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Breiner B, Johnson K, Stolarek M, Silva AL, Negrea A, Bell NM, Isaac TH, Dethlefsen M, Chana J, Ibbotson LA, Palmer RN, Bush J, Dunning AJ, Love DM, Pachoumi O, Kelly DJ, Shibahara A, Wu M, Sosna M, Dear PH, Tolle F, Petrini E, Amasio M, Shelford LR, Saavedra MS, Sheridan E, Kuleshova J, Podd GJ, Balmforth BW, Frayling CA. Single-molecule detection of deoxyribonucleoside triphosphates in microdroplets. Nucleic Acids Res 2019; 47:e101. [PMID: 31318971 PMCID: PMC6753480 DOI: 10.1093/nar/gkz611] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 06/10/2019] [Accepted: 07/03/2019] [Indexed: 11/12/2022] Open
Abstract
A new approach to single-molecule DNA sequencing in which dNTPs, released by pyrophosphorolysis from the strand to be sequenced, are captured in microdroplets and read directly could have substantial advantages over current sequence-by-synthesis methods; however, there is no existing method sensitive enough to detect a single nucleotide in a microdroplet. We have developed a method for dNTP detection based on an enzymatic two-stage reaction which produces a robust fluorescent signal that is easy to detect and process. By taking advantage of the inherent specificity of DNA polymerases and ligases, coupled with volume restriction in microdroplets, this method allows us to simultaneously detect the presence of and distinguish between, the four natural dNTPs at the single-molecule level, with negligible cross-talk.
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Affiliation(s)
- Boris Breiner
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Kerr Johnson
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Magdalena Stolarek
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Ana-Luisa Silva
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Aurel Negrea
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Neil M Bell
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Tom H Isaac
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Mark Dethlefsen
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Jasmin Chana
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Lindsey A Ibbotson
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Rebecca N Palmer
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - James Bush
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Alexander J Dunning
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - David M Love
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Olympia Pachoumi
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Douglas J Kelly
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Aya Shibahara
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Mei Wu
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Maciej Sosna
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Paul H Dear
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Fabian Tolle
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Edoardo Petrini
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Michele Amasio
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Leigh R Shelford
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Monica S Saavedra
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Eoin Sheridan
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Jekaterina Kuleshova
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Gareth J Podd
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Barnaby W Balmforth
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
| | - Cameron A Frayling
- Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK
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Guo W, Han J, Zhuang D, Liu S, Liu Y, Li L, Li H, Bao Z, Wang F, Li J. Characterization of two HIV-1 infectors during initial antiretroviral treatment, and the emergence of phenotypic resistance in reverse transcriptase-associated mutation patterns. Virol J 2015; 12:187. [PMID: 26578099 PMCID: PMC4650308 DOI: 10.1186/s12985-015-0417-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 11/04/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Highly active antiretroviral therapy (HAART) is recommended to control the infection of HIV-1. HIV-1 drug resistance becomes an obstacle to HAART due to the accumulation of specific mutations in the RT coding region. The development of resistance mutations may be more complex than previously thought. METHODS We followed two HIV-1 infectors from a HIV-1 drug resistance surveillance cohort in Henan province and evaluated CD4+ T-cell number and viral load thereafter at ten time-periods and characterized their reverse transcriptase-associated mutation patterns at each time point. Then we constructed the recombinant virus strains with these mutation patterns to mimick the viruses and test the phenotypic resistance caused by the mutation patterns on TZM-b1 cells. RESULTS CD4+ T-cell number initially increased and then decreased rapidly, while viral load decreased and then dropped sharply during initial antiretroviral treatment. The number of mutations and the combination patterns of mutations increased over time. According to the phenotypic resistance performed by recombinant virus strains, VirusT215Y/V179E/Y181C/H221Y exhibited high levels of resistance to EFV (5.57-fold), and T215Y/V179E-containing virus increased 20.20-fold in AZT resistance (p < 0.01). VirusT215Y/V179E/Y181C increased markedly in EFV resistance (p < 0.01). The IC50 for VirusT215Y/V179E/H221Y was similar to that for VirusT215Y/V179E/Y181C. VirusT215Y/K103N/Y181C/H221Y induced a dramatic IC50 increase of all the four agents (Efavirenz EFV, Zidovudine AZT, Lamivudine 3TC, and Stavudine d4T) (p < 0.01). As for VirusT215Y/K103N/Y181C, only the IC50 of EFV was significantly increased. T215Y/K103N resulted in a 26.36-fold increase in EFV (p < 0.01). T215Y/K103N/H221Y significantly increased the resistance to AZT and 3TC. The IC50 of EFV with T215Y/V179E was lower than with T215Y/K103N (F = 93.10, P < 0.0001). With T215Y/V179E, Y181C significantly increase in EFV resistance, while the interaction between 181 and 221 in EFV was not statistically significant (F = 1.20, P = 0.3052). With T215Y/K103N, neither H221Y nor Y181C showed a significant increase in EFV resistance, but the interaction between 181 and 221 was statistically significant (F = 38.12, P = 0.0003). CONCLUSIONS Data in this study suggests that pathways of viral evolution toward drug resistance appear to proceed through distinct steps and at different rates. Phenotypic resistance using recombinant virus strains with different combination of mutation patterns reveals that interactions among mutations may provide information on the impact of these mutations on drug resistance. All the result provides reference to optimize clinical treatment schedule.
