Impact of hepatitis B virus X protein on the DNA damage response during hepatocarcinogenesis

Med Mol Morphol. 2009 Sep;42(3):138-42. doi: 10.1007/s00795-009-0457-8. Epub 2009 Sep 26.

Abstract

Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal cancers worldwide. The main HCC-associated diseases are chronic infections with hepatitis B virus (HBV) and hepatitis C virus (HCV), and HBV-associated HCC is still prevalent in Asia. Many studies have suggested that HBV X protein (HBX), which is the most common ORF integrated into the host genome, plays a crucial role in hepatocarcinogenesis. However, the accumulated evidence regarding HBX-mediated signaling pathways is not concordant, and it is difficult to understand the mechanistic nature of HBX-associated hepatocarcinogenesis. For example, HBX was reported to inactivate the early responses to DNA damage via p53-dependent and -independent pathways by interacting with several DNA damage-binding proteins and was also reported to sensitize cells to p53-mediated apoptosis via ataxia-telangiectasia and Rad3-related (ATR)-dependent signaling. HBX also interferes with the centrosome replication process, resulting in rearrangement of chromosomes with micronuclei. Moreover, HBX was found to sensitize protein kinases such as Ras/Raf/mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), stress-activated protein kinase/NH2-terminal-Jun kinase (SAPK/JNK), protein kinase B (PKB/Akt), and Janus kinase/STAT (JAK/STAT), indicating that a variety of signaling pathways may be activated by HBX. In this review, we focus on the roles of HBX in DNA damage repair during HCC development, with a view to achieving a better understanding of the significance of HBX in the early steps of hepatocarcinogenesis.

Publication types

  • Review

MeSH terms

  • Carcinoma, Hepatocellular* / genetics
  • Carcinoma, Hepatocellular* / metabolism
  • Centrosome / metabolism
  • DNA Damage*
  • DNA Repair*
  • Humans
  • Liver Neoplasms* / genetics
  • Liver Neoplasms* / metabolism
  • Mitogen-Activated Protein Kinases / metabolism
  • Trans-Activators / metabolism*
  • Tumor Suppressor Protein p53 / metabolism
  • Viral Regulatory and Accessory Proteins

Substances

  • Trans-Activators
  • Tumor Suppressor Protein p53
  • Viral Regulatory and Accessory Proteins
  • hepatitis B virus X protein
  • Mitogen-Activated Protein Kinases