Treatment with PDA-66 inhibits cell proliferation and metabolic activity. SEM, RS4;11, Jurkat and MOLT4 cells were incubated with different concentrations of PDA-66. Metabolic activity was determined using WST-1 assay. The results of optical density measurement were expressed as a percentage of the DMSO treated control cells. The two upper diagrams show the results of cell count after PDA-66 treatment after 48 h (A) and 72 h (B). The lower diagrams display the influence of PDA-66 on the metabolic activity, respectively (C, D). The proliferation and metabolic activity of all cell lines was suppressed significantly at higher concentrations. Results are displayed as the mean + SD of three independent experiments. *Significant treatment effect vs. DMSO control, α = 0.05.