Implications of HIV-1 M Group Polymorphisms on Integrase Inhibitor Efficacy and Resistance: Genetic and Structural <i>in Silico</i> Analyses

Loizidou, Eriketi Z.; Kousiappa, Ioanna; Zeinalipour-Yazdi, Constantinos D.; Vijver, David van de; Kostrikis, Leondios G.

doi:10.1021/bi8019349

Cited by 25 publications

(14 citation statements)

References 22 publications

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“…Raltegravir may bind to the divalent metals and form a metal-drug complex which is unable to cross the cell membrane. It is important to note that binding of raltegravir to a divalent metal (magnesium) is a prerequisite for inhibition of HIV integrase (17). Antacids containing magnesium caused no significant change in raltegravir C max or AUC but did reduce C 12 , resulting in 75% of patients having a C 12 less than the IC 95 (15).…”

Section: Discussionmentioning

confidence: 99%

Divalent Metals and pH Alter Raltegravir Disposition In Vitro

Moss

Siccardi

Murphy

et al. 2012

Antimicrob Agents Chemother

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bRaltegravir shows marked pharmacokinetic variability in patients, with gastrointestinal pH and divalent-metal binding being potential factors. We investigated raltegravir solubility, lipophilicity, pK a , and permeativity in vitro to elucidate known interactions with omeprazole, antacids, and food, all of which increase gastric pH. Solubility of raltegravir was determined at pH 1 to 8. Lipophilicity of raltegravir was determined using octanol-water partition. Raltegravir pK a was determined using UV spectroscopy. The effects of pH, metal salts, and omeprazole on the cellular permeativity of raltegravir were determined using Caco-2 monolayers. Cellular accumulation studies were used to determine the effect of interplay between pH and ABCB1 transport on raltegravir accumulation. Samples were analyzed using liquid chromatography-tandem mass spectroscopy (LC-MS/MS) or scintillation counting. Raltegravir at 10 mM was partly insoluble at pH 6.6 and below. Raltegravir lipophilicity was pH dependent and was reduced as pH was increased from 5 to 9. The pK a of raltegravir was 6.7. Raltegravir cellular permeativity was heavily influenced by changes in extracellular pH, where apical-to-basolateral permeativity was reduced 9-fold (P < 0.05) when apical pH was increased from 5 to 8.5. Raltegravir cellular permeativity was also reduced in the presence of magnesium and calcium. Omeprazole did not alter raltegravir cellular permeativity. Cellular accumulation of raltegravir was increased independently by inhibiting ABCB1 and by lowering extracellular pH from pH 8 to 5. Gastrointestinal pH and polyvalent metals can potentially alter the pharmacokinetic properties of raltegravir, and these data provide an explanation for the variability in raltegravir exposure in patients. The evaluation of how divalent-metal-containing products, such as multivitamins, that do not affect gastric pH alter raltegravir pharmacokinetics in patients is now justified. R altegravir, the first licensed integrase inhibitor for treatment of HIV, has potent in vitro and clinical activity (22). The primary route of raltegravir metabolism is glucuronidation via UDP glucuronosyltransferase 1A1 (14), and the drug is not a substrate or inhibitor of the major cytochrome P450 enzymes (12). However, there are known drug interactions involving UGT1A1 which may alter raltegravir plasma exposure. Atazanavir inhibits UGT1A1, causing an increase in raltegravir exposure (4), and rifampin mediates induction of UGT1A1, causing a decrease in raltegravir exposure (27). In addition, raltegravir is a weak substrate for the drug transporters ABCB1, SLC22A6, and SLC15A1 and also inhibits SLC22A6 in vitro (18). Marked inter-and intrapatient variability in raltegravir plasma exposure exists, and the relationship between the pharmacokinetics (PK) and pharmacodynamics (PD) of the drug remains poorly understood (7).The pH of the gastrointestinal (GI) tract is an important factor in the absorption of many drugs, potentially altering drug release, solubility, chemical stability, charg...

