Journal of Gastroenterology

, Volume 44, Issue 8, pp 856–863 | Cite as

Interferon-α-induced mTOR activation is an anti-hepatitis C virus signal via the phosphatidylinositol 3-kinase-Akt-independent pathway

  • Azusa Matsumoto
  • Tatsuki Ichikawa
  • Kazuhiko Nakao
  • Hisamitsu Miyaaki
  • Kumi Hirano
  • Masumi Fujimito
  • Motohisa Akiyama
  • Satoshi Miuma
  • Eisuke Ozawa
  • Hidetaka Shibata
  • Shigeyuki Takeshita
  • Hironori Yamasaki
  • Masanori Ikeda
  • Nobuyuki Kato
  • Katsumi Eguchi
Original Article—Liver, Pancreas, and Biliary Tract



The interferon-induced Jak-STAT signal alone is not sufficient to explain all the biological effects of IFN. The PI3-K pathways have emerged as a critical additional component of IFN-induced signaling. This study attempted to clarify that relationship between IFN-induced PI3-K-Akt-mTOR activity and anti-viral action.


When the human normal hepatocyte derived cell line was treated with rapamycin (rapa) before accretion of IFN-α, tyrosine phosphorylation of STAT-1 was diminished. Pretreatment of rapa had an inhibitory effect on the IFN-α-induced expression of PKR and p48 in a dose dependent manner. Rapa inhibited the IFN-α inducible IFN-stimulated regulatory element luciferase activity in a dose-dependent manner. However, wortmannin, LY294002 and Akt inhibitor did not influence IFN-α inducible luciferase activity. To examine the effect of PI3-K-Akt-mTOR on the anti-HCV action of IFN-α, the full-length HCV replication system, OR6 cells were used. The pretreatment of rapa attenuated its anti-HCV replication effect in comparison to IFN-α alone, whereas the pretreatment with PI3-K inhibitors, wortmannin and LY294002 and Akt inhibitor did not influence IFN-induced anti-HCV replication.


IFN-induced mTOR activity, independent of PI3K and Akt, is the critical factor for its anti-HCV activity. Jak independent mTOR activity involved STAT-1 phosphorylation and nuclear location, and then PKR is expressed in hepatocytes.


