Molecular Biology Reports

, Volume 37, Issue 6, pp 2935–2940 | Cite as

p53 Promotes proteasome-dependent degradation of oncogenic protein HBx by transcription of MDM2

  • Lingling Xian
  • Jing Zhao
  • Jia Wang
  • Zhou Fang
  • Bo Peng
  • Wenzhang Wang
  • Xiaona Ji
  • Long Yu


Hepatitis B virus X protein (HBx) is closely involved in the development of hepatocellular carcinoma (HCC). Tumor suppressor p53 was reported to induce HBx degradation and repress its oncogenic function recently, but the molecular mechanism is unknown. In this study, we attempted to identify the underlying mechanism. We found that overexpression of p53 protein reduces the level of HBx protein and shortens its half-life, however, in MDM2 knock out cells, p53 has no effects on degradation of HBx, meanwhile, overexpression of MDM2 in absence of p53 can accelerate turnover of HBx protein. These indicate that p53-mediated HBx degradation is MDM2-dependent. MDM2 interacts with HBx in vitro and in vivo but does not promote its ubiquitination. In consistent with the results above, HCC tissue samples with wild-type p53 hardly detect HBx protein, whereas, HBx always accumulate in the tissues with mutant p53. Our data provide a possible mechanism on how p53 regulate HBx stability and also a new clue for the study of p53 mutation and HCC development.


HBx p53 MDM2 HCC Degradation Hepatitis B virus 



We thank Dr. Zhu Minghua for providing the pCMV-Myc-HBx plasmid (Changhai Hospital, the Second Military Medical University, Shanghai, China). This work was supported by the National 973 program of China (2004CB518605), the National 863 project of China (2006AA020501), the National Key Sci-Tech Special Project of China (2008ZX10002-020).

Supplementary material

11033_2009_9855_MOESM1_ESM.jpeg (440 kb)
Supplementary Fig. 1 Detection of HBx protein by western-blot in HBV-positive HCC tissues. a Western-blot analysis of HBx and p53 in HBV-positive HCC tissues with anti-HBx and DO-1 monoclonal antibody. β-actin levels are shown as loading control. p53-MU means samples with mutant p53, and p53-WT means samples with wild-type p53. b Statistical analysis of western-blot results by chi square test in the 36 HBV-positive HCC tissues (JPEG 440 kb)