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Affiliation(s)
- Wei Guo
- Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China. .,NO. 201 hospital of the People's Liberation Army of China, Liaoyang, China.
| | - Jingwan Han
- Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China.
| | - Daomin Zhuang
- Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China.
| | - Siyang Liu
- Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China.
| | - Yongjian Liu
- Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China.
| | - Lin Li
- Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China.
| | - Hanping Li
- Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China.
| | - Zuoyi Bao
- Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China.
| | - Fujiang Wang
- NO. 201 hospital of the People's Liberation Army of China, Liaoyang, China.
| | - Jingyun Li
- Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China.
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Megens S, De Wit S, Bernatchez J, Dekeersmaeker N, Vinken L, Covens K, Theys K, Camacho RJ, Vandamme AM, Götte M, Van Laethem K. Characterization of amino acids Arg, Ser and Thr at position 70 within HIV-1 reverse transcriptase. Acta Clin Belg 2014; 69:348-57. [PMID: 25103592 DOI: 10.1179/2295333714y.0000000038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES The amino acid position 70 in HIV-1 reverse transcriptase (RT) plays an important role in nucleoside RT inhibitor (NRTI) resistance. K70R is part of the thymidine analog mutations, but also other amino acid changes have been associated with NRTI resistance, such as K70E and K70G. In this study, we investigated the in vivo selection of the HIV-1 RT mutations K70S and K70T and their in vitro effect on drug resistance and replication capacity. METHODS Recombinant viruses with RT mutations were generated to measure the in vitro drug susceptibility and replication capacity. Bayesian network analysis and three-dimensional modeling were performed to understand the selection and impact of the RT70 mutations. RESULTS K70S and K70T were found at a low frequency in RTI-experienced HIV-1 patients (0.10% and 0·20%). Baeyesian network learning identified no direct association with the in vivo exposure to any specific RTI. However, direct associations of K70S with mutations within the Q151M-complex and of K70T with K65R were observed. In vitro phenotypic testing revealed only minor effects of K70R/S/T as single mutations, associated with Q151M and within the context of the Q151M-complex. DISCUSSION These results suggest that the selection of K70S/T and their phenotypic impact are influenced by the presence of other mutations in RT. However, the low impact on in vitro phenotype here observed, alongside with the low in vivo prevalence, the exclusive direct association with known major RTI mutations and the unknown correlation with in vivo response, do not yet necessitate the inclusion of K70S/T in drug resistance interpretation systems.
