scholarly journals Two Coselected Distal Mutations in HIV-1 Reverse Transcriptase (RT) Alter Susceptibility to Nonnucleoside RT Inhibitors and Nucleoside Analogs

2019 ◽  
Vol 93 (11) ◽  
Author(s):  
Paul L. Boyer ◽  
Kevin Melody ◽  
Steven J. Smith ◽  
Linda L. Dunn ◽  
Chris Kline ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Reverse Transcriptase ◽  
Active Site ◽  
Nucleoside Analogs ◽  
Transcriptase Inhibitor ◽  
Drug Resistant ◽  
Resistance Mutations ◽  
Hydrophobic Region ◽  
Nnrti Resistance ◽  
Hiv 1

ABSTRACTTwo mutations, G112D and M230I, were selected in the reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1) by a novel nonnucleoside reverse transcriptase inhibitor (NNRTI). G112D is located near the HIV-1 polymerase active site; M230I is located near the hydrophobic region where NNRTIs bind. Thus, M230I could directly interfere with NNRTI binding but G112D could not. Biochemical and virological assays were performed to analyze the effects of these mutations individually and in combination. M230I alone caused a reduction in susceptibility to NNRTIs, while G112D alone did not. The G112D/M230I double mutant was less susceptible to NNRTIs than was M230I alone. In contrast, both mutations affected the ability of RT to incorporate nucleoside analogs. We suggest that the mutations interact with each other via the bound nucleic acid substrate; the nucleic acid forms part of the polymerase active site, which is near G112D. The positioning of the nucleic acid is influenced by its interactions with the “primer grip” region and could be influenced by the M230I mutation.IMPORTANCEAlthough antiretroviral therapy (ART) is highly successful, drug-resistant variants can arise that blunt the efficacy of ART. New inhibitors that are broadly effective against known drug-resistant variants are needed, although such compounds might select for novel resistance mutations that affect the sensitivity of the virus to other compounds. Compound 13 selects for resistance mutations that differ from traditional NNRTI resistance mutations. These mutations cause increased sensitivity to NRTIs, such as AZT.

scholarly journals L74V increases the reverse transcriptase content of HIV-1 virions with non-nucleoside reverse transcriptase drug-resistant mutations L100I+K103N and K101E+G190S, which results in increased fitness

2013 ◽  
Vol 94 (7) ◽  
pp. 1597-1607 ◽  
Author(s):  
Jiong Wang ◽  
Dongge Li ◽  
Robert A. Bambara ◽  
Hongmei Yang ◽  
Carrie Dykes
Keyword(s):  
Reverse Transcriptase ◽  
Resistance Mutation ◽  
Transcriptase Inhibitor ◽  
Rnase H ◽  
Drug Resistant ◽  
Resistance Mutations ◽  
Nnrti Resistance ◽  
Reverse Transcriptase Inhibitor ◽  
Subsequent Addition ◽  
Hiv 1

The fitness of non-nucleoside reverse transcriptase inhibitor (NNRTI) drug-resistant reverse transcriptase (RT) mutants of HIV-1 correlates with the amount of RT in the virions and the RNase H activity of the RT. We wanted to understand the mechanism by which secondary NNRTI-resistance mutations, L100I and K101E, and the nucleoside resistance mutation, L74V, alter the fitness of K103N and G190S viruses. We measured the amount of RT in virions and the polymerization and RNase H activities of mutant RTs compared to wild-type, K103N and G190S. We found that L100I, K101E and L74V did not change the polymerization or RNase H activities of K103N or G190S RTs. However, L100I and K101E reduced the amount of RT in the virions and subsequent addition of L74V restored RT levels back to those of G190S or K103N alone. We conclude that fitness changes caused by L100I, K101E and L74V derive from their effects on RT content.

scholarly journals 4′-C-Methyl-2′-Deoxyadenosine and 4′-C-Ethyl-2′-Deoxyadenosine Inhibit HIV-1 Replication

