• Bulletin of the Korean Chemical Society
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• v.26 no.9
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• pp.1385-1389
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• 2005

Human hepatitis B virus (HBV) is a pathogen related to the development of liver diseases including chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). However, the efficient methods to suppress HBV replication have not been developed yet. Therefore, we have used RNA interference (RNAi) as a potential tool for the suppression of HBV replication. Here, we designed a 21 nt small intefering dsRNA (siRNA) against hepatitis B virus X (HBx) RNA with 3' overhanging ends derived from T7 promoter. It has been reported that HBV X protein plays an important role in HBV gene expression and viral replication. The suppression of HBx gene expression by the 21 nt siRNA was investigated by Northern blot analysis and chloramphenicol acetyl transferase (CAT) assay. The level of HBx mRNA was decreased by siRNA in a dose-dependent manner. We also found that the 21 nt siRNA inhibited the HBV replication in hepatocellular carcinoma cell.

• Proceedings of the Korean Society of Life Science Conference
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• 2000.12a
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• pp.39-43
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• 2000

HBV는 인체에 감염하여 간염, 간경변 및 간암을 유발하는 hepadnaviruses의 일종으로써 임상적으로 매우 중요한 바이러스이다. 그러나 이 바이러스에 의한 간암(HCC)의 발생 메커니즘은 아직 불확실하다. 최근에는 HBV의 X 단백질(HBx)이 간암 발생에 중요한 역할을 수행하는 것으로 보고되고 있다. HBx 단백질은 전사 활성인자(transcriptional activator)로써 숙주세포의 유전자발현에 영향을 미치어 세포증식 및 분화에 영향을 줄 수 있다. 본 연구에서는 HBx 단백질이 NIH 3T3 cell의 증식 및 형질전환에 미치는 영향을 조사하였다. HBx 단백질을 발현하는 세포주는 정상세포에 비하여 증식 속도가 2배 정도 빠르며, soft agar assay 결과에 의하면 대조군과 비교하여 더 많은 수의 colony를 형성하였다. 또한, 이들 HBx 발현 세포들은 접촉 저해 능력을 상실하여 HBx가 세포 형질 전환 능력을 가짐을 알수 있다 또한 HBx 발현 세포주에 있어서 p21의 RNA 및 protein수준이 정상세포에 비하여 낮으므로 HBx에 의한 증식 촉진 및 세포 형질 전환이 p21을 매개하여 이루어 짐을 알 수 있었다. HBx에 의한 p21 유전자의 발현 감소는 p21의 전사 수준에서 이루어지며 이는 p53-비의존적 경로에 의하여 이루어졌다.

• BMB Reports
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• v.52 no.5
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• pp.330-335
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• 2019

Hepatitis B virus (HBV) encoding the HBV x protein (HBx) is a known causative agent of hepatocellular carcinoma (HCC). Its pathogenic activities in HCC include interference with several signaling pathways associated with cell proliferation and apoptosis. Mutant C-terminal-truncated HBx isoforms are frequently found in human HCC and have been shown to enhance proliferation and invasiveness leading to HCC malignancy. We investigated the molecular mechanism of the reduced doxorubicin cytotoxicity by C-terminal truncated HBx. Cells transfected with C-terminal truncated HBx exhibited reduced cytotoxicity to doxorubicin compared to those transfected with full-length HBx. The doxorubicin resistance of cells expressing C-terminal truncated HBx correlated with upregulation of the ATP binding cassette subfamily B member 1(ABCB1) transporter, resulting in the enhanced efflux of doxorubicin. Inhibiting the activity of ABCB1 and silencing ABCB1 expression by small interfering ribonucleic acid (siRNA) increased the cytotoxicity of doxorubicin. These results indicate that elevated ABCB1 expression induced by C-terminal truncation of HBx was responsible for doxorubicin resistance in HCC. Hence, co-treatment with an ABCB1 inhibitor and an anticancer agent may be effective for the treatment of patients with liver cancer containing the C-terminal truncated HBx.