Advertisement

Molecular and Cellular Biochemistry

, Volume 231, Issue 1–2, pp 155–161 | Cite as

Activation of the human transforming growth factor alpha (TGF-α) gene by the hepatitis B viral X protein (HBx) through AP-2 sites

  • Jun Hwan Kim
  • Hyune Mo Rho
Article

Abstract

The HBx protein is known as a transactivator and potential oncogene, and TGF-α as a potent mitogen in hepatocellular carcinoma. By assays of serial deletion of the promoter of TGF-α gene and the cotransfection of HBx and AP-2 expression vectors, we observed that the HBx significantly activated the promoter activity through AP-2 sites located in the proximal region of the TGF-α promoter (−136 to −30). This effect was also observed in the heterologous promoter assay system containing AP-2 sites. The mutation analyses of three AP-2 sites in the promoter revealed that all three AP-2 sites contributed to the activation of the TGF-α gene in the presence of HBx. Accordingly, the mRNA level of TGF-α was significantly elevated in the HBx-expressing cell, HepG2-HBx and the HBV-producing cell, HepG2-K8. These results suggest that the HBx protein could increase the mitogenic effect of TGF-α by the transactivation of the gene through AP-2 binding sites and consequently, these interactions may accelerate the process of hepatocarcinogenesis.

