Activation of PERK-Nrf2 oncogenic signaling promotes Mdm2-mediated Rb degradation in persistently infected HCV culture

Sci Rep. 2017 Aug 23;7(1):9223. doi: 10.1038/s41598-017-10087-6.

Abstract

The mechanism of how chronic hepatitis C virus (HCV) infection leads to such a high rate of hepatocellular carcinoma (HCC) is unknown. We found that the PERK axis of endoplasmic reticulum (ER) stress elicited prominent nuclear translocation of Nrf2 in 100% of HCV infected hepatocytes. The sustained nuclear translocation of Nrf2 in chronically infected culture induces Mdm2-mediated retinoblastoma protein (Rb) degradation. Silencing PERK and Nrf2 restored Mdm2-mediated Rb degradation, suggesting that sustained activation of PERK/Nrf2 axis creates oncogenic stress in chronically infected HCV culture model. The activation of Nrf2 and its nuclear translocation were prevented by ER-stress and PERK inhibitors, suggesting that PERK axis is involved in the sustained activation of Nrf2 signaling during chronic HCV infection. Furthermore, we show that HCV clearance induced by interferon-α based antiviral normalized the ER-stress response and prevented nuclear translocation of Nrf2, whereas HCV clearance by DAAs combination does neither. In conclusion, we report here a novel mechanism for how sustained activation of PERK axis of ER-stress during chronic HCV infection activates oncogenic Nrf2 signaling that promotes hepatocyte survival and oncogenesis by inducing Mdm2-mediated Rb degradation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Retracted Publication

MeSH terms

  • Active Transport, Cell Nucleus
  • Cell Line
  • Cells, Cultured
  • Endoplasmic Reticulum Stress
  • Gene Silencing
  • Genomic Instability
  • Hepatitis C, Chronic / metabolism*
  • Hepatitis C, Chronic / pathology
  • Hepatitis C, Chronic / virology*
  • Hepatocytes / metabolism
  • Hepatocytes / virology
  • Humans
  • Immunohistochemistry
  • NF-E2-Related Factor 2 / metabolism*
  • Proteolysis
  • Proto-Oncogene Proteins c-mdm2 / metabolism*
  • Reactive Oxygen Species / metabolism
  • Retinoblastoma Protein / metabolism*
  • Signal Transduction*
  • Virus Replication
  • eIF-2 Kinase / metabolism*

Substances

  • NF-E2-Related Factor 2
  • Reactive Oxygen Species
  • Retinoblastoma Protein
  • Proto-Oncogene Proteins c-mdm2
  • eIF-2 Kinase