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Section: Discussionmentioning

confidence: 99%

Divalent Metals and pH Alter Raltegravir Disposition In Vitro

Moss

Siccardi

Murphy

et al. 2012

Antimicrob Agents Chemother

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“…In silico observations suggest that subtype-specific differences in regard to key amino acids in integrase, including those close to the catalytic site, may pose an effect on the binding of RAL [13,27,28]. Therefore, subtype-specific variations in DNA-binding domains could also affect the affinity of RAL for integrase.…”

Section: Discussionmentioning

confidence: 99%

Comparative biochemical analysis of HIV-1 subtype B and C integrase enzymes

et al. 2009

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BackgroundIntegrase inhibitors are currently being incorporated into highly active antiretroviral therapy (HAART). Due to high HIV variability, integrase inhibitor efficacy must be evaluated against a range of integrase enzymes from different subtypes.MethodsThis study compares the enzymatic activities of HIV-1 integrase from subtypes B and C as well as susceptibility to various integrase inhibitors in vitro. The catalytic activities of both enzymes were analyzed in regard to each of 3' processing and strand transfer activities both in the presence and absence of the integrase inhibitors raltegravir (RAL), elvitegravir (EVG), and MK-2048.ResultsOur results show that integrase function is similar with enzymes of either subtype and that the various integrase strand transfer inhibitors (INSTIs) that were employed possessed similar inhibitory activity against both enzymes.ConclusionThis suggests that the use of integrase inhibitors against HIV-1 subtype C will result in comparable outcomes to those obtained against subtype B infections.

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“…6). The strategy of using the early Shionogi inhibitor “5-CITEP” in 1QS4.pdb as a surrogate for the CA overhang has been used by other labs 13,14. This strategy is supported by experimental data on the kinetic properties of strand transfer inhibitors of HIV integrase, which indicated that adenosine (in the “CA overhang” generated after cleavage of the viral cDNA) acts as a “shield” or wall that impedes the rate of association of inhibitors with the active site 54…”

Section: Methodsmentioning

confidence: 99%

A Dynamic Model of HIV Integrase Inhibition and Drug Resistance

Perryman

Forli

Morris

et al. 2010

Journal of Molecular Biology

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Human immunodeficiency virus type 1 (HIV-1) integrase is one of three virally encoded enzymes essential for replication and, therefore, a rational choice as a drug target for the treatment of HIV-1 infected individuals. In 2007 raltegravir became the first integrase inhibitor approved for use in the treatment of HIV infected patients, more than a decade since the approval of the first protease inhibitor (saquinavir, Hoffman La-Roche, 1995) and two decades since the approval of the first reverse transcriptase inhibitor (retrovir, Glaxo Smithkline, 1987). The slow progress towards a clinically effective HIV-1 integrase inhibitor can at least in part be attributed to a poor structural understanding of this key viral protein. Here we describe the development of a restrained molecular dynamics protocol that produces a more accurate model of the active site of this drug target. This model provides an advance on previously described models as it ensures that the catalytic DDE motif makes correct, monodentate, interactions with the two active site magnesium ions. Dynamic restraints applied to this coordination state create models with the correct solvation sphere for the metal ion complex and highlight the coordination sites available for metal binding ligands. Applying appropriate dynamic flexibility to the core domain allowed the inclusion of multiple conformational states in subsequent docking studies. These models have allowed us to (1) explore the effects of key drug resistance mutations on the dynamic flexibility and conformational preferences of HIV integrase and to (2) study raltegravir binding in the context of these dynamic models of both wild type and the G140S/Q148H drug resistant enzyme.

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Implications of HIV-1 M Group Polymorphisms on Integrase Inhibitor Efficacy and Resistance: Genetic and Structural in Silico Analyses

Cited by 25 publications

References 22 publications

Divalent Metals and pH Alter Raltegravir Disposition In Vitro

Divalent Metals and pH Alter Raltegravir Disposition In Vitro

Comparative biochemical analysis of HIV-1 subtype B and C integrase enzymes

A Dynamic Model of HIV Integrase Inhibition and Drug Resistance

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