hepatitis B virus HBx transforming growth factor alpha hepatocellular carcinoma transactivation AP-2 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Mead JE, Fausto N: Transforming growth factor alpha may be a physiological regulator of liver regeneration by means of an autocrine mechanism. Proc Natl Acad Sci USA 86: 1558–1562, 1989Google Scholar
  2. 2.
    Derynck R, Goeddel DV, Ullrich A, Gutterman JU, Williams RD, Bringman TS, Berger WH: Synthesis of messenger RNAs for transforming growth factors alpha and beta and the epidermal growth factor receptor by human tumors. Cancer Res 47: 707–712, 1987Google Scholar
  3. 3.
    Reiss M, Stash EB, Vellucci VF, Zhou ZL: Activation of the autocrine transforming growth factor alpha pathway in human squamous carcinoma cells. Cancer Res 51: 6254–6262, 1992 (published erratum appears in Cancer Res 52: 6137, 1992)Google Scholar
  4. 4.
    Jhappan C, Stahle C, Harkins RN, Fausto N, Smith GH, Merlino GT: TGF alpha overexpression in transgenic mice induces liver neoplasia and abnormal development of the mammary gland and pancreas. Cell 61: 1137–1146, 1990Google Scholar
  5. 5.
    Rosenthal A, Lindquist PB, Bringman TS, Goeddel DV, Derynck R: Expression in rat fibroblasts of a human transforming growth factoralpha cDNA results in transformation. Cell 46: 301–309, 1986Google Scholar
  6. 6.
    Watanabe S, Lazar E, Sporn MB: Transformation of normal rat kidney (NRK) cells by an infectious retrovirus carrying a synthetic rat type alpha transforming growth factor gene. Proc Natl Acad Sci USA 84: 1258–1262, 1987Google Scholar
  7. 7.
    Ju WD, Velu TJ, Vass WC, Papageorge AG, Lowy DR: Tumorigenic transformation of NIH 3T3 cells by the autocrine synthesis of transforming growth factor alpha. New Biol 3: 380–388, 1991Google Scholar
  8. 8.
    Schreiber AB, Winkler ME, Derynck R: Transforming growth factoralpha: A more potent angiogenic mediator than epidermal growth factor. Science 232: 1250–1253, 1986Google Scholar
  9. 9.
    Shin TH, Paterson AJ, Grant JH III, Meluch AA, Kudlow JE: 5-Azacytidine treatment of HA-A melanoma cells induces Sp1 activity and concomitant transforming growth factor alpha expression. Mol Cell Biol 12: 3998–4006, 1992Google Scholar
  10. 10.
    Bjorge JD, Paterson AJ, Kudlow JE: Phorbol ester or epidermal growth factor (EGF) stimulates the concurrent accumulation of mRNA for the EGF receptor and its ligand transforming growth factor-alpha in a breast cancer cell line. J Biol Chem 264: 4021–4027, 1989Google Scholar
  11. 11.
    Raja RH, Paterson AJ, Shin TH, Kudlow JE: Transcriptional regulation of the human transforming growth factor-alpha gene. Mol Endocrinol 5: 514–520, 1991Google Scholar
  12. 12.
    Jakobovits EB, Schlokat U, Vannice JL, Derynck R, Levinson AD: The human transforming growth factor alpha promoter directs transcription initiation from a single site in the absence of a TATA sequence. Mol Cell Biol 8: 5549–5554, 1988Google Scholar
  13. 13.
    Blasband AJ, Rogers KT, Chen XR, Azizkhan JC, Lee DC: Characterization of the rat transforming growth factor alpha gene and identification of promoter sequences. Mol Cell Biol 10: 2111–2121, 1990Google Scholar
  14. 14.
    Shin TH, Paterson AJ, Kudlow JE: p53 stimulates transcription from the human transforming growth factor alpha promoter: A potential growth-stimulatory role for p53. Mol Cell Biol 15: 4694–4701, 1995Google Scholar
  15. 15.
    Shin TH, Kudlow JE: Identification and characterization of the human transforming growth factor-alpha initiator. Mol Endocrinol 8: 704–712, 1994Google Scholar
  16. 16.
    Chen X, Azizkhan JC, Lee DC: The binding of transcription factor Sp1 to multiple sites is required for maximal expression from the rat transforming growth factor alpha promoter. Oncogene 7: 1805–1815, 1992Google Scholar
  17. 17.
    Wang D, Shin TH, Kudlow JE: Transcription factor AP-2 controls transcription of the human transforming growth factor-alpha gene. J Biol Chem 272: 14244–14250, 1997Google Scholar
  18. 18.
    Berkowitz EA, Hecht CP, Azizkhan JC, Chen X, Lee DC: Transcription factor AP2 is required for expression of the rat transforming growth factor-alpha gene. Oncogene 14: 2229–2238, 1997Google Scholar
  19. 19.
    Gerber MA, Thung SN: Molecular and cellular pathology of hepatitis B. Lab Invest 52: 572–590, 1985Google Scholar
  20. 20.
    Robinson WS: Molecular events in the pathogenesis of hepadnavirusassociated hepatocellular carcinoma. Annu Rev Med 45: 297–323, 1994Google Scholar
  21. 21.
