Synergistic Inhibition of HIV-1 Reverse Transcriptase and HIV-1 Replication by Combining Trovirdine with AZT, ddl and ddC in Vitro

1996 ◽  
Vol 7 (5) ◽  
pp. 221-229 ◽  
Author(s):  
H. Zhang ◽  
L. Vrang ◽  
C. Rydergård ◽  
C. Åhgren ◽  
B. Öberg
Keyword(s):  
Reverse Transcriptase ◽  
Synergistic Effects ◽  
Inhibitory Effect ◽  
Molar Ratio ◽  
Immunodeficiency Virus ◽  
A Cell ◽  
Infected Cells ◽  
Rt Inhibitors ◽  
Hiv 1

Trovirdine (LY300046·HCI) is a potent and selective non-nucleoside human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) inhibitor (Åhgren et al., Antimicrob Ag Chemother 39: 1329, 1995). Combinations of trovirdine with other RT inhibitors, AZT, ddC., ddl and their triphosphates, were studied as well as the pyrophosphate analogue PFA in both cell-free HIV-1 polymerase assays and HIV-1-infected MT-4 cell cultures. Synergistic effects and weak synergism were observed both using RT and HIV-1 - infected cells and using different HIV-1 RT mutants and HIV-1 drug-resistant variants known to be resistant to the inhibitory effects of trovirdine. The best combination with substantial synergism was ddC-TP and trovirdine at a 20:1 molar ratio combination in a cell-free enzyme assay. This combination showed the weak synergy in MT-4 cells. Synergism was judged by the median-effect method. The inhibitory effect of trovirdine was independent of increased concentrations of AZT triphosphate and ddC triphosphate implying that trovirdine acts in a mutually exclusive manner with AZT-TP and ddC-TP as determined by the Dixon plot. The combination effects were expressed by the combination index (Cl) using end points of 50%, 70% and 90% inhibition of HIV-1 RT activity and HIV-1 replication in MT-4 cells.

scholarly journals Glycine-Amide Is an Active Metabolite of the Antiretroviral Tripeptide Glycyl-Prolyl-Glycine-Amide

2005 ◽  
Vol 49 (1) ◽  
pp. 40-44 ◽  
Author(s):  
Elin Andersson ◽  
Peter Horal ◽  
Alenka Jejcic ◽  
Stefan Höglund ◽  
Jan Balzarini ◽  
...  
Keyword(s):  
Serial Passage ◽  
Inhibitory Effect ◽  
Capsid Formation ◽  
Transmission Electron ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Simplex Virus ◽  
Hiv 1

ABSTRACT The chemically modified tripeptide glycyl-prolyl-glycine-amide (GPG-NH2) inhibits replication of human immunodeficiency virus (HIV) type 1 (HIV-1) in vitro, probably by interfering with capsid formation. The aim of the present study was to determine whether the metabolites glycyl-proline (GP-OH), glycine (G-OH), prolyl-glycine-amide (PG-NH2), proline (P-OH), and glycine-amide (G-NH2) from proteolytic cleavage may inhibit the replication of HIV-1 in vitro. PG-NH2 has previously been shown to have a modest effect on HIV-1 replication. In the present study we show that G-NH2 exhibits a pronounced inhibitory effect on HIV-1. This effect was not due to a decrease in cell proliferation or viability and could not be shown for herpes simplex virus type 1. The G-NH2 concentration that inhibited virus replication by 50% (IC50) was equimolar to that of GPG-NH2 and ranged from 3 to 41 μM. Transmission electron microscopy revealed that the effect of G-NH2 on HIV-1 morphology was equivalent to that of GPG-NH2 and showed disarranged capsid structures, indicating interference with capsid formation. Serial passage of HIV-infected cells with G-NH2 for more than 20 subcultivations did not decrease the susceptibility to the compound. The results from this study suggest that GPG-NH2 might act as a prodrug and that G-NH2 is an active antiretroviral metabolite.

