Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Silibinin inhibits hypoxia-inducible factor-1α and mTOR/p70S6K/4E-BP1 signalling pathway in human cervical and hepatoma cancer cells: implications for anticancer therapy

Oncogene volume 28, pages 313–324 (2009)Cite this article

Abstract

The hypoxia-inducible factor 1 (HIF-1) plays a critical role for tumour adaptation to microenvironmental hypoxia, and represents an appealing chemotherapeutic target. Silibinin is a nontoxic flavonoid reported to exhibit anticancer properties. However, the mechanisms by which silibinin inhibits tumour growth are not fully understood. In this study, silibinin was found to inhibit hypoxia-induced HIF-1α accumulation and HIF-1 transcriptional activity in human cervical (HeLa) and hepatoma (Hep3B) cells. Neither HIF-1α protein degradation rate nor HIF-1α steady-state mRNA level was affected by silibinin. Rather, we found that suppression of HIF-1α accumulation by silibinin correlated with strong dephosphorylation of mammalian target of rapamycin (mTOR) and its effectors ribosomal protein S6 kinase (p70S6K) and eukaryotic initiation factor 4E-binding protein-1 (4E-BP1), a pathway known to regulate HIF-1α expression at the translational level. Silibinin also activated Akt, a mechanistic feature exhibited by established mTOR inhibitors in many tumour cells. Moreover, silibinin reduced hypoxia-induced vascular endothelial growth factor (VEGF) release by HeLa and Hep3B cells, and this effect was potentiated by the PI3K/Akt inhibitor LY294002. Finally, silibinin was found to be a potent inhibitor of cell proliferation. These results show that silibinin is an effective inhibitor of HIF-1 and provide new perspectives into the mechanism of its anticancer activity.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it

$39.95

Learn more

Prices may be subject to local taxes which are calculated during checkout

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6

Accession codes

Accessions

GenBank/EMBL/DDBJ

References

  • Alvarez-Tejado M, Alfranca A, Aragonés J, Vara A, Landázuri MO, del Peso L . (2002). Lack of evidence for the involvement of the phosphoinositide 3-kinase/Akt pathway in the activation of hypoxia-inducible factors by low oxygen tension. J Biol Chem 277: 13508–13517.

    Article  CAS  Google Scholar 

  • Bhatia N, Zhao J, Wolf DM, Agarwal R . (1999). Inhibition of human carcinoma cell growth and DNA synthesis by silibinin, an active constituent of milk thistle: comparison with silymarin. Cancer Lett 147: 77–84.

    Article  CAS  Google Scholar 

  • Bjornsti MA, Houghton PJ . (2004). The TOR pathway: a target for cancer therapy. Nat Rev Cancer 4: 335–348.

    Article  CAS  Google Scholar 

  • Brown JM, Giaccia AJ . (1998). The unique physiology of solid tumors: opportunities (and problems) for cancer therapy. Cancer Res 58: 1408–1416.

    CAS  Google Scholar 

  • Brugarolas J, Lei K, Hurley RL, Manning BD, Reiling JH, Hafen E et al. (2004). Regulation of mTOR function in response to hypoxia by REDD1 and the TSC1/TSC2 tumor suppressor complex. Genes Dev 18: 2893–2904.

    Article  CAS  Google Scholar 

  • Castedo M, Ferri KF, Kroemer G . (2002). Mammalian target of rapamycin (mTOR): pro- and anti-apoptotic. Cell Death Differ 9: 99–100.

    Article  CAS  Google Scholar 

  • Chen PN, Hsieh YS, Chiou HL, Chu SC . (2005). Silibinin inhibits cell invasion through inactivation of both PI3K–Akt and MAPK signalling pathways. Chem Biol Interact 156: 141–150.

    Article  CAS  Google Scholar 

  • Deep G, Oberlies NH, Kroll DJ, Agarwal R . (2008). Isosilybin B causes androgen receptor degradation in human prostate carcinoma cells via PI3K–Akt–Mdm2-mediated pathway. Oncogene 27: 3986–3998.

