Discovery of a novel B-cell lymphoma 6 (BCL6)–corepressor interaction inhibitor by utilizing structure-based drug design

Abstract B-cell lymphoma 6 (BCL6) is a transcriptional repressor that can form complexes with corepressors via protein–protein interactions (PPIs). The complexes of BCL6 and corepressors play an important role in the formation of germinal centers (GCs), and differentiation and proliferation of lymphocytes. Therefore, BCL6–corepressor interaction inhibitors would be drug candidates for managing autoimmune diseases and cancer. Starting from high-throughput screening hits 1a and 2a , we identified a novel BCL6–corepressor interaction inhibitor 8c (cell-free enzyme-linked immunosorbent assay [ELISA] IC 50  = 0.10 µM, cell-based mammalian two-hybrid [M2H] assay IC 50  = 0.72 µM) by utilizing structure-based drug design (SBDD) based on an X-ray crystal structure of 1a bound to BCL6. Compound 8c also showed a good pharmacokinetic profile, which was acceptable for both in vitro and in vivo studies.