Figure 10.

Inhibition of the MAPK pathway reduces the clonogenic survival of EGFR-antisense cells and EGFR-CD533 cells after irradiation and U0126 treatment. Cells were irradiated (2 Gy) over 3 d (total 6 Gy) in the presence or absence of 2 μM U0126 and DMSO vehicle control. Twenty-four hours after the final irradiation and drug treatment, cells were isolated by trypsinization, and live cell number was determined by hemocytometer. Cells were washed three times in drug-free medium. Their ability to form colonies was determined by a previously described technique. Cells were plated at either 500 or 2500 cells per well. Colonies were counted 14 d after plating, when they contained ≥50 cells. Data are the means of eight separate experiments ± SEM.