title: Carnosol, a constituent of Zyflamend, inhibits aryl hydrocarbon receptor-mediated activation of CYP1A1 and CYP1B1 transcription and mutagenesis.
abstract: The aryl hydrocarbon receptor (AhR), a ligand-activated member of the basic helix-loop-helix family of transcription factors, plays a significant role in polycyclic aromatic hydrocarbon (PAH)-induced carcinogenesis. In the upper aerodigestive tract of humans, tobacco smoke, a source of PAHs, activates the AhR leading to increased expression of CYP1A1 and CYP1B1, which encode proteins that convert PAHs to genotoxic metabolites. Inhibitors of Hsp90 ATPase cause a rapid decrease in levels of AhR, an Hsp90 client protein, and thereby block PAH-mediated induction of CYP1A1 and CYP1B1. The main objective of this study was to determine whether Zyflamend, a polyherbal preparation, suppressed PAH-mediated induction of CYP1A1 and CYP1B1 and inhibited DNA adduct formation and mutagenesis. We also investigated whether carnosol, one of multiple phenolic antioxidants in Zyflamend, had similar inhibitory effects. Treatment of cell lines derived from oral leukoplakia (MSK-Leuk1) and skin (HaCaT) with benzo[a]pyrene (B[a]P), a prototypic PAH, induced CYP1A1 and CYP1B1 transcription, resulting in enhanced levels of message and protein. Both Zyflamend and carnosol suppressed these effects of B[a]P. Notably, both Zyflamend and carnosol inhibited Hsp90 ATPase activity and caused a rapid reduction in AhR levels. The formation of B[a]P-induced DNA adducts and mutagenesis was also inhibited by Zyflamend and carnosol. Collectively, these results show that Zyflamend and carnosol inhibit Hsp90 ATPase leading to reduced levels of AhR, suppression of B[a]P-mediated induction of CYP1A1 and CYP1B1, and inhibition of mutagenesis. Carnosol-mediated inhibition of Hsp90 ATPase activity can help explain the chemopreventive activity of herbs such as Rosemary, which contain this phenolic antioxidant.
authors.affiliation: Department of Surgery (Head and Neck Service), Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
authors.forename: Arash
authors.initials: A
authors.lastname: Mohebati
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Guttenplan
authors.forename: Amit
authors.initials: A
authors.lastname: Kochhar
authors.forename: Zhong-Lin
authors.initials: ZL
authors.lastname: Zhao
authors.forename: Wieslawa
authors.initials: W
authors.lastname: Kosinska
authors.forename: Kotha
authors.initials: K
authors.lastname: Subbaramaiah
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Dannenberg
mesh_terms: D045784:Abietanes / Q000494:pharmacology*; D016588:Anticarcinogenic Agents / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism*; D001564:Benzo(a)pyrene / Q000737:chemistry; D045744:Cell Line, Tumor; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism*; D065633:Cytochrome P-450 CYP1B1; D018736:DNA Adducts; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D008024:Ligands; D016296:Mutagenesis; D010936:Plant Extracts / Q000494:pharmacology*; D018336:Receptors, Aryl Hydrocarbon / Q000737:chemistry*; D014158:Transcription, Genetic
chemical_list: D045784:Abietanes; D016588:Anticarcinogenic Agents; D000975:Antioxidants; D018736:DNA Adducts; D018841:HSP90 Heat-Shock Proteins; D008024:Ligands; D010936:Plant Extracts; D018336:Receptors, Aryl Hydrocarbon; C519312:Zyflamend; D001564:Benzo(a)pyrene; C068623:carnosol; D001189:Aryl Hydrocarbon Hydroxylases; C585496:CYP1B1 protein, human; D019363:Cytochrome P-450 CYP1A1; D065633:Cytochrome P-450 CYP1B1