New Class of HIV-1 Integrase (IN) Inhibitors with a Dual Mode of Action

Manuel Tsiang,Gregg S Jones,Anita Niedziela-Majka,Elaine Kan,Eric B Lansdon,Wayne Huang,Magdeleine Hung,Dharmaraj Samuel,Nikolai Novikov,Yili Xu,Michael Mitchell,Hongyan Guo,Kerim Babaoglu,Xiaohong Liu,Romas Geleziunas,Roman Sakowicz

doi:10.1074/jbc.m112.347534

Manuel Tsiang, Gregg S Jones + Show 14 more

Open Access

https://doi.org/10.1074/jbc.m112.347534

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Abstract

tert-Butoxy-(4-phenyl-quinolin-3-yl)-acetic acids (tBPQA) are a new class of HIV-1 integrase (IN) inhibitors that are structurally distinct from IN strand transfer inhibitors but analogous to LEDGINs. LEDGINs are a class of potent antiviral compounds that interacts with the lens epithelium-derived growth factor (LEDGF) binding pocket on IN and were identified through competition binding against LEDGF. LEDGF tethers IN to the host chromatin and enables targeted integration of viral DNA. The prevailing understanding of the antiviral mechanism of LEDGINs is that they inhibit LEDGF binding to IN, which prevents targeted integration of HIV-1. We showed that in addition to the properties already known for LEDGINs, the binding of tBPQAs to the IN dimer interface inhibits IN enzymatic activity in a LEDGF-independent manner. Using the analysis of two long terminal repeat junctions in HIV-infected cells, we showed that the inhibition by tBPQAs occurs at or prior to the viral DNA 3'-processing step. Biochemical studies revealed that this inhibition operates by compound-induced conformational changes in the IN dimer that prevent proper assembly of IN onto viral DNA. For the first time, tBPQAs were demonstrated to be allosteric inhibitors of HIV-1 IN displaying a dual mode of action: inhibition of IN-viral DNA assembly and inhibition of IN-LEDGF interaction.

Highlights

Competitors of lens epithelium-derived growth factor (LEDGF) binding to HIV-1 integrase could prevent targeted integration to chromatin
LEDGINs are a class of potent antiviral compounds that interacts with the lens epithelium-derived growth factor (LEDGF) binding pocket on IN and were identified through competition binding against LEDGF
TBPQAs Are Potent Antiviral Compounds and Authentic Inhibitors of HIV-1 Integration—Three tert-Butoxy-(4-phenyl-quinolin-3-yl)-acetic acids (tBPQA), GS-A [52], GS-B [52], and GS-C [53], displayed high antiviral potency in MT-4, MT-2, and human monocytes with EC50 values ranging from 10 to 287 nM (Table 1). To assess whether these compounds were inhibitors of integration, their effects on the accumulation of 2-LTR circles, and the formation of integration junctions were determined in HIV-1-infected MT-2 cells (Table 1)

Summary

Background

Competitors of LEDGF binding to HIV-1 integrase could prevent targeted integration to chromatin. Results: LEDGF competitors like tBPQAs were found to inhibit integrase enzyme activity by preventing proper integraseviral DNA assembly. Significance: Interference with two distinct steps of integration through the same binding site represents a new antiviral paradigm. The prevailing understanding of the antiviral mechanism of LEDGINs is that they inhibit LEDGF binding to IN, which prevents targeted integration of HIV-1. Biochemical studies revealed that this inhibition operates by compound-induced conformational changes in the IN dimer that prevent proper assembly of IN onto viral DNA. TBPQAs were demonstrated to be allosteric inhibitors of HIV-1 IN displaying a dual mode of action: inhibition of IN-viral DNA assembly and inhibition of IN-LEDGF interaction. The atomic coordinates and structure factors (codes 4E1M and 4E1N) have been deposited in the Protein Data Bank, Research Collaboratory for Structural Bioinformatics, Rutgers University, New Brunswick, NJ (http://www.rcsb.org/)

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EXPERIMENTAL PROCEDURES

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DISCUSSION