Figure 2.

PAPTP and PCARBTP efficiently kill patient-derived myeloma cells ex vivo, while healthy bone marrow cells are spared from toxic effects. Isolated mononuclear bone marrow cells were cultured in IMDM 20% FCS at a concentration of 2 × 10⁶/mL and incubated with PAPTP, PCARBTP as indicated (a,b), respectively or 0.1% DMSO (solvent control). After 24 h cells were harvested and stained with Annexin V-APC and 7-AAD for cell death and simultaneously for CD19, CD38, CD138, CD45, CD269 and CD56 to properly detect myeloma cells. Samples were analyzed by flow cytometry, malignant plasma cells were defined as CD38⁺, CD138⁺, CD19⁻, CD269⁺ and CD56⁺. Shown is the mean ± SD of viable cells in % of untreated control, each dot representing the measure of one patient sample, n = 7–14, ns not significant, * p < 0.05, ** p < 0.01, **** p < 0.0001 Non-parametric ANOVA followed by Dunn’s multiple comparison and a Kruskal–Wallis test. ns: not significant.