Primer unblocking by HIV-1 reverse transcriptase and resistance to nucleoside RT inhibitors (NRTIs)

2004 ◽  
Vol 36 (9) ◽  
pp. 1687-1705 ◽  
Author(s):  
V GOLDSCHMIDT
Keyword(s):  
Reverse Transcriptase ◽  
Rt Inhibitors ◽  
Hiv 1

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 Effects of the W153L Substitution in HIV Reverse Transcriptase on Viral Replication and Drug Resistance to Multiple Categories of Reverse Transcriptase Inhibitors

2014 ◽  
Vol 58 (8) ◽  
pp. 4515-4526 ◽  
Author(s):  
Hong-Tao Xu ◽  
Susan P. Colby-Germinario ◽  
Maureen Oliveira ◽  
Daniel Rajotte ◽  
Richard Bethell ◽  
...  
Keyword(s):  
Viral Replication ◽  
Reverse Transcriptase ◽  
Rnase H ◽  
Hiv Reverse Transcriptase ◽  
Compound A ◽  
Enzymatic Function ◽  
Biochemical Assays ◽  
Rt Inhibitors ◽  
The Impact ◽  
Hiv 1

ABSTRACTA W153L substitution in HIV-1 reverse transcriptase (RT) was recently identified by selection with a novel nucleotide-competing RT inhibitor (NcRTI) termed compound A that is a member of the benzo[4,5]furo[3,2,d]pyrimidin-2-one NcRTI family of drugs. To investigate the impact of W153L, alone or in combination with the clinically relevant RT resistance substitutions K65R (change of Lys to Arg at position 65), M184I, K101E, K103N, E138K, and Y181C, on HIV-1 phenotypic susceptibility, viral replication, and RT enzymatic function, we generated recombinant RT enzymes and viruses containing each of these substitutions or various combinations of them. We found that W153L-containing viruses were impaired in viral replicative capacity and were hypersusceptible to tenofovir (TFV) while retaining susceptibility to most nonnucleoside RT inhibitors. The nucleoside 3TC retained potency against W153L-containing viruses but not when the M184I substitution was also present. W153L was also able to reverse the effects of the K65R substitution on resistance to TFV, and K65R conferred hypersusceptibility to compound A. Biochemical assays demonstrated that W153L alone or in combination with K65R, M184I, K101E, K103N, E138K, and Y181C impaired enzyme processivity and polymerization efficiency but did not diminish RNase H activity, providing mechanistic insights into the low replicative fitness associated with these substitutions. We show that the mechanism of the TFV hypersusceptibility conferred by W153L is mainly due to increased efficiency of TFV-diphosphate incorporation. These results demonstrate that compound A and/or derivatives thereof have the potential to be important antiretroviral agents that may be combined with tenofovir to achieve synergistic results.

scholarly journals The Human Immunodeficiency Virus Type 1 Nonnucleoside Reverse Transcriptase Inhibitor Resistance Mutation I132M Confers Hypersensitivity to Nucleoside Analogs

2009 ◽  
Vol 83 (8) ◽  
pp. 3826-3833 ◽  
Author(s):  
Zandrea Ambrose ◽  
Brian D. Herman ◽  
Chih-Wei Sheen ◽  
Shannon Zelina ◽  
Katie L. Moore ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Nucleoside Analogs ◽  
Replication Capacity ◽  
Immunodeficiency Virus ◽  
Viral Replication Capacity ◽  
Rt Inhibitors ◽  
Hiv 1

ABSTRACT We previously identified a rare mutation in human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT), I132M, which confers high-level resistance to the nonnucleoside RT inhibitors (NNRTIs) nevirapine and delavirdine. In this study, we have further characterized the role of this mutation in viral replication capacity and in resistance to other RT inhibitors. Surprisingly, our data show that I132M confers marked hypersusceptibility to the nucleoside analogs lamivudine (3TC) and tenofovir at both the virus and enzyme levels. Subunit-selective mutagenesis studies revealed that the mutation in the p51 subunit of RT was responsible for the increased sensitivity to the drugs, and transient kinetic analyses showed that this hypersusceptibility was due to I132M decreasing the enzyme's affinity for the natural dCTP substrate but increasing its affinity for 3TC-triphosphate. Furthermore, the replication capacity of HIV-1 containing I132M is severely impaired. This decrease in viral replication capacity could be partially or completely compensated for by the A62V or L214I mutation, respectively. Taken together, these results help to explain the infrequent selection of I132M in patients for whom NNRTI regimens are failing and furthermore demonstrate that a single mutation outside of the polymerase active site and inside of the p51 subunit of RT can significantly influence nucleotide selectivity.

