Resistance profile of the HIV-1 maturation inhibitor GSK3532795 in vitro and in a clinical study

Dicker, Ira; Zhang, Sharon; Ray, Neelanjana; Beno, Brett R.; Regueiro‐Ren, Alicia; Joshi, Samit R; Cockett, Mark I.; Krystal, Mark; Lataillade, Max

doi:10.1371/journal.pone.0224076

Cited by 16 publications

(39 citation statements)

References 38 publications

(68 reference statements)

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“…These substitutions, A224T and H219Q, are in the cyclophilin A binding loop of Gag and were detectable by passages 21 and 29, respectively. H219Q and other substitutions in the cyclophilin A binding loop (amino acids 217 to 225 in Gag) are polymorphisms in the Los Alamos Database ( 47 , 48 ) that are known to modulate incorporation of cyclophilin A into virions when virus is passaged in cyclophilin-A-rich immortalized CD4 + T cells even in the absence of drugs, thereby resulting in virion cyclophilin A levels that are optimal for replication in these cell lines ( 49 , 50 ). From these data, we infer that in the nelfinavir selection group, a tissue-culture-adaptive cyclophilin A binding loop polymorphism initially emerged in Gag and likely led to improved fitness and replication in a drug concentration 8-fold greater than the EC 50 ; this was followed later by nelfinavir-specific resistance mutations, which likely led to high level nelfinavir resistance.…”

Section: Resultsmentioning

confidence: 99%

Identification of an Antiretroviral Small Molecule That Appears To Be a Host-Targeting Inhibitor of HIV-1 Assembly

Reed

Solas²,

Kitaygorodskyy³

et al. 2021

J Virol

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Given the projected increase in multidrug resistant HIV-1, there is an urgent need for development of antiretrovirals that act on virus life-cycle stages not targeted by drugs currently in use. Host-targeting compounds are of particular interest because they can offer a high barrier to resistance. Here we report identification of two related small molecules that inhibit HIV-1 late events, an HIV-1 life cycle stage for which potent and specific inhibitors are lacking. This chemotype was discovered using cell-free protein synthesis and assembly systems that recapitulate intracellular host-catalyzed viral capsid assembly pathways. These compounds inhibit replication of HIV-1 in human T cell lines and PBMCs and are effective against a primary isolate. They reduce virus production, likely by inhibiting a post-translational step in HIV-1 Gag assembly. Notably, the compound colocalizes with HIV-1 Gag in situ; however, unexpectedly, selection experiments failed to identify compound-specific resistance mutations in gag or pol, even though known resistance mutations developed upon parallel nelfinavir selection. Thus, we hypothesized that instead of binding to Gag directly, these compounds localize to assembly intermediates, the intracellular multiprotein complexes containing Gag and host factors that form during immature HIV-1 capsid assembly. Indeed, imaging of infected cells shows compound colocalized with two host enzymes found in assembly intermediates, ABCE1 and DDX6, but not two host proteins found in other complexes. While the exact target and mechanism of action of this chemotype remain to be determined, these findings suggest that these compounds represent first-in-class, host-targeting inhibitors of intracellular events in HIV-1 assembly. IMPORTANCE The success of antiretroviral treatment for HIV-1 is at risk of being undermined by the growing problem of drug resistance. Thus, there is a need to identify antiretrovirals that act on viral life cycle stages not targeted by drugs in use, such as the events of HIV-1 Gag assembly. To address this gap, we developed a compound screen that recapitulates the intracellular events of HIV-1 assembly, including viral-host interactions that promote assembly. This effort led to identification of a new chemotype that inhibits HIV-1 replication at nanomolar concentrations, likely by acting on assembly. This compound colocalized with Gag and two host enzymes that facilitate capsid assembly. However, resistance selection did not result in compound-specific mutations in gag, suggesting that the chemotype does not directly target Gag. We hypothesize that this chemotype represents a first-in-class inhibitor of virus production that acts by targeting a viral-host complex important for HIV-1 Gag assembly.

