Keele Research Repository

Background & Aims
Metabolic syndrome can lead to the clinical manifestation of non-alcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC) as part of the natural history of NAFLD. Despite a strong causative link, NAFLD-HCC is often underrepresented in systematic genome explorations.
Methods
Here, tumor-normal pairs from 100 subjects diagnosed with NAFLD-HCC were subject to next generation sequencings. Bioinformatic analyses were performed to identify key genomic, epigenomic and transcriptomic events associated with the pathogenesis of NAFLD to NAFLD-HCC. Establishment of primary patient-derived NAFLD-HCC culture was used as a representative human model for downstream in vitro investigations of underlying CTNNB1 S45P driver mutation. Syngeneic immunocompetent mouse model was used to further test the involvement of CTNNB1mut and TNFRSF19 in reshaping the tumor microenvironment.
Results
Mutational process operative in NAFLD-liver inferred susceptibility to tumor formation through defective DNA repair pathways. Dense promoter mutations and dysregulated transcription factors accentuated activated transcriptional regulation in NAFLD-HCC, in particular the enrichment of MAZ-MYC activities. Somatic events common in HCCs arising from NAFLD and viral hepatitis B infection underscore similar driver pathways, although an incidence shift highlights CTNNB1mut dominance in NAFLD-HCC (33%). Immune exclusion correlated evidently with CTNNB1mut. ChIP-seq integrated with transcriptome and immune profiling showed for the first time a transcriptional axis of CTNNB1mut/TNFRSF19/repressed senescence-associated secretory phenotype-like (SASP-like) cytokines (including IL6 and CXCL8). This phenomenon could be reverted by Wnt-modulator ICG001.
Conclusions
The unique mutational processes in NAFLD-liver and NAFLD-HCC alludes to a “field effect”. Whereby, distinct aberrations and shift in driver events reveal a gain-of-function role of CTNNB1 mutations in immune exclusion via TNFRSF19 inhibition of SASP-like features.
LAY SUMMARY
The increasing prevalence of metabolic syndrome in adult populations poised NAFLD-induced HCC to be the major type of liver cancer of the 21st century. We showed a strong “field effect” in NAFLD-liver from mutational signatures detected and a mechanistic path of activated β-catenin in reshaping the tumor-immune microenvironment.