Fig. 4

IGFBP2 is required for acidic bile salts-induced EGFR and DNA-PKcs activation in EAC cells. a, FLO1 cells with IGFBP2 knockdown (si-IGFBP2) and control cells were treated with acidic bile salts (ABS, pH 4, 200 μM) for 20 min and then recovered for 0.5 h. Whole cell lysates were applied in western blot analysis to detect p-EGFR (Tyr1068) and p-DNA-PKcs (Thr2609). b, OE33 cells with IGFBP2 overexpressing and control cells were treated with ABS for 20 min and then recovered for 0.5 h. Whole cell lysates were used for western blot analysis to detect p-EGFR (Tyr1068) and p-DNA-PKcs (Thr2609). c and d, FLO1 cells with IGFBP2 knockdown and control cells were treated with ABS for 20 min and then recovered for 0.5 h. Immunofluorescence staining for p-DNA-PKcs (Thr2609) was performed. Quantification of positive p-DNA-PKcs cells was performed using image J and presented as a percentage of positive cells (d). *** p < 0.001