In vitro exposure of MCL cell lines to pevonedistat decreases NF-κB activity. (A) MCL cell lines were exposed to pevonedistat (125-250 nM) for up to 4 hours. Changes in NF-κB activation were analyzed using ImageStream technology. Nuclear p65 translocation into the nuclei is reported as similarity score (SS) of Dapi and p65 images. The RD metric reports the changes in SS by measuring the shift between 2 distributions. (B) Changes in the protein stability of Ikkα and phospho (P)-IkBα were analyzed through the use of western blotting after pevonedistat in vitro exposure. PMA/Ion, phorbol 12-myristate 13-acetate/ionomycin.