Correction to Synthesis, Antiviral Potency, in Vitro ADMET, and X-ray Structure of Potent CD4 Mimics as Entry Inhibitors That Target the Phe43 Cavity of HIV-1 gp120

ABSTRACT Atazanavir, which is marketed as REYATAZ, is the first human immunodeficiency virus type 1 (HIV-1) protease inhibitor approved for once-daily administration. As previously reported, atazanavir offers improved inhibitory profiles against several common variants of HIV-1 protease over those of the other peptidomimetic inhibitors currently on the market. This work describes the X-ray crystal structures of complexes of atazanavir with two HIV-1 protease variants, namely, (i) an enzyme optimized for resistance to autolysis and oxidation, referred to as the cleavage-resistant mutant (CRM); and (ii) the M46I/V82F/I84V/L90M mutant of the CRM enzyme, which is resistant to all approved HIV-1 protease inhibitors, referred to as the inhibitor-resistant mutant. In these two complexes, atazanavir adopts distinct bound conformations in response to the V82F substitution, which may explain why this substitution, at least in isolation, has yet to be selected in vitro or in the clinic. Because of its nearly symmetrical chemical structure, atazanavir is able to make several analogous contacts with each monomer of the biological dimer.

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Binding Mode Characterization of NBD Series CD4-Mimetic HIV-1 Entry Inhibitors by X-Ray Structure and Resistance Study

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.03339-14 ◽

2014 ◽

Vol 58 (9) ◽

pp. 5478-5491 ◽

Cited By ~ 23

Author(s):

Francesca Curreli ◽

Young Do Kwon ◽

Hongtao Zhang ◽

Yongping Yang ◽

Daniel Scacalossi ◽

...

Keyword(s):

Salt Bridge ◽

Binding Mode ◽

Piperidine Ring ◽

X Ray ◽

Entry Inhibitors ◽

Biophysical Studies ◽

Close Proximity ◽

Gp120 Core ◽

Hiv 1

ABSTRACTWe previously identified two small-molecule CD4 mimetics—NBD-556 and NBD-557—and synthesized a series of NBD compounds that resulted in improved neutralization activity in a single-cycle HIV-1 infectivity assay. For the current investigation, we selected several of the most active compounds and assessed their antiviral activity on a panel of 53 reference HIV-1 Env pseudoviruses representing diverse clades of clinical isolates. The selected compounds inhibited tested clades with low-micromolar potencies. Mechanism studies indicated that they act as CD4 agonists, a potentially unfavorable therapeutic trait, in that they can bind to the gp120 envelope glycoprotein and initiate a similar physiological response as CD4. However, one of the compounds, NBD-09027, exhibited reduced agonist properties, in both functional and biophysical studies. To understand the binding mode of these inhibitors, we first generated HIV-1-resistant mutants, assessed their behavior with NBD compounds, and determined the X-ray structures of two inhibitors, NBD-09027 and NBD-10007, in complex with the HIV-1 gp120 core at ∼2-Å resolution. Both studies confirmed that the NBD compounds bind similarly to NBD-556 and NBD-557 by inserting their hydrophobic groups into the Phe43 cavity of gp120. The basic nitrogen of the piperidine ring is located in close proximity to D368 of gp120 but it does not form any H-bond or salt bridge, a likely explanation for their nonoptimal antagonist properties. The results reveal the structural and biological character of the NBD series of CD4 mimetics and identify ways to reduce their agonist properties and convert them to antagonists.

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Maraviroc and Other HIV-1 Entry Inhibitors Exhibit a Class-Specific Redistribution Effect That Results in Increased Extracellular Viral Load

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00409-12 ◽

2012 ◽

Vol 56 (8) ◽

pp. 4154-4160 ◽

Cited By ~ 17

Author(s):

Victor G. Kramer ◽

Susan M. Schader ◽

Maureen Oliveira ◽

Susan P. Colby-Germinario ◽

Daniel A. Donahue ◽

...

Keyword(s):

