Marrow stromal cells protect MCL cells from F-ara-A-induced apoptosis. (A,B) Mean viability of SP-53 cells (A) or MINO cells (B) treated with F-ara-A at the time points displayed on the horizontal axis. MCL viability was higher when MCL cells were cocultured with M2-10B4 MSC cells (▨) compared with MCL without stromal cell support ([graphic024]). Results are presented as mean relative viability compared with untreated controls (100%) and are the mean ± SEM values of triplicates. *Significant protection of MCL cells from F-ara-A cytotoxicity compared with control sample (P < .05). (C) Cell viability of MCL cells was determined by staining with DiOC₆ and PI. Contour plot represents supernatant and migrated fractions of pretreated with 10 μM F-ara-A SP-53 cells after 72 hours of cultivation on M2-10B4. The predominance of vital cells (DiOC₆^bright, PI^exclusion) was detected for migrated fraction (right panel) compared with supernatant fraction (left panel). The percentage of vital cells is displayed in each contour map. (D) Viability of migrated and supernatant fractions of MCL cells pretreated with 10 μM F-ara-A after 24, 48, and 72 hours of cultivation on stromal cells. Results are represented relative to untreated controls and are mean ± SEM values of 3 different experiments.