Synergistic Inhibitory Effects of Cetuximab and Cisplatin on Human Colon Cancer Cell Growth via Inhibition of the ERK-Dependent EGF Receptor Signaling Pathway

Figure 4

Effects of the combined treatment of cetuximab and cisplatin on AP-1 and NF-κB activity. Cells were treated with cetuximab (30 μg/mL) or cisplatin (2 μg/mL) alone or the combination of both agents. (a) The activation of AP-1 in HCT116 and SW480 cells was investigated by EMSA. (b) Cell protein extracts were fractioned into either nuclear (NE) or cytosolic (CE) extract and the expression of c-Fos and c-Jun in each fraction was detected by Western blotting. (c) The effects of the combined treatment of cetuximab and cisplatin on the activation of NF-κB were investigated by EMSA. (d) The expression of p50, p65, IκB-α, and p-IκB-α proteins in nuclear (NE) and cytosolic (CE) extracts was detected by Western blotting. The β-actin and histone-H1 proteins were used as loading controls. After densitometric quantification, data was expressed as the mean ± SD of three independent experiments. indicates statistically significant differences from the control. indicates statistically significant differences from the cetuximab treatment alone.