title: Synthesis and evaluation of orally active small molecule HIV-1 Nef antagonists.
abstract: The HIV-1 Nef accessory factor enhances viral replication and promotes immune system evasion of HIV-infected cells, making it an attractive target for drug discovery. Recently we described a novel class of diphenylpyrazolodiazene compounds that bind directly to Nef in vitro and inhibit Nef-dependent HIV-1 infectivity and replication in cell culture. However, these first-generation Nef antagonists have several structural liabilities, including an azo linkage that led to poor oral bioavailability. The azo group was therefore replaced with either a one- or two-carbon linker. The resulting set of non-azo analogs retained nanomolar binding affinity for Nef by surface plasmon resonance, while inhibiting HIV-1 replication with micromolar potency in cell-based assays without cytotoxicity. Computational docking studies show that these non-azo analogs occupy the same predicted binding site within the HIV-1 Nef dimer interface as the original azo compound. Computational methods also identified a hot spot for inhibitor binding within this site that is defined by conserved HIV-1 Nef residues Asp108, Leu112, and Pro122. Pharmacokinetic evaluation of the non-azo B9 analogs in mice showed that replacement of the azo linkage dramatically enhanced oral bioavailability without substantially affecting plasma half-life or clearance. The improved oral bioavailability of non-azo diphenylpyrazolo Nef antagonists provides a starting point for further drug lead optimization in support of future efficacy testing in animal models of HIV/AIDS.
authors: Department of Microbiology and Molecular Genetics, University of Pittsburgh School of School of Medicine, Pittsburgh, PA 15219 USA.
authors: Lori A
authors: LA
authors: Emert-Sedlak
authors: Fox Chase Chemical Diversity Center, Inc., Doylestown, PA 18902 USA.
authors: H Marie
authors: HM
authors: Loughran
authors: Department of Microbiology and Molecular Genetics, University of Pittsburgh School of School of Medicine, Pittsburgh, PA 15219 USA.
authors: Haibin
authors: H
authors: Shi
authors: Conifer Point Pharmaceuticals, Doylestown, PA 18902 USA.
authors: John L
authors: JL
authors: Kulp
authors: Department of Microbiology and Molecular Genetics, University of Pittsburgh School of School of Medicine, Pittsburgh, PA 15219 USA.
authors: Sherry T
authors: ST
authors: Shu
authors: Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, Pittsburgh, PA 15261 USA.|University of Pittsburgh Drug Discovery Institute, Pittsburgh, PA 15260 USA.
authors: Jielu
authors: J
authors: Zhao
authors: Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, Pittsburgh, PA 15261 USA.|University of Pittsburgh Drug Discovery Institute, Pittsburgh, PA 15260 USA.|Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260 USA.
authors: Billy W
authors: BW
authors: Day
authors: Fox Chase Chemical Diversity Center, Inc., Doylestown, PA 18902 USA.
authors: Jay E
authors: JE
authors: Wrobel
authors: Fox Chase Chemical Diversity Center, Inc., Doylestown, PA 18902 USA.
authors: Allen B
authors: AB
authors: Reitz
authors: Department of Microbiology and Molecular Genetics, University of Pittsburgh School of School of Medicine, Pittsburgh, PA 15219 USA.
authors: Thomas E
authors: TE
authors: Smithgall
mesh_terms: D000284:Administration, Oral; D000818:Animals; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000138:chemical synthesis* / Q000494:pharmacology*; D001665:Binding Sites / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015497:HIV-1 / Q000187:drug effects; D051379:Mice; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D008968:Molecular Conformation; D062105:Molecular Docking Simulation; D054852:Small Molecule Libraries / Q000008:administration & dosage / Q000138:chemical synthesis / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured; D014779:Virus Replication / Q000187:drug effects; D054311:nef Gene Products, Human Immunodeficiency Virus / Q000037:antagonists & inhibitors*
chemical_list: D019380:Anti-HIV Agents; D054852:Small Molecule Libraries; D054311:nef Gene Products, Human Immunodeficiency Virus
keywords: Antiretroviral drug discovery; HIV Nef; HIV-1; Nef inhibitors