mTOR STAT-1 Interferon HCV PKR 





Hepatitis C virus


Signal transducers and activators of transcription


IFN-stimulated gene factor 3


IFN-stimulated regulatory element


Double-stranded RNA-dependent protein kinase




Phosphatidylinositol 3-kinase


Mammalian target of rapamycin


Small interfering RNA


  1. 1.
    Fattovich G, Stroffolini T, Zagni I, Donato F. Hepatocellular carcinoma in cirrhosis: incidence and risk factors. Gastroenterology. 2004;127:S35–50.PubMedCrossRefGoogle Scholar
  2. 2.
    Pawlotsky JM, Chevaliez S, McHutchison JG. The hepatitis C virus life cycle as a target for new antiviral therapies. Gastroenterology. 2007;132:1979–98.PubMedCrossRefGoogle Scholar
  3. 3.
    Persico M, Capasso M, Persico E, Svelto M, Russo R, Spano D, et al. Suppressor of cytokine signaling 3 (SOCS3) expression and hepatitis C virus-related chronic hepatitis: insulin resistance and response to antiviral therapy. Hepatology. 2007;46:1009–15.PubMedCrossRefGoogle Scholar
  4. 4.
    Walsh MJ, Jonsson JR, Richardson MM, Lipka GM, Purdie DM, Clouston AD, et al. Non-response to antiviral therapy is associated with obesity and increased hepatic expression of suppressor of cytokine signaling 3 (SOCS-3) in patients with chronic hepatitis C, viral genotype 1. Gut. 2006;55:529–35.PubMedCrossRefGoogle Scholar
  5. 5.
    Huang Y, Feld JJ, Sapp RK, Nanda S, Lin JH, Blatt LM, et al. Defective hepatic response to interferon and activation of suppressor of cytokine signaling 3 in chronic hepatitis C. Gastroenterology. 2007;132:733–44.PubMedCrossRefGoogle Scholar
  6. 6.
    Taylor MW, Tsukahara T, Brodsky L, Schaley J, Sanda C, Stephens MJ, et al. Changes in gene expression during pegylated interferon and ribavirin therapy of chronic hepatitis C virus distinguish responders from nonresponders to antiviral therapy. J Virol. 2007;81:3391–401.PubMedCrossRefGoogle Scholar
  7. 7.
    Lan KH, Lan KL, Lee WP, Sheu ML, Chen MY, Lee YL, et al. HCV NS5A inhibits interferon-alpha signaling through suppression of STAT1 phosphorylation in hepatocyte-derived cell lines. J Hepatol. 2007;46:759–67.PubMedCrossRefGoogle Scholar
  8. 8.
    van Boxel-Dezaire AH, Rani MR, Stark GR. Complex modulation of cell type-specific signaling in response to type I interferons. Immunity. 2006;25:361–72.PubMedCrossRefGoogle Scholar
  9. 9.
    Ichikawa T, Nakao K, Nakata K, Yamashita M, Hamasaki K, Shigeno M, et al. Involvement of IL-1beta and IL-10 in IFN-alpha-mediated antiviral gene induction in human hepatoma cells. Biochem Biophys Res Commun. 2002;294:414–22.PubMedCrossRefGoogle Scholar
  10. 10.
    Kaur S, Uddin S, Platanias LC. The PI3’ kinase pathway in interferon signaling. J Interferon Cytokine Res. 2005;25:780–7.PubMedCrossRefGoogle Scholar
  11. 11.
    Kaur S, Lal L, Sassano A, Majchrzak-Kita B, Srikanth M, Baker DP, et al. Regulatory effects of mammalian target of rapamycin-activated pathways in type I and II interferon signaling. J Biol Chem. 2007;282:1757–68.PubMedCrossRefGoogle Scholar
  12. 12.
    Kudchodkar SB, Del Prete GQ, Maguire TG, Alwine JC. AMPK-mediated inhibition of mTOR kinase is circumvented during immediate-early times of human cytomegalovirus infection. J Virol. 2007;81:3649–51.PubMedCrossRefGoogle Scholar
  13. 13.
    Minami K, Tambe Y, Watanabe R, Isono T, Haneda M, Isobe K, et al. Suppression of viral replication by stress-inducible GADD34 protein via the mammalian serine/threonine protein kinase mTOR pathway. J Virol. 2007;81:11106–15.PubMedCrossRefGoogle Scholar
  14. 14.
    Ishida H, Li K, Yi M, Lemon SM. p21-activated kinase 1 is activated through the mammalian target of rapamycin/p70 S6 kinase pathway and regulates the replication of hepatitis C virus in human hepatoma cells. J Biol Chem. 2007;282:11836–48.PubMedCrossRefGoogle Scholar
  15. 15.
    Guo H, Zhou T, Jiang D, Cuconati A, Xiao GH, Block TM, et al. Regulation of hepatitis B virus replication by the phosphatidylinositol 3-kinase-Akt signal transduction pathway. J Virol. 2007;81:10072–80.PubMedCrossRefGoogle Scholar
  16. 16.
    Mannova P, Beretta L. Activation of the N-Ras-PI3K-Akt-mTOR pathway by hepatitis C virus: control of cell survival and viral replication. J Virol. 2005;79:8742–9.PubMedCrossRefGoogle Scholar
  17. 17.
    Nishimura D, Ishikawa H, Matsumoto K, Shibata H, Motoyoshi Y, Fukuta M, et al. DHMEQ, a novel NF-kappaB inhibitor, induces apoptosis and cell-cycle arrest in human hepatoma cells. Int J Oncol. 2006;29:713–9.PubMedGoogle Scholar
  18. 18.
    Ikeda M, Abe K, Dansako H, Nakamura T, Naka K, Kato N. Efficient replication of a full-length hepatitis C virus genome, strain O, in cell culture, and development of a luciferase reporter system. Biochem Biophys Res Commun. 2005;329:1350–9.PubMedCrossRefGoogle Scholar
