Relationship of potency and resilience to drug resistant mutations for GW420867X revealed by crystal structures of inhibitor complexes for wild-type, Leu100Ile, Lys101Glu, and Tyr188Cys mutant HIV-1 reverse transcriptases.

The selection of drug resistant viruses is a major problem in efforts to combat HIV and AIDS, hence, new compounds are required. We report crystal structures of wild-type and mutant HIV-1 RT with bound non-nucleoside (NNRTI) GW420867X, aimed at investigating the basis for its high potency and improved drug resistance profile compared to the first-generation drug nevirapine. GW420867X occupies a smaller volume than many NNRTIs, yet accesses key regions of the binding pocket. GW420867X has few contacts with Tyr188, hence, explaining the small effect of mutating this residue on inhibitor-binding potency. In a mutated NNRTI pocket, GW420867X either remains in a similar position compared to wild-type (RT(Leu100Ile) and RT(Tyr188Cys)) or rearranges within the pocket (RT(Lys101Glu)). For RT(Leu100Ile), GW420867X does not shift position, in spite of forming different side-chain contacts. The small bulk of GW420867X allows adaptation to a mutated NNRTI binding site by repositioning or readjustment of side-chain contacts with only small reductions in binding affinity.

Structure-activity relationship studies of novel benzophenones leading to the discovery of a potent, next generation HIV nonnucleoside reverse transcriptase inhibitor.

Despite the progress of the past two decades, there is still considerable need for safe, efficacious drugs that target human immunodeficiency virus (HIV). This is particularly true for the growing number of patients infected with virus resistant to currently approved HIV drugs. Our high throughput screening effort identified a benzophenone template as a potential nonnucleoside reverse transcriptase inhibitor (NNRTI). This manuscript describes our extensive exploration of the benzophenone structure-activity relationships, which culminated in the identification of several compounds with very potent inhibition of both wild type and clinically relevant NNRTI-resistant mutant strains of HIV. These potent inhibitors include 70h (GW678248), which has in vitro antiviral assay IC(50) values of 0.5 nM against wild-type HIV, 1 nM against the K103N mutant associated with clinical resistance to efavirenz, and 0.7 nM against the Y181C mutant associated with clinical resistance to nevirapine. Compound 70h has also demonstrated relatively low clearance in intravenous pharmacokinetic studies in three species, and it is the active component of a drug candidate which has progressed to phase 2 clinical studies.

Design of non-nucleoside inhibitors of HIV-1 reverse transcriptase with improved drug resistance properties. 1.

We have used a structure-based approach to design a novel series of non-nucleoside inhibitors of HIV-1 RT (NNRTIs). Detailed analysis of a wide range of crystal structures of HIV-1 RT-NNRTI complexes together with data on drug resistance mutations has identified factors important for tight binding of inhibitors and resilience to mutations. Using this approach we have designed and synthesized a novel series of quinolone NNRTIs. Crystal structure analysis of four of these compounds in complexes with HIV-1 RT confirms the predicted binding modes. Members of this quinolone series retain high activity against the important resistance mutations in RT at Tyr181Cys and Leu100Ile.

Design of non-nucleoside inhibitors of HIV-1 reverse transcriptase with improved drug resistance properties. 2.

HIV-1 nonnucleoside reverse transcriptase inhibitors (NNRTIs) are part of the combination therapy currently used to treat HIV infection. The features of a new NNRTI drug for HIV treatment must include selective potent activity against both wild-type virus as well as against mutant virus that have been selected by use of current antiretroviral treatment regimens. Based on analogy with known HIV-1 NNRTI inhibitors and modeling studies utilizing the X-ray crystal structure of inhibitors bound in the HIV-1 RT, a series of substituted 2-quinolones was synthesized and evaluated as HIV-1 inhibitors.

Novel benzophenones as non-nucleoside reverse transcriptase inhibitors of HIV-1.

GW4511, GW4751, and GW3011 showed IC50 values < or =2 nM against wild type HIV-1 and <10 nM against 16 mutants. They were particularly potent against NNRTI-resistant viruses containing Y181C-, K103N-, and K103N-based double mutations, which account for a significant proportion of the clinical failure of the three currently marketed NNRTIs. The antiviral data together with the favorable pharmacokinetic data of GW4511 suggested that these benzophenones possess attributes of a new NNRTI drug candidate.

1,4-Bis(5-(naphthalen-1-yl)thiophen-2-yl)naphthalene, a small molecule, functions as a novel anti-HIV-1 inhibitor targeting the interaction between integrase and cellular Lens epithelium-derived growth factor.

