Fig. 7

HuR is a sponging target of circPPFIA1s and is required for regulation of metastatic potential. A Venn diagram demonstrated the overlapping gene of the interacting RBPs with circPPFIA1 predicted by databases (circInteractome, RBPDB, and Starbase). B Validation of interaction of HuR with circPPFIA1s. The level of HuR in ASO pulldown materials was determined by western blot analysis. C To demonstrate the interaction between circPPFIA1s and HuR, the level of circPPFIA1-L and -S in HuR RIP was determined by semi-qPCR. D, E The expression level of HuR in KM12C and KM12L4 cells was determined by western blot analysis (D). Localization of HuR was examined by Western blot analysis followed by cellular fractionation (E). F, G The effect of circPPFIA1s silencing on the expression (F) and localization (G) of HuR was examined by western blot analysis. H The expression levels of circPPFIA1-L and -S were determined by semi-qPCR in HuR-silenced KM12L4 cells. I Transwell invasion and migration assays were carried out to check whether HuR regulates metastatic potential of KM12L4 cells. J Requirement of HuR in circPPFIA1s-regulated metastatic potential. KM12C cells were transfected with indicated siRNAs and the invasive and migratory abilities were examined by transwell invasion and migration assays, respectively. Statistical analyses were performed using the Student’s t-test using three independent experiments (*p < 0.05). All data represent mean ± standard variation (SD)