RSL3 combined with cisplatin induces ferroptosis in cisplatin-resistant nasopharyngeal carcinoma cells

Background: To investigate whether RAS-selective lethal 3 (RSL3) combined with cisplatin can induce ferroptosis in cisplatin (DDP) resistant nasopharyngeal carcinoma (NPC) cells. Methods: The sensitivity of nasopharyngeal carcinoma cell lines HNE-1, CEN2Z, HONE-1 and cisplatin-resistant strain HNE-1/DDP to DDP and RAS was detected by CCK-8 method. After combined treatment of RSL3 and DDP, CCK-8 method was used. Changes of HNE-1/DDP cell activity, cell death and cellular reactive oxygen species (ROS) levels were detected by flow cytometry, cellular Fe 2+ and MDA levels were detected by Fe 2+ and malondialdehyde (MDA) kits, proteins linked to ferroptosis. Results: The sensitivity of HNE-1/DDP to DDP was much lower than that of normal HNE-1 cell line, and the IC50 of RAS was as high as (45.89±6.89) μmol/L. Flow cytometry results showed that when HNE-1/DDP was treated with RSL3 or DDP alone, the mortality rate did not exceed 30%, and the increase in ROS level did not exceed 15%. RSL3 combined with DDP could increase the cell death rate of HNE-1/DDP to 89.69% ± 9.48% and the ROS level to 18.72% ± 3.05%. Combined treatment raised intracellular Fe 2+ and MDA levels, reduced the expression of the ferroptosis-related protein glutathione peroxidase 4 (GPX4), and reversed RSL3 combination by the ferroptosis inhibitor Ferrostatin-1. DDP-induced death of cell inhibited the increase of ROS, Fe 2+ and MDA levels. Conclusions: RSL3 combined with DDP can induce ferroptosis in cisplatin-resistant strain HNE-1/DDP.