Study on Expression of PD-L1 and Resistance Mechanism on Glioma U87 Cells Induced by Cisplatin

OBJECTIVE To investigate the effect of PD-L1 expression on the cisplatin(CDDP) resistance of U87 cells. METHODS U87 CDDP drug-resistant cell line(U87/CDDP) was established and the cell viability was estimated by CCK-8 to verify drug resistance after treated with different concentration of CDDP for 24 h. Then the U87/CDDP cells were transferred PD-L1 shRNA, and CCK-8, BrdU staining, flow cytometry was performed to detected the proliferation and apoptosis. Meanwhile, the mRNA expression of PD-L1, Bax, caspase-3, Survivin was detected by qRT-PCR, while the protein expression of PD-L1, Bax, caspase-3, cleaved-caspase-3, P53 was detected by Western blotting. RESULTS The result of CCK-8 showed that U87/CDDP was established successfully. After treated with same concentration of CDDP 24 h, the proliferation of PD-L1 shRNA-U87/CDDP cells was decreased and the apoptosis was increased compared with non transfected U87/CDDP cells. Meanwhile, compared to the control group, the mRNA expression of Bax, caspase-3 and the protein expression of Bax, cleaved-caspase-3 and P53 was significantly increased, while the mRNA expression of PD-L1, Survivin and the protein expression of PD-L1 was significantly decreased in PD-L1 shRNA transfected and CDDP treated U87/CDDP cells. CONCLUSION The tolerance of CDDP on U87 cells can reverse by down-regulating the expression of PD-L1.