Discovery of a diaminoquinoxaline benzenesulfonamide antagonist of HIV-1 Nef function using a yeast-based phenotypic screen

Retrovirology. 2013 Nov 14:10:135. doi: 10.1186/1742-4690-10-135.

Abstract

Background: HIV-1 Nef is a viral accessory protein critical for AIDS progression. Nef lacks intrinsic catalytic activity and binds multiple host cell signaling proteins, including Hck and other Src-family tyrosine kinases. Nef binding induces constitutive Hck activation that may contribute to HIV pathogenesis by promoting viral infectivity, replication and downregulation of cell-surface MHC-I molecules. In this study, we developed a yeast-based phenotypic screen to identify small molecules that inhibit the Nef-Hck complex.

Results: Nef-Hck interaction was faithfully reconstituted in yeast cells, resulting in kinase activation and growth arrest. Yeast cells expressing the Nef-Hck complex were used to screen a library of small heterocyclic compounds for their ability to rescue growth inhibition. The screen identified a dihydrobenzo-1,4-dioxin-substituted analog of 2-quinoxalinyl-3-aminobenzene-sulfonamide (DQBS) as a potent inhibitor of Nef-dependent HIV-1 replication and MHC-I downregulation in T-cells. Docking studies predicted direct binding of DQBS to Nef which was confirmed in differential scanning fluorimetry assays with recombinant purified Nef protein. DQBS also potently inhibited the replication of HIV-1 NL4-3 chimeras expressing Nef alleles representative of all M-group HIV-1 clades.

Conclusions: Our findings demonstrate the utility of a yeast-based growth reversion assay for the identification of small molecule Nef antagonists. Inhibitors of Nef function discovered with this assay, such as DQBS, may complement the activity of current antiretroviral therapies by enabling immune recognition of HIV-infected cells through the rescue of cell surface MHC-I.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Anti-HIV Agents / isolation & purification
  • Anti-HIV Agents / pharmacology*
  • Benzenesulfonamides
  • Drug Evaluation, Preclinical / methods*
  • Humans
  • Molecular Docking Simulation
  • Protein Binding / drug effects
  • Proto-Oncogene Proteins c-hck / antagonists & inhibitors*
  • Proto-Oncogene Proteins c-hck / genetics
  • Quinoxalines / isolation & purification
  • Quinoxalines / pharmacology*
  • Saccharomyces cerevisiae / drug effects*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / growth & development
  • Sulfonamides / isolation & purification
  • Sulfonamides / pharmacology*
  • nef Gene Products, Human Immunodeficiency Virus / antagonists & inhibitors*
  • nef Gene Products, Human Immunodeficiency Virus / genetics

Substances

  • Anti-HIV Agents
  • Quinoxalines
  • Sulfonamides
  • nef Gene Products, Human Immunodeficiency Virus
  • nef protein, Human immunodeficiency virus 1
  • HCK protein, human
  • Proto-Oncogene Proteins c-hck