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Impact of Y181C and/or H221Y mutation patterns of HIV-1 reverse transcriptase on phenotypic resistance to available non-nucleoside and nucleoside inhibitors in China. BMC Infect Dis 2014; 14:237. [PMID: 24885612 PMCID: PMC4024112 DOI: 10.1186/1471-2334-14-237] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 04/28/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The aim of this study was to investigate the role of K101Q, Y181C and H221Y emerging in HIV-1 reverse transcriptase with different mutations patterns in phenotypic susceptibility to currently available NNRTIs (nevirapine NVP, efavirenz EFV) and NRTIs (zidovudine AZT, lamivudine 3TC, stavudine d4T) in China. METHODS Phenotype testing of currently available NNRTIs (NVP, EFV) and NRTIs (AZT, 3TC, d4T) was performed on TZM-b1 cells using recombined virus strains. P ≤ 0.05 was defined significant considering the change of 50% inhibitory drug concentration (IC50) compared with the reference, while P ≤ 0.01 was considered to be statistically significant considering multiple comparisons. RESULTS Triple-mutation K101Q/Y181C/H221Y and double-mutation K101Q/Y181C resulted in significant increase in NVP resistance (1253.9-fold and 986.4-fold), while only K101Q/Y181C/H221Y brought a 5.00-fold significant increase in EFV resistance. Remarkably, K101Q/H221Y was hypersusceptible to EFV (FC = 0.04), but was significantly resistant to the three NRTIs. Then, the interaction analysis suggested the interaction was not significant to NVP (F = 0.77, P = 0.4061) but significant to EFV and other three NRTIs. CONCLUSION Copresence of mutations reported to be associated with NNRTIs confers significant increase to NVP resistance. Interestingly, some may increase the susceptibility to EFV. Certainly, the double mutation (K101Q/H221Y) also changes the susceptibility of viruses to NRTIs. Interaction between two different sites makes resistance more complex.
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Juhász E, Ghidán A, Kemény B, Nagy K. Emergence of antiretroviral drug resistance in therapy-naive HIV infected patients in Hungary. Acta Microbiol Immunol Hung 2008; 55:383-94. [PMID: 19130746 DOI: 10.1556/amicr.55.2008.4.3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mutations in the HIV-1 genes associated with resistance to antiretroviral drugs were detected also in primary HIV infected individuals who did not receive antiretroviral treatment. Drug resistance genotyping of HIV pol gene was done by in situ DNA hybridization using a Line Probe Assay and by direct sequencing. Viral variants harbouring resistance mutations such as: M41, T69R, K70R, M184V, T215Y in the pol gene were detected in 14% of the subjects. HIV mutants resistant to NRT inhibitors were found in 10 and 20% of patients infected before and after the year 2000, respectively. Multiple drug resistant viruses (2-3 drug classes) were present in 3.5% of the mainly recently infected patients. In protease gene only minor resistant mutations were found such as L101 and A71V. These findings indicate the evolution of drug resistance showing a correlation with the time of introduction of combination therapy in our country, where more than 70% of HIV infections were by homo/bisexual transmission. This confirms the transmission of drug-resistant HIV shown by genotype testing during primary infection in therapy-naive patients and initiates serious clinical and public health consequences.
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Affiliation(s)
- Emese Juhász
- Institute of Medical Microbiology, Semmelweis University, Budapest, Hungary
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Paolucci S, Baldanti F, Campanini G, Cancio R, Belfiore A, Maga G, Gerna G. NNRTI-selected mutations at codon 190 of human immunodeficiency virus type 1 reverse transcriptase decrease susceptibility to stavudine and zidovudine. Antiviral Res 2007; 76:99-103. [PMID: 17640745 DOI: 10.1016/j.antiviral.2007.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 04/10/2007] [Accepted: 06/05/2007] [Indexed: 10/23/2022]
Abstract
The non-nucleoside reverse transcriptase (RT) inhibitor (NNRTI)-binding pocket of HIV-1 RT spans codons 100-110, 180-190 and 220-240 and mutations in these domains are responsible for HIV-1 NNRTI resistance. Recombinant HIV-1 strains carrying G190S/A/E, G190S+T215Y, T215Y and K103N mutations were constructed to evaluate susceptibility to both NNRTIs and nucleoside RT inhibitors (NRTIs). In addition, purified recombinant RT enzymes were obtained to determine the degree of in vitro inhibition by drugs of both classes. High-level resistance to nevirapine and moderate level resistance to both stavudine and zidovudine were associated with G190S/A/E substitutions. The simultaneous presence of G190S and T215Y decreased stavudine and zidovudine susceptibility more than T215Y alone. On the other hand, G190S was associated with a marked decrease in RT catalytic efficiency, while T215Y showed a more limited effect. Interestingly, the simultaneous presence of G190S and T215Y was associated with a reduction in the impairment of the G190S-mutated enzyme. Mutations in the HIV-1 RT NNRTI binding pocket may be associated with cross-resistance to NRTI. Selection of double mutants, with further decrease in NRTI susceptibility, might be favoured by the compensatory effect of T215Y on the reduction of RT catalytic efficiency associated with G190S.
