Chemokine Expression Profiles of Human Hepatoma Cell Lines Mediated by Hepatitis B Virus X Protein

The hepatitis B virus X protein (HBx), which is encoded by hepatitis B virus (HBV), plays crucial roles in the tumorigenesis of HBV associated hepatocellular carcinoma (HCC). Recent studies suggest that the HBx is involved in regulation of host immune cytokines and chemokines in HBV-associated HCC patients. However, effects of the HBx on autocrine chemokine expression profiles of hepatoma cells, which were shown in modulation of tumor-immune cell interactions, have not been investigated comprehensively. In the present study, human hepatoma cell lines SMMC-7721 and HepG2 were transfected with HBx-expressing plasmid. Human chemokine antibody array 1 (RayBio®), which simultaneously detects 38 chemokine factors, was used to determine chemokine expression profiles. Real-time polymerase chain reaction (real-time PCR) was used to further confirm the differential expression of chemokines. Chemokine antibody array revealed that all 38 chomekines were found to be expressed by SMMC-7721 and HepG2 cell lines. Interleukin-8 (IL-8) was obviously up-regulated, and epithelial neutrophil-activating protein 78 (ENA78), eosinophil chemotactic protein-1 (Eotaxin-1), monocyte chemotactic protein-1 (MCP-1), MCP-2, MCP-3 and macrophage inflammatory protein-3β (MIP-3β) were significantly declined in both cell lines following transfection of HBx-expressing plasmid. Other chemokines showed little or no significant changes. HBx-induced differential chemokine expression levels were validated by real-time PCR. Hierarchical cluster analysis identified a distinction of chomekine expression profiles between HBX-expressing hepatoma cell lines and controls. Our findings provide new evidence that HBx is able to selectively regulate chomekines in hepatoma cells that may be involved in the regulation of tumor-immune cell interactions.