2011 ◽  
Vol 55 (5) ◽  
pp. 2379-2389 ◽  
Author(s):  
B. Christie Vu ◽  
Paul L. Boyer ◽  
Maqbool A. Siddiqui ◽  
Victor E. Marquez ◽  
Stephen H. Hughes
Keyword(s):  
Reverse Transcriptase ◽  
Dna Synthesis ◽  
Cultured Cells ◽  
Nucleoside Analogs ◽  
Transcriptase Inhibitor ◽  
Resistance Mutations ◽  
Viral Dna ◽  
Infected Cells ◽  
Hiv 1

ABSTRACTIt is important to develop new anti-HIV drugs that are effective against the existing drug-resistant mutants. Because the excision mechanism is an important pathway for resistance to nucleoside analogs, we are preparing analogs that retain a 3′-OH and can be extended after they are incorporated by the viral reverse transcriptase. We show that 4′-C-alkyl-deoxyadenosine (4′-C-alkyl-dA) compounds can be phosphorylated in cultured cells and can inhibit the replication of HIV-1 vectors: 4′-C-methyl- and 4′-C-ethyl-dA show both efficacy and selectivity against HIV-1. The compounds are also effective against viruses that replicate using reverse transcriptases (RTs) that carry nucleoside reverse transcriptase inhibitor resistance mutations, with the exception of the M184V mutant. Analysis of viral DNA synthesis in infected cells showed that viral DNA synthesis is blocked by the incorporation of either 4′-C-methyl- or 4′-C-ethyl-2′-deoxyadenosine.In vitroexperiments with purified HIV-1 RT showed that 4′-C-methyl-2′-dATP can compete with dATP and that incorporation of the analog causes pausing in DNA synthesis. The 4′-C-ethyl compound also competes with dATP and shows a differential ability to block DNA synthesis on RNA and DNA templates. Experiments that measure the ability of the compounds to block DNA synthesis in infected cells suggest that this differential block to DNA synthesis also occurs in infected cells.

scholarly journals Antiviral Activity of MK-4965, a Novel Nonnucleoside Reverse Transcriptase Inhibitor

2009 ◽  
Vol 53 (6) ◽  
pp. 2424-2431 ◽  
Author(s):  
Ming-Tain Lai ◽  
Vandna Munshi ◽  
Sinoeun Touch ◽  
Robert M. Tynebor ◽  
Thomas J. Tucker ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Reverse Transcriptase ◽  
Transcriptase Inhibitor ◽  
Cross Resistance ◽  
Resistance Mutations ◽  
Nnrti Resistance ◽  
Development Of Resistance ◽  
Reverse Transcriptase Inhibitor ◽  
Hiv 1

ABSTRACT Nonnucleoside reverse transcriptase inhibitors (NNRTIs) are the mainstays of therapy for the treatment of human immunodeficiency virus type 1 (HIV-1) infections. However, the effectiveness of NNRTIs can be hampered by the development of resistance mutations which confer cross-resistance to drugs in the same class. Extensive efforts have been made to identify new NNRTIs that can suppress the replication of the prevalent NNRTI-resistant viruses. MK-4965 is a novel NNRTI that possesses both diaryl ether and indazole moieties. The compound displays potency at subnanomolar concentrations against wild-type (WT), K103N, and Y181C reverse transcriptase (RT) in biochemical assays. MK-4965 is also highly potent against the WT virus and two most prevalent NNRTI-resistant viruses (viruses that harbor the K103N or the Y181C mutation), against which it had 95% effective concentrations (EC95s) of <30 nM in the presence of 10% fetal bovine serum. The antiviral EC95 of MK-4965 was reduced approximately four- to sixfold when it was tested in 50% human serum. Moreover, MK-4965 was evaluated with a panel of 15 viruses with NNRTI resistance-associated mutations and showed a superior mutant profile to that of efavirenz but not to that of etravirine. MK-4965 was similarly effective against various HIV-1 subtypes and viruses containing nucleoside reverse transcriptase inhibitor or protease inhibitor resistance-conferring mutations. A two-drug combination study showed that the antiviral activity of MK-4965 was nonantagonistic with each of the 18 FDA-licensed drugs tested vice versa in the present study. Taken together, these in vitro data show that MK-4965 possesses the desired properties for further development as a new NNRTI for the treatment of HIV-1 infection.