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Affiliation(s)
- Stefania Paolucci
- Servizio di Virologia, IRCCS Policlinico San Matteo, 27100 Pavia, Italy
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Ceccherini-Silberstein F, Svicher V, Sing T, Artese A, Santoro MM, Forbici F, Bertoli A, Alcaro S, Palamara G, d'Arminio Monforte A, Balzarini J, Antinori A, Lengauer T, Perno CF. Characterization and structural analysis of novel mutations in human immunodeficiency virus type 1 reverse transcriptase involved in the regulation of resistance to nonnucleoside inhibitors. J Virol 2007; 81:11507-19. [PMID: 17686836 PMCID: PMC2045529 DOI: 10.1128/jvi.00303-07] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Resistance to antivirals is a complex and dynamic phenomenon that involves more mutations than are currently known. Here, we characterize 10 additional mutations (L74V, K101Q, I135M/T, V179I, H221Y, K223E/Q, and L228H/R) in human immunodeficiency virus type 1 (HIV-1) reverse transcriptase which are involved in the regulation of resistance to nonnucleoside reverse transcriptase inhibitors (NNRTIs). These mutations are strongly associated with NNRTI failure and strongly correlate with the classical NNRTI resistance mutations in a data set of 1,904 HIV-1 B-subtype pol sequences from 758 drug-naïve patients, 592 nucleoside reverse transcriptase inhibitor (NRTI)-treated but NNRTI-naïve patients, and 554 patients treated with both NRTIs and NNRTIs. In particular, L74V and H221Y, positively correlated with Y181C, were associated with an increase in Y181C-mediated resistance to nevirapine, while I135M/T mutations, positively correlated with K103N, were associated with an increase in K103N-mediated resistance to efavirenz. In addition, the presence of the I135T polymorphism in NNRTI-naïve patients significantly correlated with the appearance of K103N in cases of NNRTI failure, suggesting that I135T may represent a crucial determinant of NNRTI resistance evolution. Molecular dynamics simulations show that I135T can contribute to the stabilization of the K103N-induced closure of the NNRTI binding pocket by reducing the distance and increasing the number of hydrogen bonds between 103N and 188Y. H221Y also showed negative correlations with type 2 thymidine analogue mutations (TAM2s); its copresence with the TAM2s was associated with a higher level of zidovudine susceptibility. Our study reinforces the complexity of NNRTI resistance and the significant interplay between NRTI- and NNRTI-selected mutations. Mutations beyond those currently known to confer resistance should be considered for a better prediction of clinical response to reverse transcriptase inhibitors and for the development of more efficient new-generation NNRTIs.
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Temesgen Z, Cainelli F, Poeschla EM, Vlahakis SAR, Vento S. Approach to salvage antiretroviral therapy in heavily antiretroviral-experienced HIV-positive adults. THE LANCET. INFECTIOUS DISEASES 2006; 6:496-507. [PMID: 16870528 DOI: 10.1016/s1473-3099(06)70550-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Despite dramatic declines in HIV-associated morbidity and mortality as a result of highly active antiretroviral therapy, management of heavily treatment-experienced patients remains complex and challenging. Treatment response rates with subsequent antiretroviral regimens are lower than with initial antiretroviral therapy. Additionally, increased mortality has been associated with multidrug-resistant HIV. We review data relevant to management of such patients and offer a systematic approach to constructing a salvage antiretroviral regimen.
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Affiliation(s)
- Zelalem Temesgen
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota 55905, USA.
