Fig. 5

SP1 is a target gene of miR-31-5p and indirectly regulated by circ-0001875. a Venn diagram showing 72 genes that are putative miR-31-5p targets predicted by three databases (Targetscan, miRDB and miRWalk). b RT-qPCR of the expression of SP1 mRNA in NSCLC cells. c–d Relative expression of SP1 in NSCLC tumor and adjacent tissues (n = 72). e IHC staining of SP1 expression in xenograft tumors in the four groups (circ-0001875 overexpression vector (pLCDH-circ-0001875), control vector (pLCDH-vector), circ-0001875 shRNA (sh-circ-0001875) and control shRNA (sh-NC)). The images are shown at 400 × magnification. Scale bar = 50 μm. f A schematic of the SP1 wild-type (SP1 WT) and mutant-type (SP1 MUT) luciferase reporter plasmids. g Relative luciferase activities of the SP1 WT and SP1 MUT reporters in 293A cells transfected with miR-31-5p mimics or mimic NC. h–i RT-qPCR and western blot of SP1 mRNA and protein in cells transfected with miR-31-5p mimics and inhibitor. j–m Relative expression of SP1 at both the mRNA and protein levels in the indicated groups (si-NC + inhibitor NC, si-circ-0001875 + inhibitor NC, si-circ-0001875 + miR-31-5p inhibitor and vector + mimics NC, circ-0001875 + mimics NC, circ-0001875 + miR-31-5p mimics). Data are shown as the means ± SD. *p < 0.05, **p < 0.01, ***p < 0.001