Inhibiting early-stage events in HIV-1 replication by small-molecule targeting of the HIV-1 capsid

J Virol. 2012 Aug;86(16):8472-81. doi: 10.1128/JVI.05006-11. Epub 2012 May 30.

Abstract

The HIV-1 capsid (CA) protein plays essential roles in both early and late stages of virl replication and has emerged as a novel drug target. We report hybrid structure-based virtual screening to identify small molecules with the potential to interact with the N-terminal domain (NTD) of HIV-1 CA and disrupt early, preintegration steps of the HIV-1 replication cycle. The small molecule 4,4'-[dibenzo[b,d]furan-2,8-diylbis(5-phenyl-1H-imidazole-4,2-diyl)]dibenzoic acid (CK026), which had anti-HIV-1 activity in single- and multiple-round infections but failed to inhibit viral replication in peripheral blood mononuclear cells (PBMCs), was identified. Three analogues of CK026 with reduced size and better drug-like properties were synthesized and assessed. Compound I-XW-053 (4-(4,5-diphenyl-1H-imidazol-2-yl)benzoic acid) retained all of the antiviral activity of the parental compound and inhibited the replication of a diverse panel of primary HIV-1 isolates in PBMCs, while displaying no appreciable cytotoxicity. This antiviral activity was specific to HIV-1, as I-XW-053 displayed no effect on the replication of SIV or against a panel of nonretroviruses. Direct interaction of I-XW-053 was quantified with wild-type and mutant CA protein using surface plasmon resonance and isothermal titration calorimetry. Mutation of Ile37 and Arg173, which are required for interaction with compound I-XW-053, crippled the virus at an early, preintegration step. Using quantitative PCR, we demonstrated that treatment with I-XW-053 inhibited HIV-1 reverse transcription in multiple cell types, indirectly pointing to dysfunction in the uncoating process. In summary, we have identified a CA-specific compound that targets and inhibits a novel region in the NTD-NTD interface, affects uncoating, and possesses broad-spectrum anti-HIV-1 activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-HIV Agents / chemical synthesis
  • Anti-HIV Agents / pharmacology*
  • Anti-HIV Agents / toxicity
  • Calorimetry
  • Capsid Proteins / antagonists & inhibitors*
  • Cell Line
  • HIV-1 / drug effects*
  • HIV-1 / physiology*
  • Humans
  • Microbial Sensitivity Tests
  • Protein Binding
  • Real-Time Polymerase Chain Reaction
  • Reverse Transcription / drug effects
  • Simian Immunodeficiency Virus / drug effects
  • Surface Plasmon Resonance
  • Virus Internalization / drug effects
  • Virus Replication / drug effects
  • Virus Uncoating / drug effects*

Substances

  • Anti-HIV Agents
  • Capsid Proteins