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Hossain MM, Parniak MA. In vitro microbicidal activity of the nonnucleoside reverse transcriptase inhibitor (NNRTI) UC781 against NNRTI-resistant human immunodeficiency virus type 1. J Virol 2006; 80:4440-6. [PMID: 16611904 PMCID: PMC1472006 DOI: 10.1128/jvi.80.9.4440-4446.2006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The nonnucleoside reverse transcriptase inhibitor (NNRTI) UC781 is under development as a microbicide to prevent sexual transmission of the human immunodeficiency virus type 1 (HIV-1). However, NNRTI-resistant HIV-1 is increasingly prevalent in the infected population, and one of the concerns for NNRTI-based microbicides is that they will be ineffective against drug-resistant virus and may in fact selectively transmit NNRTI-resistant virus. We evaluated the microbicidal activity of UC781 against UC781-resistant (UCR), efavirenz-resistant (EFVR), and nevirapine-resistant (NVPR) strains in a variety of microbicide-relevant tests, including inactivation of cell-free virus, inhibition of cell-to-cell HIV-1 transmission, and the ability of UC781 pretreatment to protect cells from subsequent infection in the absence of exogenous drug. UC781 was 10- to 100-fold less effective against NNRTI-resistant HIV-1 compared to wild-type (wt) virus in each of these tests, with UC781 microbicidal activity against the various virus strains being wt > or = NVPR > UCR > or = EFVR. Breakthrough experiments using UC781-pretreated cells and mixtures of wt and NNRTI-resistant HIV-1 showed that UC781-pretreatment selected for NNRTI-resistant HIV-1. However, the efficacy of UC781 was dose dependent, and 25 microM UC781 provided essentially equivalent microbicidal activity against NNRTI-resistant and wt virus. The amount of UC781 in topical microbicide formulations under current development is approximately 100-fold greater than this concentration, so transmission of NNRTI-resistant virus may not be an issue at these microbicide formulation levels of UC781. Nonetheless, the reduced microbicidal activity of UC781 against NNRTI-resistant HIV-1 suggests that additional antiviral agents should be included in NNRTI-based microbicide formulations.
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Affiliation(s)
- Mohammad M Hossain
- University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania 15261, USA
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10
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Buckheit RW. Understanding HIV resistance, fitness, replication capacity and compensation: targeting viral fitness as a therapeutic strategy. Expert Opin Investig Drugs 2005; 13:933-58. [PMID: 15268633 DOI: 10.1517/13543784.13.8.933] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The increasingly prevalent emergence of drug-resistant virus strains in patients being treated with highly active antiretroviral regimens and the increasing rates of transmission of drug-resistant virus strains have focused attention on the critical need for additional antiretroviral agents with novel mechanisms of action and enhanced potency. Furthermore, novel means of employing highly active antiretroviral therapy are needed to reduce or eliminate the virological treatment failures that currently occur. Over the past several years, evidence has mounted supporting the fact that the emergence of resistant strains is associated with reductions in viral fitness, yielding decreases in plasma virus load in treated patients harbouring resistant populations of the virus. Additional mutations that serve to modify fitness (compensatory mutations) and mutations that impact the viral replication capacity also emerge under the selective pressure of drug treatment, and have both negative and positive effects on virus growth. Fitness is generally accepted to refer to the ability of HIV to replicate in a defined environment and thus is used to describe the viral replication potential in the absence of the drug. Although viral fitness and replication capacity are related in some ways, it is important to recognise that viral fitness is not the same as viral replication capacity. This review will assess the recent literature on antiviral drug resistance, viral fitness and viral replication capacity, and discuss means by which the adaptability of HIV to respond rapidly to antiviral treatment through mutation may be used against it. This would be done by treating patients with an aim to lock the deleterious mutations into the resistant virus genome, resulting in a positive therapeutic outcome despite the presence of resistance to the selecting agents. The review will specifically discuss the literature on nucleoside and non-nucleoside reverse transcriptase inhibitors, protease inhibitors, integrase inhibitors, fusion inhibitors, as well as other biological factors involved in viral fitness.
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Affiliation(s)
- Robert W Buckheit
- ImQuest BioSciences, Inc., 7340 Executive Way, Suite R, Frederick, Maryland 21704, USA.
