(d) DLD1 cells expressing FOXO(A3)-ER were transfected with glutamine synthetase (GS) siRNA or non-template (NT) control siRNA, and stimulated with 4-OHT for 24 h with or without 3-methyladenine (3-MA). Apoptosis was determined by FACS analysis after labelling cells with annexin V (AxV)-phycoerythrin and DAPI. The graph shows relative fold versus control samples, mean ±  s.e.m. (n=3). *P0.05. 