5‐aza‐dC–induced apoptosis in dopaminergic neuronal cells. N27 cells, treated with 5‐aza‐dC (5 μM) for 24–48 h (A) or S‐adenosyl methionine (SAM) (250 μg/mL) for 92 h (B), were stained with annexin V‐FITC. DNA laddering assay (C) in N27 cells treated with 5‐aza‐dC (5 μM) for 24 h and in SH‐SY5Y cells treated with 5‐aza‐dC (10 μM) for 24 h. SH‐SY5Y cells (D) treated with 5‐aza‐dC (5 μM) for 24 h were stained with annexin V‐FITC and propidium iodide (PI) and then viewed under a fluorescence microscope (green only, early apoptotic stage; green and red together, middle apoptotic stage; red only, late apoptotic stage). 5aza, 5‐aza‐2′‐deoxycytidine.