FIGURE 4.

Celecoxib activates ERK1/2 signaling (A), which contributes to celecoxib-induced DR5 up-regulation (B). A, the indicated cell lines were treated with 50 μm celecoxib for the given times. B, the indicated cell lines were transfected with control (Ctrl) or ERK1/2 siRNA for 48 h and then treated with and without 50 μm celecoxib (CCB) for an additional 10 h. After treatment, the cells were harvested for preparation of whole cell protein lysates and subsequent Western blot analysis for the given proteins.