tokens: LAN - 1 or SH - SY5Y cells were seeded in duplicates onto 6 - well plates at a density of 2 x 104 cells per cm2 and cotransfected 24 h later with 0 . 5 mu g ( 2 . 5 mu g / ml ) of pGL3 firefly luciferase reporter gene plasmid under the control of either pE1B - hWAF1 or pE1B - BAX using lipofectamine 2000 and 1 mu g of either a p53 expressing plasmid or an empty vector .