Anti-HIV Activity of MDL 74968, a Novel Acyclonucleotide Derivative of Guanine: Drug Resistance and Drug Combination Effects <i>in Vitro</i>

Taylor, D.L.; Ahmed, Sohail; Brennan, T.; Navé, Jean-François; Casara, Patrick; Tyms, A. S.

doi:10.1177/095632029600700505

Cited by 3 publications

(10 citation statements)

References 32 publications

(21 reference statements)

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“…In addition to the codon change at position 184, a partial change of lysine to arginine at position 65, after prolonged passage in the presence of dOTC, was also recorded. This K65R mutation has been observed previously in vitro and confers resistance to 3TC, ddC (Gu et al, 1994), PMEA (Gu et al, 1995a;Taylor et al, 1996) and abacavir (Tisdale et al, 1997). The 65R/184V double mutant has also been previously observed in a patient on ddC therapy (Gu et al, 1995b).…”

Section: Discussionmentioning

confidence: 90%

“…The wild-type HIV-1 strain RF was cultured in C8166 cells in the presence of different concentrations of dOTC, (-)dOTC and (+)dOTC and resistant virus selected as previously described for other drug-resistant variants (Taylor et al, 1996). Mutants with resistance to 3TC were selected in parallel and the highest concentrations of compound used were 200 µM.…”

Section: Selection Of Drug-resistant Virus and Pcr Sequencingmentioning

confidence: 99%

“…After incubation at 37°C for 3 days, the cell-free culture fluid was assayed for levels of p24 viral antigen using the Murex HIV Antigen ELISA (Abbott). For assays using MT-4 cells, the MTT cell viability assay was used as described previously (Taylor et al, 1996). For assays in PBMCs, 3-day PHA-and IL-2-stimulated cells were washed and infected with clinical isolates or laboratory strains of HIV-1 (virus input ranged from 50-5000 pg of p24 per 10 7 cells) for 2 h at room temperature.…”

Section: Antiviral Assaysmentioning

confidence: 99%

“…Virus was screened for drug-sensitivity in MT-4 cells by MTT cell viability assay and the RT gene sequenced after 10, 15 and 20 passages. For sequencing, DNA was purified from drug-treated virus-infected cells and the RT gene amplified from proviral DNA as described previously (Taylor et al, 1996). Sequencing was performed on two independently generated PCR amplifications using the primers described previously (Taylor et al, 1996) and the Big Dye terminator cycle sequencing ready reaction kit (Applied Biosystems, UK), according to the manufacturer's instructions.…”

Section: Selection Of Drug-resistant Virus and Pcr Sequencingmentioning

confidence: 99%

“…AZT-, 3TC-, PMEA-, nevirapine-and saquinavir-resistant strains of HIV-1 RF were obtained after culture of virus in the presence of increasing concentrations of compound as described previously (Taylor et al, 1996(Taylor et al, , 1997) and the mutations determined by sequencing the RT or protease genes. T-cells were cultured in RPMI 1640 (Gibco BRL) supplemented with 10% fetal calf serum, and antibiotics.…”

Section: Virus and Cellsmentioning

confidence: 99%

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Drug Resistance and Drug Combination Features of the Human Immunodeficiency Virus Inhibitor, BCH-10652 [(±)-2′-Deoxy-3′-Oxa-4′-Thiocytidine, dOTC]

Taylor¹,

Ahmed²,

Tyms³

et al. 2000

Antivir Chem Chemother

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The heterosubstituted nucleoside analogue dOTC [(±)-2′-deoxy-3′-oxa-4′-thiocytidine, BCH-10652] is a racemic compound structurally related to 3TC (lamivudine), but has the oxygen and sulphur in the furanosyl ring transposed. Both the enantiomers (-)dOTC (BCH-10618) and (+)dOTC (BCH-10619) had equivalent activity against wild-type strains of HIV-1 in C8166 T-cells (EC50 1.0–10.0 μM) and in PBMCs (EC50 0.1–3.0 μM). Investigation of the activity of dOTC and its enantiomers against laboratory strains of HIV-1 with defined resistance to 3TC, AZT (zidovudine), ddl (didanosine), PMEA (adefovir), nevirapine and saquinavir indicated that sensitivity was maintained (< 3-fold change in EC50) in all cases, with the exception of HIV-1RF 3TC-resistant viruses. The degree of resistance recorded for dOTC (four- to sevenfold), (-)dOTC (five- to eightfold) and (+)dOTC (five- to > 18-fold) against these M184I or M184V mutants, was significantly less than that recorded for 3TC (>100-fold). In addition, the inhibitory effect of the compounds against clinical isolates of HIV-1 recovered from patients with suspected resistance to 3TC and AZT was investigated. Clinical isolates were genotyped using the Murex Line Probe Assay (LiPA) and subgrouped into wild-type, 3TC-resistant and dual 3TC/AZT-resistant, as well as undefined or mixed genotype populations. Compared with the mean EC50 values obtained with genotypically and phenotypically wild-type clinical isolates, the mean EC50 values calculated for isolates phenotypically resistant to 3TC or 3TC and AZT were only 2.6-, 1.6- and 8.2-fold higher for dOTC, (-)dOTC and (+)dOTC, respectively. When the rate of emergence of virus resistant to dOTC and its enantiomers in vitro was investigated, virus resistant to (+)dOTC was readily selected for (< 10 passages), and a methionine (ATG) to isoleucine (ATA) amino acid change at codon 184 was identified. In contrast, virus resistant to dOTC and (-)dOTC took longer to appear (15–20 passages), with a methionine (ATG) to valine (GTG) amino acid change at position 184 identified in both cases. In addition, virus passaged 20 times in the presence of dOTC also had a partial lysine (AAA) to arginine (AGA) exchange at position 65. These viruses showed only low-level resistance to dOTC and its enantiomers, but were highly resistant to 3TC. The antiviral effects of dOTC in combination with the nucleoside RT inhibitors AZT, 3TC, d4T (stavudine) and ddl, the non-nucleoside RT inhibitor nevirapine and the protease inhibitors saquinavir, ritonavir and indinavir was investigated. Two-way drug combination assays were carried out in peripheral blood mononuclear cell (PBMC) cultures by measuring the reduction in p24 viral antigen levels, and data was analysed using the MacSynergy II program. dOTC in combination with 3TC or d4T showed a moderate synergistic effect while all other combinations had an additive interaction.