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Tachedjian G, Mijch A. Virological significance, prevalence and genetic basis of hypersusceptibility to nonnucleoside reverse transcriptase inhibitors. Sex Health 2004; 1:81-9. [PMID: 16334989 DOI: 10.1071/sh03012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Nonnucleoside reverse transcriptase inhibitors (NNRTI) are used to treat HIV-infected individuals in combination with nucleoside analogues (NRTI) and protease inhibitors. Long-term treatment with antiretroviral agents results in the emergence of strains with decreased susceptibility (resistance) to the drugs and is one of the major factors in loss of drug efficacy. Conversely, there have been recent reports of HIV strains with increased susceptibility (hypersusceptibility) to NNRTIs. These isolates emerge in patients on long-term antiretroviral therapy particularly in individuals receiving NRTIs. The prevalence of NNRTI hypersusceptibility ranges between 17.5 and 50% in NRTI-treatment experienced compared to 10% in NRTI-naïve patients. There is an inverse correlation between NNRTI hypersusceptibility and phenotypic NRTI resistance and a direct correlation between the number of NRTI resistance mutations present in the HIV reverse transcriptase. Re-sensitisation of phenotypic NNRTI resistance has been reported by NRTI mutations and is not likely to be detected using genotypic resistance assays. Recent studies demonstrate that NNRTI hypersusceptible virus at baseline is likely to predict better virological outcomes in patients on NNRTI-based salvage regimens compared to patients with NNRTI susceptible virus. These studies have implications for the sequence of antiretroviral drug use where patients may benefit from NRTI therapy before the introduction of NNRTIs, however more studies are needed to examine this treatment rationale.
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Affiliation(s)
- Gilda Tachedjian
- Molecular Interactions Group, Macfarlane Burnet Institute for Medical Research and Public Health, GPO Box 2284, Melbourne, Vic. 3001, Australia.
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Jeffrey JL, Feng JY, Qi CCR, Anderson KS, Furman PA. Dioxolane guanosine 5'-triphosphate, an alternative substrate inhibitor of wild-type and mutant HIV-1 reverse transcriptase. Steady state and pre-steady state kinetic analyses. J Biol Chem 2003; 278:18971-9. [PMID: 12651859 DOI: 10.1074/jbc.m210113200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The frequency of human immunodeficiency virus, type 1 (HIV-1) mutations in response to antiviral therapy and resulting drug resistance is of major concern. Amdoxovir ((-)-beta-D-2,6-diaminopurine dioxolane), the prodrug of dioxolane guanosine (DXG), is currently in phase I/II clinical development for the treatment of HIV-1 infection. In vitro, HIV-1 mutants resistant to 3'-azido-3'-deoxythymidine (M41L/D67N/K70R/T215Y/K219Q) and (-)beta-L-2',3'-dideoxy-3'-thiacytidine (3TC) (M184V) remain sensitive to DXG. HIV-1 with the reverse transcriptase mutations K65R, L74V, and/or Q151M were less sensitive to DXG, whereas the mutation K103N re-sensitized the virus to the inhibitory effect of DXG. In order to understand these observations at the enzyme level, we investigated the inhibition of the HIV-1 reverse transcriptase-catalyzed viral DNA synthesis by dioxolane guanosine 5'-triphosphate (DXG-TP), 3'-azido-3'-deoxythymidine-TP, and 3TC-TP by using steady state kinetic analysis and the incorporation of DXG-5'-monophosphate by using pre-steady state kinetic analysis. This mechanistic study provided detailed information on the amdoxovir-related drug resistance at a molecular level. Overall, the enzymatic data correlated well with the antiviral data obtained from cell culture experiments and further supported the use of amdoxovir for the treatment of nucleoside reverse transcriptase inhibitor-experienced patients.
