Resistance Profile of the Human Immunodeficiency Virus Type 1 Reverse Transcriptase Inhibitor Abacavir (1592U89) after Monotherapy and Combination Therapy

Harrigan, P. Richard; Stone, Chris; Griffin, Phillip T.; Nájera, Isabel; Bloor, Stuart; Kemp, Sharon D.; Tisdale, Margaret; Larder, Brendan A.

doi:10.1086/315317

Cited by 134 publications

(108 citation statements)

References 28 publications

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“…Cell culture and clinical data have shown that viruses that contain the L74V and M184V mutations display low to medium levels of resistance to ABC and ddI and that the level of resistance was increased when both mutations were present within the same RT gene (8,16,18,39,52). Here, we initially studied the efficiencies of incorporation of CBV-TP and ddATP, i.e., the active metabolites of ABC and ddI, respectively, with WT HIV-1 RT and relevant mutated enzymes in cell-free assays.…”

Section: Resultsmentioning

confidence: 99%

Diminished RNA Primer Usage Associated with the L74V and M184V Mutations in the Reverse Transcriptase of Human Immunodeficiency Virus Type 1 Provides a Possible Mechanism for Diminished Viral Replication Capacity

Diallo

Marchand

Wei

et al. 2003

J Virol

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The emergence of drug resistance-conferring mutations can severely compromise the success of chemotherapy directed against human immunodeficiency virus type 1 (HIV-1). The M184V and/or L74V mutation in the reverse transcriptase (RT) gene are frequently found in viral isolates from patients treated with the nucleoside RT inhibitors lamivudine (3TC), abacavir (ABC), and didanosine (ddI). However, the effectiveness of combination therapy with regimens containing these compounds is often not abolished in the presence of these mutations; it has been conjectured that diminished fitness of HIV-1 variants containing L74V and M184V may contribute to sustained antiviral effects in such cases. We have determined that viruses containing both L74V and M184V are more impaired in replication capacity than viruses containing either mutation alone. To understand the biochemical mechanisms responsible for this diminished fitness, we generated a series of recombinant mutated enzymes containing either or both of the L74V and M184V substitutions. These enzymes were tested for their abilities to bypass important rate-limiting steps during the complex process of reverse transcription. We studied both the initiation of minus-strand DNA synthesis with the cognate replication primer human tRNA 3Lys and the initiation of plus-strand DNA synthesis, using a short RNA primer derived from the viral polypurine tract. We observed that the efficiencies of both reactions were diminished with enzymes containing either L74V or M184V and that these effects were significantly amplified with the double mutant. We also show that release from intrinsic pausing sites during reverse transcription appears to be a major obstacle that cannot be efficiently bypassed. Our data suggest that the efficiency of RNA-primed DNA synthesis represents an important consideration that can affect viral replication kinetics.Although considerable progress has been made in the treatment of human immunodeficiency virus type 1 (HIV-1)-associated disease, the emergence of mutated variants of HIV-1 that are resistant to antiviral drugs represents a major problem. The prolonged clinical use of nucleoside reverse transcriptase (RT) analogue chain terminators, e.g., abacavir (ABC), 2Ј,3Ј-dideoxyinosine (ddI or didanosine), and (Ϫ)-2Ј,3Ј-dideoxy-3Ј-thiacytidine (3TC or lamivudine), gives rise to resistant viruses that contain mutations in the RT enzyme (5,8,11,48,52,54,56). These nucleoside RT inhibitors (NRTIs) compete with natural deoxynucleoside triphosphate (dNTP) pools after being phosphorylated by cellular kinases for incorporation into viral DNA. DNA synthesis is blocked once the chain terminator is incorporated, since these nucleoside analogues lack a 3Ј-OH group, which is required to continue the polymerization process (24,44,45).A single amino acid substitution in RT, i.e., M184V, is sufficient to confer high-level resistance to 3TC (5,11,47,54). The M184V mutation is rapidly selected both in tissue culture and in vivo. Experiments with recombinant mutant enzymes have show...