Diversity of HIV-1 subtypes and transmitted drug-resistance mutations among minority HIV-1 variants in a Turkish cohort

2021 ◽  
Vol 19 ◽  
Author(s):  
Rabia Can Sarinoglu ◽  
Uluhan Sili ◽  
Ufuk Hasdemir ◽  
Burak Aksu ◽  
Guner Soyletir ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Reverse Transcriptase ◽  
Transcriptase Inhibitor ◽  
Transmitted Drug Resistance ◽  
Resistance Mutations ◽  
Drug Resistance Mutations ◽  
Subtype B ◽  
Treatment Naïve ◽  
Reverse Transcriptase Inhibitor ◽  
Hiv 1

Background: The World Health Organization (WHO) recommends the surveillance of transmitted drug resistance mutations (TDRMs) to ensure the effectiveness and sustainability of HIV treatment programs. Objective: Our aim was to determine the TDRMs and evaluate the distribution of HIV-1 subtypes using and compared next-generation sequencing (NGS) and Sanger-based sequencing (SBS) in a cohort of 44 antiretroviral treatment-naïve patients. Methods: All samples that were referred to the microbiology laboratory for HIV drug resistance analysis between December 2016 and February 2018 were included in the study. After exclusions, 44 treatment-naive adult patients with a viral load of >1000 copies/mL were analyzed. DNA sequencing for reverse transcriptase and protease regions was performed using both DeepChek ABL single round kit and Sanger-based ViroSeq HIV-1 Genotyping System. The mutations and HIV-1 subtypes were analyzed using the Stanford HIVdb version 8.6.1 Genotypic Resistance software, and TDRMs were assessed using the WHO surveillance drug-resistance mutation database. HIV-1 subtypes were confirmed by constructing a maximum-likelihood phylogenetic tree using Los Alamos IQ-Tree software. Results: NGS identified nucleos(t)ide reverse transcriptase inhibitor (NRTI)-TDRMs in 9.1% of the patients, non-nucleos(t)ide reverse transcriptase inhibitor (NNRTI)-TDRMs in 6.8% of the patients, and protease inhibitor (PI)-TDRMs in 18.2% of the patients at a detection threshold of ≥1%. Using SBS, 2.3% and 6.8% of the patients were found to have NRTI- and NNRTI-TDRMs, respectively, but no major PI mutations were detected. M41L, L74I, K65R, M184V, and M184I related to NRTI, K103N to NNRTI, and N83D, M46I, I84V, V82A, L24I, L90M, I54V to the PI sites were identified using NGS. Most mutations were found in low-abundance (frequency range: 1.0% - 4.7%) HIV-1 variants, except M41L and K103N. The subtypes of the isolates were found as follows; 61.4% subtype B, 18.2% subtype B/CRF02_AG recombinant, 13.6% subtype A, 4.5% CRF43_02G, and 2.3% CRF02_AG. All TDRMs, except K65R, were detected in HIV-1 subtype B isolates.. Conclusion: The high diversity of protease site TDRMs in the minority HIV-1 variants and prevalence of CRFs were remarkable in this study. All minority HIV-1 variants were missed by conventional sequencing. TDRM prevalence among minority variants appears to be decreasing over time at our center.

scholarly journals Selective Excision of AZTMP by Drug-Resistant Human Immunodeficiency Virus Reverse Transcriptase

2001 ◽  
Vol 75 (10) ◽  
pp. 4832-4842 ◽  
Author(s):  
Paul L. Boyer ◽  
Stefan G. Sarafianos ◽  
Edward Arnold ◽  
Stephen H. Hughes
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Nucleoside Analogs ◽  
Azido Group ◽  
Resistance Mutations ◽  
Immunodeficiency Virus ◽  
Azt Resistance ◽  
Hiv 1

