The effect of survival factors on growth inhibition induced by rapamycin and/or dexamethasone. Karpas 707 cells, U-1958 cells, or purified MM cells from patient 4 or patient 7 were preincubated for 1 hour with rapamycin and/or dexamethasone (open bars) before addition of the MM survival factors rIGF-I (dotted bars), LongR3-IGF-I (shaded bars), or rIL-6 (filled bars). At 48 hours the relative number of viable cells was analyzed by the resazurin assay. Three independent experiments were preformed, and one representative is shown. The results are presented as mean ± SD, where n = 3.