    Caselmann WH: Trans-activation of cellular genes by hepatitis B virus proteins: A possible mechanism of hepatocarcinogenesis. Adv Virus Res 47: 253–302, 1996Google Scholar
  22. 22.
    Andrisani OM, Barnabas S: The transcriptional function of the hepatitis B virus X protein and its role in hepatocarcinogenesis (review). Int J Oncol 15: 373–379, 1999Google Scholar
  23. 23.
    Caselmann WH, Koshy R: Transactivators of HBV, signal transduction and tumorigenesis. In: R. Koshy, W.H. Caselmann (eds). Hepatitis B Virus: Molecular Mechanisms in Disease and Novel Strategies for Therapy. Imperial College Press, London, 1998, pp 161–181Google Scholar
  24. 24.
    Hsia CC, Thorgeirsson SS, Tabor E: Expression of hepatitis B surface and core antigens and transforming growth factor-alpha in ‘oval cells’ of the liver in patients with hepatocellular carcinoma. J Med Virol 43: 216–221, 1994Google Scholar
  25. 25.
    Chung YH, Kim JA, Song BC, Lee GC, Koh MS, Lee YS, Lee SG, Suh DJ: Expression of transforming growth factor-alpha mRNA in livers of patients with chronic viral hepatitis and hepatocellular carcinoma. Cancer 89: 977–982, 2000Google Scholar
  26. 26.
    Tabor E, Farshid M, Di Bisceglie A, Hsia CC: Increased expression of transforming growth factor alpha after transfection of a human hepatoblastoma cell line with the hepatitis B virus. J Med Virol 37: 271–273, 1992Google Scholar
  27. 27.
    Ono M, Morisawa K, Nie J, Ota K, Taniguchi T, Saibara T, Onishi S: Transactivation of transforming growth factor alpha gene by hepatitis B virus preS1. Cancer Res 58: 1813–1816, 1998Google Scholar
  28. 28.
    Lee SG, Rho HM: Transcriptional repression of the human p53 gene by hepatitis B viral X protein. Oncogene 19: 468–471, 2000Google Scholar
  29. 29.
    Kim YH, Park KH, Rho HM: Transcriptional activation of the Cu,Znsuperoxide dismutase gene through the AP2 site by ginsenoside Rb2 extracted from a medicinal plant, Panax ginseng. J Biol Chem 271: 24539–24543, 1996Google Scholar
  30. 30.
    Parker BA, Stark GR: Regulation of simian virus 40 transcription: Sensitive analysis of the RNA species present early in infections by virus or viral DNA. J Virol 31: 360–369, 1979Google Scholar
  31. 31.
    Choi CY, Choi BH, Park GT, Rho HM: Activating transcription factor 2 (ATF2) down-regulates hepatitis B virus X promoter activity by the competition for the activating protein 1 binding site and the formation of the ATF2-Jun heterodimer. J Biol Chem 272: 16934–16939, 1997Google Scholar
  32. 32.
    Ausubel F, Brent R, Kingston R, Moore D, Seidman J, Smith J, Struhl K: In: Short Protocols in Molecular Biology, 4th edn. John Wiley & Sons, Inc., New York, 1999Google Scholar
  33. 33.
    Chomczynski P, Sacchi N: Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem 162: 156–159, 1987Google Scholar
  34. 34.
    Kim SH, Hong SP, Kim SK, Lee WS, Rho HM: Replication of a mutant hepatitis B virus with a fused X-C reading frame in hepatoma cells. J Gen Virol 73: 2421–2424, 1992Google Scholar
  35. 35.
    Han J, Yoo HY, Choi BH, Rho HM: Selective transcriptional regulations in the human liver cell by hepatitis B viral X protein. Biochem Biophys Res Commun 272: 525–530, 2000Google Scholar
  36. 36.
    Seto E, Mitchell PJ, Yen TS: Transactivation by the hepatitis B virus X protein depends on AP-2 and other transcription factors. Nature 344: 72–74, 1990Google Scholar
  37. 37.
    Marriott SJ, Lee TH, Slagle BL, Butel JS: Activation of the HTLV-I long terminal repeat by the hepatitis B virus X protein. Virology 224: 206–213, 1996Google Scholar
  38. 38.
    Imagawa M, Chiu R, Karin M: Transcription factor AP-2 mediates induction by two different signal-transduction pathways: Protein kinase C and cAMP. Cell 51: 251–260, 1987Google Scholar
  39. 39.
    Hyman SE, Comb M, Pearlberg J, Goodman HM: An AP-2 element acts synergistically with the cyclic AMP-and phorbol ester-inducible enhancer of the human proenkephalin gene. Mol Cell Biol 9: 321–324, 1989Google Scholar
  40. 40.
    Kannan P, Buettner R, Chiao PJ, Yim SO, Sarkiss M, Tainsky MA: Nras oncogene causes AP-2 transcriptional self-interference, which leads to transformation. Genes Dev 8: 1258–1269, 1994Google Scholar
  41. 41.
    Menzo S, Clementi M, Alfani E, Bagnarelli P, Iacovacci S, Manzin A, Dandri M, Natoli G, Levrero M, Carloni G: Trans-activation of epidermal growth factor receptor gene by the hepatitis B virus X-gene product. Virology 196: 878–882, 1993Google Scholar

Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • Jun Hwan Kim
  • Hyune Mo Rho

There are no affiliations available

Personalised recommendations