ABSTRACT Two distinct mechanisms can be envisioned for resistance of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) to nucleoside analogs: one in which the mutations interfere with the ability of HIV-1 RT to incorporate the analog, and the other in which the mutations enhance the excision of the analog after it has been incorporated. It has been clear for some time that there are mutations that selectively interfere with the incorporation of nucleoside analogs; however, it has only recently been proposed that zidovudine (AZT) resistance can involve the excision of the nucleoside analog after it has been incorporated into viral DNA. Although this proposal resolves some important issues, it leaves some questions unanswered. In particular, how do the AZT resistance mutations enhance excision, and what mechanism(s) causes the excision reaction to be relatively specific for AZT? We have used both structural and biochemical data to develop a model. In this model, several of the mutations associated with AZT resistance act primarily to enhance the binding of ATP, which is the most likely pyrophosphate donor in the in vivo excision reaction. The AZT resistance mutations serve to increase the affinity of RT for ATP so that, at physiological ATP concentrations, excision is reasonably efficient. So far as we can determine, the specificity of the excision reaction for an AZT-terminated primer is not due to the mutations that confer resistance, but depends instead on the structure of the region around the HIV-1 RT polymerase active site and on its interactions with the azido group of AZT. Steric constraints involving the azido group cause the end of an AZT 5′-monophosphate-terminated primer to preferentially reside at the nucleotide binding site, which favors excision.

scholarly journals Combination Therapy with Tenofovir Disoproxil Fumarate/Emtricitabine/Elvitegravir/Cobicistat Plus Darunavir Once Daily in Antiretroviral-Naive and Treatment-Experienced Patients: A Retrospective Review

2018 ◽  
Vol 17 ◽  
pp. 232595741775226 ◽  
Author(s):  
Mark J. Naccarato ◽  
Deborah M. Yoong ◽  
Ignatius W. Fong ◽  
Kevin A. Gough ◽  
Marian A. Ostrowski ◽  
...  
Keyword(s):  
Reverse Transcriptase ◽  
Tenofovir Disoproxil Fumarate ◽  
Retrospective Chart Review ◽  
Transcriptase Inhibitor ◽  
Primary Objective ◽  
Fixed Dose ◽  
Drug Resistant ◽  
Once Daily ◽  
Dose Combination ◽  
Hiv 1

Background: Patients with drug-resistant HIV often require complex antiretroviral regimens. However, combining fixed-dose combination tablets such as tenofovir–disoproxil–fumarate, emtricitabine, and cobicistat-boosted elvitegravir (TDF/FTC/EVG/cobi) with darunavir (DRV) can provide a simple, once-daily (QD), 2-tablet regimen for patients with drug-resistant HIV. Primary objective was to determine the percentage of patients with HIV-1 RNA <40 copies/mL at 48 weeks. Methods: We performed a retrospective chart review of patients initiated on TDF/FTC/EVG/cobi plus DRV. Results: Among the 21 included patients, prior resistance showed a median of 2 nucleoside reverse transcriptase inhibitor mutations, 1 nonnucleoside reverse transcriptase mutation, and 1 protease inhibitor mutation. At week 48, 14 (67%) patients achieved HIV-1 RNA <40 copies/mL, 1 patient experienced viral rebound, and 6 (29%) had missing data or discontinued therapy. No patient discontinued for adverse events. Conclusion: According to this observational study, QD TDF/FTC/EVG/cobi plus DRV is considered safe, well tolerated, and generally effective in suppressing HIV drug-resistant virus.

scholarly journals HIV Drug Resistance Mutations in Patients with HIV and HIV-TB Coinfection After Failure of First-Line Therapy: A Prevalence Study in a Resource-Limited Setting

