Effects of Sulforaphane in Ferroptosis, Apoptosis, and Senescence induced by Cigarette Smoke in Human Bronchial Epithelial Cells: a Mechanistic Study

Background Cigarette smoke (CS) is a leading risk factor for pulmonary diseases. It has been implicated that ferroptosis and apoptosis are involved in CS-induced lung senescence. Sulforaphane (SFN) is a phytochemical with anti-oxidative and anti-inflammatory effects. However, we investigated the effects of CS on oxidative damage, apoptosis, ferroptosis, and senescence in the human bronchial epithelial cell line (BEAS-2B) and the preventive role of SFN. Materials and Methods BEAS-2B cells were exposed to CS extract (CSE) and varying concentrations of SFN (5, 10, and 20 µg/ml). Cytotoxicity and senescence were evaluated by MTT assay, clonogenic assay, Annexin V/PI flow cytometry, and SA-β-galactosidase staining method. Also, the involvement of the ferroptosis pathway and oxidative stress were measured via reactive oxygen species (ROS), glutathione (GSH), lipid peroxidation (LPO) levels, and intracellular iron assessment. Results Our results showed that CSE resulted in a concentration-dependent decline in the viability and clonogenic potential of BEAS-2B cells and induced senescence through intracellular ROS generation, LPO, and GSH oxidation, which led to ferroptosis and apoptosis. However, SFN protects against CSE cytotoxicity as measured by MTT and colony formation assay. Furthermore, SFN reduced CSE-induced oxidative stress and inhibited CSE-induced ferroptosis, as shown by lowering iron and MDA. Subsequently, SFN alleviated CSE-induced apoptotic and senescence in BEAS-2B cells. Conclusion This study strongly supports the idea that SFN could ameliorate CSE-induced lung toxicity via inhibition of oxidative redox, ferroptosis, and the apoptotic pathway, which results in a decrease in senescence and enhanced clonogenic potential in BEAS-2B cells.