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Aim:: To design, synthesis and in vitro evaluation of 4-oxo-6-substituted phenyl-2- thioxo1,2,3,4-tetrahydropyrimidine-5-carbonitrile derivatives as HIV integrase strand transfer inhibitors. Background:: Human immunodeficiency virus-1 (HIV-1), a member of retroviridae family, is the primary causative agent of acquired immunodeficiency syndrome (AIDS). Three enzymes viz: integrase (IN), reverse transcriptase (RT) and protease play important role in its replication cycle. HIV-1 integrase is responsible for the incorporation of viral DNA into human chromosomal DNA by catalyzing two independent reactions, 3′-processing (3′-P) and strand transfer (ST), which are observed as the “point of no-return” in HIV infection. Objective:: To develop inhibitors against HIV integrase strand transfer step. Methods:: Our previous results indicated that tetrahydro pyrimidine-5-carboxamide derivatives are potent HIV-1 IN inhibitors (unpublished results from our laboratory). Taking clue from above studies and our own experience, we hypothesized 4-oxo-6-substituted phenyl-2-thioxo1,2,3,4- tetrahydropyrimidine-5-carbonitrile analogues (14a to 14n) as inhibitors of HIV-1 Integrase strand transfer. Prototype compound 14 can be viewed as hybrid structure having characteristics of dihydropyrimidine derivatives 10-12 and tyrphostin 13. Result:: A total of fourteen derivatives of 4-oxo-6-substituted phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine- 5-carbonitrile (14a-14n) were synthesized and evaluated using HIV-1 Integrase Assay Kit (Xpressbio Life Science Products, USA). The percentage inhibition of all compounds was investigated at 10 μM concentration and IC50 value of few highly active compounds was studied. The obtained results were validated by in silico molecular docking study using Glide (maestro version 9.3, Schrödinger suite) in extra precision (XP) mode. Conclusion:: Fourteen 4-oxo-6-substituted phenyl-2-thioxo 1,2,3,4-tetrahydropyrimidine-5-carbonitrile analogues were synthesized and evaluated for HIV-1 IN inhibitory activity. Three compounds 14a, 14e, and 14h exhibited significant percentage inhibition of HIV-1 IN. There was good in vitro - in silico correlation. However, none of the derivative was active against HIV-1 and HIV-2 below their cytotoxic concentration. It needs to be seen whether these compounds can be explored further for their anti-HIV or cytotoxic potential.

Integrase (IN) strand transfer inhibitors (INSTIs) are recent compounds in the antiretroviral arsenal used against HIV. INSTIs work by blocking retroviral integration; an essential step in the viral lifecycle that is catalyzed by the virally encoded IN protein within a nucleoprotein assembly called an intasome. Recent structures of lentiviral intasomes from simian immunodeficiency virus (SIV) and HIV have clarified the INSTI binding modes within the intasome active sites and helped elucidate an important mechanism of viral resistance. The structures provide an accurate depiction of interactions of intasomes and INSTIs to be leveraged for structure-based drug design. Here, we review these recent structural findings and contrast with earlier studies on prototype foamy virus intasomes. We also present and discuss examples of the latest chemical compounds that show promising inhibitory potential as INSTI candidates.

The World Health Organization (WHO) has put forth recommendations for the use of integrase (IN) strand transfer inhibitors (INSTIs) to be part of the first-line combination antiretroviral therapy regimen to treat HIV infections. The knowledge of pretreatment drug resistance against INSTIs is still scarce in resource-limited settings (RLS). We characterized the

Background: A series of eighteen 2-Oxo-N-substituted phenyl- 2H-chromene-3- carboxamide analogues has been evaluated for HIV-1 integrase (IN) inhibition. Methods: The derivatives were synthesized via a two-step pathway commencing with 2- hydroxybenzaldehyde and diethyl malonate followed by hydrolysis of ester and coupling with various aromatic amines. The HIV-1 IN inhibitory potential of these compounds has been studied relative to dolutegravir, a known HIV-1 IN inhibitor using a standard available kit. Results: Six molecules (compounds 13h, 13i, 13l, 13p to 13r) showed significant inhibition of HIV- 1 integrase 3′-strand transfer with IC50 values less than 1.7 μM. The presence of chromene-3- carboxamide motif was shown to be crucial for the enzymatic activity. In addition, molecular modelling studies were also done to justify the IN inhibition and in vitro-in silico correlation was drawn. Conclusion: However, these compounds did not show HIV-1 and HIV-2 inhibition below their cytotoxic concentration indicating that these compounds cannot be taken further for anti-HIV activity as such and require structural modification.