2019 ◽  
Vol 18 ◽  
pp. 232595821984906
Author(s):  
Nawaid Hussain Khan ◽  
Mikashmi Kohli ◽  
Kartik Gupta ◽  
Bimal Kumar Das ◽  
Ravindra Mohan Pandey ◽  
...  
Keyword(s):  
Reverse Transcriptase ◽  
Drug Resistant ◽  
Resistance Mutations ◽  
Reverse Transcriptase Inhibitors ◽  
Nucleoside Reverse Transcriptase Inhibitors ◽  
First Line Therapy ◽  
Resource Limited ◽  
High Prevalence ◽  
Hiv 1 ◽  
Limited Setting

Introduction: The present study aimed to report the prevalent HIV-1 drug-resistant mutations in patients with HIV-1 alone and tuberculosis (TB) coinfection alone to improve our understanding of the mutation patterns and aid treatment decisions. Methods: Patients with HIV-1 and HIV-TB on treatment for more than 1 year with suspected failure were recruited. Sequencing of protease and two-thirds of the region of reverse transcriptase gene was done for drug-resistant mutations. Results: In the HIV-TB group (n = 25), 88%, 92%, and 12% had mutations to nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), and protease inhibitors (PIs), respectively. In the HIV-alone group (n = 25), 84%, 100%, and 4% had mutations to NRTIs, NNRTIs, and PIs, respectively. M184V, M41L, D67N, G190A, A98G, and K103N were the most common mutations seen. Conclusion: There is a high prevalence of drug-resistant mutations in HIV and HIV-TB coinfected patients.

scholarly journals The HEPT Analogue WPR-6 Is Active against a Broad Spectrum of Nonnucleoside Reverse Transcriptase Drug-Resistant HIV-1 Strains of Different Serotypes

2015 ◽  
Vol 59 (8) ◽  
pp. 4882-4888 ◽  
Author(s):  
Weisi Xu ◽  
Jianxiong Zhao ◽  
Jianping Sun ◽  
Qianqian Yin ◽  
Yan Wang ◽  
...  
Keyword(s):  
Reverse Transcriptase ◽  
Highly Active Antiretroviral Therapy ◽  
Therapeutic Index ◽  
Transcriptase Inhibitor ◽  
Resistance Mutations ◽  
Highly Active ◽  
Hiv Drugs ◽  
Reverse Transcriptase Inhibitor ◽  
Hiv 1

ABSTRACTNonnucleoside reverse transcriptase inhibitors (NNRTIs) are important components of the highly active antiretroviral therapy (HAART) used to treat human immunodeficiency type 1 virus (HIV-1). However, because of the emergence of drug resistance and the adverse effects of current anti-HIV drugs, it is essential to develop novel NNRTIs with an excellent safety profile, improved activity against NNRTI-resistant viruses, and enhanced activity against clinical isolates of different subtypes. Here, we have identified 1-[(benzyloxy)methyl]-6-(3,5-dimethylbenzyl)-5-iodopyrimidine-2,4(1H,3H)-dione (WPR-6), a novel NNRTI with a 50% effective concentration (EC50) of 2 to 4 nM against laboratory-adapted HIV-1 strain SF33 and an EC50of 7 to 14 nM against nucleoside reverse transcriptase inhibitor-resistant HIV-1 strain 7391 with a therapeutic index of >1 × 104. A panel of five representative clinical virus isolates of different subtypes circulating predominantly in China was highly sensitive to WPR-6, with EC50s ranging from 1 to 6 nM. In addition, WPR-6 showed excellent antiviral potency against the most prevalent NNRTI-resistant viruses containing the K103N and Y181C mutations. To determine whether WPR-6 selects for novel resistant mutants,in vitroresistance selection was conducted with laboratory-adapted HIV-1 strain SF33 on MT-4 cells. The results demonstrated that V106I and Y188L were the two dominant NNRTI-associated resistance mutations detected in the breakthrough viruses. Taken together, thesein vitrodata indicate that WPR-6 has greater efficacy than the reference HEPT analogue TNK651 and the marketed drug nevirapine against HIV-1. However, to develop it as a new NNRTI, further improvement of its pharmacological properties is warranted.

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