Virtual High-Throughput Screening To Identify Novel Activin Antagonists

  • J Med Chem. 2015 Jul 23;58(14):5637-48. doi: 10.1021/acs.jmedchem.5b00753.
Jie Zhu  1  2 ,  Rama K Mishra  3 ,  Gary E Schiltz  3 ,  Yogeshwar Makanji  1 ,  Karl A Scheidt  3  4  5 ,  Andrew P Mazar  5  6 ,  Teresa K Woodruff  1  2  6
Affiliations
  • 1. †Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, 303 East Superior Street, Lurie 10-250, Chicago, Illinois 60611, United States.
  • 2. ‡Center for Reproductive Science, Northwestern University, Evanston, Illinois 60208, United States.
  • 3. §Center for Molecular Innovation and Drug Discovery, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.
  • 4. ⊥Department of Chemistry, Northwestern University, Evanston, 60208, Illinois, United States.
  • 5. ∥Department of Pharmacology, Northwestern University, Chicago, Illinois 60611, United States.
  • 6. □Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, Illinois 60208, United States.
PMID: 26098096 DOI: 10.1021/acs.jmedchem.5b00753
Abstract

Activin belongs to the TGFβ superfamily, which is associated with several disease conditions, including cancer-related cachexia, preterm labor with delivery, and osteoporosis. Targeting activin and its related signaling pathways holds promise as a therapeutic approach to these diseases. A small-molecule ligand-binding groove was identified in the interface between the two activin βA subunits and was used for a virtual high-throughput in silico screening of the ZINC database to identify hits. Thirty-nine compounds without significant toxicity were tested in two well-established activin assays: FSHβ transcription and HepG2 cell Apoptosis. This screening workflow resulted in two lead compounds: NUCC-474 and NUCC-555. These potential activin antagonists were then shown to inhibit activin A-mediated cell proliferation in ex vivo ovary cultures. In vivo testing showed that our most potent compound (NUCC-555) caused a dose-dependent decrease in FSH levels in ovariectomized mice. The Blitz competition binding assay confirmed target binding of NUCC-555 to the activin A:ActRII that disrupts the activin A:ActRII complex's binding with ALK4-ECD-Fc in a dose-dependent manner. The NUCC-555 also specifically binds to Activin A compared with Other TGFβ superfamily member myostatin (GDF8). These data demonstrate a new in silico-based strategy for identifying small-molecule activin antagonists. Our approach is the first to identify a first-in-class small-molecule antagonist of activin binding to ALK4, which opens a completely new approach to inhibiting the activity of TGFβ receptor superfamily members. in addition, the lead compound can serve as a starting point for lead optimization toward the goal of a compound that may be effective in activin-mediated diseases.

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