HCC-derived SNU cell lines as model systems to study HBV life cycle

Area of Science:

• Hepatology and Virology
• Molecular Biology
• Cancer Research

Background:

• Human SNU cell lines are derived from hepatocellular carcinomas linked to chronic hepatitis B virus (HBV) infection.
• Previous studies suggest varying levels of HBV replication in these cell lines.

Purpose of the Study:

• To investigate the status of HBV replication in human SNU cell lines.
• To characterize HBV-related RNA species, including integrant-transcribed and spliced RNAs.
• To explore the mechanisms of HBV replication suppression in these models.

Main Methods:

• RNA-sequencing to analyze intracellular HBV RNA and DNA markers.
• Detection of HBV core antigen (HBcAg) and HBV DNA.
• Transfection experiments with an HBV replication-initiating vector in SNU cell lines and Huh7 cells.

Main Results:

• Most SNU cell lines (SNU-423, SNU-368, SNU-398, SNU-182, SNU-449, SNU-475, SNU-354, SNU-739, SNU-387) showed no detectable HBV replication, while SNU-761 and SNU-886 maintained residual replication.
• Undetectable HBcAg and low HBV DNA confirmed suppressed replication in parental SNU cell lines.
• Various 5'-human-HBV-3' and 5'-HBV-human-3' RNAs, including those encoding HBV envelope proteins, were detected.
• Known and novel spliced HBV RNAs were found, some independent of replication.
• SNU cell lines did not support efficient HBV replication upon transfection, exhibiting three distinct patterns of replication marker accumulation.

Conclusions:

• SNU cell lines, particularly those without active HBV replication, are valuable models for studying integrant-transcribed and spliced HBV RNAs.
• The observed patterns of replication marker accumulation suggest host-mediated mechanisms suppressing HBV replication.
• Further analysis of these SNU cell lines can advance understanding of HBV-host interactions and inform the development of novel anti-HBV interventions.