NF-κB and ERK phosphorylation and IL-6 and cyclin D1 expression are reduced by IRAK2 knockdown. (A) NF-κB phosphorylation in BCSC1 and BCSC3, comparing control (CV) and IRAK2 knockdown cells (shIRAK2). The NF-κB activity was assessed after culturing the cells for 5 days in the presence of doxycycline and using the EnzyFluo phosphorylation assay kit (BioAssay Systems, ABIN5691837). The NF-κB activity was defined by normalising the signal of phosphorylated NF-κB (pNF-κB) to the signal of the NF-κB total protein content. Data (n = 3) are presented as means ± SEM; statistical analysis was performed using unpaired Student’s t-test. (B–G) IL-6 expression (B) and its quantification (C), ERK phosphorylation (pERK) and total protein content (D) and its quantification (E), cyclin D1 expression (F) and its quantification (G) assessed using Western blot in BCSC1, BCSC3 and MDA-MB-468 CV and shIRAK2 cells cultured in doxycycline-containing medium for 5 days. Data are presented as means ± SEM; statistical analysis was performed using unpaired Student’s t-test. *, p < 0.05; **, p < 0.01; ***, p < 0.001.