    Article  CAS  Google Scholar 

  • Fan QW, Knight ZA, Goldenberg DD, Yu W, Mostov K, Stokoe D et al. (2006). A dual PI3 kinase/mTOR inhibitor reveals emergent efficacy in glioma. Cancer Cell 9: 341–349.

    Article  CAS  Google Scholar 

  • Ferrara N . (2004). Vascular endothelial growth factor: basic science and clinical progress. Endocr Rev 25: 581–611.

    Article  CAS  Google Scholar 

  • Fingar DC, Blenis J . (2004). Target of rapamycin (TOR): an integrator of nutrient and growth factor signals and coordinator of cell growth and cell cycle progression. Oncogene 23: 3151–3171.

    Article  CAS  Google Scholar 

  • Giaccia A, Siim BG, Johnson RS . (2003). HIF-1 as a target for drug development. Nat Rev Drug Discov 2: 803–811.

    Article  CAS  Google Scholar 

  • Gu M, Singh RP, Dhanalakshmi S, Agarwal C, Agarwal R . (2007). Silibinin inhibits inflammatory and angiogenic attributes in photocarcinogenesis in SKH-1 hairless mice. Cancer Res 67: 3483–3491.

    Article  CAS  Google Scholar 

  • Guertin DA, Sabatini DM . (2007). Defining the role of mTOR in cancer. Cancer Cell 12: 9–22.

    Article  CAS  Google Scholar 

  • Hanahan D, Folkman J . (1996). Patterns and emerging mechanisms of the angiogenic switch during tumorigenesis. Cell 86: 353–364.

    Article  CAS  Google Scholar 

  • Hockel M, Vaupel P . (2001). Tumor hypoxia: definitions and current clinical, biologic, and molecular aspects. J Natl Cancer Inst 93: 266–276.

    Article  CAS  Google Scholar 

  • Huang J, Dibble CC, Matsuzaki M, Manning BD . (2008). The TSC1–TSC2 complex is required for proper activation of mTOR complex 2. Mol Cell Biol 28: 4104–4115.

    Article  CAS  Google Scholar 

  • Hudson CC, Liu M, Chiang GG, Otterness DM, Loomis DC, Kaper F et al. (2002). Regulation of hypoxia-inducible factor 1alpha expression and function by the mammalian target of rapamycin. Mol Cell Biol 22: 7004–7014.

    Article  CAS  Google Scholar 

  • Jiang BH, Semenza GL, Bauer C, Marti HH . (1996). Hypoxia-inducible factor 1 levels vary exponentially over a physiologically relevant range of O2 tension. Am J Physiol 271: C1172–C1180.

    Article  CAS  Google Scholar 

  • Lah JJ, Cui W, Hu KQ . (2007). Effects and mechanisms of silibinin on human hepatoma cell lines. World J Gastroenterol 13: 5299–5305.

    Article  CAS  Google Scholar 

  • Laughner E, Taghavi P, Chiles K, Mahon PC, Semenza GL . (2001). HER2 (neu) signaling increases the rate of hypoxia-inducible factor 1alpha (HIF-1α) synthesis: novel mechanism for HIF-1-mediated vascular endothelial growth factor expression. Mol Cell Biol 21: 3995–4004.

    Article  CAS  Google Scholar 

  • Manning BD . (2004). Balancing Akt with S6K: implications for both metabolic diseases and tumorigenesis. J Cell Biol 167: 399–403.

    Article  CAS  Google Scholar 

  • Masson M, Willam C, Maxwell PH, Pugh CW, Ratcliffe PJ . (2001). Independent function of two destruction domains in hypoxia-inducible factor-alpha chains activated by prolyl hydroxylation. EMBO J 20: 5197–5206.

    Article  CAS  Google Scholar 

  • Mateo J, García-Lecea M, Cadenas S, Hernández C, Moncada S . (2003). Regulation of hypoxia-inducible factor-1alpha by nitric oxide through mitochondria-dependent and -independent pathways. Biochem J 376: 537–544.

