title: Cytotoxicity and aryl hydrocarbon receptor-mediated activity of n-heterocyclic polycyclic aromatic hydrocarbons: structure-activity relationships.
abstract: Toxic effects of many persistent organic pollutants (e.g., polychlorinated biphenyls or polychlorinated dibenzo-p-dioxins and furans) are mediated via the aryl hydrocarbon receptor (AhR). Although polycyclic aromatic hydrocarbons (PAHs) and their derivatives also activate AhR, their toxic effects remain to be fully elucidated. In the present study, we used the in vitro H4IIE-luc transactivation cell assay to investigate cytotoxicity and potencies to activate AhR by 29 individual PAHs and their N-heterocyclic derivatives (aza-PAHs). The aza-PAHs were found to be significantly more cytotoxic and more potent inducers of AhR than their unsubstituted analogues. Several aza-PAHs, such as dibenz[a,h]acridine or dibenz[a,i]acridine, activated AhR within picomolar concentrations, comparable to the effects of reference 2,3,7,8-tetrachlorodibenzo-p-dioxin. Ellipsoidal volume, molar refractivity, and molecular size were the most important descriptors derived from the modeling of quantitative structure-activity relationships for potencies to activate AhR. Comparable relative toxic potencies (induction equivalency factors) for individual aza-PAHs are derived, and their use for evaluation of complex contaminated samples is discussed.
authors.affiliation: RECETOX-Research Centre for Environmental Chemistry and Ecotoxicology, Masaryk University, Kamenice 126/3, CZ62500 Brno, Czech Republic.
authors.forename: Iva
authors.initials: I
authors.lastname: Sovadinová
authors.forename: Ludĕk
authors.initials: L
authors.lastname: Bláha
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Janosek
authors.forename: Klára
authors.initials: K
authors.lastname: Hilscherová
authors.forename: John P
authors.initials: JP
authors.lastname: Giesy
authors.forename: Paul D
authors.initials: PD
authors.lastname: Jones
authors.forename: Ivan
authors.initials: I
authors.lastname: Holoubek
mesh_terms: D000818:Animals; D001681:Biological Assay; D045744:Cell Line, Tumor; D005786:Gene Expression Regulation / Q000187:drug effects; D006571:Heterocyclic Compounds / Q000737:chemistry* / Q000633:toxicity*; D057927:Hydrophobic and Hydrophilic Interactions; D015394:Molecular Structure; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry* / Q000633:toxicity*; D021281:Quantitative Structure-Activity Relationship; D051381:Rats; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics / Q000378:metabolism*
chemical_list: D006571:Heterocyclic Compounds; D011084:Polycyclic Aromatic Hydrocarbons; D018336:Receptors, Aryl Hydrocarbon