Fig. 4

Gefitinib limits basal and RENCA macrobead-mediated EGFR activity and contributes to an additive inhibitory effect in DU145 cells. In-cell Western analysis of total EGFR, phosphorylated EGFR (pY1068) and overlay (normalized pY1068/EGFR) in DU145 cells pre-treated with gefitinib (GF) or 0.01% DMSO for 2 h at the indicated concentrations followed by culture in (a) naïve media, or (b) 5-day conditioned media from > 18 wk. RENCA macrobeads. Each column represents the mean normalized intensity in arbitrary units (AU) (n = 6–8) ± SD. *p < 0.001, compared with vehicle control. (c) DU145 cells pre-treated with gefitinib or 0.01% DMSO were cultured with naïve media or together with > 18 wk. RENCA macrobeads in a cell culture insert system for 5 days. Cells cultured in naïve media were used as a control. Histogram represents percent survival calculated as the percent absorbance of co-cultured samples relative to naïve media samples. Each column represents the mean survival (n = 3) ± SD