Synergistic Effect of Radiation and Interleukin-6 on Hepatitis B Virus Reactivation in Liver Through STAT3 Signaling Pathway
Journal
International Journal of Radiation Oncology Biology Physics
Journal Volume
75
Journal Issue
5
Pages
1545-1552
Date Issued
2009
Author(s)
Abstract
Purpose: Hepatitis B virus (HBV) reactivation can occur after radiotherapy (RT) for hepatobiliary malignancies. Our previous in vitro culture study identified interleukin-6 (IL-6) as the main bystander mediator of RT-induced HBV replication. We attempted to examine the molecular mechanism in HBV-transgenic mice. Methods and materials: HBV transgenic mice were treated with whole liver RT (4 Gy daily for 5 days) with or without administration of IL-6 (400 ng twice daily for 15 days). The serum level of HBV DNA was measured using real-time polymerase chain reaction, and the IL-6 concentration was measured using enzyme-linked immunosorbent assay. The intensity of immunostaining with antibodies to HBV core protein and phosphorylated signal transducer and activator of transcription (STAT)3 in the mouse liver was qualitatively analyzed. HepG2.2.15 cells (a?human hepatoblastoma cell line that persistently produces HBV DNA) were used to investigate the molecular role of IL-6 plus RT in HBV reactivation. Results: HBV reactivation was induced in vivo with IL-6 plus RT (5.58-fold) compared with RT alone (1.31-fold, p = .005), IL-6 alone (1.31-fold, p = .005), or sham treatment (1.22-fold, p = .004). HBV core protein staining confirmed augmentation of intrahepatic HBV replication. IL-6 plus RT-induced HBV DNA replication in HepG2.2.15 cells was suppressed by the STAT3 inhibitor AG490 and by transfection with dominant-negative STAT3 plasmid. Phosphorylated STAT3 staining was strongest in liver tissue from mice treated with IL-6 plus RT. The mobility shift assay demonstrated that reactivation was mediated through the interaction of phosphorylated STAT3/hepatocyte nuclear factor-3 complex with HBV enhancer 1. Conclusion: RT to the liver and longer sustained IL-6 induced HBV reactivation through the STAT3 signal transduction pathway. ? 2009 Elsevier Inc. All rights reserved.
SDGs
Other Subjects
Cell culture; DNA; Genes; Liver; Nucleic acids; Phosphorylation; Piezoelectric transducers; Proteins; Radiotherapy; Transcription; Cell lines; Core proteins; DNA replications; Enzyme linked immunosorbent assay; HBV replication; Hepatitis B virus; Hepatobiliary; Immunostaining; In-vitro; In-vivo; Interleukin-6; Liver tissue; Mobility shift assays; Molecular mechanism; Mouse liver; Nuclear factors; Reactivation; Real-time polymerase chain reaction; Serum levels; Signal transducers; Signal transduction pathways; Signaling pathways; Synergistic effect; Transgenic mice; Signal transduction; hepatitis B core antibody; hepatocyte nuclear factor 3; interleukin 6; n benzyl 2 cyano 3 (3,4 dihydroxyphenyl)acrylamide; STAT3 protein; virus DNA; animal cell; animal experiment; animal model; article; cell culture; controlled study; enzyme linked immunosorbent assay; gel mobility shift assay; Hepatitis B virus; human; human cell; immunohistochemistry; immunoprecipitation; mouse; nonhuman; priority journal; protein phosphorylation; qualitative analysis; radiation dose; radiotherapy; real time polymerase chain reaction; signal transduction; transgenic animal; virus reactivation; virus replication; Western blotting
Publisher
Elsevier Inc.
Type
journal article