The G140S mutation in HIV integrases from raltegravir-resistant patients rescues catalytic defect due to the resistance Q148H mutation

Abstract

Raltegravir (MK-0518) is the first integrase (IN) inhibitor to be approved by the US FDA and is currently used in clinical treatment of viruses resistant to other antiretroviral compounds. Virological failure of Raltegravir treatment is associated with mutations in the IN gene following two main distinct genetic pathways involving either the N155 or Q148 residue. Importantly, in most cases, an additional mutation at the position G140 is associated with the Q148 pathway. Here, we investigated the viral DNA kinetics for mutants identified in Raltegravir-resistant patients. We found that (i) integration is impaired for Q148H when compared with the wild-type, G140S and G140S/Q148H mutants; and (ii) the N155H and G140S mutations confer lower levels of resistance than the Q148H mutation. We also characterized the corresponding recombinant INs properties. Enzymatic performances closely parallel ex vivo studies. The Q148H mutation ‘freezes’ IN into a catalytically inactive state. By contrast, the conformational transition converting the inactive form into an active form is rescued by the G140S/Q148H double mutation. In conclusion, the Q148H mutation is responsible for resistance to Raltegravir whereas the G140S mutation increases viral fitness in the G140S/Q148H context. Altogether, these results account for the predominance of G140S/Q148H mutants in clinical trials using Raltegravir.

Differential Sensitivities of Retroviruses to Integrase Strand Transfer Inhibitors

“…The double mutation conferred significant resistance to both compounds, as the EC 50 s of RAL and EVG were about 1.9 M and 2.3 M, respectively (FC values, 241 and 1,762, respectively; Table 1). These results are fully consistent with those of previous studies that concluded the secondary G140S change increased the overall level of resistance to RAL conferred by the primary Q148H mutation and repaired an inherent IN catalytic defect (6,26). Moreover, they established our ability to detect relatively large FCs in sensitivity to INSTIs ( Table 1).…”

Substitutions at Amino Acid Positions 143, 148, and 155 of HIV-1 Integrase Define Distinct Genetic Barriers to Raltegravir Resistance In Vivo

“…At this point, all available data suggest that N155H variants are preferentially selected early in RAL treatment failure but are subsequently replaced by variants containing other primary mutations after the further acquisition of secondary mutations under RAL pressure (26). The later emergence of Q148H variants is also consistent with the observation that this mutation impairs integration which can be rescued by the addition of a G140S mutation (6). Based on our survey of 200 clinical isolates, single substitution Q148H variants were rarely observed in vivo and, when identified, rapidly acquired G140S.…”

Effect of HIV-1 Integrase Resistance Mutations When Introduced into SIVmac239 on Susceptibility to Integrase Strand Transfer Inhibitors

“…3). In HIV-1, the relative viral fitness of IN mutant viruses in competition with WT showed that Q148R resulted in a reduction in viral fitness to ϳ59% of WT levels, while N155H caused only a 24% reduction in relative fitness (52)(53)(54). The addition of the G140S mutation to Q148R diminished replication capacity to levels similar to those seen for Q148R-mutated HIV-1 (59% of WT levels) (54).…”