Abstract
Concomitant hepatocyte apoptosis and regeneration is a hallmark of chronic liver diseases (CLDs) predisposing to hepatocellular carcinoma (HCC). Here, we mechanistically link caspase-8-dependent apoptosis to HCC development via proliferation- and replication-associated DNA damage. Proliferation-associated replication stress, DNA damage, and genetic instability are detectable in CLDs before any neoplastic changes occur. Accumulated levels of hepatocyte apoptosis determine and predict subsequent hepatocarcinogenesis. Proliferation-associated DNA damage is sensed by a complex comprising caspase-8, FADD, c-FLIP, and a kinase-dependent function of RIPK1. This platform requires a non-apoptotic function of caspase-8, but no caspase-3 or caspase-8 cleavage. It may represent a DNA damage-sensing mechanism in hepatocytes that can act via JNK and subsequent phosphorylation of the histone variant H2AX.
Keywords:
DNA damage response; apoptosis; hepatocellular carcinoma; liver; replication stress.
Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Apoptosis
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Carcinogenesis / metabolism*
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Carcinogenesis / pathology*
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Carcinoma, Hepatocellular / pathology
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Caspase 8 / metabolism*
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Cell Proliferation
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Cellular Senescence
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Chronic Disease
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Crosses, Genetic
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DNA Damage*
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DNA Repair
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Fas-Associated Death Domain Protein / metabolism
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Female
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Genomic Instability
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Hepatectomy
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Hepatocytes / pathology
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Histones / metabolism
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Humans
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JNK Mitogen-Activated Protein Kinases / metabolism
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Liver / metabolism
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Liver / pathology
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Liver Neoplasms / enzymology*
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Liver Neoplasms / pathology*
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Liver Regeneration
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Male
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Mice
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Myeloid Cell Leukemia Sequence 1 Protein / metabolism
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Phosphorylation
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Receptor-Interacting Protein Serine-Threonine Kinases / metabolism
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Receptors, Tumor Necrosis Factor, Type I / metabolism
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Risk Factors
Substances
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Fadd protein, mouse
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Fas-Associated Death Domain Protein
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Histones
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Mcl1 protein, mouse
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Myeloid Cell Leukemia Sequence 1 Protein
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Receptors, Tumor Necrosis Factor, Type I
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gamma-H2AX protein, mouse
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Receptor-Interacting Protein Serine-Threonine Kinases
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Ripk1 protein, mouse
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JNK Mitogen-Activated Protein Kinases
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Caspase 8