Sequential adaptive changes in a c-Myc-driven model of hepatocellular carcinoma

J Biol Chem. 2017 Jun 16;292(24):10068-10086. doi: 10.1074/jbc.M117.782052. Epub 2017 Apr 21.

Abstract

Hepatocellular carcinoma (HCC) is a common cancer that frequently overexpresses the c-Myc (Myc) oncoprotein. Using a mouse model of Myc-induced HCC, we studied the metabolic, biochemical, and molecular changes accompanying HCC progression, regression, and recurrence. These involved altered rates of pyruvate and fatty acid β-oxidation and the likely re-directing of glutamine into biosynthetic rather than energy-generating pathways. Initial tumors also showed reduced mitochondrial mass and differential contributions of electron transport chain complexes I and II to respiration. The uncoupling of complex II's electron transport function from its succinate dehydrogenase activity also suggested a mechanism by which Myc generates reactive oxygen species. RNA sequence studies revealed an orderly progression of transcriptional changes involving pathways pertinent to DNA damage repair, cell cycle progression, insulin-like growth factor signaling, innate immunity, and further metabolic re-programming. Only a subset of functions deregulated in initial tumors was similarly deregulated in recurrent tumors thereby indicating that the latter can "normalize" some behaviors to suit their needs. An interactive and freely available software tool was developed to allow continued analyses of these and other transcriptional profiles. Collectively, these studies define the metabolic, biochemical, and molecular events accompanyingHCCevolution, regression, and recurrence in the absence of any potentially confounding therapies.

Keywords: Yes-associated protein (YAP); energy metabolism; glycolysis; hepatocellular carcinoma; β-catenin.

MeSH terms

  • Animals
  • Carcinogenesis
  • Carcinoma, Hepatocellular / metabolism*
  • Carcinoma, Hepatocellular / pathology
  • Carcinoma, Hepatocellular / prevention & control
  • DNA Repair
  • Electron Transport Complex I / genetics
  • Electron Transport Complex I / metabolism
  • Electron Transport Complex II / genetics
  • Electron Transport Complex II / metabolism
  • Female
  • Gene Expression Profiling
  • Gene Expression Regulation, Neoplastic*
  • Gene Silencing
  • Humans
  • Liver / metabolism*
  • Liver / pathology
  • Liver Neoplasms / metabolism*
  • Male
  • Mice, Transgenic
  • Mitochondrial Turnover
  • Neoplasm Recurrence, Local / metabolism
  • Neoplasm Recurrence, Local / pathology
  • Neoplasm Recurrence, Local / physiopathology
  • Neoplasm Recurrence, Local / prevention & control
  • Neoplasms, Experimental / metabolism*
  • Neoplasms, Experimental / pathology
  • Neoplasms, Experimental / prevention & control
  • Proto-Oncogene Proteins c-myc / genetics
  • Proto-Oncogene Proteins c-myc / metabolism*
  • Reactive Oxygen Species / metabolism
  • Tumor Burden
  • Up-Regulation*

Substances

  • Myc protein, mouse
  • Proto-Oncogene Proteins c-myc
  • Reactive Oxygen Species
  • Electron Transport Complex II
  • Electron Transport Complex I