CD274 and glioblastoma: Conversely, in the TR-GBM cells with PD-L1 ablation, we found that knock-down of PD-L1 aggravated the promoting effects of high-dose TMZ stimulation on cell apoptosis in TR-GBM cells, implying that silencing of PD-L1 increased TMZ-sensitivity in TR-GBM cells (Fig. 4b).