GPX4 and glioblastoma: Moreover, in vivo experimental results indicated that as compared with Fe3O4, the GSH content and protein expression of GPX4 and xCT were markedly reduced, and the ROS level and Fe2+ content was significantly increased in orthotopic drug-resistant GBM tissue in Fe3O4-siPD-L1@M-BV2 and Fe3O4-siPD-L1@M-BV2 + magnet treatment group.