Plinabulin induces cell death in patient tumor (CD138⁺) cells and inhibits BMSC-induced MM cell growth. (A) Purified patient MM cells were treated with plinabulin (8nM) for 48 hours, and cell death was measured with Trypan Blue Exclusion assays. Data presented are mean ± SD of triplicate samples (P < .05 for all patients). (B) PBMCs from 5 healthy donors were treated with plinabulin (0.1μM and 1μM) for 48 hours and then analyzed for viability with MTT assay. Data presented are mean ± SD of triplicate samples (P < .05; n = 3). (C) MM.1S cells were treated with plinabulin (8nM, 48 hours) in the presence or absence of 3 different patient BMSCs, and cell growth was measured with thymidine incorporation. Data presented are mean ± SD of triplicate samples (P < .05; n = 3,). (D) MM.1S and MM.1R cells were treated with plinabulin (8nM, 48 hours) in the presence or absence of rhIL-6 (10 ng/mL), and then cell growth was measured with thymidine incorporation. Data presented are mean ± SD of triplicate samples (P < .05 for all the cell lines).