NDRG1 expression decreases total EGFR, EGFR phosphorylation, and EGFR dimerization in response to EGF in PANC-1 and HT-29 cells. PANC-1 (A) and HT-29 (B) vector control (VC) or NDRG1 overexpressing (NDRG1) cells were incubated with control media (Ctrl) or media containing EGF (EGF; 10 ng/ml; 10 min/37 °C), and the levels of total EGFR as well as EGFR phosphorylated at Tyr-1068, Tyr-1086, and Tyr-1148 were examined by Western blot. β-Actin was used as a loading control. C, EGFR dimerization was examined in PANC-1 (panel i) and HT-29 (panel ii) cells by cross-linking with 3,3′-dithiobis-(sulfosuccinimidylpropionate) (see “Experimental Procedures”) and immunoprecipitating EGFR. D, EGFR dimerization was examined in PANC-1 VC and NDRG1 cells using EGF incubation times of 2, 5, and 10 min at 37 °C. Western blots are typical of three independent experiments, with densitometric analysis representing mean ± S.D. (three experiments). Relative to untreated vector control cells: *, p < 0.05; **, p < 0.01; ***, p < 0.001. Relative to EGF-treated vector control cells: #, p < 0.05; ##, p < 0.01; ###, p < 0.01. Relative to untreated NDRG1 overexpressing cells: †, p < 0.05; ††, p < 0.01.