The expression of BCL11B suppresses the growth of ATLL-derived cells.

<p>(A) The growth inhibitory effects of <i>BCL11B</i> expression in the ATLL-derived T-cell lines as determined by a colony survival assay. The Jurkat cells and the ATLL-derived cell lines (OMT and KKI) were lentivirally transduced with equal concentrations of a <i>BCL11B-GFP</i> or <i>GFP</i> virus and selected with blasticidin for 2–5 weeks. Representative images of the drug-resistant colonies in Jurkat, OMT and KKI cells are shown (left upper panel). The ectopically expressed GFP or <i>BCL11B-GFP</i> signal after the blasticidin selection was confirmed by fluorescent microscope (left lower panel). The relative number of colonies in the cells transduced with <i>BCL11B</i> was determined as the percentage of those transduced with the control GFP virus. (n = 3, **p<0.01 by Student’s t-test) (right upper panel). (B) The expression of <i>BCL11B</i> led to the suppression of DNA synthesis in OMT cells but not in Jurkat cells. The OMT and Jurkat cells were nucleofected with <i>GFP</i> or <i>BCL11B-GFP</i> expression plasmids. Cells entering the S phase were detected using an anti-BrdU mouse monoclonal antibody (red). The GFP or BCL11B-GFP signals were detected with an anti-GFP antibody (green). The arrows indicate colocalization. The graph indicates the percentage of nuclei that incorporated BrdU in BCL11B-GFP- or GFP-positive cells. At least 100 BCL11B-GFP- or GFP-positive cells were scored for each sample in three independent experiments, and the frequency of the cells in S phase was determined by the quantitation of the BrdU-positive nuclei. (n = 3, **p<0.01 by Student’s t-test). (C) Cell death assessed by PI staining in the <i>BCL11B</i>-GFP-expressing cells<b>.</b> The OMT and the Jurkat cells were stained with PI at 4 days after the nucleofection and the percentage of dead cells (PI-positive) in BCL11B-GFP- or GFP-positive cells was determined by FACS. At least 5000 BCL11B-GFP- or GFP-positive cells were scored for each sample in three independent experiments, and the frequency of PI⁺ cells in <i>BCL11B-GFP</i>⁺ or GFP⁺ cells was determined (n = 3, **p<0.01 by Student’s t-test).