GPX4 overexpressed non-small cell lung cancer cells are sensitive to RSL3-induced ferroptosis

Abstract Ferroptosis is a type of programmed cell death, that can be induced by inhibiting antioxidant enzymes glutathione peroxidase 4 (GPX4) or cystine/glutamate transporter (system Xc − ), increased intracellular concentrations of iron, and lipid peroxidation. Recently, it has been suggested that ferroptosis can be an effective way to induce cell death in various cancers, although the specific relevance and mechanism of ferroptosis have not been fully elucidated. In this study, the anticancer effects of ferroptosis inducers, erastin, and RSL3 on non-small cell lung cancer (NSCLC) cells were investigated. RSL3-induced cell death much more effectively in NSCLC cells than erastin with very limited cytotoxicity in BEAS-2B, normal bronchial epithelial cell. The sensitivity of NSCLC cells to RSL3-induced cell death was different among NSCLC cells, which was dependent on GPX4 expression levels, and rescued by ferrostatin-1, a ferroptosis inhibitor, but not by Z-VAD-FMK, chloroquine, bafilomycin A1, and necrostatain-1. RSL3 induced ferroptosis by increased lipid peroxidation, intracellular LIP concentration, and ROS, and inhibition of GSH to GSSH conversion through the inhibition of GPX4, and induction of Nrf2/HO1. Furthermore, RSL3 induced autophagosome, but disrupted formation of autolysosome from autophagosome. Knockdown of GPX4 had a similar effect on ferroptosis phenotypes to that of RSL3. Zebrafish xenograft model in vivo confirmed in vitro result of RSL3. Taken together, this study provides evidence that RSL3-induced ferroptosis depends on the regulation of GPX4- Nrf2/HO1 in NSCLC cells. This process may aid in predicting the ferroptosis response in NSCLC as well as drug resistant cancer cells.