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Section: Resultsmentioning

confidence: 99%

Identification of an Antiretroviral Small Molecule That Appears To Be a Host-Targeting Inhibitor of HIV-1 Assembly

Reed

Solas²,

Kitaygorodskyy³

et al. 2021

J Virol

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“…Two other substitutions in Gag became dominant during Nelfinavir selection, A224T and H219Q (indicated in blue in Fig 7B), at passage 21 and 29. H219Q and other substitutions in the cyclophilin A binding loop, amino acids 217-225 in Gag, are polymorphisms found in the Los Alamos Database (41, 42)that are known to reduce incorporation of cyclophilin A into virions when virus is passaged in cyclophilin-A-rich immortalized CD4+T cells even in the absence of drugs, thereby resulting in virion cyclophilin A levels that are optimal for replication in cyclophilin-A-rich cell lines (43, 44). Thus, from these data, we infer that in the Nelfinavir selection group, tissue-culture-adaptive cyclophilin A binding loop polymorphisms initially emerged in Gag and likely led to improved fitness and low-level resistance (replication in a drug concentration 8-fold greater than the EC50); these were followed later by Nelfinavir-specific resistance mutations, which likely led to high level Nelfinavir resistance.…”

Section: Resultsmentioning

confidence: 99%

“…Known tissue-culture adaptations were observed in Gag, involving cyclophilin A loop polymorphisms, during PAV206 and Nelfinavir selection. These polymorphisms are known to reduce the amount of cyclophilin A incorporated into virions when virus is passaged in cyclophilin A-rich immortalized CD4+ T cells, in the presence or absence of antiretroviral drugs (43, 44). Additionally, a second set of mutations was observed in PAV206 and Nelfinavir.…”

Section: Discussionmentioning

confidence: 99%

Identification of an antiretroviral small molecule that appears to be a host-targeting inhibitor of HIV-1 assembly

Reed

Solas²,

Kitaygorodskyy³

et al. 2020

Preprint

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Given the projected increase in multidrug resistant HIV-1, there is an urgent need for development of antiretrovirals that act on virus life-cycle stages that are not targeted by antiretrovirals currently in use. Host-targeting drugs are of particular interest because they can offer a high barrier to resistance. Here we report identification of two related small molecules that inhibit HIV-1 late events, a stage of the HIV-1 life cycle for which potent and specific inhibitors are lacking. This chemotype was discovered using cell-free protein synthesis and assembly systems that recapitulate intracellular host-catalyzed viral capsid assembly pathways. These compounds inhibit replication of HIV-1 in human T cell lines and PBMCs and are effective against a primary isolate. They reduce virus production, likely by inhibiting a post-translational step in HIV-1 Gag assembly. Notably, the compound colocalizes with HIV-1 Gag in situ; however, unexpectedly, selection experiments failed to identify compound-specific resistance mutations in gag or pol, even though known resistance mutations developed in a parallel nelfinavir selection. Thus, we hypothesized that instead of binding to Gag directly, these compounds might localize to assembly intermediates, the intracellular multiprotein complexes containing Gag and host factors that are formed during immature HIV-1 capsid assembly. Indeed, imaging of infected cells showed colocalization of the compound with two host enzymes found in assembly intermediates, ABCE1 and DDX6. While the exact target and mechanism of action of this chemotype remain to be determined, these findings suggest that these compounds represent first-in-class, host-targeting inhibitors of intracellular events in HIV-1 assembly.IMPORTANCEThe success of antiretroviral treatment for HIV-1 is at risk of being undermined by the growing problem of drug resistance. Thus, there is a need to identify antiretrovirals that act on viral life cycle stages not targeted by drugs in use, such as the events of HIV-1 Gag assembly. To address this gap, we developed a compound screen that recapitulates the intracellular events of HIV-1 assembly, including viral-host interactions that promote assembly. This effort led to identification of a new chemotype that inhibits HIV-1 replication at nanomolar concentrations by inhibiting virus production. This compound colocalized with Gag and two host enzymes that facilitate capsid assembly but resistance selection did not result in compound-specific mutations in gag, suggesting that the chemotype does not directly target Gag. We hypothesize that this chemotype may represent a first-in-class inhibitor of virus production that acts by targeting a viral-host complex important for HIV-1 Gag assembly.

