(A) Western blot analysis of POPDC1 expression following transfection with POPDC1 siRNA confirmed POPDC1 suppression in MCF7 (n=3), MDA231 (n=3) and SKBR3 (n=3) cells. Graphs below image panels represent densitometric quantification of protein bands. Protein bands were normalized by calculating the POPDC1/β-actin ratio. Normalized ratios were subsequently expressed as a ratio relative to control bands (no siRNA) to determine protein fold changes. (B) Suppression of POPDC1 with POPDC1 siRNA significantly promoted cell migration in MCF7 (n=5), MDA231 cells (n=5) and SKBR3 cells (n=5). Boyden chamber assay was performed over a 3-h incubation period to allow cell migration across the polycarbonate membrane; scale bars = 250 μm. (C) Suppression of POPDC1 with POPDC1 siRNA significantly promoted cell proliferation in MDA231 cells (n=5) and SKBR3 cells (n=5), but not in MCF7 cells (n=4). Cells were transfected for 36 h prior to overnight starvation in serum-free medium and subsequent incubation in 10% AlamarBlue® dye for 4 h. Comparisons of protein fold change ratios, mean % migration and mean % proliferation were conducted using ANOVA with Dunnett’s post hoc test. Mean values presented ± SEM; **P≤0.01, ***P≤0.001.