    Article  CAS  Google Scholar 

  • O'Reilly KE, Rojo F, She QB, Solit D, Mills GB, Smith D et al. (2006). mTOR inhibition induces upstream receptor tyrosine kinase signaling and activates Akt. Cancer Res 66: 1500–1508.

    Article  CAS  Google Scholar 

  • Pore N, Liu S, Shu HK, Li B, Haas-Kogan D, Stokoe D et al. (2004). Sp1 is involved in Akt-mediated induction of VEGF expression through and HIF-1-independent mechanism. Mol Biol Cell 15: 4841–4853.

    Article  CAS  Google Scholar 

  • Sabatini DM . (2006). mTOR and cancer: insights into a complex relationship. Nat Rev Cancer 6: 729–734.

    Article  CAS  Google Scholar 

  • Saller R, Meier R, Brignoli R . (2001). The use of silymarin in the treatment of liver diseases. Drugs 61: 2035–2063.

    Article  CAS  Google Scholar 

  • Sarbassov DD, Ali SM, Sengupta S, Sheen J, Hsu P, Bagley A et al. (2006). Prolonged rapamycin treatment inhibits mTORC2 assembly and Akt/PKB. Mol Cell 22: 159–168.

    Article  CAS  Google Scholar 

  • Sarbassov DD, Guertin DA, Ali SM, Sabatini DM . (2005). Phosphorylation and regulation of Akt/PKB by the rictor–mTOR complex. Science 307: 1098–1101.

    Article  CAS  Google Scholar 

  • Schofield CJ, Ratcliffe PJ . (2004). Oxygen sensing by HIF hydroxylases. Nat Rev Mol Cell Biol 5: 343–354.

    Article  CAS  Google Scholar 

  • Semenza GL . (2002). HIF-1 and tumor progression: pathophysiology and therapeutics. Trends Mol Med 8: S62–S67.

    Article  CAS  Google Scholar 

  • Semenza GL . (2003). Targeting HIF-1 for cancer therapy. Nat Rev Cancer 3: 721–732.

    Article  CAS  Google Scholar 

  • Singh RP, Dhanalakshmi S, Agarwal C, Agarwal R . (2005). Silibinin strongly inhibits growth and survival of human endothelial cells via cell cycle arrest and downregulation of survivin, Akt and NF-kappaB: implications for angioprevention and antiangiogenic therapy. Oncogene 24: 1188–1202.

    Article  CAS  Google Scholar 

  • Singh RP, Gu M, Agarwal R . (2008). Silibinin inhibits colorectal cancer growth by inhibiting tumor cell proliferation and angiogenesis. Cancer Res 68: 2043–2050.

    Article  CAS  Google Scholar 

  • Sun SY, Rosenberg LM, Wang X, Zhou Z, Yue P, Fu H et al. (2005). Activation of Akt and eIF4E survival pathways by rapamycin-mediated mammalian target of rapamycin inhibition. Cancer Res 65: 7052–7058.

    Article  CAS  Google Scholar 

  • Thomas GV, Tran C, Mellinghoff IK, Welsbie DS, Chan E, Fueger B et al. (2006). Hypoxia-inducible factor determines sensitivity to inhibitors of mTOR in kidney cancer. Nat Med 12: 122–127.

    Article  CAS  Google Scholar 

  • van den Beucken T, Koritzinsky M, Wouters BG . (2006). Translational control of gene expression during hypoxia. Cancer Biol Ther 5: 749–755.

    Article  CAS  Google Scholar 

  • Varghese L, Agarwal C, Tyagi A, Singh RP, Agarwal R . (2005). Silibinin efficacy against human hepatocellular carcinoma. Clin Cancer Res 11: 8441–8448.

    Article  CAS  Google Scholar 

  • Wang GL, Jiang BH, Rue EA, Semenza GL . (1995). Hypoxia-inducible factor 1 is a basic–helix–loop–helix–PAS heterodimer regulated by cellular O2 tension. Proc Natl Acad Sci USA 92: 5510–5514.

    Article  CAS  Google Scholar 

  • Wang GL, Semenza GL . (1995). Purification and characterization of hypoxia-inducible factor 1. J Biol Chem 270: 1230–1237.

