TN14003 antagonizes protective effects of marrow stromal cells. (A) Determination of cell viability by staining with DiOC₆ and PI. Presented are contour maps of CLL B cells from one patient defining the relative green (DiOC₆) and red (PI) fluorescence intensities of CLL cells on the horizontal and vertical axes, respectively. The vital cell population (DiOC₆^bright, PI^exclusion) was determined for CLL cells cultured in the presence (top row) or absence (bottom row) of M2-10B4 cells and 72 hours after treatment with 10 μM F-ara-A and TN14003. The percentage of vital cells is displayed in each contour map. (B) CLL cells were cultured on M2-10B4 stromal cells and treated with 10 μM F-ara-A or the combination of F-ara-A and 10 μg/mL TN14003. Cell viability was measured 24, 48, and 72 hours after treatment, as indicated on the horizontal axis. Data represent the mean relative viability of CLL cells treated with 10 μM F-ara-A (▨) or 10 μM F-ara-A and TN14003 (▪) compared with the respective viability of CLL cells cultured on M2-10B4 stromal cells without F-ara-A or TN14003 (controls). Displayed are the mean ± SEM values of 10 patient samples (^*P < .05).