Fig. 3. CircBANP sequestered let-7a in GC cells. (A) Schematic of the putative let-7a-binding sequence in circBANP and the mutated seed sequence. (B) Let-7a expression was assessed by qRT-PCR in MKN-74 and MKN-45 cells transfected with miR-NC mimic or let-7a mimic. (C and D) CircBANP luciferase reporter plasmid harboring the wild-type seed sequence for let-7a (circBANP-Wt) or a site-directed mutant of seed sequence (circBANP-Mut) was transfected into MKN-74 and MKN-45 cells together with miR-NC mimic or let-7a mimic, followed by the measurement of the luciferase activity. (E) The enrichment of circBANP was determined by qRT-PCR in cell lysates incubated with Bio-miR-NC, Bio-let-7a or Bio-let-7a-Mut. (F) The enrichment of let-7a was evaluated by qRT-PCR in cell lysates incubated with Bio-NC, Bio-circBANP or Bio-circBANP-Mut. (G and H) The levels of circBANP and let-7a were detected by qRT-PCR in MKN-74 and MKN-45 cells transfected with si-NC or si-circBANP-1. (I and J) Let-7a expression was assessed in 56 pairs GC tissues and adjacent normal gastric tissues, GC cell lines (MKN-45, MKN-74, AGS and HGC-27) and GES-1 cells. (K) Correlation between circBANP expression and let-7a level in GC tissues was determined using Spearman test. *P < 0.05 vs. miR-NC mimic, Bio-miR-NC mimic, Bio-NC, si-NC or normal control.