RIP3 Inhibits Inflammatory Hepatocarcinogenesis but Promotes Cholestasis by Controlling Caspase-8- and JNK-Dependent Compensatory Cell Proliferation

• RIP3- and Caspase-8-dependent pathways are activated in chronically inflamed livers
• RIP3 limits compensatory proliferation via a pathway involving Caspase-8 and JNK
• RIP3 impedes Caspase-8-dependent chromosomal aberrations and inhibits tumor growth
• RIP3 promotes jaundice and cholestasis by limiting biliary ductular reactions

SummaryFor years, the term “apoptosis” was used synonymously with programmed cell death. However, it was recently discovered that receptor interacting protein 3 (RIP3)-dependent “necroptosis” represents an alternative programmed cell death pathway activated in many inflamed tissues. Here, we show in a genetic model of chronic hepatic inflammation that activation of RIP3 limits immune responses and compensatory proliferation of liver parenchymal cells (LPC) by inhibiting Caspase-8-dependent activation of Jun-(N)-terminal kinase in LPC and nonparenchymal liver cells. In this way, RIP3 inhibits intrahepatic tumor growth and impedes the Caspase-8-dependent establishment of specific chromosomal aberrations that mediate resistance to tumor-necrosis-factor-induced apoptosis and underlie hepatocarcinogenesis. Moreover, RIP3 promotes the development of jaundice and cholestasis, because its activation suppresses compensatory proliferation of cholangiocytes and hepatic stem cells. These findings demonstrate a function of RIP3 in regulating carcinogenesis and cholestasis. Controlling RIP3 or Caspase-8 might represent a chemopreventive or therapeutic strategy against hepatocellular carcinoma and biliary disease.

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