Figure 2

EGF and IL-1β synergistically promote ERK1/2-mediated IBDC cell migration and invasion. A: Increased expression of activated ERK1/2 was detected in BT474 cells after stimulation with EGF. Western blotting demonstrating that pre-treatment with U0126 significantly inhibited EGF-induced ERK1/2 activation in BT474 cells. B, Increased expression of activated ERK1/2 was detected after the stimulation of BT474 cells with IL-1β. Western blotting demonstrating that pre-treatment with U0126 significantly inhibited IL-1β-induced ERK1/2 activation in BT474 cells. C, Western blots confirmed that the transfection of ERK1/2 siRNA dose-dependently reduced ERK1/2 expression in BT474 cells. D, Stronger activation of ERK1/2 was detected in EGF plus IL-1β-stimulated BT474 cells (an approximate 2- to 3-fold increase) compared to EGF or IL-1β alone. ERK1/2 siRNA and U0126 inhibited both EGF and IL-1β-induced ERK1/2 activation. E and F, Increased numbers of migrating and invading BT474 cells were observed after stimulation with EGF plus IL-1β, leading to a 2-fold increase compared to either EGF or IL-1β alone. ERK1/2 siRNA and U0126 inhibited EGF plus IL-1β-induced cell migration and invasion. G, Representative light microscopy images of BT474 cell migration and invasion in the Transwell assay. ^** and ^▼▼, P < 0.05 vs. siRNA negative control-transfected cells stimulated with EGF plus IL-1β; ^ΔΔ and ^◇◇, P < 0.05 vs. untransfected cells stimulated with EGF plus IL-1β. Bars are the mean ± SD of migrating and invading cells. Cells were counted as the number of cells per field of view.