Translocation of viral integrase (IN) into the nucleus is a critical precondition of integration during the life cycle of HIV, a causative agent of Acquired Immunodeficiency Syndromes (AIDS). As the first discovered cellular factor to interact with IN, Lens epithelium-derived growth factor (LEDGF/p75) plays an important role in the process of integration. Disruption of the LEDGF/p75-IN interaction has provided a great interest for anti-HIV agent discovery. In this work, we reported that one small molecular compound, 1,4-bis(5-(naphthalen-1-yl)thiophen-2-yl)naphthalene(Compound 15), potently inhibit the IN-LEDGF/p75 interaction and affect the HIV-1 IN nuclear distribution at 1 µM. The putative binding mode of Compound 15 was constructed by a molecular docking simulation to provide structural insights into the ligand-binding mechanism. Compound 15 suppressed viral replication by measuring p24 antigen production in HIV-1IIIB acute infected C8166 cells with EC50 value of 11.19 µM. Compound 15 might supply useful structural information for further anti-HIV agent discovery.

Structural basis for the improved drug resistance profile of new generation benzophenone non-nucleoside HIV-1 reverse transcriptase inhibitors.

Owing to the emergence of resistant virus, next generation non-nucleoside HIV reverse transcriptase inhibitors (NNRTIs) with improved drug resistance profiles have been developed to treat HIV infection. Crystal structures of HIV-1 RT complexed with benzophenones optimized for inhibition of HIV mutants that were resistant to the prototype benzophenone GF128590 indicate factors contributing to the resilience of later compounds in the series (GW4511, GW678248). Meta-substituents on the benzophenone A-ring had the designed effect of inducing better contacts with the conserved W229 while reducing aromatic stacking interactions with the highly mutable Y181 side chain, which unexpectedly adopted a "down" position. Up to four main-chain hydrogen bonds to the inhibitor also appear significant in contributing to resilience. Structures of mutant RTs (K103N, V106A/Y181C) with benzophenones showed only small rearrangements of the NNRTIs relative to wild-type. Hence, adaptation to a mutated NNRTI pocket by inhibitor rearrangement appears less significant for benzophenones than other next-generation NNRTIs.

Anti-human immunodeficiency virus type 1 activity of the nonnucleoside reverse transcriptase inhibitor GW678248 in combination with other antiretrovirals against clinical isolate viruses and in vitro selection for resistance.

GW678248, a novel nonnucleoside reverse transcriptase inhibitor, has been evaluated for anti-human immunodeficiency virus activity in a variety of in vitro assays against laboratory strains and clinical isolates. When GW678248 was tested in combination with approved drugs in the nucleoside and nucleotide reverse transcriptase inhibitor classes or the protease inhibitor class, the antiviral activities were either synergistic or additive. When GW678248 was tested in combination with approved drugs in the nonnucleoside reverse transcriptase inhibitor class, the antiviral activities were either additive or slightly antagonistic. Clinical isolates from antiretroviral drug-experienced patients were selected for evaluation of sensitivity to GW678248 in a recombinant virus assay. Efavirenz (EFV) and nevirapine (NVP) had > or = 10-fold increases in their 50% inhibitory concentrations (IC50s) for 85% and 98% of the 55 selected isolates, respectively, whereas GW678248 had a > or = 10-fold increase in the IC50 for only 17% of these isolates. Thus, 81 to 83% of the EFV- and/or NVP-resistant viruses from this data set were susceptible to GW678248. Virus populations resistant to GW678248 were selected by in vitro dose-escalating serial passage. Resistant progeny viruses recovered after eight passages had amino acid substitutions V106I, E138K, and P236L in the reverse transcriptase-coding region in one passage series and amino acid substitutions K102E, V106A, and P236L in a second passage series.

Antiviral activity of GW678248, a novel benzophenone nonnucleoside reverse transcriptase inhibitor.

The compound GW678248 is a novel benzophenone nonnucleoside reverse transcriptase inhibitor (NNRTI). Preclinical assessment of GW678248 indicates that this compound potently inhibits wild-type (WT) and mutant human immunodeficiency virus type 1 (HIV-1) reverse transcriptase in biochemical assays, with 50% inhibitory concentrations (IC(50)s) between 0.8 and 6.8 nM. In HeLa CD4 MAGI cell culture virus replication assays, GW678248 has an IC(50) of < or =21 nM against HIV-1 isogenic strains with single or double mutations known to be associated with NNRTI resistance, including L100I, K101E, K103N, V106A/I/M, V108I, E138K, Y181C, Y188C, Y188L, G190A/E, P225H, and P236L and various combinations. An IC(50) of 86 nM was obtained with a mutant virus having V106I, E138K, and P236L mutations that resulted from serial passage of WT virus in the presence of GW678248. The presence of 45 mg/ml human serum albumin plus 1 mg/ml alpha-1 acid glycoprotein increased the IC(50) approximately sevenfold. Cytotoxicity studies with GW678248 indicate that the 50% cytotoxicity concentration is greater than the level of compound solubility and provides a selectivity index of >2,500-fold for WT, Y181C, or K103N HIV-1. This compound exhibits excellent preclinical antiviral properties and, as a prodrug designated GW695634, is being developed as a new generation of NNRTI for the treatment of HIV-1 in combination with other antiretroviral agents.