  19. 19.
    Obora A, Shiratori Y, Okuno M, Adachi S, Takano Y, Matsushima-Nishiwaki R, et al. Synergistic induction of apoptosis by acyclic retinoid and interferon-beta in human hepatocellular carcinoma cells. Hepatology. 2002;36:1115–24.PubMedCrossRefGoogle Scholar
  20. 20.
    Wang C, Pflugheber J, Sumpter R Jr, Sodora DL, Hui D, Sen GC, et al. Alpha interferon induces distinct translational control programs to suppress hepatitis C virus RNA replication. J Virol. 2003;77:3898–912.PubMedCrossRefGoogle Scholar
  21. 21.
    Liu WL, Su WC, Cheng CW, Hwang LH, Wang CC, Chen HL, et al. Ribavirin up-regulates the activity of double-stranded RNA-activated protein kinase and enhances the action of interferon-alpha against hepatitis C virus. J Infect Dis. 2007;196:425–34.PubMedCrossRefGoogle Scholar
  22. 22.
    Tamada Y, Nakao K, Nagayama Y, Nakata K, Ichikawa T, Kawamata Y, et al. p48 Overexpression enhances interferon-mediated expression and activity of double-stranded RNA-dependent protein kinase in human hepatoma cells. J Hepatol. 2002;37:493–9.PubMedCrossRefGoogle Scholar
  23. 23.
    Dowling RJ, Zakikhani M, Fantus IG, Pollak M, Sonenberg N. Metformin inhibits mammalian target of rapamycin-dependent translation initiation in breast cancer cells. Cancer Res. 2007;67:10804–12.PubMedCrossRefGoogle Scholar
  24. 24.
    Mamane Y, Petroulakis E, LeBacquer O, Sonenberg N. mTOR, translation initiation and cancer. Oncogene. 2006;25:6416–22.PubMedCrossRefGoogle Scholar
  25. 25.
    Hanada M, Feng J, Hemmings BA. Structure, regulation and function of PKB/AKT–a major therapeutic target. Biochim Biophys Acta. 2004;1697:3–16.PubMedGoogle Scholar
  26. 26.
    Hresko RC, Mueckler M. mTOR.RICTOR is the Ser473 kinase for Akt/protein kinase B in 3T3–L1 adipocytes. J Biol Chem. 2005;280:40406–16.PubMedCrossRefGoogle Scholar
  27. 27.
    Engelman JA, Luo J, Cantley LC. The evolution of phosphatidylinositol 3-kinases as regulators of growth and metabolism. Nat Rev Genet. 2006;7:606–19.PubMedCrossRefGoogle Scholar
  28. 28.
    Molnarfi N, Hyka-Nouspikel N, Gruaz L, Dayer JM, Burger D. The production of IL-1 receptor antagonist in IFN-beta-stimulated human monocytes depends on the activation of phosphatidylinositol 3-kinase but not of STAT1. J Immunol. 2005;174:2974–80.PubMedGoogle Scholar
  29. 29.
    Parmar S, Smith J, Sassano A, Uddin S, Katsoulidis E, Majchrzak B, et al. Differential regulation of the p70 S6 kinase pathway by interferon alpha (IFNalpha) and imatinib mesylate (STI571) in chronic myelogenous leukemia cells. Blood. 2005;106:2436–43.PubMedCrossRefGoogle Scholar
  30. 30.
    Nguyen H, Ramana CV, Bayes J, Stark GR. Roles of phosphatidylinositol 3-kinase in interferon-gamma-dependent phosphorylation of STAT1 on serine 727 and activation of gene expression. J Biol Chem. 2001;276:33361–8.PubMedCrossRefGoogle Scholar
  31. 31.
    Fang P, Hwa V, Rosenfeld RG. Interferon-gamma-induced dephosphorylation of STAT3 and apoptosis are dependent on the mTOR pathway. Exp Cell Res. 2006;312:1229–39.PubMedCrossRefGoogle Scholar
  32. 32.
    El-Hashemite N, Zhang H, Walker V, Hoffmeister KM, Kwiatkowski DJ. Perturbed IFN-gamma-Jak-signal transducers and activators of transcription signaling in tuberous sclerosis mouse models: synergistic effects of rapamycin-IFN-gamma treatment. Cancer Res. 2004;64:3436–43.PubMedCrossRefGoogle Scholar
  33. 33.
    Matsumoto K, Okano J, Murawaki Y. Differential effects of interferon alpha-2b and beta on the signaling pathways in human liver cancer cells. J Gastroenterol. 2005;40:722–32.PubMedCrossRefGoogle Scholar

Copyright information

© Springer 2009

Authors and Affiliations

  • Azusa Matsumoto
    • 1
  • Tatsuki Ichikawa
    • 2
  • Kazuhiko Nakao
    • 2
  • Hisamitsu Miyaaki
    • 2
  • Kumi Hirano
    • 1
  • Masumi Fujimito
    • 2
  • Motohisa Akiyama
    • 2
  • Satoshi Miuma
    • 2
  • Eisuke Ozawa
    • 2
  • Hidetaka Shibata
    • 2
  • Shigeyuki Takeshita
    • 2
  • Hironori Yamasaki
    • 3
  • Masanori Ikeda
    • 4
  • Nobuyuki Kato
    • 4
  • Katsumi Eguchi
    • 2
  1. 1.Department of Clinical Pharmaceutics, Graduate School of Biomedical SciencesNagasaki UniversityNagasakiJapan
  2. 2.The First Department of Internal Medicine, Graduate School of Biomedical SciencesNagasaki UniversityNagasakiJapan
  3. 3.Health Research Center, Graduate School of Biomedical SciencesNagasaki UniversityNagasakiJapan
  4. 4.Department of Molecular Biology, Graduate School of Medicine and DentistryOkayama UniversityOkayamaJapan

Personalised recommendations