Fig. 2.

MAPK signaling is activated upon erlotinib treatment in cells with depleted PIK3R2 but not depleted PIK3CA or PIK3CB.

(A-C) SKOV3 cells were transfected with siRNA targeting (A) PIK3R2, (B) PIK3CA or (C) PIK3CB for 24 h prior to treatment with erlotinib for an additional 72 h. Protein lysates were collected for Western blotting with the indicated antibodies. Representative blots of 3 independent experiments are shown. The numbers below the blots indicate the mean densitometry values normalized to those of α/β-tubulin or to the corresponding total proteins (for phosphoproteins) of the 3 experiments.