Hepatitis C virus and alcohol: same mitotic targets but different signaling pathways

Area of Science:

• Hepatology and Oncology
• Molecular Biology
• Cellular Mechanisms of Cancer

Background:

• Chromosomal aberrations are common in Hepatitis C virus (HCV) and alcohol-related hepatocellular carcinomas (HCCs).
• The precise mechanisms driving these aberrations during hepatocarcinogenesis remain unclear.
• Deregulation of mitotic proteins, including Cyclin B1, Aurora kinase A, and gamma-tubulin phosphorylation, is implicated.

Purpose of the Study:

• To investigate alterations in Cyclin B1, Aurora kinase A, and gamma-tubulin expression.
• To explore the associated intracellular signaling pathways in HCV- and alcohol-induced HCC.
• To analyze these changes in both in vitro and in vivo models.

Main Methods:

• Analysis of molecular defects in human hepatoma cells expressing HCV proteins, with or without ethanol treatment.
• Examination of liver tissues from control subjects and patients with HCV- or alcohol-related HCC.
• Assessment of Cyclin B1, Aurora kinase A, and tyrosine-phosphorylated gamma-tubulin expression and signaling pathways (PKR, JNK, p38MAPK).

Main Results:

• HCV and alcohol significantly increased the expression of Cyclin B1, Aurora kinase A, and tyrosine-phosphorylated gamma-tubulin in HCC tissues.
• In vitro studies indicated that HCV requires RNA-activated protein kinase (PKR), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38MAPK) pathways.
• Ethanol exposure bypassed these specific HCV-related pathways.

Conclusions:

• HCV and alcohol converge on common mitotic proteins to promote hepatocarcinogenesis.
• Distinct intracellular signaling pathways are utilized by HCV and alcohol in this process.
• Understanding these divergent mechanisms offers insights into targeted therapeutic strategies for HCC.