Effects of Oxidized Pyrenes on the Biological Responses in the Human Bronchial Epithelial Cells

Abstract

Although polycyclic aromatic hydrocarbons (PAHs) are toxic, the effects of oxidized PAHs on health and biological responses remain unclear. In this study, we examined the in vitro effects of varying concentrations of pyrene, a type of PAH, and its quinone forms, namely 4,5-pyrenequinone (PyQ) and 1,8-PyQ + 1,6-PyQ, on human lung epithelial (BEAS-2B) cells. We evaluated cell viability, apoptosis, and the production of interleukin (IL)-6, IL-8, soluble intercellular adhesion molecule-1 (sICAM-1), and reactive oxygen species (ROS). Exposure to 1 μM 4,5-PyQ or 1,8-PyQ + 1,6-PyQ increased the cellular activity. At 3 µM, 4,5-PyQ increased the number of late apoptotic and/or necrotic cells compared with those in the control, whereas 1,8-PyQ + 1,6-PyQ increased the number of dead cells. Exposure to 4,5-PyQ at 10 µM decreased IL-6 production and exposure to both 4,5-PyQ and 1,8-PyQ + 1,6-PyQ at 3 or 10 µM decreased IL-8 production. sICAM-1 production was increased after 1,8-PyQ + 1,6-PyQ exposure at 10 µM. In the presence of cells, 4,5-PyQ and 1,8-PyQ + 1,6-PyQ increased ROS production significantly in a concentration-dependent manner; similar results were observed with 1,8-PyQ + 1,6-PyQ without cells. Overall, our results suggest that oxidized PAHs induce stronger respiratory toxicity/inflammatory responses than PAHs.