Reagents
D,L-SFN (CH3-SO-(CH 2)4-NCS, purity 99 %) was purchased from LKT Laboratories (St. Paul, MN). Tissue culture media, penicillin/streptomycin antibiotic mixture and fetal bovine serum were from GIBCO (Grand Island, NY). DMSO, sodium pyruvate, thiazolyl blue tetrazolium bromide (MTT), the anti-β-actin, anti-mouse and anti-rabbit antibodies conjugated with HRP were from Sigma (St. Louis, MO). The antibodies against p-Akt (Ser-473) and p-S6K1 (Thr-389) were from Cell Signaling Technology (Danvers, MA).