CD274 and glioblastoma: After Fe3O4-siPD-L1@M-BV2 was taken up by orthotopic drug-resistant GBM cells, the disulfide bond between Fe3O4 nanoparticles and siPD-L1 was broken by intracellular GSH, releasing siPD-L1 and inhibiting the protein expression of PD-L1 in orthotopic drug-resistant GBM cells [40].