Sympathetic circadian dysfunction in obesity-related hepatocarcinogenesis

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Project Summary This RO1 application directly addresses NCI PQ6 by investigating the role of circadian dysfunction of the sympathetic nervous system (SNS) in hepatocarcinogenesis. Retrospective clinical studies strongly suggest that sympathetic dysfunction is a key etiologic factor in human cancers, and that -blockers are potential anticancer agents. However, the role of sympathetic dysfunction in tumorigenesis and the mechanisms of -blocker-directed anticancer effects are significant knowledge gaps. We will define the molecular basis for the impact of circadian dysregulation of the sympathetic nervous system (SNS) on spontaneous hepatocarcinogenesis and test the ability of -blockers to prevent non-alcoholic fatty liver disease (NAFLD)-induced hepatocellular carcinoma (HCC). The incidence of HCC has increased >3-fold since the 1980s and it is currently the fastest rising cause of cancer-related death in the U.S. The increase in HCC incidence is coupled with the prevalence of obesity, obesity-related NAFLD, and chronic circadian disruption. NAFLD is now emerging as the leading driver of HCC in the 21st century. However, no efficient approaches for prevention, early diagnosis, and treatment of NAFLD- induced HCC are available. We discovered that chronic circadian dysfunction induces obesity-related metabolic syndrome, NAFLD, and HCC in normal chow fed wild-type mice following a pathophysiological pathway strikingly similar to that observed in obese humans. We identified intrahepatic cholestasis as the key proximal pathophysiological mechanism that stimulates the progression from NAFLD to nonalcoholic steatohepatitis (NASH), fibrosis, and eventually hepatocarcinogenesis. We demonstrated that circadian dysfunction of - adrenergic receptor (ADR)-mediated sympathetic signaling is an essential molecular mechanism that drives nuclear receptor dysfunction, cholestasis and oncogenic activation to promote HCC. We propose 3 broad aims to study the role of sympathetic dysfunction in hepatocarcinogenesis: 1) Characterize hepatic gene deregulation signatures associated with ADR-mediated SNS circadian dysfunction by ChIPseq and RNAseq. 2) Define ADR circadian dysfunction induced serum and hepatic bile acid profiles, liver pathologies, HCC risk, and the premalignant gene signature driving HCC initiation. 3) Define the role of - blocker propranolol in prevention of circadian dysfunction-induced NAFLD-associated HCC. Our studies will not only define the role of sympathetic circadian dysfunction in NFALD-induced oncogenic activation and hepatocarcinogenesis, but also provide an unprecedented opportunity to design -blocker- directed personalized and complementary strategies for anti-HCC chronotherapy.