To investigate the effect of cisplatin on the expression of programmed death ligand 1 (PD-L1) in hepatocellular carcinoma Hep3B cells and the effect of PD-L1 on cisplatin sensitivity.

Hep3B cells were treated with 0, 5, 10, 20 mg/L cisplatin, and the expression of PD-L1 was detected by qPCR and Western blotting. Hep3B cells were treated in control group (PBS only), cisplatin group (5 mg/L), MK2206 group (AKT inhibitor, 5 μmol/L) and cisplatin+MK2206 group (5 μmol/L MK2206 was administered 1 hour before cisplatin treatment), and the expressions of AKT, p-AKT and PD-L1 were detected by Western blotting. siRNA-PD-L1 was transfected into Hep3B cells. Western blotting was used to detect the expression of PD-L1 and epithelial-mesenchymal transition markers (E-cadherin and N-cadherin). CCK-8, scratch assay and Transwell test were used to detect the changes of cell function.

Cisplatin could up-regulate the protein level of PD-L1 in Hep3B cells (P<0.05). Compared with the control group, 5 mg/L cisplatin significantly increased the mRNA level of PD-L1 in Hep3B cells (P<0.05). MK2206 could attenuate the promoting effect of cisplatin on p-AKT and PD-L1 expression in Hep3B cells (P<0.05). There was no significant difference in the protein level of AKT. siRNA-PD-L1 could attenuate the promoting effect of cisplatin on PD-L1 expression in Hep3B cells (P<0.05), enhance the inhibitory effect of cisplatin on proliferation, migration and invasion of Hep3B cells, enhance the promoting effect of cisplatin on E-cadherin expression and the inhibitory effect of cisplatin on N-cadherin expression in Hep3B cells (P<0.05).

Cisplatin can promote the expression of PD-L1 in hepatocellular carcinoma Hep3B cells, and its mechanism may be related to the up-regulation of phosphorylation level of AKT pathway proteins. Inhibition of PD-L1 expression may enhance the sensitivity of Hep3B cells to cisplatin.