Validation of microarray results by real-time, reverse transcription (RT) PCR and Western blotting. (A) Fold changes for microarray and RT-PCR at 6 h comparing S-nitrosoglutathione (GSNO; 400 μM) to glutathione (GSH; 400 μM) incubated cells. (B) Correlation of fold change comparing the two methods after logarithmic transformation. Results are means ± SE of the last three microarray experiments for which material was available for RT-PCR (performed in triplicate). (C) Representative Western blots of cell cycle genes detected by specific antibody and enhanced chemiluminescence. Differentiated U937 cells (1 × 107) were incubated with PBS, GSH (400 μM) or GSNO (400 μM) for 12 h and then lysed for Western blotting. (D) Western blot results quantified with laser densitometry and expressed as ratios relative to PBS control values. Data are means ± SE of three or four independent experiments.