Viral Load ◽

Clinical Success ◽

Antiretroviral Drugs ◽

Virus Infectivity ◽

Reverse Transcriptase Enzyme ◽

Entry Inhibitors ◽

Hiv 1 ◽

Entry Inhibition ◽

Redistribution Effect

ABSTRACTHIV entry inhibitors, such as maraviroc (MVC), prevent cell-free viruses from entering the cells. In clinical trials, patients who were treated with MVC often displayed viral loads that were above the limit of conventional viral load detection compared to efavirenz-based regimens. We hypothesize that viruses blocked by entry inhibitors may be redistributed to plasma, where they artificially increase viral load measurements compared to those with the use of antiretroviral drugs (ARVs) that act intracellularly. We infected PM-1 cells with CCR5-tropic HIV-1 BaL or CXCR4-tropic HIV-1 NL4-3 in the presence of inhibitory concentrations of efavirenz, raltegravir, enfuvirtide, maraviroc, and AMD3100, the latter three being entry inhibitors. Supernatant viral load, reverse transcriptase enzyme activity, and intracellular nucleic acid levels were measured at times up to 24 h postinfection. Infectivity of redistributed dual-tropic HIV-1 was assessed using TZM-bl cells. Extracellular viral load analysis revealed that entry inhibitor-treated cells had higher levels of virus in the supernatant than the cells treated with other ARVs at 8 h postinfection. By 24 h, the supernatant viral load was still higher for entry inhibitors than other ARVs. We observed a correlation between viral load and the step of entry inhibition. Dual-tropic virus infectivity was undiminished utilizing the CCR5 coreceptor following redistribution by CXCR4 entry inhibition. Thisin vitromodel indicates that entry inhibitors exhibit a redistribution effect unseen with intracellular ARV drugs. Based on these results, the effectiveness of some entry inhibitors may be underestimated if plasma viral load is used as a sole indicator of clinical success.

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env Chimeric Virus Technology for Evaluating Human Immunodeficiency Virus Susceptibility to Entry Inhibitors

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.46.12.3954-3962.2002 ◽

2002 ◽

Vol 46 (12) ◽

pp. 3954-3962 ◽

Cited By ~ 30

Author(s):

Valery Fikkert ◽

Peter Cherepanov ◽

Kristel Van Laethem ◽

Anke Hantson ◽

Barbara Van Remoortel ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Chimeric Virus ◽

Cross Resistance ◽

Wild Type ◽

Phenotypic Analysis ◽

Phenotypic Resistance ◽

Entry Inhibitors ◽

Immunodeficiency Virus ◽

Hiv 1

ABSTRACT We describe the development of chimeric virus technology (CVT) for human immunodeficiency virus (HIV) type 1 (HIV-1) env genes gp120, gp41, and gp160 for evaluation of the susceptibilities of HIV to entry inhibitors. This env CVT allows the recombination of env sequences derived from different strains into a proviral wild-type HIV-1 clone (clone NL4.3) from which the corresponding env gene has been deleted. An HIV-1 strain (strain NL4.3) resistant to the fusion inhibitor T20 (strain NL4.3/T20) was selected in vitro in the presence of T20. AMD3100-resistant strain NL3.4 (strain NL4.3/AMD3100) was previously selected by De Vreese et al. (K. De Vreese et al., J. Virol. 70:689-696, 1996). NL4.3/AMD3100 contains several mutations in its gp120 gene (De Vreese et al., J. Virol. 70:689-696, 1996), whereas NL4.3/T20 has mutations in both gp120 and gp41. Phenotypic analysis revealed that NL4.3/AMD3100 lost its susceptibility to dextran sulfate, AMD3100, AMD2763, T134, and T140 but not its susceptibility to T20, whereas NL4.3/T20 lost its susceptibility only to the inhibitory effect of T20. The recombination of gp120 of NL4.3/AMD3100 and gp41 of NL4.3/T20 or recombination of the gp160 genes of both strains into a wild-type background reproduced the phenotypic (cross-)resistance profiles of the corresponding strains selected in vitro. These data imply that mutations in gp120 alone are sufficient to reproduce the resistance profile of NL4.3/AMD3100. The same can be said for gp41 in relation to NL4.3/T20. In conclusion, we demonstrate the use of env CVT as a research tool in the delineation of the region important for the phenotypic (cross-)resistance of HIV strains to entry inhibitors. In addition, we obtained a proof of principle that env CVT can become a helpful diagnostic tool in assessments of the phenotypic resistance of clinical HIV isolates to HIV entry inhibitors.

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TAK-220, a Novel Small-Molecule CCR5 Antagonist, Has Favorable Anti-Human Immunodeficiency Virus Interactions with Other Antiretrovirals In Vitro

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.49.8.3483-3485.2005 ◽

2005 ◽

Vol 49 (8) ◽

pp. 3483-3485 ◽

Cited By ~ 23

Author(s):

Cécile L. Tremblay ◽

Françoise Giguel ◽

Yongbiao Guan ◽

Ting-Chao Chou ◽

Katsunori Takashima ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Ccr5 Antagonist ◽

Entry Inhibitors ◽

New Class ◽

Immunodeficiency Virus ◽

Virus Interactions ◽

Anti Hiv ◽

Hiv 1

ABSTRACT TAK-220 is a CCR5 antagonist, part of the new class of anti-human immunodeficiency virus type 1 (anti-HIV-1) entry inhibitors. We evaluated the anti-HIV-1 interactions between TAK-220 and various antiretrovirals in vitro. Synergy was observed with all drugs at the 90 and 95% inhibitory concentrations. The favorable drug interactions observed suggest that further clinical evaluation is warranted.

