Synergic effects of 9,10-phenanthrenequinone and cadmium on pro-inflammatory responses in airway epithelial cells

•We examined combined effects of metal and PAHs as components of PM2.5 on airway.•Co-exposure to Cd and 9,10-PQ additively/synergistically increased IL-6 or IL-8.•Co-exposure to Cd and Phe resulted in no acceleration of pro-inflammatory responses.•Combination of Cd and a quinone derivative can exacerbate respiratory diseases.

We investigated the synergic effects of components of particulate matter with aerodynamic diameters ≤2.5 μm (PM2.5) on airway inflammation. Co-exposure to cadmium (Cd) and 9,10-phenanthrenequinone (9,10-PQ) additively/synergistically increased pro-inflammatory responses in airway epithelial cells, whereas co-exposure to Cd and phenanthrene resulted in no acceleration. These results suggest that the combination of metal and a quinone derivative can contribute to the exacerbation of respiratory diseases by PM2.5.