Imidazo[1,5-b]Pyridazine-D4T Conjugates: Synthesis and Anti-Human Immunodeficiency Virus Evaluation

1998 ◽  
Vol 9 (3) ◽  
pp. 205-223 ◽  
Author(s):  
M Renoud-Grappin ◽  
C Fossey ◽  
G Fontaine ◽  
D Ladurée ◽  
AM Aubertin ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Clear Trend ◽  
The Third ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Rt Inhibitors ◽  
Anti Hiv ◽  
Hiv 1

In an attempt to combine the human immunodeficiency virus type 1 (HIV-D-inhibitory capacity of 2′,3 -dideoxy-2,3 -didehydronucleoside analogues [nucleoside reverse transcriptase (RT) inhibitors; NRTI] and non-nucleoside RT inhibitors (NNRTI), we have designed, synthesized and evaluated for their anti-HIV activity several heterodimers of the general formula [d4T]-NH-(CH2)n-NH-[imidazo[1,5–b]pyridazine]. The synthesis of these heterodimers was conducted in three parts. The first part focused on the synthesis of the NRTI. The second part was devoted to the NNRTI and the NNRTI linked to appropriate spacers; [NNRTI]-NH-(CH2)n-NH2. In the third part, the condensation between the NRTI and the [NNRTI]-NH-(CH2)n-NH2 was performed. The in vitro inhibitory activities against HIV-1 of the [d4T]-NH-(CH2)n-NH-[imidazo[1,5–b]pyridazine] heterodimers were found to be comparable to that of d4T (stavudine) in HIV-infected cells. Moreover, the heterodimers were endowed with anti-HlV-2 activity and with anti-nevirapine-resistant HIV-1 activity. None of the heterodimers proved markedly cytotoxic to CEM-SS or MT-4 cells. There was not a clear trend toward antiviral potency on lengthening the methylene spacer in the [d4T]-NH-(CH2)n-NH-[imidazo[1,5–b]pyridazine] heterodimers.

Combination of mutations in human immunodeficiency virus type 1 reverse transcriptase required for resistance to the carbocyclic nucleoside 1592U89.

1997 ◽  
Vol 41 (5) ◽  
pp. 1094-1098 ◽  
Author(s):  
M Tisdale ◽  
T Alnadaf ◽  
D Cousens
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
In Vitro Selection ◽  
Fold Reduction ◽  
Immunodeficiency Virus ◽  
Rt Inhibitors ◽  
Carbocyclic Nucleoside ◽  
Hiv 1

The carbocyclic nucleoside 1592U89 is a selective inhibitor of the human immunodeficiency virus (HIV), targeting the reverse transcriptase (RT). In vitro selection studies were undertaken to generate resistant variants with both HIV type 1 (HIV-1) wild-type strain HIV-1(HXB2) and 3'-azido-3'-deoxythymidine (AZT)-resistant strain HIV-1(RTMC). At least two or three mutations in RT were required to produce a 10-fold reduction in susceptibility. The first RT mutation selected was at codon 184, methionine (M) to valine (V), for HIV-1(HXB2) and HIV-1(RTMC), conferring two- and fivefold resistance, respectively. Two additional mutations were selected with HIV-1(HXB2), either leucine (L) 74 to V and lysine (K) 65 to arginine (R) (first-passage series) or L74 to V and tyrosine (Y) 115 to phenylalanine (F) (second-passage series). Cloned variants, obtained from the 1592U89 selection, were either double RT mutants 65R/184V and 74V/184V or triple RT mutant 74V/115Y/184V. Molecular clones were constructed with single, double, and triple combinations of these mutations for resistance analysis with different RT inhibitors. Each individual mutation conferred only low-level resistance (two- to fourfold) to 1592U89 in the HXB2 background. Double mutants containing the 184V mutation and triple mutants showed slightly greater levels of resistance to 1592U89 (7- to 11-fold). Some of the 1592U89-resistant variants were cross-resistant with 2',3'-dideoxycytidine, 2',3'-dideoxyinosine, and (-)-2'-deoxy-3'-thiacytidine, but none were resistant to 2',3'-didehydro-3'-deoxythymidine or AZT.

scholarly journals Reverse Transcriptase Inhibitors Can Selectively Block the Synthesis of Differently Sized Viral DNA Transcripts in Cells Acutely Infected with Human Immunodeficiency Virus Type 1

