Figure 7.

IRS-1 and -2 were required for sensitivity to anti-IGF-IR strategies. (A) T47D-YA, T47D-YA/IRS-1, and T47D-YA/IRS-2 cells were plated in triplicate in 24-well tissue culture plates at a density of 10 000 cells per well in growth media. After 24 h, cells were washed twice with 1 × PBS and switched to SFM for 24 h. Cells were then treated with SFM, 3 μg ml⁻¹ αIR-3, 5 nM IGF-I or 3 μg ml⁻¹ αIR-3 plus 5 nM IGF-I for 5 days and cell number estimated using the MTT assay. Data are represented as fold increase over each cell line's SFM readings. Error bars represent s.e. of the mean and ^* represents a significant difference (P<0.05) in absorbance in samples treated with IGF-I compared to SFM. P-values: T47D-YA/IRS-1 #20 (P=0.0141). Data are representative of three independent experiments. (B) T47D-YA, T47D-YA/IRS-1 and T47D-YA/IRS-2 cells were plated on gold particle-coated coverslips. Cells were allowed to adhere and then treated with SFM, 3 μg ml⁻¹ αIR-3, 5 nM IGF-I or 3 μg ml⁻¹ αIR-3 plus 5 nM IGF-I for 24 h. Coverslip images were captured using a brightfield microscope with a neutral density filter and the area on the coverslip cleared by cell movement was computed using Simple PCI software. Data are presented as fold increase of the mean area cleared compared to each cell line's SFM readings. Error bars represent s.e. of the mean and ^* represents a significant difference (P<0.05) in samples treated with IGF-I compared to SFM. P-values: YA/IRS-2 #10 (P=0.0169). Results are representative of three independent experiments.