HIV-1 integrase enzyme is responsible for the integration of viral DNA into the host genomic DNA. Integrase strand transfer inhibitors (INSTIs) are highly potent antiretroviral agents that inhibit this process, and are internationally approved for the treatment of both naïve and treated HIV-1 patients. However, their long-term efficacy is threatened by development of drug resistance strains resulting in resistance mutations. This work aimed to examine the effect of INSTI resistance-associated mutations (RAMs) and polymorphisms on the structure of HIV-1 subtype C (HIV-1C) integrase. Genetic analysis was performed on seven HIV-1C infected individuals with virologic failure after at least 6 months of INSTI-based antiretroviral therapy, presenting at the King Edward VIII hospital in Durban, South Africa. These were compared with sequences from 41 INSTI-naïve isolates. Integrase structures of selected isolates were modeled on the SWISS model online server. Molecular docking and dynamics simulations were also conducted using AutoDock-Vina and AMBER 18 force fields, respectively. Only one INSTI-treated isolate (14.28%) harboured major mutations (G140A + Q148R) as well as the E157Q minor mutation. Interestingly, S119T and V151I were only found in patients failing raltegravir (an INSTI drug). Molecular modeling and docking showed that RAMs and polymorphisms associated with INSTI-based therapy affect protein stability and this is supported by their weakened hydrogen-bond interactions compared to the wild-type. To the best of our knowledge, this is the first study to identify a double mutant in the 140's loop region from South African HIV-1C isolates and study its effects on Raltegravir, Elvitegravir, and Dolutegravir binding.Communicated by Ramaswamy H. Sarma.

Strengths and weaknesses of an HIV drug Retroviruses replicate by inserting a copy of their RNA, which has been reverse transcribed into DNA, into the host genome. This process involves the intasome, a nucleoprotein complex comprising copies of the viral integrase bound at the ends of the viral DNA. HIV integrase strand-transfer inhibitors (INSTIs) stop HIV from replicating by blocking the viral integrase and are widely used in HIV treatment. Cook et al. describe structures of second-generation inhibitors bound to the simian immunodeficiency virus (SIV) intasome and to an intasome with integrase mutations known to cause drug resistance. Passos et al. describe the structures of the HIV intasome bound to a second-generation inhibitor and to developmental compounds that are promising drug leads. These structures show how mutations can cause subtle changes in the active site that affect drug binding, show the basis for the higher activity of later-generation inhibitors, and may guide development of better drugs. Science , this issue p. 806 , p. 810

PURPOSE OF REVIEW: Weight gain and obesity among people living with HIV (PLWH) is a serious problem that occurs often after initiation of antiretroviral therapy but may be worse with integrase strand transfer inhibitors (INSTIs). This paper comprehensively reviews available data and summarizes our current understanding of the topic. RECENT FINDINGS: Recent studies support the concept that weight gain and treatment emergent obesity are worse with INSTI-based regimens, particularly dolutegravir. Women and non-whites appear to be the most at risk, and the accompanying nucleoside reverse transcriptase inhibitor may play a role. Lipohypertrophy, an abnormal accumulation of visceral fat and/or ectopic fat depots, continues to be a problem among PLWH, but the role of INSTIs is inconsistent. The pathogenesis of weight gain and changes in body composition in HIV, especially with INSTIs, is poorly understood but may lead to serious co-morbidities, such as cardiovascular disease and diabetes. SUMMARY: Although INSTI-based regimens are highly efficacious for viral suppression, they appear to cause more weight gain and treatment emergent obesity than non-INSTI-based regimens and may increase the risk of weight-related co-morbidities. More studies are needed to understand the pathogenesis of weight gain with INSTIs in PLWH, in order to prevent this serious complication.

