CD274 and glioblastoma: Cell apoptosis was examined by using the Annexin V-FITC/PI double staining assay, and the results showed that both compound C and SBI-0206965 abrogated the inhibiting effects of PD-L1-ex on cell apoptosis in TS-GBM cells treated with high-dose TMZ (Fig. 6a–d), suggesting that blockage of AMPK/ULK1 pathway was effective to abrogate the promoting effects of PD-L1-ex on TMZ-resistance in TS-GBM cells.