Viral Hepatitis
Copyright ©The Author(s) 2003. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jul 15, 2003; 9(7): 1521-1524
Published online Jul 15, 2003. doi: 10.3748/wjg.v9.i7.1521
Aggregate formation of hepatitis B virus X protein affects cell cycle and apoptosis
Chang-Zheng Song, Zeng-Liang Bai, Chang-Cheng Song, Qing-Wei Wang
Chang-Zheng Song, Zeng-Liang Bai, Laboratory of Immunobiology, College of Life Sciences, Shandong University, Jinan 250100, Shandong Province, China
Chang-Zheng Song, Shandong Research Center for Medical Biotechnology, Shandong Academy of Medical Sciences, Jinan 250062, Shandong Province, China
Chang-Cheng Song, Basic Research Laboratory, National Cancer Institute at Frederick, MD 21702, USA
Qing-Wei Wang, Cancer Research Center, Qilu Hospital of Shandong University, Jinan 250012, Shandong Province, China
Author contributions: All authors contributed equally to the work.
Correspondence to: Dr. Chang-Zheng Song, Project of Viral Vaccine, Shandong Research Center for Medical Biotechnology, Shandong Academy of Medical Sciences, Jinan 250062, Shandong Province, China.
Telephone: +86-531-2919611
Received: December 28, 2002
Revised: January 4, 2003
Accepted: February 18, 2003
Published online: July 15, 2003

AIM: To investigate whether the formation of aggregated HBx has a potential linking with its cellular responses.

METHODS: Recombinant HBx was expressed in Escherichia coli and purified by Ni-NTA metal-affinity chromatography. Anti-HBx monoclonal antibody was developed for immunocytochemical detection. Bicistronic expression vector harboring full-length DNA of HBx was employed for transfection of human HepG2 cells. Immunocytochemical staining was used to examine the intracellular HBx aggregates in cells. The effects of HBx aggregation on cell cycle and apoptosis were assessed by flow cytometry.

RESULTS: Immunocytochemical staining revealed most of the HBx was formed intracellular aggregate in cytoplasm and frequently accumulated in large granules. Flow cytometry analysis showed that HepG2 cells transfected with vector harboring HBx significantly increased apoptosis and largely accumulated in the G0-G1 phase by maintenance in serum medium for 36 h. Control cells without HBx aggregates in the presence of serum entered S phase and proliferated more rapidly at the same time. EGFP fluorescence in HBx expression cells was significantly decreased.

CONCLUSION: Our observations show that cells with HBx aggregate undergo growth arrest and apoptosis, whereas control cells without HBx remain in growth and progression into S phase. Our data may provide helpful information to understand the biological effects of HBx aggregates on cells.

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