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Section: Discussionmentioning

confidence: 90%

Section: Selection Of Drug-resistant Virus and Pcr Sequencingmentioning

confidence: 99%

Section: Antiviral Assaysmentioning

confidence: 99%

Section: Selection Of Drug-resistant Virus and Pcr Sequencingmentioning

confidence: 99%

Section: Virus and Cellsmentioning

confidence: 99%

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Drug Resistance and Drug Combination Features of the Human Immunodeficiency Virus Inhibitor, BCH-10652 [(±)-2′-Deoxy-3′-Oxa-4′-Thiocytidine, dOTC]

Taylor¹,

Ahmed²,

Tyms³

et al. 2000

Antivir Chem Chemother

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Viral quasispecies and the problem of vaccine-escape and drug-resistant mutants

Domingo

Menéndez‐Arias

Quiñones‐Mateu

et al. 1997

Progress in Drug Research/Fortschritte Der Arzneimittelforschung/Progrès Des Recherches Pharmaceutiques

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Pyrido [1,2a] Indole Derivatives Identified as Novel Nonnucleoside Reverse Transcriptase Inhibitors of Human Immunodeficiency Virus Type 1

Taylor

Ahmed

Chambers

et al. 1999

Antivir Chem Chemother

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Pyrido [1,2a] indole derivatives were identified as potent inhibitors of human immunodeficiency virus type 1 (HIV-1) replication during a random screening programme. The compounds showed no antiviral activity against HIV-2 or in cells chronically infected with HIV-1, but had good inhibitory effect against purified HIV-1 reverse transcriptase (RT) in an in vitro assay. They were therefore classified as nonnucleoside RT inhibitors (NNRTI). The synthesis of additional compounds of the same class revealed a structure—activity relationship. The most potent compound of the series, BCH-1, had similar antiviral activity to the licensed NNRTI nevirapine against laboratory strains of HIV-1 cultured in cell lines and primary clinical isolates of HIV-1 cultured in peripheral blood mononuclear cells. However, BCH-1 showed greater cytotoxicity, providing a narrow selectivity index in the order of 35. BCH-1 had equivalent antiviral activity against viruses resistant to the nucleoside RT inhibitors zidovudine, didanosine and lamivudine and maintained better activity (less than threefold change in IC50) than nevirapine against viruses resistant to a range of NNRTIs with the single amino acid changes L100I, K103N, E138K or Y181C in the RT. Viruses with single V106A or Y188C amino acid changes showed five- and 10-fold resistance to BCH-1, respectively, in contrast to nevirapine, which had a >100-fold change in IC50. However, virus with both V106A and Y188C amino acid changes showed higher level resistance (>15-fold) to BCH-1. Virus with >10-fold resistance to BCH-1 was rapidly selected for after growth in increasing concentrations of compound and was shown to be cross-resistant to nevirapine. Sequencing of this virus revealed two amino acid changes at positions 179 (V to D) and 181 (Y to C) in the RT. BCH-1 represents a new class of NNRTI, which may act as a lead to identify more selective compounds.

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Anti-HIV Activity of MDL 74968, a Novel Acyclonucleotide Derivative of Guanine: Drug Resistance and Drug Combination Effects in Vitro

Cited by 3 publications

References 32 publications

Drug Resistance and Drug Combination Features of the Human Immunodeficiency Virus Inhibitor, BCH-10652 [(±)-2′-Deoxy-3′-Oxa-4′-Thiocytidine, dOTC]

Drug Resistance and Drug Combination Features of the Human Immunodeficiency Virus Inhibitor, BCH-10652 [(±)-2′-Deoxy-3′-Oxa-4′-Thiocytidine, dOTC]

Viral quasispecies and the problem of vaccine-escape and drug-resistant mutants

Pyrido [1,2a] Indole Derivatives Identified as Novel Nonnucleoside Reverse Transcriptase Inhibitors of Human Immunodeficiency Virus Type 1

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