6-[1-(4-Fluorophenyl)methyl-1 H-pyrrol-2-yl)]-2,4-dioxo-5-hexenoic acid ethyl ester a novel diketo acid derivative which selectively inhibits the HIV-1 viral replication in cell culture and the ribonuclease H activity in vitro

• Published in: Antiviral research 2005-02, Vol.65 (2), p.117-124
• Main Authors: Tramontano, Enzo, Esposito, Francesca, Badas, Roberta, Di Santo, Roberto, Costi, Roberta, La Colla, Paolo
• Format: Article
• Language: English
• Subjects: AIDS; Anti-HIV Agents - chemistry; Anti-HIV Agents - metabolism; Anti-HIV Agents - pharmacology; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antiviral agents; Biological and medical sciences; Caproates - chemistry; Caproates - metabolism; Caproates - pharmacology; Diketoacid; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - metabolism; Enzyme Inhibitors - pharmacology; Esters - chemistry; Esters - metabolism; Esters - pharmacology; HIV; HIV-1 - drug effects; HIV-1 - physiology; Humans; In Vitro Techniques; Kinetics; Magnesium - metabolism; Medical sciences; Pharmacology. Drug treatments; Pyrroles - chemistry; Pyrroles - metabolism; Pyrroles - pharmacology; Reverse transcriptase; Reverse Transcriptase Inhibitors - chemistry; Reverse Transcriptase Inhibitors - pharmacology; Ribonuclease H; Ribonuclease H - antagonists & inhibitors; Virus Replication - drug effects
• ISSN: 0166-3542; 1872-9096
• DOI: 10.1016/j.antiviral.2004.11.002

The human immunodeficiency virus-type 1 (HIV-1) reverse transcriptase (RT) is a multifunctional enzyme which displays DNA polymerase activity, which recognizes RNA and DNA templates, and a degradative ribonuclease H (RNase H) activity. While both RT functions are required for retroviral replication, until now only the polymerase function has been widely explored as drug target. We have identified a novel diketo acid derivative, 6-[1-(4-fluorophenyl)methyl-1 H-pyrrol-2-yl)]-2,4-dioxo-5-hexenoic acid ethyl ester (RDS 1643), which inhibits in enzyme assays the HIV-1 RT-associated polymerase-independent RNase H activity but has no effect on the HIV-1 RT-associated RNA-dependent DNA polymerase (RDDP) activity and on the RNase H activities displayed by the Avian Myeloblastosis Virus and E. coli. Time-dependence studies revealed that the compound is active independently on the order of its addition to the reaction mixture, and inhibition kinetics studies demonstrated that RDS 1643 inhibits the RNase H activity noncompetitively, with a K I value of 17 μM. When RDS 1643 was combined with non-nucleoside RT inhibitors (NNRTI), such as efavirenz and nevirapine, results indicated that RDS 1643 does not affect the NNRTIs anti-RDDP activity and that, vice versa, the NNRTIs do not alter the RNase H inhibition by RDS 1643. When assayed on the viral replication in cell-based assays, RDS 1643 inhibited the HIV-1 IIIB strain with an EC 50 of 14 μM. Similar results were obtained against the Y181C and Y181C/K103N HIV-1 NNRTI resistant mutant strains. RDS 1643 may be the first HIV-1 inhibitor selectively targeted to the viral RT-associated RNase-H function.