesity and NAFLD associated HCC—which in up to 50% of humans, arises in the absence of advanced fibrosis or cirrhosis. C3H/He mice are susceptible to both o besity[16] and hepatoma d evelopment[17] with age

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Conclusion