In the era of modern bone-friendly antiretroviral therapy (ART) regimens for people living with HIV (PLWH), this review discusses the research gaps and management concerns that remain for individuals who have already been exposed to ART with negative effects on bone metabolism, especially children and adolescents who have not acquired peak bone mass, and older adults who have additional risk factors for fracture. Data now support the use of avoidance of TDF and use of bone-friendly regimens that include integrase strand transfer inhibitors in PLWH with increased risk of fracture for either ART initiation or switch. Despite significant advances in our understanding of ART choice for PLWH with regard to bone health, additional diagnostic tests to determine fracture risk and management strategies beyond ART choice are necessary, especially in vulnerable PLWH populations, such as children and adolescents and older adults.

Excessive weight gain has been reported with integrase strand transfer inhibitors (INSTIs). We evaluated weight changes in virologically suppressed adults with HIV who switched from non-INSTI regimens to raltegravir (RAL)-containing or dolutegravir (DTG)-containing antiretroviral therapy.Retrospective single-centre cohort.Adults who switched to RAL or DTG before or between January 2015 and October 2017 were identified. Virologically suppressed, treatment-experienced (≥2 years) individuals, at least 6 months on INSTI, with weight measurements 2 years or less pre and postswitch were included. Our analysis used a random effects model with linear slope pre and post-INSTI with adjustment for age, sex, ethnicity, preswitch-regimen (protease inhibitor vs. nonprotease inhibitor), and RAL vs. DTG use.A total of 378 individuals, 81.2% male, 70.1% white ethnicity, median age of 49 years, median of four weight measurements per participant, and median weight and BMI at switch of 76.6 kg and 25.3 kg/m, respectively, were included. Weight increased by an average of 0.63 kg/year (95% confidence interval 0.17-1.09) preswitch with no overall change in rate of weight gain postswitch [+0.05 kg/year (-0.61-0.71, P = 0.88)]. In our adjusted model, a transition from minimal weight change to weight gain postswitch was isolated to older individuals though this lacked statistical significance [e.g., +1.59 kg/year (-0.26-3.45) if aged 65 years]. Our findings did not differ by sex, ethnicity, preswitch regimen, or RAL vs. DTG. Similar results were seen for BMI and after adjusting for fixed nucleoside/nucleotide reverse transcriptase inhibitor backbone.We found no clear evidence of an overall increase in rate of weight gain following switch to INSTI in virologically suppressed individuals.

Background: A series of novel 3-(1,3-dioxoisoindolin-2-yl)-N-substituted phenyl benzamide derivatives was synthesized and tested in vitro against human immunodeficiency virus type-1 Integrase (HIV-1 IN). Methods: Out of the 18 analogues, six (compounds 16c, 16h, 16i, 16m, 16n and 16r) showed significant inhibition of strand transfer by HIV-1 integrase. For these six compounds. IC50 was below 5.0 µM. In silico docking studies revealed that the presence of 2-phenyl isoindoline-1,3-dione motif was essential as it was found to interact with active site magnesium. Results: To further confirm the results, cell-based HIV-1 and HIV-2 inhibitory assay was carried out. Conclusion: These compounds possess structural features not seen in previously reported HIV-1 integrase inhibitors and thus can help further optimization of anti-HIV-1 integrase activity.

