Fig. 4

Circ_0017109 promotes FZD4 expression via sponging miR-671-5p. A miR-671-5p target sequence in the FZD4 3′-UTR was predicted using Targetscan database. B Luciferase activity of wild type or mutated FZD4 reporter in the presence of miR-NC or miR-671-5p mimic. C FZD4 mRNA and protein expression in H1229 and A549 cells after the transfection of miR-671-5p mimic. D The effect of circ_0017109 silencing and miR-671-5p inhibitor on FZD4 protein level. E Relative FZD4 expression in NSCLC tumor and normal lung tissue samples. F Relative miR-671-5p levels in NSCLC tumor and normal lung tissue samples. G Correlation of FZD4 expression and miR-671-5p in NSCLC tumor samples. H FZD4 level and circ_0017109 expression in NSCLC tumor samples. ***, P < 0.001 compared with si-NC group, and ^^^, P < 0.001 compared with si-circ_0017109 group