Figure 4

MicroRNAs such as miR-15, miR-16 and miR-128 are involved in downregulation of Smurf2 protein in triple-negative breast cancer. Human triple-negative breast cancer cell lines, BT549, MDA-MB-436 and DU4475 cells, were transfected with microRNA inhibitors against miR-15a, miR-15b, miR-16 and miR-128, or nonspecific ssRNA as negative control (NC), and cellular levels of Smurf2 protein were determined at 24 h (A, B) or 48 h (C) post-transfection by immunoblotting. The density of each Smurf2 signal on immunoblots was normalized by that of α-tubulin, and presented as relative expression levels to that in negative control (NC) as 1.0. Quantified data on bar graphs show means + SEM from three experiments, and the asterisks indicate statistically significant (p < 0.05) differences from negative control (NC).