Flavopiridol and UCN-01 down-regulate antiapoptotic proteins.

Representative immunoblot data show down-regulation of antiapoptosis proteins by kinase inhibitors. B-CLL cells were cultured with or without 0.1 μmol/L flavopiridol or 1 μmol/L UCN-01 for 2 days. Whole cell lysates were then prepared, normalized for protein content (25 μg), and subjected to SDS-PAGE/immunoblot analysis with the use of antibodies specific for Bcl-2, Mcl-1, Bax, Bak, BAG-1, XIAP, and β-actin with ECL-based detection. Data illustrate a representative B-CLL sample and are derived from a single blot by means of the MAD immunoblotting method. Note that B-CLLs express both long (BAG-1L) and short (BAG-1) isoforms of BAG-119 and that both were down-regulated by kinase inhibitors.