    Article  CAS  Google Scholar 

  • Wellington K, Jarvis B . (2001). Silymarin: a review of its clinical properties in the management of hepatic disorders. BioDrugs 15: 465–489.

    Article  CAS  Google Scholar 

  • Wood SM, Wiesener MS, Yeates KM, Okada N, Pugh CW, Maxwell PH et al. (1998). Selection and analysis of a mutant cell line defective in the hypoxia-inducible factor-1 α-subunit (HIF-1α). Characterization of hif-1alpha-dependent and -independent hypoxia-inducible gene expression. J Biol Chem 273: 8360–8368.

    Article  CAS  Google Scholar 

  • Wright G, Higgin JJ, Raines RT, Steenbergen C, Murphy E . (2003). Activation of the prolyl hydroxylase oxygen-sensor results in induction of GLUT1, heme oxygenase-1, and nitric-oxide synthase proteins and confers protection from metabolic inhibition to cardiomyocytes. J Biol Chem 278: 20235–20239.

    Article  CAS  Google Scholar 

  • Xu Q, Briggs J, Park S, Niu G, Kortylewski M, Zhang S et al. (2005). Targeting Stat3 blocks both HIF-1 and VEGF expression induced by multiple oncogenic growth signaling pathways. Oncogene 24: 5552–5560.

    Article  CAS  Google Scholar 

  • Zhong H, Chiles K, Feldser D, Laughner E, Hanrahan C, Georgescu MM et al. (2000). Modulation of hypoxia-inducible factor 1alpha expression by the epidermal growth factor/phosphatidylinositol 3-kinase/PTEN/AKT/FRAP pathway in human prostate cancer cells: implications for tumor angiogenesis and therapeutics. Cancer Res 60: 1541–1545.

    CAS  PubMed  Google Scholar 

  • Zhong H, De Marzo AM, Laughner E, Lim M, Hilton DA, Zagzag D et al. (1999). Overexpression of hypoxia-inducible factor 1α in common human cancers and their metastases. Cancer Res 59: 5830–5835.

    CAS  PubMed  Google Scholar 

  • Zi X, Agarwal R . (1999). Silibinin decreases prostate-specific antigen with cell growth inhibition via G1 arrest, leading to differentiation of prostate carcinoma cells: implications for prostate cancer intervention. Proc Natl Acad Sci USA 96: 7490–7495.

    Article  CAS  Google Scholar 

  • Zi X, Feyes DK, Agarwal R . (1998). Anticarcinogenic effect of a flavonoid antioxidant, silymarin, in human breast cancer cells MDA-MB 468: induction of G1 arrest through an increase in Cip1/p21 concomitant with a decrease in kinase activity of cyclin-dependent kinases and associated cyclins. Clin Cancer Res 4: 1055–1064.

    CAS  PubMed  Google Scholar 

Download references

Acknowledgements

This work was supported by grants from ISCIII (FIS03-0924 and FIS07-1168 to JM). PG-M holds a fellowship from the Centro Nacional de Investigaciones Cardiovasculares (CNIC)-Bancaja predoctoral program. CNIC is supported by the Spanish Ministry of Health and Consumer Affairs and the Pro-CNIC Foundation.

Author information

Authors and Affiliations

  1. Department of Regenerative Cardiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain

    P García-Maceira & J Mateo

Authors
  1. P García-Maceira
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. J Mateo
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to J Mateo.

Additional information

Supplementary Information accompanies the paper on the Oncogene website (http://www.nature.com/onc)

Supplementary information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

García-Maceira, P., Mateo, J. Silibinin inhibits hypoxia-inducible factor-1α and mTOR/p70S6K/4E-BP1 signalling pathway in human cervical and hepatoma cancer cells: implications for anticancer therapy. Oncogene 28, 313–324 (2009). https://doi.org/10.1038/onc.2008.398

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/onc.2008.398

Keywords

  • hypoxia-inducible factor-1α
  • silibinin
  • cancer
  • mTOR
  • angiogenesis

This article is cited by

Search

Advanced search

Quick links