Figure 5: Association of perifosine-(PER-) induced cytotoxicity with glutathione (GSH) content and thioredoxin reductase activity (TrxRed) in head and neck cancer cells. FaDu, Cal-27, and SCC-25 cells were analyzed for mean baseline TrxRed activity (a) and mean total GSH content (b) and compared to their respective mean surviving fraction in response to 5  M PER (FaDu and Cal-27) or 10  M PER (SCC-25).