PD-L1 is directly targeted by miR-142. (A) Bioinformatics prediction of the binding site of miR-142 on PD-L1. (B) The interaction between miR-142 and PD-L1 was verified by a luciferase reporter assay. (C) RT-qPCR showed the relative PD-L1 expression in DDP-sensitive (n=21) and DDP-resistant (n=25) lung adenocarcinoma tissues. (D) RT-qPCR and (E) western blotting showed the relative PD-L1 expression in A549, A549/DDP, HCC827 and HCC827/DDP cells. (F) RT-qPCR and (G) western blotting showed the relative PD-L1 expression in A549/DDP and HCC827/DDP cells transfected with NC mimics, miR-142 mimics, miR-NC inhibitor and miR-142 inhibitor. The data are presented as the mean ± SD. *P<0.05. PD-L1, programmed cell death 1 ligand 1; miR, microRNA; RT-qPCR, reverse transcription-quantitative PCR; DDP, cisplatin; NC, negative control; WT, wild-type; Mut, mutant.