Differentiated cells (100 nanomolar phorbol 12-myristate 13-acetate for 48 h) treated with glutathione (400 micromolar) plus dibutyryl cAMP (100 micromolar) for 6 h. Total RNA was isolated using RNeasy Mini Kit and Qiashredder column. Targets were produced using standard Affymetrix procedures from 10 micrograms of total RNA.