The effect of rapamycin and dexamethasone on growth in 6 different MM cell lines. Karpas 707, U-1958, LP-1, RPMI 8226, EJM, and U-266-1970 cells were treated with indicated concentrations of rapamycin alone (□) or in combination with dexamethasone (▪). At 72 hours of incubation the plates were washed and incubated with the redox-dye resazurin as described in “Materials and methods.” The plates were analyzed by fluorometry, and the amount of emitted light, proportional to the number of living cells, was determined. Four experiments were performed and one representative is shown. Data are expressed as mean ± SD where n = 3.