Rational design of selective small-molecule inhibitors for β-catenin/B-cell lymphoma 9 protein-protein interactions.
Selective inhibition of α-helix-mediated protein-protein interactions (PPIs) with small organic molecules provides great potential for the discovery of chemical probes and therapeutic agents. Protein Data Bank data mining using the HippDB database indicated that (1) the side chains of hydrophobic projecting hot spots at positions i, i + 3, and i + 7 of an α-helix had few orientations when interacting with the second protein and (2) the hot spot pockets of PPI complexes had different sizes, shapes, and chemical groups when interacting with the same hydrophobic projecting hot spots of α-helix. On the basis of these observations, a small organic molecule, 4'-fluoro-N-phenyl-[1,1'-biphenyl]-3-carboxamide, was designed as a generic scaffold that itself directly mimics the binding mode of the side chains of hydrophobic projecting hot spots at positions i, i + 3, and i + 7 of an α-helix. Convenient decoration of this generic scaffold led to the selective disruption of α-helix-mediated PPIs. A series of small-molecule inhibitors selective for β-catenin/B-cell lymphoma 9 (BCL9) over β-catenin/cadherin PPIs was designed and synthesized. The binding mode of new inhibitors was characterized by site-directed mutagenesis and structure-activity relationship studies. This new class of inhibitors can selectively disrupt β-catenin/BCL9 over β-catenin/cadherin PPIs, suppress the transactivation of canonical Wnt signaling, downregulate the expression of Wnt target genes, and inhibit the growth of Wnt/β-catenin-dependent cancer cells.
Department of Chemistry, Center for Cell and Genome Science, University of Utah , Salt Lake City, Utah 84112-0850, United States.
Logan R
LR
Hoggard
Department of Chemistry, Center for Cell and Genome Science, University of Utah , Salt Lake City, Utah 84112-0850, United States.
Yongqiang
Y
Zhang
Department of Chemistry, Center for Cell and Genome Science, University of Utah , Salt Lake City, Utah 84112-0850, United States.
Min
M
Zhang
Department of Chemistry, Center for Cell and Genome Science, University of Utah , Salt Lake City, Utah 84112-0850, United States.
Vanja
V
Panic
Department of Chemistry, Center for Cell and Genome Science, University of Utah , Salt Lake City, Utah 84112-0850, United States.
John A
JA
Wisniewski
Department of Chemistry, Center for Cell and Genome Science, University of Utah , Salt Lake City, Utah 84112-0850, United States.
Haitao
H
Ji
D015195:Drug Design; D006801:Humans; D008958:Models, Molecular; D015394:Molecular Structure; D009363:Neoplasm Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D054852:Small Molecule Libraries / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014157:Transcription Factors; D051176:beta Catenin / Q000737:chemistry / Q000378:metabolism*
C111180:BCL9 protein, human; D009363:Neoplasm Proteins; D054852:Small Molecule Libraries; D014157:Transcription Factors; D051176:beta Catenin