Dithiolethiones D3T and ACDT protect against iron overload-induced cytotoxicity and serve as ferroptosis inhibitors in U-87 MG cells

Abstract

Iron overload-induced oxidative stress is implicated in various neurodegenerative disorders. Given the numerous adverse effects associated with current iron chelators, natural antioxidants are being explored as alternative therapeutic options. Dithiolethiones found in cruciferous vegetables have emerged as promising candidates against a wide range of toxicants owing to their lipophilic and cytoprotective properties. Here, we test the dithiolethiones D3T and ACDT against ferric ammonium citrate (FAC)-induced toxicity in U-87 MG astrocytoma cells. Exposure to 15 mM FAC for 24 hours resulted in 54% cell death. A 24-hour pretreatment with 50 µM D3T and ACDT prevented this cytotoxicity. Both dithiolethiones exhibited antioxidant effects by activating the Nrf2 transcription factor and upregulating levels of intracellular glutathione (GSH). This resulted in the successful inhibition of FAC-induced reactive oxygen species, lipid peroxidation, and cell death. Additionally, D3T and ACDT upregulated expression of the Nrf2-mediated iron storage protein ferritin which consequently reduced the total labile iron pool. A 24-hour pretreatment with D3T and ACDT also prevented cell death induced by the ferroptosis inducer erastin by upregulating the xCT transporter expression. The resulting increase in intracellular GSH and alleviation of lipid peroxidation was comparable to that caused by ferrostatin-1, a specific ferroptosis inhibitor. Collectively, our findings demonstrate that dithiolethiones may show promise as potential therapeutic options for the treatment of iron overload disorders.