Impact of nelfinavir resistance mutations on in vitro phenotype, fitness, and replication capacity of human immunodeficiency virus type 1 with subtype B and C proteases (original) (raw)
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Replicative Fitness of Protease Inhibitor-Resistant Mutants of Human Immunodeficiency Virus Type 1
1999
The relative replicative fitness of human immunodeficiency virus type 1 (HIV-1) mutants selected by different protease inhibitors (PIs) in vivo was determined. Each mutant was compared to wild type (WT), NL4-3, in the absence of drugs by several methods, including clonal genotyping of cultures infected with two competing viral variants, kinetics of viral antigen production, and viral infectivity/virion particle ratios. A nelfinavir-selected protease D30N substitution substantially decreased replicative capacity relative to WT, while a saquinavirselected L90M substitution moderately decreased fitness. The D30N mutant virus was also outcompeted by the L90M mutant in the absence of drugs. A major natural polymorphism of the HIV-1 protease, L63P, compensated well for the impairment of fitness caused by L90M but only slightly improved the fitness of D30N. Multiply substituted indinavir-selected mutants M46I/L63P/V82T/I84V and L10R/M46I/L63P/V82T/I84V were just as fit as WT. These results indicate that the mutations which are usually initially selected by nelfinavir and saquinavir, D30N and L90M, respectively, impair fitness. However, additional mutations may improve the replicative capacity of these and other drug-resistant mutants. Hypotheses based on the greater fitness impairment of the nelfinavir-selected D30N mutant are suggested to explain observations that prolonged responses to delayed salvage regimens, including alternate PIs, may be relatively common after nelfinavir failure.
Journal of General Virology, 2006
Human immunodeficiency virus type 1 subtype C isolates belong to one of the most prevalent strains circulating worldwide and are responsible for the majority of new infections in the sub-Saharan region and other highly populated areas of the globe. In this work, the impact of drug-resistance mutations in the protease gene of subtype C viruses was analysed and compared with that of subtype B counterparts. A series of recombinant subtype C and B viruses was constructed carrying indinavir (IDV)-resistance mutations (M46V, I54V, V82A and L90M) and their susceptibility to six FDA-approved protease inhibitor compounds (amprenavir, indinavir, lopinavir, ritonavir, saquinavir and nelfinavir) was determined. A different impact of these mutations was found when nelfinavir and lopinavir were tested. The IDV drug-resistance mutations in the subtype C protease backbone were retained for a long period in culture without selective pressure when compared with those in subtype B counterparts in washout experiments.
Memórias do Instituto Oswaldo Cruz, 2011
The human immunodeficiency virus type 1 (HIV-1) protease mutation D30N is exclusively selected by the protease inhibitor (PI) nelfinavir and confers resistance to this drug. We demonstrate that D30N increases the susceptibility to saquinavir (SQV) and amprenavir in HIV-1 subtype B isolates and that the N88D mutation in a D30N background neutralizes this effect. D30N also suppresses indinavir (IDV) resistance caused by the M46I mutation. Interestingly, in patients with viruses originally containing the D30N mutation who were treated with IDV or SQV, the virus either reversed this mutation or acquired N88D, suggesting an antagonistic effect of D30N upon exposure to these PIs. These findings can improve direct salvage drug treatment in resource limited countries where subtype B is epidemiologically important and extend the value of first and second line PIs in these populations.
Antimicrobial Agents and Chemotherapy, 2004
Differences in baseline polymorphisms between subtypes may result in development of diverse mutational pathways during antiretroviral treatment. We compared drug resistance in patients with human immunodeficiency virus subtype C (referred to herein as "subtype-C-infected patients") versus subtype-B-infected patients following protease inhibitor (PI) therapy. Genotype, phenotype, and replication capacity (Phenosense; Virologic) were determined. We evaluated 159 subtype-C-and 65 subtype-B-infected patients failing first PI treatment. Following nelfinavir treatment, the unique nelfinavir mutation D30N was substantially less frequent in C (7%) than in B (23%; P ؍ 0.03) while L90M was similar (P < 0.5). Significant differences were found in the rates of M36I (98 and 36%), L63P (35 and 59%), A71V (3 and 32%), V77I (0 and 36%), and I93L (91 and 32%) (0.0001 < P < 0.05) in C and B, respectively. Other mutations were L10I/V, K20R, M46I, V82A/I, I84V, N88D, and N88S. Subtype C samples with mutation D30N showed a 50% inhibitory concentration (IC 50 ) change in susceptibility to nelfinavir only. Other mutations increased IC 50 correlates to all PIs. Following accumulation of mutations, replication capacity of the C virus was reduced from 43% ؎ 22% to 22% ؎ 15% (P ؍ 0.04). We confirmed the selective nature of the D30N mutation in C, and the broader cross-resistance of other common protease inhibitor mutations. The rates at which these mutational pathways develop differ in C and subtype-B-infected patients failing therapy, possibly due to the differential impact of baseline polymorphisms. Because mutation D30N is not preferentially selected in nelfinavir-treated subtype-C-infected patients, as it is in those infected with subtype B, the consideration of using this drug initially to preserve future protease inhibitor options is less relevant for subtype-C-infected patients.
