miR-451a downregulates the PI3K/AKT signaling pathway via targeting PDPK1. (A) Target mRNAs of miR-451a were predicted using StarBase and Kyoto Encyclopedia of Genes and Genomes signaling pathway enrichment analysis was conducted using The Database for Annotation, Visualization and Integrated Discovery software. The bubble plot represents the top 10 enriched pathways. (B) Identified complementary binding site between miR-451a and PDPK1 mRNA was predicted using StarBase. (C) Relative luciferase activity of PDPK1 MT or WT following the transfection of miR-451a mimics or mimic controls was analyzed using dual luciferase reporter assays. PDPK1 (D) mRNA and (E) protein expression levels in A431 and SCC-12 cells following the transfection of the miR-451a mimic or mimic control were determined using reverse transcription-quantitative PCR or western blotting, respectively. (F) Extent of PI3K/AKT signaling pathway phosphorylation in A431 and SCC-12 cells following the transfection of miR-451a mimic or mimic control was analyzed using western blotting. The data are presented as the mean ± SD. One-way ANOVA and Tukey's multiple comparison tests were used to determine statistical significances. *P<0.05. miR, microRNA; PDPK1, 3-phosphoinositide-dependent protein kinase-1; MT, mutant; WT, wild-type; p-, phosphorylated.