PRODUCTION OF A NOVEL RECOMBINANT CELL-LINE FOR USE AS A BIOASSAY SYSTEM FOR DETECTION OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN-LIKE CHEMICALS

Exposure to specific halogenated aromatic hydrocarbons (HAHs), such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), can produce a wide variety of species-and tissue-specific toxic and biological effects. The presence of HAHs in environmental samples as complex mixtures has made it difficult to predict the biological and toxic potency of these chemicals. We have used aspects of the molecular mechanism of action of these chemicals to develop a species-specific bioassay system for detection of bioactive HAHs in complex mixtures. Here we describe construction and utilization of a recombinant expression vector that responds to these HAHs with the induction of an easily measurable gene product, heat-stable human placental alkaline phosphatase (PAP). This vector contains the PAP gene under TCDD-inducible control of four dioxin-responsive DNA enhancer elements. HAH-inducible expression of PAP from the recombinant vector occurs in a dose-and Ah-receptor-(AhR-) dependent manner. Stable transfection of this vector into mouse hepatoma cells has produced a novel cell line in which AhR-dependent induction of gene expression can easily be measured. This transfected cell line can readily be used for detection and relative quantitation of AhR agonist in complex mixtures of environmental and biological samples and for identification and characterization of novel AhR agonists.