In vitro dosimetry analyses for acrolein exposure in normal human lung epithelial cells and human lung cancer cells

Establishing accurate dosimetry is important for assessing the toxicity of xenobiotics as well as for comparing responses between different test systems. In this study, we used acrolein as a model toxicant and defined the concentration-response relationships of the key adverse responses in normal human bronchial epithelial (NHBE) cells and human mucoepidermoid pulmonary carcinoma (NCI-H292) cells. Direct trace analysis of intracellular free acrolein is extremely challenging, if not impossible. Therefore, we developed a new method for indirectly estimating the intracellular uptake of acrolein. A 10-min treatment was employed to capture the rapid occurrence of the key alkylation reactions of acrolein. Responses, including protein carbonylation, GSH depletion, and GSH-acrolein (GSH-ACR) adduct formation, were all linearly correlated with acrolein uptake in both cell types. Compared to the NCI-H292 mucoepidermoid carcinoma cells, NHBE cells were more sensitive to acrolein exposure. Furthermore, results from the time-course studies demonstrated that depletion and conjugation of GSH were the primary adverse events and directly associated with the cytotoxicity induced by acrolein. In summary, these data suggest that cell susceptibility to acrolein exposure is closely associated with acrolein uptake and formation of GSH-ACR adducts. The dosimetric analysis presented in this study may provide useful information for computational modeling and risk assessment of acrolein using different test systems.