IJzermans, J. | Search bioRxiv

bioRxiv2019

Mutational impact of chronic alcohol use on stem cells in cirrhotic liver

Excessive alcohol consumption increases the risk of developing liver cancer, but the mechanism through which alcohol drives carcinogenesis is as yet unknown. Here, we determined the mutational consequences of chronic alcohol use on the genome of human liver stem cells prior to cancer development. No change in base substitution rate or spectrum could be detected. Analysis of the trunk mutations in an alcohol-related liver tumor by multi-site whole-genome sequencing confirms the absence of specific alcohol-induced mutational signatures driving the development of liver cancer. However, we did identify an enrichment of nonsynonymous base substitutions in cancer genes in stem cells of the cirrhotic livers, such as recurrent nonsense mutations in PTPRK that disturb Epidermal Growth Factor (EGF)-signaling. Our results thus suggest that chronic alcohol use does not contribute to carcinogenesis through altered mutagenicity, but instead induces microenvironment changes which provide a fertile ground for selection of cells with oncogenic mutations.

cancer biology↗

bioRxiv2019

Human liver organoids; a patient-derived primary model for HBV Infection and Related Hepatocellular Carcinoma

The molecular events that drive Hepatitis B virus (HBV)-mediated transformation and tumorigenesis have remained largely unclear, due to the absence of a relevant primary model system. Here we propose the use of human liver organoids as a platform for modeling HBV infection and related tumorigenesis. We first describe a primary ex vivo HBV-infection model derived from healthy donor liver organoids after challenge with recombinant virus or HBV-infected patient serum. HBV infected organoids produced cccDNA, expressed intracellular HBV RNA and proteins, and produced infectious HBV. This ex vivo HBV infected primary differentiated hepatocyte organoid platform was amenable to drug screening for both anti-HBV activity as well as for drug-induced toxicity. We also studied HBV replication in transgenically modified organoids; liver organoids exogenously overexpressing the HBV receptor NTCP by lentiviral transduction were not more susceptible to HBV, suggesting the necessity for additional host factors for efficient infection. We also generated transgenic organoids harboring integrated HBV, representing a long-term culture system also suitable for viral production and the study of HBV transcription. Finally, we generated HBV-infected patient-derived liver organoids from non-tumor cirrhotic tissue of explants from liver transplant patients. Interestingly, transcriptomic analysis of patient-derived liver organoids indicated the presence of an aberrant early cancer gene signature, which clustered with the HCC cohort on the TCGA LIHC dataset and away from healthy liver tissue, and may provide invaluable novel biomarkers for disease surveillance and development of HCC in HBV infected patients.

cancer biology↗