T4-DA-Rap1 cells show dose-dependent resistance to reversion by inhibitors of EGFR and MAPK. A, phase-contrast images and immunofluorescence localization of α6-integrin in T4-DA-Rap1 cells with or without 70 nmol/L AG1478 in three-dimensional lrECM. B, levels of β1-integrin, EGFR, and phospho-EGFR in three-dimensional lrECM–cultured T4-vector cells, and T4-DA-Rap1 cells in the presence and absence of 70 nmol/L AG1478. C, dose-dependent effect of reverting agents on T4-DA-Rap1 cells in three-dimensional lrECM. Cells were treated with different doses of inhibitors against EGFR (AG1478 and mAb225), MEK (PD98059), or PI3K (LY294002). Bar, 5 μm.