Lovastatin reduces Mcl-1 protein levels by depletion of intracellular pools of GGPP. Plasma cell lines (A) RPMI 8226, (B) L363, (C) XG-1, and (D) U266 were treated for 2 or 4 days with solvent control, or lovastatin (5 μM for XG-1 and 30 μM for RPMI 8226, U266, and L363) alone (▪) or in combination with mevalonate (100 μM; ○), FOH (10 μM; □), or GGOH (10 μM; •). After protein isolation, Mcl-1, Bcl-XL, Bcl-2, and Bax were determined by Western blot analysis. Furthermore, the proapoptotic 23-kDa Bcl-2 form was detected after long exposure of the film. Data are representative of at least 3 independent experiments. The percentage of apoptotic cells was determined using the annexin V assay. Shown is the sum of the percentages of early and late apoptotic cells. Experiments were performed 3 times in triplicate. Data are presented as mean ± SEM.