Characterize virologic and immunologic outcomes of INSTI-based antiretroviral therapy (ART) in experienced patients with and without virologic failure.Prospective clinical cohort.ART-experienced, INSTI-naive participants in the University of North Carolina Center for AIDS Research HIV Clinical Cohort (UCHCC) initiating an INSTI-containing regimen 2007-2016 were followed from INSTI initiation (baseline) to the earliest of: outcome of interest, loss to follow-up (LTFU, 1 year without clinical visit), or death. Outcomes of interest were virologic failure (first of two consecutive viral loads at least 200 copies/ml more than 2 weeks apart, or one viral load ≥200 before LTFU) and immune recovery (first CD4 ≥500 cells/μl). Patients with baseline viral load at least 50 copies/ml were given 24 weeks before meeting virologic failure criteria. Kaplan-Meier curves and Cox proportional hazards models compared INSTI regimens and patient characteristics.Of 773 patients, 32% were women, 59% African-American, and 42% had a viral load at least 50 copies/ml at INSTI initiation. After 2 years, 5% of patients with baseline viral load less than 50 copies/ml experienced virologic failure, compared with 35% of patients with baseline viral load at least 50 copies/ml (P 0.01). Among patients with baseline viral load less than 50 copies/ml, dolutegravir/NRTIs was associated with longer time to virologic failure [adjusted hazard ratio (aHR) 0.11, 95% confidence interval (CI) 0.01-0.80], whereas among patients with baseline viral load at least 50 copies/ml, raltegravir/NRTIs was associated with longer time to virologic failure (aHR 0.35, 95% CI 0.18-0.68), both compared with elvitegravir/NRTIs. After 5 years suppressed, irrespective of baseline viral load, 61% of patients experienced immune recovery.In this cohort, INSTI-containing regimens led to low virologic failure rates in patients switching ART while suppressed. Viremic patients initiating INSTIs were at high risk of virologic failure during follow-up.

Background Regardless of chronic treatment with antiretroviral therapy (ART), the switching rate for ART regarding anchor drugs has not been articulated in real-world clinical-settings in Japan. We assessed switch rates and time-to-switch of ART regimens according to anchor drug classes (integrase strand transfer inhibitors (INSTI), non-nucleoside reverse transcriptase inhibitors (NNRTI) and protease inhibitors (PI)) and common switching patterns of anchor drug classes in people living with human immunodeficiency virus (HIV) (PLWH) from 2008 to 2016. Methods This retrospective, observational study used data of 1694 PLWH drawn from a large-scale medical claims database. The median time-to-switch and switch rates of anchor drug class were estimated by Kaplan-Meier analysis. To estimate 95% confidence intervals for switch rates and median days, the Brookmeyer and Crowley method and Greenwood method were used respectively. The switching patterns were summarized based on the time of switching. The switch rates were compared between two anchor drug classes for each year using log-rank tests. Results We focused our results on 2011–2016 (n = 1613), during which most ART prescriptions were observed. A total of 268 patients switched anchor drug class from the first to a second regimen. The switch rate constantly increased over four years for NNRTIs (17.8–45.2%) and PIs (16.2–47.6%), with median time-to-switch of 1507 and 1567 days, respectively, while INSTI maintained a low switch rate (2.3–7.6%), precluding median-days calculation. The majority originally treated with NNRTI and PI switched to INSTI regardless of the switching timing after starting the first regimen (

Dietary supplements and medications containing polyvalent cations can interact with integrase strand transfer inhibitors (INSTIs) and decrease exposure to INSTIs. In this cross-sectional study of 513 people living with HIV (PLWH) who were on stable antiretroviral therapy, 57.5% and 6.6% reported concurrent use of dietary supplements and antacids, respectively. In the multivariable analysis, the use of antacids, but not dietary supplements containing polyvalent cations, was associated with HIV viremia in PLWH who received INSTI-based ART.

Integrase strand transfer inhibitors (INSTIs) block the integration step of the retroviral lifecycle and are first-line drugs used for the treatment of HIV-1/AIDS. INSTIs have a polycyclic core with heteroatom triads, chelate the metal ions at the active site, and have a halobenzyl group that interacts with viral DNA attached to the core by a flexible linker. The most broadly effective INSTIs inhibit both wild-type (WT) integrase (IN) and a variety of well-known mutants. However, because there are mutations that reduce the potency of all of the available INSTIs, new and better compounds are needed. Models based on recent structures of HIV-1 and red-capped mangabey SIV INs suggest modifications in the INSTI structures that could enhance interactions with the 3'-terminal adenosine of the viral DNA, which could improve performance against INSTI resistant mutants. We designed and tested a series of INSTIs having modifications to their naphthyridine scaffold. One of the new compounds retained good potency against an expanded panel of HIV-1 IN mutants that we tested. Our results suggest the possibility of designing inhibitors that combine the best features of the existing compounds, which could provide additional efficacy against known HIV-1 IN mutants.