1999 ◽  
Vol 73 (8) ◽  
pp. 6700-6707 ◽  
Author(s):  
Yudong Quan ◽  
Liwei Rong ◽  
Chen Liang ◽  
Mark A. Wainberg
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Reverse Transcription ◽  
Viral Dna ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Rt Inhibitors ◽  
Hiv 1

ABSTRACT We have recently reported that the in vitro inhibition of human immunodeficiency virus type 1 (HIV-1) reverse transcription by inhibitors of reverse transcriptase (RT) occurred most efficiently when the expected DNA products of RT reactions were long (Quan et al., Nucleic Acids Res. 26:5692–5698, 1998). Here, we have used a quantitative PCR to analyze HIV-1 reverse transcription within acutely infected cells treated with RT inhibitors. We found that levels of minus-strand strong-stop DNA [(−)ssDNA] formed in acutely infected MT2 cells were only slightly reduced if cells were infected with viruses that had been generated in the presence of either azidothymidine or nevirapine (5 μM) and maintained in the presence of this drug throughout the viral adsorption period and thereafter. Control experiments in which virus inoculation of cells was performed at 4°C, followed directly by cell extraction, showed that less than 1% of total (−)ssDNA within acutely infected cells was attributable to its presence within adsorbed virions. In contrast, synthesis of intermediate-length reverse-transcribed DNA products decreased gradually as viral DNA strand elongation took place in the presence of either of these inhibitors. This establishes that nucleoside and nonnucleoside RT inhibitors can exert similar temporal impacts in regard to inhibition of viral DNA synthesis. Generation of full-length viral DNA, as expected, was almost completely blocked in the presence of these antiviral drugs. These results provide insight into the fact that high concentrations of drugs are often needed to yield inhibitory effects in cell-free RT assays performed with short templates, whereas relatively low drug concentrations are often strongly inhibitory in cellular systems.

scholarly journals Extended Interactions between HIV-1 Viral RNA and tRNALys3 Are Important to Maintain Viral RNA Integrity

2020 ◽  
Vol 22 (1) ◽  
pp. 58
Author(s):  
Thomas Gremminger ◽  
Zhenwei Song ◽  
Juan Ji ◽  
Avery Foster ◽  
Kexin Weng ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Potential Interaction ◽  
Viral Rna ◽  
Primer Binding Site ◽  
Rna Integrity ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Extended Interaction ◽  
Hiv 1

The reverse transcription of the human immunodeficiency virus 1 (HIV-1) initiates upon annealing of the 3′-18-nt of tRNALys3 onto the primer binding site (PBS) in viral RNA (vRNA). Additional intermolecular interactions between tRNALys3 and vRNA have been reported, but their functions remain unclear. Here, we show that abolishing one potential interaction, the A-rich loop: tRNALys3 anticodon interaction in the HIV-1 MAL strain, led to a decrease in viral infectivity and reduced the synthesis of reverse transcription products in newly infected cells. In vitro biophysical and functional experiments revealed that disruption of the extended interaction resulted in an increased affinity for reverse transcriptase (RT) and enhanced primer extension efficiency. In the absence of deoxyribose nucleoside triphosphates (dNTPs), vRNA was degraded by the RNaseH activity of RT, and the degradation rate was slower in the complex with the extended interaction. Consistently, the loss of vRNA integrity was detected in virions containing A-rich loop mutations. Similar results were observed in the HIV-1 NL4.3 strain, and we show that the nucleocapsid (NC) protein is necessary to promote the extended vRNA: tRNALys3 interactions in vitro. In summary, our data revealed that the additional intermolecular interaction between tRNALys3 and vRNA is likely a conserved mechanism among various HIV-1 strains and protects the vRNA from RNaseH degradation in mature virions.

scholarly journals Novel Nonnucleoside Inhibitors That Select Nucleoside Inhibitor Resistance Mutations in Human Immunodeficiency Virus Type 1 Reverse Transcriptase

2006 ◽  
Vol 50 (8) ◽  
pp. 2772-2781 ◽  
Author(s):  
Zhijun Zhang ◽  
Michelle Walker ◽  
Wen Xu ◽  
Jae Hoon Shim ◽  
Jean-Luc Girardet ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Immunodeficiency Virus ◽  
Nonnucleoside Inhibitors ◽  
Rt Inhibitors ◽  
Hiv 1 ◽  
M184v Mutation