  1. 1.
    Schluter V, Meyer M, Hofschneider PH, Koshy R, Caselmann WH (1994) Integrated hepatitis B virus X and 3’ truncated preS/S sequences derived from human hepatomas encode functionally active transactivators. Oncogene 9:3335–3344PubMedGoogle Scholar
  2. 2.
    Murakami S (1999) Hepatitis B virus X protein: structure, function and biology. Intervirology 42:81–99CrossRefPubMedGoogle Scholar
  3. 3.
    Yen TSB (1996) Hepadnaviral X protein: review of recent progress. J Biomed Sci 3:20–30CrossRefPubMedGoogle Scholar
  4. 4.
    Zhang X, Zhang H, Ye L (2006) Effects of hepatitis B virus X protein on the development of liver cancer. J Lab Clin Med 147:58–66CrossRefPubMedGoogle Scholar
  5. 5.
    Moon EJ, Jeong CH, Jeong JW, Kim KR, Yu DY, Murakami S, Kim CW, Kim KW (2003) Hepatitis B virus X protein induces angiogenesis by stabilizing hypoxia-inducible factor-1α. FASEB J 18:382–384PubMedGoogle Scholar
  6. 6.
    Hu Z, Zhang Z, Doo E, Coux O, Goldberg AL, Liang TJ (1999) Hepatitis B virus X protein is both a substrate and a potential inhibitor of the proteasome complex. J Virol 73:7231–7240PubMedGoogle Scholar
  7. 7.
    Kim CM, Koike K, Saito I, Miyamura T, Jay G (1991) HBx gene of hepatitis B virus induces liver cancer in transgenic mice. Nature 351:317–320CrossRefPubMedGoogle Scholar
  8. 8.
    Ullrich SJ, Zeng ZZ, Jay G (1994) Transgenic mouse models of human gastric and hepatic carcinomas. Semin Cancer Biol 5:61–68PubMedGoogle Scholar
  9. 9.
    Koike K, Moriyama K, Iino S (1994) High-level expression of hepatitis B virus HBx gene and hepatocarcinogenesis in transgenic mice. Hepatology 19:810–819CrossRefPubMedGoogle Scholar
  10. 10.
    Koike K (1995) Hepatitis B virus HBx gene and hepatocarcinogenesis. Intervirology 38:134–142PubMedGoogle Scholar
  11. 11.
    Vousden KH (2002) Activation of the p53 tumor suppressor protein. Biochim Biophys Acta 1602:47–59PubMedGoogle Scholar
  12. 12.
    Ravi R, Mookerjee B, Bhujwalla ZM, Sutter CH, Artemov D, Zeng Q et al (2000) Regulation of tumor angiogenesis by p53-induced degradation of hypoxiainducible factor 1alpha. Genes Dev 14:34–44PubMedGoogle Scholar
  13. 13.
    Sengupta S, Wasylyk B (2001) Ligand-dependent interaction of the glucocorticoid receptor with p53 enhances their degradation by Hdm2. Genes Dev 15:2367–2380CrossRefPubMedGoogle Scholar
  14. 14.
    Park SG, Min JY, Chung C, Hsieh A, Jung G (2009) Tumor suppressor protein p53 induces degradation of the oncogenic protein HBx. Cancer Lett 282:229–237CrossRefPubMedGoogle Scholar
  15. 15.
    Kim JH, Kang S, Kim J, Ahn BY (2003) Hepatitis B virus core protein stimulates the proteasome-mediated degradation of viral X protein. J Virol 77:7166–7173CrossRefPubMedGoogle Scholar
  16. 16.
    Hofmann TG et al (2002) Regulation of p53 activity by its interaction with homeodomain-interacting protein kinase-2. Nature Cell Biol 4:1–10CrossRefPubMedGoogle Scholar
  17. 17.
    Ling MT, Chiu YT, Lee TK, Leung SC, Fung MK, Wang X, Wong KF, Wong YC (2008) Id-1 induces proteasome-dependent degradation of the HBX protein. J Mol Biol 382:34–43CrossRefPubMedGoogle Scholar
  18. 18.
    Sdek P, Ying H, Chang DL, Qiu W, Zheng H, Touitou R, Allday MJ, Xiao ZX (2005) MDM2 promotes proteasome-dependent ubiquitin-independent degradation of retinoblastoma protein. Mol Cell 20:699–708CrossRefPubMedGoogle Scholar
  19. 19.
    Kim JH, Sohn SY, Benedict Yen TS, Ahn BY (2007) Ubiquitin-dependent and -independent proteasomal degradation of hepatitis B virus X protein. Biochem Biophys Res Commun 366:1036–1042CrossRefPubMedGoogle Scholar
  20. 20.
    Bouchard MJ, Schneider RJ (2004) The enigmatic X gene of hepatitis B virus. J Virol 78:12725–12734CrossRefPubMedGoogle Scholar
  21. 21.
    Wang XW, Forrester K, Yeh H, Feitelson MA, Gu JR, Harris CC (1994) Hepatitis B virus X protein inhibits p53 sequence-specific DNA binding, transcriptional activity, and association with transcription factor ERCC3. Proc Natl Acad Sci USA 91:2230–2234CrossRefPubMedGoogle Scholar
  22. 22.
    Truant R, Antunovic J, Greenblatt J, Prives C, Cromlish JA (1995) Direct interaction of the hepatitis B virus HBx protein with p53 leads to inhibition by HBx of p53 response element-directed transactivation. J Virol 69:1851–1859PubMedGoogle Scholar
  23. 23.
    Ueda H, Ullrich SJ, Gangemi JD, Kappel CA, Ngo L, Feitelson MA, Jay G (1995) Functional inactivation but not structural mutation of p53 causes liver cancer. Nat Genet 9:41–47CrossRefPubMedGoogle Scholar
  24. 24.
    Kwun HJ, Jang KL (2004) Natural variants of hepatitis B virus X protein have differential effects on the expression of cyclin-dependent kinase inhibitor p21 gene. Nucleic Acids Res 32:2202–2213CrossRefPubMedGoogle Scholar
  25. 25.
    Wang JH, Yun C, Kim S, Chae S, Lee YI, Kim WH, Lee JH, Kim W, Cho H (2008) Reactivation of p53 in cells expressing hepatitis B virus X-protein involves p53 phosphorylation and a reduction of Hdm2. Cancer Sci 99:888–893CrossRefPubMedGoogle Scholar
  26. 26.
    Ahn JY, Jung EY, Kwun HJ, Lee CW, Sung YC, Jang KL (2002) Dual effects of hepatitis B virus X protein on the regulation of cell cycle control depending on the status of cellular p53 protein. J Gen Virol 83:2765–2772PubMedGoogle Scholar
  27. 27.
    Chirillo P, Pagano S, Natoli G, Puri PL, Burgio VL, Balsano C, Levrero M (1997) The hepatitis B virus X gene induces p53-mediated programmed cell death. Proc Natl Acad Sci USA 94:8162–8167CrossRefPubMedGoogle Scholar
  28. 28.
    Tannapfel A, Wittekind C (2002) Genes involved in hepatocellular carcinoma: deregulation in cell cycling and apoptosis. TVirchows Arch 440:345–352CrossRefGoogle Scholar
  29. 29.
    Hussain SP, Schwank J, Staib F, Wang XW, Harris CC (2007) TP53 mutations and hepatocellular carcinoma: insights into the etiology and pathogenesis of liver cancer. Oncogene 26:2166–2176CrossRefPubMedGoogle Scholar
  30. 30.
    Puisieux A, Ji J, Guillot C, Legros Y, Soussi T, Isselbacher K et al (1995) p53-mediated cellular response to DNA damage in cells with replicative hepatitis B virus. Proc Natl Acad Sci USA 92:1342–1346CrossRefPubMedGoogle Scholar
  31. 31.
    Groisman IJ, Koshy R, Henkler F, Groopman JD, Alaoui-Jamali MA (1999) Downregulation of DNA excision repair by the hepatitis B virus-x protein occurs in p53-proficient and p53-deficient cells. Carcinogenesis 20:479–483CrossRefPubMedGoogle Scholar
  32. 32.
    Madden CR, Finegold MJ, Slagle BL (2002) Altered DNA mutation spectrum in aflatoxin B1-treated transgenic mice that express the hepatitis B virus X protein. J Virol 76:11770–11774CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • Lingling Xian
    • 1
    • 2
  • Jing Zhao
    • 1
  • Jia Wang
    • 1
  • Zhou Fang
    • 1
  • Bo Peng
    • 1
  • Wenzhang Wang
    • 1
  • Xiaona Ji
    • 1
  • Long Yu
    • 1
  1. 1.State Key Laboratory of Genetic Engineering, Institute of GeneticsSchool of Life Sciences, Fudan UniversityShanghaiPeople’s Republic of China
  2. 2.Ministry of Education Key Laboratory of Xinjiang Endemic and Ethnic DiseaseShihezi UniversityShiheziPeople’s Republic of China

Personalised recommendations