Non-Nucleoside HIV-1 Reverse Transcriptase (RT) Inhibitors: Past, Present, and Future Perspectives

2002 ◽  
Vol 8 (8) ◽  
pp. 615-657 ◽  
Author(s):  
Giuseppe Campiani ◽  
Anna Ramunno ◽  
Giovanni Maga ◽  
Vito Nacci ◽  
Caterina Fattorusso ◽  
...  
Keyword(s):  
Reverse Transcriptase ◽  
Future Perspectives ◽  
Rt Inhibitors ◽  
Hiv 1

HIV-1 reverse transcriptase (RT) genotype and susceptibility to RT inhibitors during abacavir monotherapy and combination therapy

AIDS ◽  
2000 ◽  
Vol 14 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Veronica Miller ◽  
Mounir Ait-Khaled ◽  
Chris Stone ◽  
Philip Griffin ◽  
Despina Mesogiti ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Reverse Transcriptase ◽  
Rt Inhibitors ◽  
Hiv 1

Effects of Human Immunodeficiency Virus Type 1 Resistance to Protease Inhibitors on Reverse Transcriptase Processing, Activity, and Drug Sensitivity

1999 ◽  
Vol 73 (4) ◽  
pp. 3455-3459 ◽  
Author(s):  
Laurence Carron de la Carrière ◽  
Sylvie Paulous ◽  
François Clavel ◽  
Fabrizio Mammano
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Protease Inhibitors ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Resistance Mutations ◽  
Immunodeficiency Virus ◽  
Rt Inhibitors ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) variants resistant to protease inhibitors often display a reduced replicative capacity as a result of an impairment of protease function. Such fitness-impaired viruses display Gag precursor maturation defects. Here, we report that some protease inhibitor-resistant viruses also display abnormalities in the processing of reverse transcriptase (RT) by the protease. In three recombinant viruses carrying resistant protease sequences from patient plasma, we observed a marked decrease in the amount of mature RT subunits and of particle-associated RT activity compared to their parental pretherapy counterparts. We investigated the possibility that a decrease in the amount of particle-associated mature RT could affect the sensitivity of the corresponding virus to RT inhibitors. We observed a twofold increase of sensitivity to zidovudine (AZT) when a virus which carried AZT mutations was processed by a resistant protease. Interestingly, the presence of AZT-resistance mutations partially rescued the replication defect associated with the mutated protease. The interplay between resistance to protease inhibitors and to RT inhibitors described here may be relevant to the therapeutic control of HIV-1 infection.

scholarly journals Genotypic and phenotypic changes during culture of a multinucleoside-resistant human immunodeficiency virus type 1 strain in the presence and absence of additional reverse transcriptase inhibitors.

1996 ◽  
Vol 40 (12) ◽  
pp. 2887-2890 ◽  
Author(s):  
R W Shafer ◽  
M A Winters ◽  
A K Iversen ◽  
T C Merigan
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Reverse Transcriptase Inhibitors ◽  
Lamivudine Resistance ◽  
Immunodeficiency Virus ◽  
Rt Inhibitors ◽  
Hiv 1

The observation that human immunodeficiency virus type 1 (HIV-1) mutations conferring resistance to one reverse transcriptase (RT) inhibitor may suppress resistance to other RT inhibitors provides a rationale for treating HIV-1 with certain RT inhibitor combinations. We examined phenotypic and genotypic changes during culture of a multinucleoside (zidovudine, didanosine, zalcitibine, and stavudine)-resistant HIV-1 strain with and without additional RT inhibitors (nevirapine and lamivudine). The development of nevirapine or lamivudine resistance by the multinucleoside-resistant strain was not accompanied by a reduction in zidovudine or didanosine resistance.

scholarly journals Non-Nucleoside HIV-1 Reverse Transcriptase Inhibitors: Synthesis and Biological Evaluation of Novel Quinoxalinylethylpyridylthioureas as Potent Antiviral Agents

2000 ◽  
Vol 11 (2) ◽  
pp. 141-155 ◽  
Author(s):  
G Campiani ◽  
M Fabbrini ◽  
E Morelli ◽  
V Nacci ◽  
G Greco ◽  
...  
Keyword(s):  
Reverse Transcriptase ◽  
Antiviral Agents ◽  
Human Monocyte ◽  
Biological Evaluation ◽  
Single Amino Acid ◽  
Enzymatic Assays ◽  
Immunodeficiency Virus ◽  
Heterocyclic Derivatives ◽  
Rt Inhibitors ◽  
Hiv 1

New heterocyclic derivatives of ethylpyridylthiourea, quinoxalinylethylpyridylthiourea (QXPT) and analogues, inhibited human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) activity and prevented HIV-1 cytopathogenicity in T4 lymphocytes. Several of these novel non-nucleoside RT inhibitors, with a substituted pyrroloquinoxalinone heteroaromatic skeleton, showed inhibitory activity against wild-type RT as well as against mutant RTs containing the single amino acid substitutions L100I, K103N, V106A, Y181I and Y188L that was much greater than other non-nucleoside inhibitors such as nevirapine. Maximum potency in enzymatic assays was achieved with a fluoropyrroloquinoxaline skeleton linked to the ethylpyridylthiourea moiety (FQXPT). In cell-based assays on different cell lines and on human monocyte-macrophages, 6-FQXPT exhibited EC50 values in the nanomolar range, with a promising selectivity index. Moreover, 6-FQXPT showed synergistic antiviral activity with zidovudine.

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