Transfection of the super-repressor in CTCL lines inhibits NF-κB activation and induces apoptosis. (A) Dose-dependent inhibition of NF-κB transcriptional activation in CTCL cell lines. CTCL cell lines (MyLa, SeAx, and HuT-78 cells) were transiently transfected with a control luciferase vector lacking κB sequences (lanes 1) or with a κB reporter plasmid without (lane 2) or with a plasmid vector expressing the IκBα super-repressor (pIκBα S32/36A) at 2 different concentrations 0.4 μg (lane 3) and 1.2 μg (lane 4). Results are expressed as the ratio of luciferase activity normalized on the basis of β-galactosidase expression. The data are representative of 3 independent experiments performed in duplicate. (B) Dose-dependent increase in apoptosis of SeAx cell line. The numbers in each bottom panel indicate the percentages of propidium iodide–positive cells 24 hours after transfection with IκBα super-repressor. Above each flow cytometry panel is shown the morphological status of cells, as observed by phase-contrast microscopy (Leitz, 25 ×/2.6 NA objective). Numeric pictures were taken at the same magnification just before harvesting transfected cells. IκBα SR = IκBα super-repressor. Similar results were obtained in 3 independent experiments.