Perifosine enhances cytotoxicity of conventional (Dex, Mel, Dox) agents. MM.1S cells were cultured for 12 hours with control medium (□) and with 2.5 μm(▪) or 5 μm (▪) perifosine in the presence or absence of (A) Dex, 50 nm and 100 nm; (B) Mel, 2-5 μm and 5 μm; and (C) Dox, 50 nm and 100 nm. Cytotoxicity was assessed by MTT assay; data represent the mean plus or minus SD of quadruplicate cultures.