Figure 2

Time-dependent changes of HER ligand concentrations in cell lysates. HMEC lines expressing different levels of HER receptors were treated with 12 ng/ml EGF for up to 24 h. Cell lysates were collected at t = 0, 0.5, 2, 8 and 24 h, and ELISA microarray analysis was used to determine the concentration of A) AREG and B) TGF-α in cell lysates from the parental HER1 cell line (diamonds), HER2 (squares) and HER3 (triangles). Results are presented as ng ligand per mg cell-lysate protein. Data points and crossbars represent the mean and standard deviation of five replicates, each from a separate culture dish. The symbols denote statistically significant differences between the parental HER1 and HER2 (*) or HER3 (#) by both analysis of variance and Fisher's protected least significant difference analysis.