Robust lanthanide-based assays for the detection of anti-apoptotic Bcl-2-family protein antagonists

Anti-apoptotic Bcl-2-family proteins (Bcl-2, Bcl-xL, Bfl-1, Mcl-1, Bcl-W and Bcl-B) have been recently validated as drug discovery targets for cancer, owed to their ability to confer tumor resistance to chemotherapy or radiation. The anti-apoptotic activity of Bcl-2 proteins is due to their ability to heterodimerize with their pro-apoptotic counterparts (proteins such as Bad, Bim or Bid) via a conserved peptide region termed BH3. Thus, molecules that mimic pro-apoptotic BH3 domains represent a direct approach to overcoming the protective effects of anti-apoptotic proteins such as Bcl-2 and Bcl-xL. Here, we report on the development and evaluation of two novel Lanthanide-based assays that are formatted for high-throughput screening of small molecules capable of antagonizing BH3–Bcl-2 interactions. The assay conditions, robustness and reproducibility (Z′ factors) are described. These assays represent useful tools to enable further studies in the search for novel, safe and effective anti-cancer agents targeting Bcl-2-family proteins.