ABSTRACT Mutations in and around the catalytic site of the reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1) are associated with resistance to nucleoside RT inhibitors (NRTIs), whereas changes in the hydrophobic pocket of the RT are attributed to nonnucleoside RT inhibitor (NNRTI) resistance. In this study, we report a novel series of nonnucleoside inhibitors of HIV-1, exemplified by VRX-329747 and VRX-413638, which inhibit both NNRTI- and NRTI-resistant HIV-1 isolates. Enzymatic studies indicated that these compounds are HIV-1 RT inhibitors. Surprisingly, however, following prolonged (6 months) tissue culture selection, this series of nonnucleoside inhibitors did not select NNRTI-resistant mutations in HIV-1 RT. Rather, four mutations (M41L, A62T/V, V118I, and M184V) known to cause resistance to NRTIs and two additional novel mutations (S68N and G112S) adjacent to the catalytic site of the enzyme were selected. Although the M184V mutation appears to be the initial mutation to establish resistance, this mutation alone confers only a two- to fourfold decrease in susceptibility to VRX-329747 and VRX-413638. At least two additional mutations must accumulate for significant resistance. Moreover, while VRX-329747-selected viruses are resistant to lamivudine and emtricitabine due to the M184V mutation, they remain susceptible to zidovudine, stavudine, dideoxyinosine, abacavir, tenofovir, and efavirenz. These results directly demonstrate that VRX-329747 and VRX-413638 are novel nonnucleoside inhibitors of HIV-1 RT with the potential to augment current therapies.

scholarly journals The Late-Domain-Containing Protein p6 Is the Predominant Phosphoprotein of Human Immunodeficiency Virus Type 1 Particles

2002 ◽  
Vol 76 (3) ◽  
pp. 1015-1024 ◽  
Author(s):  
Barbara Müller ◽  
Tilo Patschinsky ◽  
Hans-Georg Kräusslich
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Metabolic Labeling ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
A Minor ◽  
Hiv 1

ABSTRACT The Gag-derived protein p6 of human immunodeficiency virus type 1 (HIV-1) plays a crucial role in the release of virions from the membranes of infected cells. It is presumed that p6 and functionally related proteins from other viruses act as adapters, recruiting cellular factors to the budding site. This interaction is mediated by so-called late domains within the viral proteins. Previous studies had suggested that virus release from the plasma membrane shares elements with the cellular endocytosis machinery. Since protein phosphorylation is known to be a regulatory mechanism in these processes, we have investigated the phosphorylation of HIV-1 structural proteins. Here we show that p6 is the major phosphoprotein of HIV-1 particles. After metabolic labeling of infected cells with [ortho- 32P]phosphate, we found that phosphorylated p6 from infected cells and from virus particles consisted of several forms, suggesting differential phosphorylation at multiple sites. Apparently, phosphorylation occurred shortly before or after the release of p6 from Gag and involved only a minor fraction of the total virion-associated p6 molecules. Phosphoamino acid analysis indicated phosphorylation at Ser and Thr, as well as a trace of Tyr phosphorylation, supporting the conclusion that multiple phosphorylation events do occur. In vitro experiments using purified virus revealed that endogenous or exogenously added p6 was efficiently phosphorylated by virion-associated cellular kinase(s). Inhibition experiments suggested that a cyclin-dependent kinase or a related kinase, most likely ERK2, was involved in p6 phosphorylation by virion-associated enzymes.

scholarly journals Potent Synergistic Anti-Human Immunodeficiency Virus (HIV) Effects Using Combinations of the CCR5 Inhibitor Aplaviroc with Other Anti-HIV Drugs

2008 ◽  
Vol 52 (6) ◽  
pp. 2111-2119 ◽  
Author(s):  
Hirotomo Nakata ◽  
Seth M. Steinberg ◽  
Yasuhiro Koh ◽  
Kenji Maeda ◽  
Yoshikazu Takaoka ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Synergistic Effects ◽  
Immunodeficiency Virus ◽  
Approved Drugs ◽  
Hiv Drugs ◽  
Nonparametric Statistical ◽  
Anti Hiv ◽  
Ccr5 Inhibitor ◽  
Hiv 1

