FIGURE 7.

ER-retained EGFR MutR1-6 transforms cells in a growth factor-independent manner. A, NIH 3T3 fibroblasts stably expressing vector, WT EGFR, EGFR Mut R1-5, EGFR Mut R1-6, EGFR L393H (LH), or EGFR Mut R1-6/L393H incubated with or without EGF (100 ng/ml) were cultured in soft agar. The data shown represent the mean ± S.D. for colonies per 2.25 cm² from at least three independent experiments. B, representative images of the colonies quantified in A. Scale bar, 100 μm. C, two different clones of NIH 3T3 fibroblasts stable expressing EGFR Mur R1-6 cultured in soft agar as in A (Mean ± S.D. from three independent experiments). Western blot analysis using an anti-EGFR antibody was performed on whole cell lysates from the same two clones without or with EGF stimulation to determine relative expression levels. D, three different clones of NIH 3T3 fibroblasts stably expressing EGFR Mut R1-6/L393H cultured in soft agar as in A (mean ± S.D. from three independent experiments). Western blot analysis using an anti-EGFR antibody was performed on whole cell lysates from the same three clones and vector control cells without or with EGF stimulation to determine relative expression levels. The blot is representative of trends observed in multiple experiments.