Effect of inhibitors on myeloma cell growth.

(A) Wild-type ras–expressing control (WT) or mutant N-ras (N) and K-ras (K) cells incubated without IL-6 and with or without the following inhibitors: farnesyl transferase inhibitor FTI-277 (FTI) at 50 μM, rapamycin (RAP) at 10 nM, PD98059 (PD) at 50 μM, or LY294002 (LY) at 10 μM. MTT assay was performed after 48 hours. Data are the percentage of control (compared with cells incubated without inhibitors), means ± SDs of 3 to 5 separate experiments for each inhibitor. *Significantly lower than effects on wild-type cells (WT), P < .05. (B) Mutant N-ras–containing cells were infected with control adenovirus (Ad-CMV) or virus expressing the IKB superrepressor (IKB-sr) at MOIs of 50 and 100. MTT assays were performed 48 hours later with comparison with noninfected cells. Data are means ± SDs of 3 separate experiments. *Significantly different from Ad-CMV group,P < .05.