Fig. 5

Akt-dependent β-catenin phosphorylation mediated spermine-induced PD-L1 expression. A, B Effects of β-catenin knockdown on spermine-induced CD274 mRNA (A) and PD-L1 protein (B) expression in SNU-368 cells. S: spermine; 1: 1^#β-catenin siRNA; 2: 2^# β-catenin siRNA. *p < 0.05, **p < 0.01, one-way ANOVA, n = 5 independent experiments per group. C, D The expression of CD274 mRNA (C) and PD-L1 protein (D) in SNU-368 cells expressing WT β-catenin or β-catenin S552A mutant for 24 h. ***p < 0.001 compared with vector group, one-way ANOVA, n = 5 independent experiments per group. E ChIP analysis of the amounts of β-catenin recruited to the CD274 promoter regions in SNU-368 cells treated with spermine (200 µM) for 24 h. ***p < 0.001, two-tailed unpaired t test, n = 4 independent experiments per group. F IHC staining of β-catenin and PD-L1 in 24 human HCC specimens. Scale bar, 50 μm. G Spearman correlation analysis of β-catenin and PD-L1 IHC scores. Note that the scores of some samples overlap