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“…Although, as mentioned above, it is likely that BVM and PF96 bind in a similar fashion, the low solubility of PF96 has stymied attempts to directly demonstrate this. Similarly, recent characterization of other second-generation MIs has provided further evidence of six-helix bundle binding and stabilization [ 84 , 85 , 86 ]. Resistance to MIs appears to arise via several mechanisms: loss of compound binding, compound dependency, and increased rates of CA-SP1 processing [ 59 , 63 , 66 , 87 , 88 ].…”

Section: Mis That Block Ca-sp1 Processingmentioning

confidence: 98%

“…Although high protein binding and poor solubility continue to present challenges for this class of molecules, the second-generation molecules display improvements in these properties relative to BVM. The BVM analog GSK-3532795/BMS-955176, was recently taken into clinical trials with largely favorable outcomes in terms of its ability to suppress viral replication [ 84 , 101 , 102 , 103 ]. However, clinical development of this compound was halted because of gastrointestinal intolerability and the emergence of the SP1-A1V resistance mutation, which is often observed with this class of molecules in vitro [ 103 ].…”

Section: Mis That Block Ca-sp1 Processingmentioning

confidence: 99%

HIV-1 Maturation: Lessons Learned from Inhibitors

Kleinpeter

Freed

2020

Viruses

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Since the emergence of HIV and AIDS in the early 1980s, the development of safe and effective therapies has accompanied a massive increase in our understanding of the fundamental processes that drive HIV biology. As basic HIV research has informed the development of novel therapies, HIV inhibitors have been used as probes for investigating basic mechanisms of HIV-1 replication, transmission, and pathogenesis. This positive feedback cycle has led to the development of highly effective combination antiretroviral therapy (cART), which has helped stall the progression to AIDS, prolong lives, and reduce transmission of the virus. However, to combat the growing rates of virologic failure and toxicity associated with long-term therapy, it is important to diversify our repertoire of HIV-1 treatments by identifying compounds that block additional steps not targeted by current drugs. Most of the available therapeutics disrupt early events in the replication cycle, with the exception of the protease (PR) inhibitors, which act at the virus maturation step. HIV-1 maturation consists of a series of biochemical changes that facilitate the conversion of an immature, noninfectious particle to a mature infectious virion. These changes include proteolytic processing of the Gag polyprotein by the viral protease (PR), structural rearrangement of the capsid (CA) protein, and assembly of individual CA monomers into hexamers and pentamers that ultimately form the capsid. Here, we review the development and therapeutic potential of maturation inhibitors (MIs), an experimental class of anti-HIV-1 compounds with mechanisms of action distinct from those of the PR inhibitors. We emphasize the key insights into HIV-1 biology and structure that the study of MIs has provided. We will focus on three distinct groups of inhibitors that block HIV-1 maturation: (1) compounds that block the processing of the CA-spacer peptide 1 (SP1) cleavage intermediate, the original class of compounds to which the term MI was applied; (2) CA-binding inhibitors that disrupt capsid condensation; and (3) allosteric integrase inhibitors (ALLINIs) that block the packaging of the viral RNA genome into the condensing capsid during maturation. Although these three classes of compounds have distinct structures and mechanisms of action, they share the ability to block the formation of the condensed conical capsid, thereby blocking particle infectivity.

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Resistance profile of the HIV-1 maturation inhibitor GSK3532795 in vitro and in a clinical study

Cited by 16 publications

References 38 publications

Identification of an Antiretroviral Small Molecule That Appears To Be a Host-Targeting Inhibitor of HIV-1 Assembly

Identification of an Antiretroviral Small Molecule That Appears To Be a Host-Targeting Inhibitor of HIV-1 Assembly

Identification of an antiretroviral small molecule that appears to be a host-targeting inhibitor of HIV-1 assembly

HIV-1 Maturation: Lessons Learned from Inhibitors

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