Evaluation of sensitizers found in wastewater from paper recycling areas, and their activation of the aryl hydrocarbon receptor in vitro.
The in vitro potential of sensitizers and related compounds (SRCs) originating from impurities in waste paper in activating the human aryl hydrocarbon receptor (AhR) α was assessed using yeast reporter gene as well as cytochrome P450 (CYP)1A1 and ethoxyresorufin O-deethylase (EROD) assays. In the yeast assay, eight compounds exhibited agonist activity, and their activity relative to β-naphthoflavone (BNF) ranged from 1.4 × 10(-4) to 8.3 × 10(-2), with the highest activity observed for benzyl 2-naphthyl ether (BNE). In the EROD assay, six compounds caused a more significant induction of CYP1A-dependent activity than did the vehicle control at 50 μM (p<0.01), and their induction levels were 5.1- to 11-fold more potent; 1,2-bis(3-methylphenoxy)ethane (BME) was the most effective inducer. The water from the waste paper recycling area was fractioned using solid-phase extraction (SPE) combined with a C18 disk and florisil cartridge. In gas chromatography-mass spectrometry (GC-MS) analysis, SRCs were detected in the first fraction, at a total concentration of 5.5 μg/L. This fraction also activated AhR, and its activity, expressed as a BNF equivalent value, was 0.42 nM in the yeast assay. The contribution ratio of active compounds accounted for up to 34% and 4.4% observed activity of the fraction and total samples, respectively. To our knowledge, this is the first study to show that paper industry-related compounds, namely aromatic sensitizers, activate AhR by using a yeast assay and HepG2 cells.
['Terasaki|Masanori|M|', 'Yasuda|Michiko|M|', 'Shimoi|Kayoko|K|', 'Jozuka|Kazuhiko|K|', 'Makino|Masakazu|M|', 'Shiraishi|Fujio|F|', 'Nakajima|Daisuke|D|']
D051792:Basic Helix-Loop-Helix Transcription Factors D001681:Biological Assay D019363:Cytochrome P-450 CYP1A1 D004784:Environmental Monitoring D004987:Ethers D066298:In Vitro Techniques D010209:Paper D018336:Receptors, Aryl Hydrocarbon D059027:Recycling D062065:Waste Water D014874:Water Pollutants, Chemical
Aromatic sensitizers Effect-directed analysis Human HepG2 ethoxyresorufin O-deethylase assay Human aryl hydrocarbon receptor α Paper mill effluent Yeast YCM3 assay