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Affiliation(s)
- Jerry L Jeffrey
- Triangle Pharmaceuticals, Inc., a subsidiary of Gilead Sciences, Durham, North Carolina 27717, USA
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Matsumi S, Kosalaraksa P, Tsang H, Kavlick MF, Harada S, Mitsuya H. Pathways for the emergence of multi-dideoxynucleoside-resistant HIV-1 variants. AIDS 2003; 17:1127-37. [PMID: 12819513 DOI: 10.1097/00002030-200305230-00003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To investigate the mechanism by which the Q151M mutation in reverse transcriptase (RT) that confers multi-dideoxynucleoside resistance on HIV-1 and that requires a two base change (CAG-->ATG) develops, and to understand the reason for the relatively lengthy period of time required for its emergence under therapy with multiple nucleoside RT inhibitors (NRTI). DESIGN AND METHODS Propagation assays and competitive HIV-1 replication assays were used to evaluate the fitness of various infectious clones, including two putative intermediates (HIV-1(Q151K(AAG)) and HIV-(1Q151L(CTG))) for HIV-1(Q151M(ATG)), in terms of sensitivity to zidovudine and didanosine. Steady-state kinetic constants of recombinant RT were also determined. RESULTS HIV-1(Q151L) replicated relatively poorly while HIV-1(Q151K) failed to replicate. When HIV-1(Q151L) was propagated further, it took three pathways in continuing to replicate: (i) HIV-1(Q151L) changed to HIV-1(Q151M) in eight of 16 experiments; (ii) HIV-1(Q151L) reverted to wild-type HIV-1 (HIV-1(WT)) in four of 16 experiments; and (iii) HIV-1(Q151L) acquired an additional mutation M230I in four of 16 experiments improving HIV-1 fitness. The relative order of replicative fitness without drugs was: HIV-1(Q151M) > HIV-1(WT) > HIV-1(Q151L/M230I) > HIV-1(M230I) >> HIV-1(Q151L) >>> HIV-1(Q151K), HIV-1(Q151K/M230I). HIV-1(Q151M) was less susceptible to drugs, while HIV-1(Q151L/M230I) was as sensitive as HIV-1(WT). Enzymatic assays corroborated that HIV-1(Q151L) is more replication-competent than HIV-1(WT) and HIV-1(Q151K) in the presence of drugs. CONCLUSION HIV-1(Q151M) probably develops through a poorly replicating HIV-1(Q151L); however, it is also possible that it occurs through two concurrent base changes. The present data should explain the mechanism by which HIV-1(Q151M) emerges after long-term chemotherapy with NRTI.
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Affiliation(s)
- Shintaro Matsumi
- The Experimental Retrovirology Section, HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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Balzarini J, Pannecouque C, De Clercq E, Aquaro S, Perno CF, Egberink H, Holý A. Antiretrovirus activity of a novel class of acyclic pyrimidine nucleoside phosphonates. Antimicrob Agents Chemother 2002; 46:2185-93. [PMID: 12069973 PMCID: PMC127315 DOI: 10.1128/aac.46.7.2185-2193.2002] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel class of acyclic nucleoside phosphonates has been discovered in which the base consists of a pyrimidine preferably containing an amino group at C-2 and C-4 and a 2-(phosphonomethoxy)ethoxy (PMEO) or a 2-(phosphonomethoxy)propoxy (PMPO) group at C-6. The 6-PMEO 2,4-diaminopyrimidine (compound 1) and 6-PMPO 2,4-diaminopyrimidine (compound 11) derivatives showed potent activity against human immunodeficiency virus (HIV) in the laboratory (i.e., CEM and MT-4 cells) and in primary (i.e., peripheral blood lymphocyte and monocyte/macrophage) cell cultures and pronounced activity against Moloney murine sarcoma virus in newborn NMRI mice. Their in vitro and in vivo antiretroviral activity was comparable to that of reference compounds 9-[(2-phosphonomethoxy)ethyl]adenine (adefovir) and (R)-9-[(2-phosphonomethoxy)-propyl]adenine (tenofovir), and the enantiospecificity of (R)- and (S)-PMPO pyrimidine derivatives as regards their antiretroviral activity was identical to that of the classical (R)- and (S)-9-(2-phosphonomethoxy)propyl purine derivatives. The prototype PMEO and PMPO pyrimidine analogues were relatively nontoxic in cell culture and did not markedly interfere with host cell macromolecular (i.e., DNA, RNA, or protein) synthesis. Compounds 1 and 11 should be considered attractive novel pyrimidine nucleotide phosphonate analogues to be further pursued for their potential as antiretroviral agents in the clinical setting.
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Affiliation(s)
- J Balzarini
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium.
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Affiliation(s)
- B Larder
- Visible Genetics Inc., 184 Cambridge Science Park, Cambridge CB4 0GA, UK.
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