ABSTRACT Aplaviroc (AVC), an experimental CCR5 inhibitor, potently blocks in vitro the infection of R5-tropic human immunodeficiency virus type 1 (R5-HIV-1) at subnanomolar 50% inhibitory concentrations. Although maraviroc is presently clinically available, further studies are required to determine the role of CCR5 inhibitors in combinations with other drugs. Here we determined anti-HIV-1 activity using combinations of AVC with various anti-HIV-1 agents, including four U.S. Food and Drug Administration-approved drugs, two CCR5 inhibitors (TAK779 and SCH-C) and two CXCR4 inhibitors (AMD3100 and TE14011). Combination effects were defined as synergistic or antagonistic when the activity of drug A combined with B was statistically greater or less, respectively, than the additive effects of drugs A and A combined and drugs B and B combined by using the Combo method, described in this paper, which provides (i) a flexible choice of interaction models and (ii) the use of nonparametric statistical methods. Synergistic effects against R5-HIV-1Ba-L and a 50:50 mixture of R5-HIV-1Ba-L and X4-HIV-1ERS104pre (HIV-1Ba-L/104pre) were seen when AVC was combined with zidovudine, nevirapine, indinavir, or enfuvirtide. Mild synergism and additivity were observed when AVC was combined with TAK779 and SCH-C, respectively. We also observed more potent synergism against HIV-1Ba-L/104pre when AVC was combined with AMD3100 or TE14011. The data demonstrate a tendency toward greater synergism with AVC plus either of the two CXCR4 inhibitors compared to the synergism obtained with combinations of AVC and other drugs, suggesting that the development of effective CXCR4 inhibitors may be important for increasing the efficacies of CCR5 inhibitors.

An Approach towards the Synthesis of Potential Metal-Chelating TSAO-T Derivatives as Bidentate Inhibitors of Human Immunodeficiency virus Type 1 Reverse Transcriptase

1998 ◽  
Vol 9 (5) ◽  
pp. 412-421 ◽  
Author(s):  
C Chamorro ◽  
M-J Camarasa ◽  
M-J Pérez-Pérez ◽  
E de Clercq ◽  
J Balzarini ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Parent Compound ◽  
Immunodeficiency Virus ◽  
Anti Hiv ◽  
Hiv 1

Novel derivatives of the potent human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) inhibitor TSAO-T have been designed, synthesized and tested for their in vitro antiretro-viral activity against HIV. These TSAO-T derivatives have been designed as potential bidentate inhibitors of HIV-1 RT, which combine in their structure the functionality of a non-nucleoside RT inhibitor (TSAO-T) and a bivalent ion-chelating moiety (a β-diketone moiety) linked through an appropriate spacer to the N-3 of thymine of TSAO-T . Some of the new compounds have an anti-HIV-1 activity comparable to that of the parent compound TSAO-T, but display a markedly increased antiviral selectivity. There was a clear relationship between antiviral activity and the length of the spacer group that links the TSAO molecule with the chelating moiety. A shorter spacer invariably resulted in increased antiviral potency. None of the TSAO-T derivatives were endowed with anti-HIV-2 activity.

scholarly journals Human Immunodeficiency Virus Types 1 and 2 Exhibit Comparable Sensitivities to Zidovudine and Other Nucleoside Analog Inhibitors In Vitro

2007 ◽  
Vol 52 (1) ◽  
pp. 329-332 ◽  
Author(s):  
Robert A. Smith ◽  
Geoffrey S. Gottlieb ◽  
Donovan J. Anderson ◽  
Crystal L. Pyrak ◽  
Bradley D. Preston
Keyword(s):  
Human Immunodeficiency Virus ◽  
Viral Replication ◽  
Reverse Transcriptase ◽  
Antiviral Therapy ◽  
Nucleoside Analogs ◽  
Nucleoside Analog ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Indicator Cell

ABSTRACT Using an indicator cell assay that directly quantifies viral replication, we show that human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2, respectively) exhibit similar sensitivities to 3′-azido-3′-deoxythymidine (zidovudine) as well as other nucleoside analog inhibitors of reverse transcriptase. These data support the use of nucleoside analogs for antiviral therapy of HIV-2 infection.

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