Evidence of Estrogen- and TCDD-Like Activities in Crude and Fractionated Extracts of PM10 Air Particulate Material Using in Vitro Gene Expression Assays

Abstract

Polar and nonpolar fractions prepared from an organic extract of inhalable air particulate material collected from an urban location in downtown Toronto, Ontario, Canada, were examined for estrogen and Ah receptor-mediated activities using in vitro gene expression assays. The presence of estrogenic activity was determined using MCF-7 human breast cancer cells transiently transfected with a Gal4-human estrogen receptor chimera and a Gal4-regulated luciferase reporter gene. 2,3,7,8-Tetracholordibenzo-p-dioxin (TCDD)-like activity was detected using Hepa 1c1c7 cells transiently transfected with a CYP1A1-regulated reporter gene (pGudLuc 1.1). Significant estrogenic and TCDD-like activity was detected in the crude extract and in the nonpolar fractions. Results from the analyses of nine environmentally prevalent polyaromatic hydrocarbons (PAH) indicated that PAH might be significant contributors to the observed activity. Surprisingly, three PAH, namely benzo[a]pyrene, chrysene, and benz[a]anthracene, were found...