Blocking nuclear export decreases viability of human CALM-AF10 leukemia cell lines. (A) Confirmation of expression of the CALM-AF10 transcript in P31/Fujioka (P31/Fuji) and U937 cells by RT-PCR. GAPDH serves as a control for equal input of RNA for RT-PCR. (B-C) CALM-AF10–positive (P31/Fujioka and U937) and CALM-AF10–negative (K562 and THP-1) cell lines were grown in the presence of increasing concentrations of LMB (0, 0.1, 0.5, 1 nM) for 17 h (B) or 42 h (C). The number of viable cells was determined by flow cytometry and is shown as a percent of untreated for each cell line. Results are shown as mean ± SEM from 3-6 independent experiments. The viabilities of both P31/Fujioka and U937 cell lines are statistically different from either K562 or THP-1 at 0.5 and 1 nM LMB, as determined by two-way ANOVA followed by Bonferroni’s Multiple Comparison Test: *P < .05.