title: A novel cell-based high-throughput screen for inhibitors of HIV-1 gene expression and budding identifies the cardiac glycosides.
abstract: OBJECTIVE
  Highly active antiretroviral therapy (HAART) is the mainstay of treatment for HIV-1 infection. While current HAART regimens have been extremely effective, issues of associated toxicity, cost and resistance remain and there is a need for novel antiretroviral compounds to complement the existing therapy. We sought to develop a novel high-throughput method for identifying compounds that block later steps in the life cycle not targeted by current therapy.
  
  
  METHODS
  We designed a high-throughput screen to identify inhibitors of post-integration steps in the HIV-1 life cycle. The screening method was applied to a library of compounds that included numerous FDA-approved small molecules.
  
  
  RESULTS
  Among the small molecules that inhibited late stages in HIV-1 replication were members of the cardiac glycoside family. We demonstrate that cardiac glycosides potently inhibit HIV-1 gene expression, thereby reducing the production of infectious HIV-1. We demonstrate that this inhibition is dependent upon the human Na(+)/K(+)-ATPase, but independent of cardiac glycoside-induced increases in intracellular Ca(2+).
  
  
  CONCLUSIONS
  We have validated a novel high-throughput screen to identify small molecule inhibitors of HIV-1 gene expression, virion assembly and budding. Using this screen, we have demonstrated that a number of FDA-approved compounds developed for other purposes potently inhibit HIV-1 replication, including the cardiac glycosides. Our work indicates that the entire cardiac glycoside family of drugs shows potential for antiretroviral drug development.
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Laird
authors.forename: Evelyn E
authors.initials: EE
authors.lastname: Eisele
authors.forename: S Alireza
authors.initials: SA
authors.lastname: Rabi
authors.forename: Daria
authors.initials: D
authors.lastname: Nikolaeva
authors.forename: Robert F
authors.initials: RF
authors.lastname: Siliciano
mesh_terms: D019380:Anti-HIV Agents / Q000494:pharmacology*; D002301:Cardiac Glycosides / Q000494:pharmacology*; D058492:Drug Repositioning; D015497:HIV-1 / Q000502:physiology*; D057166:High-Throughput Screening Assays; D006801:Humans; D014775:Virus Activation / Q000187:drug effects*; D057074:Virus Release / Q000187:drug effects*
chemical_list: D019380:Anti-HIV Agents; D002301:Cardiac Glycosides
keywords: HAART; antiretroviral; digoxin