Selective Degradation of GSPT1 by Cereblon Modulators Identified via a Focused Combinatorial Library

  • ACS Chem Biol. 2020 Oct 16;15(10):2722-2730. doi: 10.1021/acschembio.0c00520.
Chelsea E Powell  1  2 ,  Guangyan Du  1  2 ,  Jianwei Che  1  2 ,  Zhixiang He  1  2 ,  Katherine A Donovan  1  2 ,  Hong Yue  1  2 ,  Eric S Wang  1  2 ,  Radosław P Nowak  1  2 ,  Tinghu Zhang  1  2 ,  Eric S Fischer  1  2 ,  Nathanael S Gray  1  2
Affiliations
  • 1. Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, United States.
  • 2. Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States.
PMID: 32865967 DOI: 10.1021/acschembio.0c00520
Abstract

Cereblon (CRBN) is an E3 Ligase adapter protein that can be reprogrammed by imide-class compounds such as thalidomide, lenalidomide, and pomalidomide to induce the degradation of neo-substrate proteins. In order to identify additional small molecule CRBN modulators, we implemented a focused combinatorial library approach where we fused an imide-based CRBN-binding pharmacophore to a heterocyclic scaffold, which could be further elaborated. We screened the library for CRBN-dependent antiproliferative activity in the multiple myeloma cell line MM1.S and identified five hit compounds. Quantitative chemical proteomics of hit compounds revealed that they induced selective degradation of GSPT1, a translation termination factor that is currently being explored as a therapeutic target for the treatment of acute myeloid leukemia. Molecular docking studies with CRBN and GSPT1 followed by analogue synthesis identified a possible hydrogen bond interaction with the central pyrimidine ring as a molecular determinant of hit compounds' selectivity. This study demonstrates that a focused combinatorial library design, phenotypic screening, and chemical proteomics can provide a suitable workflow to efficiently identify novel CRBN modulators.

Products