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Section: Resultsmentioning

confidence: 99%

Diminished RNA Primer Usage Associated with the L74V and M184V Mutations in the Reverse Transcriptase of Human Immunodeficiency Virus Type 1 Provides a Possible Mechanism for Diminished Viral Replication Capacity

Diallo

Marchand

Wei

et al. 2003

J Virol

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“…The mutant enzymes K65R and L74V confer resistance to the drugs dideoxyinosine, dideoxycytosine, and lamivudine (3TC); D67N and K70R confer resistance to AZT; and E89G confers resistance to multiple drugs (18,19,51,62). K65R also confers resistance to 9-R-2-phosphonomethoxypropyl adenine (tenofovir) and abacavir (1592U89) (21,61). K65R has been previously reported to increase the fidelity of purified RT eightfold while L74V had no affect on cell-free fidelity when the lacZ␣ gene was employed to detect ct mutations (58).…”

Section: Analysis Of Hiv-1 Rt Single-amino-acid Variants On Virus Mutmentioning

confidence: 99%

“…However, the Y115F and Y115V RT variants were found in lacZ␣ cell-free fidelity assays to have slightly lower error rates than that of wt RT (5). The Y115F mutation confers resistance to abacavir (21). Nonconservative changes at the Y115 residue have been found to result in a dramatic reduction in the ability of purified HIV-1 RT to discriminate against ribonucleotides in the presence of both magnesium and manganese cations (6).…”

Section: Analysis Of Hiv-1 Rt Single-amino-acid Variants On Virus Mutmentioning

confidence: 99%

Influence of Reverse Transcriptase Variants, Drugs, and Vpr on Human Immunodeficiency Virus Type 1 Mutant Frequencies

Mansky

Rouzic

Bénichou

et al. 2003

J Virol

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The evolution of drug resistance is a major complication of human immunodeficiency virus type 1 (HIV-1) chemotherapy. HIV-1 reverse transcriptase (RT) is a major target of antiretroviral therapy and ultimately the target of drug resistance mutations. Previous studies have indicated that drug-resistant HIV-1 RTs can alter HIV-1 mutant frequencies. In this study, we have tested a panel of HIV-1 RT variants for their ability to influence virus mutant frequencies. The RT variants tested included drug-resistant RT variants as well as other variants analyzed in enzyme fidelity studies with the lacZ␣ gene as a mutation target and/or implicated as being important for enzyme fidelity by structural studies. Combinations of mutations that alone had a statistically significant influence on virus mutant frequencies resulted in different mutant frequency phenotypes. Furthermore, when virus replication occurred in the presence of drugs [e.g., 3-azido-3-deoxythymidine, (؊)2/,3-dideoxy-3-thiacytidine, hydroxyurea, thymidine, or thioguanine] with selected RT variants, virus mutant frequencies increased. Similarly, Vpr variants deficient for binding to the uracil DNA glycosylase repair enzyme were observed to influence HIV-1 virus mutant frequencies when tested alone or in combination with RT variants. In summary, these observations indicate that HIV-1 mutant frequencies can significantly change by single amino acid substitutions in RT and that these effects can be altered by additional mutations in RT, by drugs, and/or by expression of Vpr variants. Such altered virus mutant frequencies could impact HIV-1 dynamics and evolution in small population sizes.

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“…For instance, the presence of K65R or L74V (J. Eron, Jr. et al, 2006;Gallant et al, 2006;Moyle et al, 2005) point mutations ( Figure 2 and Table 2) in addition to the M184V is sufficient for high level resistance to ddI and ABC , particularly in patients with non-subtype B clades (Harrigan et al, 2000;Lanier et al, 2004a;Svarovskaia et al, 2007;M. A. Winters et al, 1997 .…”

Section: Point Mutations Associated With Resistance To Nrtismentioning

confidence: 99%

Point Mutations Associated with HIV-1 Drug Resistance, Evasion of the Immune Response and AIDS Pathogenesis

Khati¹,

Millroy²

2012

Point Mutation

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Resistance Profile of the Human Immunodeficiency Virus Type 1 Reverse Transcriptase Inhibitor Abacavir (1592U89) after Monotherapy and Combination Therapy

Cited by 134 publications

References 28 publications

Diminished RNA Primer Usage Associated with the L74V and M184V Mutations in the Reverse Transcriptase of Human Immunodeficiency Virus Type 1 Provides a Possible Mechanism for Diminished Viral Replication Capacity

Diminished RNA Primer Usage Associated with the L74V and M184V Mutations in the Reverse Transcriptase of Human Immunodeficiency Virus Type 1 Provides a Possible Mechanism for Diminished Viral Replication Capacity

Influence of Reverse Transcriptase Variants, Drugs, and Vpr on Human Immunodeficiency Virus Type 1 Mutant Frequencies

Point Mutations Associated with HIV-1 Drug Resistance, Evasion of the Immune Response and AIDS Pathogenesis

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