Heat shock protein 90 inhibitors suppress aryl hydrocarbon receptor-mediated activation of CYP1A1 and CYP1B1 transcription and DNA adduct formation Academic Article uri icon


MeSH Major

  • Aryl Hydrocarbon Hydroxylases
  • Benzoquinones
  • Cytochrome P-450 CYP1A1
  • DNA Adducts
  • HSP90 Heat-Shock Proteins
  • Lactams, Macrocyclic
  • Receptors, Aryl Hydrocarbon
  • Triterpenes


  • The aryl hydrocarbon receptor (AhR), a client protein of heat shock protein 90 (HSP90), plays a significant role in polycyclic aromatic hydrocarbon (PAH)-induced carcinogenesis. Tobacco smoke, a source of PAHs, activates the AhR, leading to enhanced transcription of CYP1A1 and CYP1B1, which encode proteins that convert PAHs to genotoxic metabolites. The main objectives of this study were to determine whether HSP90 inhibitors suppress PAH-mediated induction of CYP1A1 and CYP1B1 or block benzo(a)pyrene [B(a)P]-induced formation of DNA adducts. Treatment of cell lines derived from oral leukoplakia (MSK-Leuk1) or esophageal squamous cell carcinoma (KYSE450) with a saline extract of tobacco smoke, B(a)P, or dioxin induced CYP1A1 and CYP1B1 transcription, resulting in enhanced levels of message and protein. Inhibitors of HSP90 [17-allylamino-17-demethoxygeldanamycin (17-AAG); celastrol] suppressed these inductive effects of PAHs. Treatment with 17-AAG and celastrol also caused a rapid and marked decrease in amounts of AhR protein without modulating levels of HSP90. The formation of B(a)P-induced DNA adducts in MSK-Leuk1 cells was inhibited by 17-AAG, celastrol, and alpha-naphthoflavone, a known AhR antagonist. The reduction in B(a)P-induced DNA adducts was due, at least in part, to reduced metabolic activation of B(a)P. Collectively, these results suggest that 17-AAG and celastrol, inhibitors of HSP90, suppress the activation of AhR-dependent gene expression, leading, in turn, to reduced formation of B(a)P-induced DNA adducts. Inhibitors of HSP90 may have a role in chemoprevention in addition to cancer therapy.

publication date

  • November 2008



  • Academic Article



  • eng

PubMed Central ID

  • PMC2680610

Digital Object Identifier (DOI)

  • 10.1158/1940-6207.CAPR-08-0149

PubMed ID

  • 19138996

Additional Document Info

start page

  • 485

end page

  • 93


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