Functional effects of miR-150 expression in T-ALL cells. (A) Relative cell numbers of Jurkat, MOLT-3, and DND41 cells 72 hours after transduction with the lentiviral vector LV-pre-miR-150 or LV-control (P < .05; t test). The relative cell numbers were calculated by setting the value of the control at 1. The figure shows the average of 4 independent experiments ± SD. (B) Caspase 3/7 Activity Test on Jurkat, MOLT-3, and DND41 cells 72 hours after transduction with the lentiviral vector LV-pre-miR-150 or LV-control. As a positive control for activated caspase activity, we treated T-ALL cells with the protein synthesis inhibitor anisomycin (2 μg/mL) for 24 hours. In standard culture conditions (10% FCS), miR-150 overexpression induces a significant increase of caspase activity in Jurkat and MOLT-3 T-ALL cell lines. In the DND41 cell line, miR-150-forced expression induces an increase in the caspase activity only when the cells are cultured in serum deprivation (1% FCS), although it is not detectable in normal serum conditions (10% FCS). The level of caspase activity was expressed in terms of absolute intensity of luminescence measured in counts per second (cps). The figure shows the result of one representative experiment of 2 for each cell line. (C) Western blot analysis to detect uncleaved and cleaved poly(adenosine 5′-diphosphate-ribose) polymerase in lysates of Jurkat and DND41 cells treated as described in panel B.