Fig. 5

TRAIL promotes PD-L1 expression by upregulating the p-ERK/STAT3 signaling pathway. a, b Analysis of TNFSF10 high- and low-expression genes; TNFSF10 and CD274 expression was significantly positively correlated in TCGA database. c TRAIL and PD-L1 expression was significantly positively correlated in human ESCC tissues (n = 20), as evidenced by immunohistochemistry. d RT-qPCR of CD274 mRNA levels in TRAIL-knockdown (left) and overexpressed (right) ESCC cell lines. e KEGG enrichment analysis of differentially expressed genes. f Western blotting of STAT3, p-STAT3, ERK1/2, p-ERK1/2, PD-L1, and b-actin expression in TRAIL-knockdown KYSE150 or TRAIL-overexpressed EC1. g, h RT-qPCR and western blotting of PD-L1 mRNA and protein levels after adding STAT3 or ERK inhibitors for 24 h; GAPDH and b-actin were used as control for RT-qPCR and western blotting, respectively. i Silenced STAT3 in EC1 cells overexpressing TRAIL and the expression of PD-L1 was inhibited in gene and protein level. The data are presented as the mean ± SEM. ***P < 0.001, **P < 0.01, (unpaired t-test)