The Human Immunodeficiency Virus (HIV) infection is a global pandemic that has claimed 33 million lives to date. One of the most efficacious treatment for naïve or pre-treated HIV patients is with the HIV integrase strand transfer inhibitors (INSTIs). However, given that HIV treatment is life-long, the emergence of HIV-1 strains resistant to INSTIs is an imminent challenge. In this work, we showed two best regression QSAR models that were constructed using a boosted Random Forest algorithm and a boosted K* algorithm to predict the pIC50 values of INSTIs. Subsequently, the regression QSAR models were deployed against the Drugbank database for drug repositioning. The top ranked compounds were further evaluated for their target engagement activity using molecular docking studies and their potential as INSTIs evaluated from our literature search. Our study offers the first example of a large-scale regression QSAR modelling effort for discovering highly active INSTIs to combat HIV infection.

The IS26 family includes the ISs that are commonly found associated with antibiotic resistance genes in multiply resistant Gram-negative and Gram-positive bacteria. IS26 is most prevalent in Gram-negative species and can generate the clusters of antibiotic resistance genes interspersed with directly oriented IS26 seen in multiply resistant pathogens., IS26 forms cointegrates using two distinct routes, a copy-in mechanism involving one insertion sequence (IS) and a target and a targeted conservative mechanism involving two ISs in different DNA molecules. In this study, the ability of IS26 and some close relatives, IS1006, IS1008, and a natural hybrid, IS1006/IS1008, which are found predominantly in Acinetobacter spp., to interact was examined. IS1006/1008 consists of 175 bp from IS1006 at the left end, with the remainder from IS1008. These ISs all have the same 14-bp terminal inverted repeats, and the Tnp26, Tnp1006, and Tnp1008 transposases, with pairwise identities of 83.7% to 93.1%, should be able to recognize each other’s ends. In a recA-negative Escherichia coli strain, IS1006, IS1008, and IS1006/1008 each formed cointegrates via the copy-in route and via the targeted conservative route, albeit at frequencies for the targeted reaction at least 10-fold lower than for IS26. However, using mixed pairs, targeted cointegration was detected only when IS1008 was paired with the IS1006/1008 hybrid, which also encodes Tnp1008, and the targeted cointegrates formed all arose from a reaction occurring at the end where the DNA sequences are identical. The reaction also occurred at the end with extended DNA identity using IS26 paired with IS26::catA1, an artificially constructed IS26 derivative that includes the catA1 gene. Thus, both identical transposases and identical DNA sequences at the reacting end were required. These features indicate that the targeted conservative pathway proceeds via a single transposase-catalyzed strand transfer, followed by migration and resolution of the Holliday junction formed. IMPORTANCE The IS26 family includes the ISs that are commonly found associated with antibiotic resistance genes in multiply resistant Gram-negative and Gram-positive bacteria. IS26 is most prevalent in Gram-negative species and can generate the clusters of antibiotic resistance genes interspersed with directly oriented IS26 seen in multiply resistant pathogens. This ability relies on the novel dual mechanistic capabilities of IS26 family members. However, the mechanism underlying the recently discovered targeted conservative mode of cointegrate formation mediated by IS26, IS257/IS431, and IS1216, which is unlike any previously studied IS movement mechanism, is not well understood. An important question is what features of the IS and the transposase are key to allowing IS26 family members to undertake targeted conservative reaction. In this study, this question was addressed using mixed-partner crosses involving IS26 and naturally occurring close relatives of IS26 that are found near resistance genes in Acinetobacter baumannii and are widespread in Acinetobacter species.