Figure 4.

DLEU2 acts as a molecular sponge for microRNA‐455 (miR‐455). A, The putative miR‐455‐binding site in the PDLEU2 sequence is shown. B, Quantitative real‐time PCR analysis of miR‐455 in PaCa‐2 cells after DLEU2 knockdown and in AsPC‐1 cells after DLEU2 overexpression. C, Luciferase reporter gene assays were used to evaluate the interaction between miR‐455 and DLEU2 in PaCa‐2 cells (left) and AsPc‐1 cells (right). MUT, mutant. D, RNA immunoprecipitation assay was carried out in PaCa‐2 cells (left) and AsPc‐1 cells (right) transiently overexpressing miR‐455, followed by quantitative real‐time PCR to detect DLEU2 or GAPDH expression associated with AGO2. RNA levels are presented as fold enrichment of Ago2 relative to IgG immunoprecipitates. E, DLEU2 siRNA or control siRNA was transfected into PaCa‐2 cells, together with (or without) miR‐455 inhibitor. The cells were assayed for cell proliferation (left) and invasion (right). F, DLEU2 vector or control vector was transfected into AsPC‐1 cells, together with (or without) miR‐455 mimic. The cells were assayed for cell proliferation (left) and invasion (right). *P < .05