Transcription profiling of erB2-dependent response over time to EGF and HRG stimulation of human mammary luminal epithelial cells

Our aim was to identify time-dependent changes in gene expression associated with Epidermal Growth Factor (EGF) and Hergulin B1 (HRG) stimulation of normal human mammary luminal epithelial cells (HB4a) and a derivative cell line (C3.6)overexpressing the receptor tyrosine kinase ErbB2/HER2. Serum-starved HB4a parental cells and ErbB2-overexpressing C3.6 cells were stimulated with EGF or HRG for 4 h, 18 h and 24 h or left unstimulated (0 h) prior to microarray analysis of mRNA levels of 9,932 probes, representing ~6,000 genes. Four replicates of each sample were co-hybridized to chips with a common RNA reference allowing direct comparison of gene expression across all experimental conditions: time, growth factor and cell line.