title: Discovery of a small molecule Tat-trans-activation-responsive RNA antagonist that potently inhibits human immunodeficiency virus-1 replication.
abstract: Antiretroviral therapy to treat AIDS uses molecules that target the reverse transcriptase and protease enzymes of human immunodeficiency virus, type 1 (HIV-1). A major problem associated with these treatments, however, is the emergence of drug-resistant strains. Thus, there is a compelling need to find drugs against other viral targets. One such target is the interaction between Tat, an HIV-1 regulatory protein essential for viral replication, and trans-activation-responsive (TAR) RNA. Here we describe the design and synthesis of an encoded combinatorial library containing 39,304 unnatural small molecules. Using a rapid high through-put screening technology, we identified 59 compounds. Structure-activity relationship studies led to the synthesis of 19 compounds that bind TAR RNA with high affinities. In the presence of a representative Tat-TAR inhibitor (5 microM TR87), we observed potent and sustained suppression of HIV replication in cultured cells over 24 days. The same concentration of this inhibitor did not exhibit any toxicity in cell cultures or in mice. TR87 was also shown to specifically disrupt Tat-TAR binding in vitro and inhibit Tat-mediated transcriptional activation in vitro and in vivo, providing a strong correlation between its activities and inhibition of HIV-1 replication. These results provide a structural scaffold for further development of new drugs, alone or in combination with other drugs, for treatment of HIV-1-infected individuals. Our results also suggest a general strategy for discovering pharmacophores targeting RNA structures that are essential in progression of other infectious, inflammatory, and genetic diseases.
authors.affiliation: Chemical Biology Program, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605-2324, USA.
authors.forename: Seongwoo
authors.initials: S
authors.lastname: Hwang
authors.forename: Natarajan
authors.initials: N
authors.lastname: Tamilarasu
authors.forename: Karen
authors.initials: K
authors.lastname: Kibler
authors.forename: Hong
authors.initials: H
authors.lastname: Cao
authors.forename: Akbar
authors.initials: A
authors.lastname: Ali
authors.forename: Yueh-Hsin
authors.initials: YH
authors.lastname: Ping
authors.forename: Kuan-Teh
authors.initials: KT
authors.lastname: Jeang
authors.forename: Tariq M
authors.initials: TM
authors.lastname: Rana
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology; D001331:Automation; D002219:Carbamates / Q000737:chemistry; D002478:Cells, Cultured; D002849:Chromatography, Gas; D004305:Dose-Response Relationship, Drug; D031541:Fluorescence Resonance Energy Transfer; D015696:Gene Products, tat / Q000737:chemistry*; D015497:HIV-1 / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008024:Ligands; D051379:Mice; D008954:Models, Biological; D008956:Models, Chemical; D015233:Models, Statistical; D009690:Nucleic Acid Conformation; D009842:Oligopeptides / Q000737:chemistry / Q000494:pharmacology*; D019151:Peptide Library; D011485:Protein Binding; D012313:RNA / Q000737:chemistry / Q000378:metabolism; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D013329:Structure-Activity Relationship; D015533:Transcriptional Activation; D054322:tat Gene Products, Human Immunodeficiency Virus
chemical_list: D000998:Antiviral Agents; D002219:Carbamates; D015696:Gene Products, tat; D008024:Ligands; D009842:Oligopeptides; D019151:Peptide Library; C478396:TR 87 compound; D054322:tat Gene Products, Human Immunodeficiency Virus; D012313:RNA; D012194:RNA-Directed DNA Polymerase