HIV-1 genotypes related to failure of nelfinavir as the first protease inhibitor treatment
Brazilian Journal of Infectious Diseases, 2005
Combined antiretroviral therapy results in sustained viral suppression and a decrease in mortality and morbidity due to HIV infection. Intrinsic strength, durability and absence of crossresistance are key factors in the selection of antiretrovirals. Failure with nelfinavir has been associated with two protease gene mutations, D30N and L90M. The D30N mutation does not result in cross-resistance with other protease inhibitors, and it decreases viral fitness. In order to check for this mutation after failure with nelfinavir, the 246 HIV-1 genotyping test was performed on virus samples from 55 patients with failure of nelfinavir as the first protease inhibitor. Most (84%) of the viral strains were of subtype B. Nucleosides associated with mutations (NAM) were observed in 80% of the tests; no INS69, complex 151, K65R and L74V mutations, which give multi-resistance to nucleoside analogue reverse transcriptase inhibitors to tenofovir and DDI, respectively, were observed. In the tests for protease gene mutations, the D30N mutation was found in 57%, L90M in 18% and the wild-type virus in 25%. These data are similar to published reports, showing that alternative therapies used after failure with nelfinavir may be more successful, as the D30N mutation does not cause cross-resistance to other protease inhibitors.
Biochemistry, 2003
Development of resistance mutations in enzymatic targets of human immunodeficiency virus 1 (HIV-1) hampers the ability to provide adequate therapy. Of special interest is the effect mutations outside the active site of HIV-1 protease have on inhibitor binding and virus viability. We engineered protease mutants containing the active site mutation D30N alone and with the nonactive site polymorphisms M36I and/or A71V. We determined the K i values for the inhibitors nelfinavir, ritonavir, indinavir, KNI272, and AG1776 as well as the catalytic efficiency of the mutants. Single and double mutation combinations exhibited a decrease in catalytic efficiency, while the triple mutant displayed catalytic efficiency greater than that of the wild type. Variants containing M36I or A71V alone did not display a significant change in binding affinities to the inhibitors tested. The variant containing mutation D30N displayed a 2-6-fold increase in K i for all inhibitors tested, with nelfinavir showing the greatest increase. The double mutants containing a combination of mutations D30N, M36I, and A71V displayed -0.5-fold to +6-fold changes in the K i of all inhibitors tested, with ritonavir and nelfinavir most affected. Only the triple mutant showed a significant increase (>10-fold) in K i for inhibitor nelfinavir, ritonavir, or AG-1776 displaying 22-, 19-, or 15-fold increases, respectively. Our study shows that the M36I and A71V mutations provide a greater level of inhibitor cross-resistance combined with active site mutation D30N. M36I and A71V, when present as natural polymorphisms, could aid the virus in developing active site mutations to escape inhibitor binding while maintaining catalytic efficiency. † wt , the protease species from laboratory strain LAI; LAI , the D30N mutant of LAI; LAI 36 , the M36I mutant of LAI; LAI 71 , the A71V mutant of LAI; LAI 30/36 , the D30N and M36I double mutant of LAI; LAI 30/71 , the D30N and A71V double mutant of LAI; LAI 36/71 , the M36I and A71V double mutant of LAI; LAI 30/36/71 , the D30N, M36I, and A71V triple mutant of LAI.
Journal of Virology, 2001
Twenty-four of over 24,000 patients genotyped over the past 3 years were found to have human immunodeficiency virus (HIV) isolates that possess an insert in the protease gene. In this report, we evaluated the spectrum of protease gene insertion mutations in patient isolates and analyzed the effect of these various insertion mutations on viral phenotypes. The inserts were composed of 1, 2, 5, or 6 amino acids that mapped at or between codons 35 and 38, 17 and 18, 21 and 25, or 95 and 96. Reduced susceptibility to protease inhibitors was found in isolates which possess previously reported drug resistance mutations. Fitness assays, including replication and competition experiments, showed that most of the isolates with inserts grew somewhat better than their counterparts with a deletion of the insert. These experiments demonstrate that, rarely, insertion mutations can develop in the HIV type 1 protease gene, are no more resistant than any other sequences which have similar associated r...
Antimicrobial Agents and Chemotherapy, 2001
The objective of this observational study was to assess the genetic variability in the human immunodeficiency virus (HIV) protease gene from HIV type 1 (HIV-1)-positive (clade B), protease inhibitor-naı̈ve patients and to evaluate its association with the subsequent effectiveness of a protease inhibitor-containing triple-drug regimen. The protease gene was sequenced from plasma-derived virus from 116 protease inhibitor-naı̈ve patients. The virological response to a triple-drug regimen containing indinavir, ritonavir, or saquinavir was evaluated every 3 months for as long as 2 years ( n = 40). A total of 36 different amino acid substitutions compared to the reference sequence (HIV-1 HXB2) were detected. No substitutions at the active site similar to the primary resistance mutations were found. The most frequent substitutions (prevalence, >10%) at baseline were located at codons 15, 13, 12, 62, 36, 64, 41, 35, 3, 93, 77, 63, and 37 (in ascending order of frequency). The mean number...
Journal of Virology, 2009
Mutations can accumulate in the protease and gag genes of human immunodeficiency virus in patients who fail therapy with protease inhibitor drugs. Mutations within protease, the drug target, have been extensively studied. Mutations in gag have been less well studied, mostly concentrating on cleavage sites. A retroviral vector system has been adapted to study full-length gag , protease, and reverse transcriptase genes from patient-derived viruses. Patient plasma-derived mutant full-length gag , protease, and gag -protease from a multidrug-resistant virus were studied. Mutant protease alone led to a 95% drop in replication capacity that was completely rescued by coexpressing the full-length coevolved mutant gag gene. Cleavage site mutations have been shown to improve the replication capacity of mutated protease. Strikingly, in this study, the matrix region and part of the capsid region from the coevolved mutant gag gene were sufficient to achieve full recovery of replication capacity ...