ToxSci Advance Access originally published online on July 13, 2005
Toxicological Sciences 2005 87(2):337-343; doi:10.1093/toxsci/kfi258
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Trans, Trans-2,4-Decadienal, a Product Found in Cooking Oil Fumes, Induces Cell Proliferation and Cytokine Production Due to Reactive Oxygen Species in Human Bronchial Epithelial Cells
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* Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Kaoshiung, Taiwan, R.O.C., and Institute of Medical and Molecular Toxicology, Chung Shan Medical University, Taichung, Taiwan, R.O.C.
Received May 22, 2005; accepted July 5, 2005
Dienaldehydes are by-products of peroxidation of polyunsaturated lipids and commonly found in many foods or food-products. Both National Cancer Institute (NCI) and NTP have expressed great concern on the potential genotoxicity and carcinogenicity of dienaldehydes. Trans, trans-2,4-decadienal (tt-DDE or 2,4-De), a specific type of dienaldehyde, is abundant in heated oils and has been associated with lung adenocarcinoma development in women due to their exposure to oil fumes during cooking. Cultured human bronchial epithelial cells (BEAS-2B cells) were exposed to 0.1 or 1.0 µM tt-DDE for 45 days, and oxidative stress, reactive oxygen species (ROS) production, GSH/GSSG ratio, cell proliferation, and expression of TNF
and IL-1ß were measured. The results show that tt-DDE induced oxidative stress, an increase in ROS production, and a decrease in GSH/GSSG ratio (glutathione status) in a dose-dependent manner. Treatment of BEAS-2B cells with 1.0 µM tt-DDE for 45 days increased cell proliferation and the expression and release of pro-inflammatory cytokines TNF and IL-1ß. Cotreatment of BEAS-2B cells with antioxidant N-acetylcysteine prevented tt-DDE-induced cell proliferation and release of cytokines. Therefore, these results suggest that tt-DDE-induced changes may be due to increased ROS production and enhanced oxidative stress. Since increased cell proliferation and the release of TNF- and IL-1ß are believed to be involved in tumor promotion, our results suggest that tt-DDE may play a role in cancer promotion. Previous studies on dienaldehydes have focused on their genotoxic or carcinogenic effects in the gastrointestinal tract; the present study suggests a potential new role of tt-DDE as a tumor promoter in human lung epithelial cells.
Key Words: tt-DDE; dienaldehydes; cell proliferation; cytokines.