Secondly, Fe3O4-siPD-L1@M-BV2 decreased the protein expression of PD-L1, x-CT and GPX4 in orthotopic drug-resistant GBM tissue in dose-dependent manner. As compared with Fe3O4-siPD-L1, Fe3O4-siPD-L1@M-BV2 reduced the protein expression of PD-L1, xCT and GPX4 more strongly. The protein expressions of PD-L1, xCT and GPX4 in orthotopic drug-resistant GBM tissue were less in Fe3O4-siPD-L1@M-BV2 + magnet group than that in Fe3O4-siPD-L1@M-BV2 group (Fig. 8A, B). Here, CD274 is linked to glioblastoma.