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New triazolothiadiazole and triazolothiadiazine derivatives as kinesin Eg5 and HIV inhibitors: synthesis, QSAR and modeling studies

Zeitschrift für Naturforschung B ◽

10.1515/znb-2014-0162 ◽

2015 ◽

Vol 70 (1) ◽

pp. 47-58 ◽

Cited By ~ 5

Author(s):

Imtiaz Khan ◽

Shahid Hameed ◽

Najim A. Al-Masoudi ◽

Nabeel A. Abdul-Reda ◽

Jim Simpson

Keyword(s):

Amino Acids ◽

Spectroscopic Analysis ◽

Docking Study ◽

Aromatic Acids ◽

X Ray ◽

Atpase Assay ◽

Phenacyl Bromides ◽

Kinesin Eg5 ◽

Hiv 1

AbstractA new series of fused 1,2,4-triazoles, namely 6-aryl-3-(furan-2-yl)-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles 3a–h and 4a–f as well as 6-aryl-3-(furan-2-yl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines 5a–h, were synthesized by the condensation of 4-amino-5-(furan-2-yl)-4H-1,2,4-triazole-3-thiol (2) with substituted aromatic acids and phenacyl bromides, respectively. The structures of the newly synthesized compounds were established using spectroscopic analysis, while that of 3e was confirmed independently by a single-crystal X-ray structure determination. The compounds were evaluated for their antiviral activity against the replication of HIV-1 and HIV-2 in MT-4 cells using an MTT assay. In a docking study, 4b interacted with several amino acids in the reverse transcriptase (RT) binding site of HIV-1. Some new analogues were selected for evaluation of their Eg5 inhibitory activity using an in vitro malachite green ATPase assay. The QSAR of these new analogues was studied as well.

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Polymer-coupled Systems for Blocking the Viral Fusion 1. Modeling in silico the in vitro HIV-1 Entry Inhibitors

Antiviral Research ◽

10.1016/j.antiviral.2011.03.075 ◽

2011 ◽

Vol 90 (2) ◽

pp. A46 ◽

Cited By ~ 1

Author(s):

V. Tsvetkov ◽

A. Veselovski ◽

A. Serbin

Keyword(s):

In Silico ◽

Coupled Systems ◽

Viral Fusion ◽

Entry Inhibitors ◽

Hiv 1

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In vitro susceptibility to fostemsavir is not affected by long-term exposure to antiviral therapy in MDR HIV-1-infected patients

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkaa178 ◽

2020 ◽

Vol 75 (9) ◽

pp. 2547-2553 ◽

Cited By ~ 1

Author(s):

Francesco Saladini ◽

Alessia Giannini ◽

Federica Giammarino ◽

Franco Maggiolo ◽

Francesca Vichi ◽

...

Keyword(s):

In Vitro Susceptibility ◽

Viral Tropism ◽

Entry Inhibitors ◽

Optimal Screening ◽

Therapy Option ◽

Env Protein ◽

Aids Diagnosis ◽

Hiv 1 ◽

Phenotypic Susceptibility

Abstract Objectives Fostemsavir is the prodrug of the HIV-1 attachment inhibitor temsavir and is currently under clinical assessment in heavily treatment-experienced patients with limited therapeutic options. We evaluated the genotypic and phenotypic susceptibility to temsavir in a panel of samples collected from patients harbouring MDR strains enrolled in the Italian PRESTIGIO Registry. Methods Plasma samples from 24 patients were used for HIV-1 gp120 sequencing, while viral tropism and susceptibility to temsavir were assessed through a homemade phenotypic assay with pseudotyped viruses expressing patient-derived Env protein. Results Of the 24 patients enrolled, 18 (75%) were male, median (IQR) age was 55 years (52–61), time since HIV-1 diagnosis was 27 years (24–30), time on ART was 26 years (23–27) and 11 (46%) had a previous AIDS diagnosis. Exposure to entry inhibitors (maraviroc and/or enfuvirtide) had occurred in 19 (79%) patients. Among 23/24 gp120 sequences obtained, temsavir resistance-associated mutations (RAMs) were detected in three cases (two M426L and one S375N). Pseudotyped viruses were obtained from 23/24 samples and viral tropism was CXCR4-tropic, CCR5-tropic and dual/mixed-tropic in six, nine and eight cases, respectively. Phenotypic susceptibility to temsavir was comparable to the reference WT viruses NL4-3 and AD8 in all samples, irrespective of RAMs. Viral tropism and exposure to entry inhibitors did not impact temsavir susceptibility. Conclusions These data support the use of fostemsavir as a valuable therapy option in patients harbouring MDR virus. The role of laboratory testing in optimal screening of patients eligible for fostemsavir treatment remains to be investigated.

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