ABSTRACT
Two targeted sets of novel 1,5-diaryl-1H-imidazole-4-carboxylic acids 10 and carbohydrazides 11 were designed and synthesized from their corresponding ester intermediates 17, which were prepared via cycloaddition of ethyl isocyanoacetate 16 and diarylimidoyl chlorides 15. Evaluation of these new target scaffolds in the AlphaScreenTM HIV-1 IN-LEDGF/p75 inhibition assay identified seventeen compounds exceeding the pre-defined 50% inhibitory threshold at 100 µM concentration. Further evaluation of these compounds in the HIV-1 IN strand transfer assay at 100 µM showed that none of the compounds (with the exception of 10a, 10l, and 11k, with marginal inhibitory percentages) were actively bound to the active site, indicating that they are selectively binding to the LEDGF/p75-binding pocket. In a cell-based HIV-1 antiviral assay, compounds 11a, 11b, 11g, and 11h exhibited moderate antiviral percentage inhibition of 33-45% with cytotoxicity (CC50) values of >200 µM, 158.4 µM, >200 µM, and 50.4 µM, respectively. The antiviral inhibitory activity displayed by 11h was attributed to its toxicity. Upon further validation of their ability to induce multimerization in a Western blot gel assay, compounds 11a, 11b, and 11h appeared to increase higher-order forms of IN.
Subject(s)
Adaptor Proteins, Signal Transducing/antagonists & inhibitors , HIV Integrase Inhibitors/chemistry , HIV Integrase Inhibitors/chemical synthesis , HIV Integrase/drug effects , Transcription Factors/antagonists & inhibitors , Catalytic Domain , Cell Line , Computer Simulation , Drug Design , Drug Evaluation, Preclinical , HIV Integrase/chemistry , HIV Integrase/metabolism , HIV Integrase Inhibitors/pharmacology , Host Microbial Interactions/drug effects , Humans , Imidazoles/chemical synthesis , Imidazoles/chemistry , Imidazoles/pharmacology , Molecular Docking Simulation , Molecular Structure , Protein Multimerization/drug effectsABSTRACT
Novel ethyl 2-(5-aryl-1H-imidazol-1-yl)-acetates 17 and propionates 18, together with their acetic acid 19 and acetohydrazide 20 derivatives, were designed and synthesized using TosMIC chemistry. Biological evaluation of these newly synthesized scaffolds in the HIV-1 Vpu- Host BST-2 ELISA assay identified seven hits (17a, 17b, 17c, 17g, 18a, 20f and 20g) with greater than 50% inhibitory activity. These hits were validated in the HIV-1 Vpu- Host BST-2 AlphaScreen™ and six of the seven compounds were found to have comparable percentage inhibitory activities to those of the ELISA assay. Compounds 17b and 20g, with consistent percentage inhibitory activities across the two assays, had IC50 values of 11.6 ± 1.1 µM and 17.6 ± 0.9 µM in a dose response AlphaScreen™ assay. In a cell-based HIV-1 antiviral assay, compound 17b exhibited an EC50 = 6.3 ± 0.7 µM at non-toxic concentrations (CC50 = 184.5 ± 0.8 µM), whereas compound 20g displayed antiviral activity roughly equivalent to its toxicity (CC50 = 159.5 ± 0.9 µM). This data suggests that compound 17b, active in both cell-based and biochemical assays, provides a good starting point for the design of possible lead compounds for prevention of HIV-1 Vpu and host BST-2 protein binding in new anti-HIV therapeutics.
Subject(s)
Anti-HIV Agents/pharmacology , HIV-1/drug effects , Human Immunodeficiency Virus Proteins/antagonists & inhibitors , Imidazoles/pharmacology , Protein Multimerization/drug effects , Viral Regulatory and Accessory Proteins/antagonists & inhibitors , Anti-HIV Agents/chemical synthesis , Antigens, CD , Cell Line , Drug Design , GPI-Linked Proteins/antagonists & inhibitors , HIV-1/chemistry , Humans , Imidazoles/chemical synthesis , Microbial Sensitivity Tests , Virus Replication/drug effectsABSTRACT
We describe here the synthesis of libraries of novel 1-subtituted-5-aryl-1H-imidazole, 5-aryl-4-tosyl-4,5-dihydro-1,3-oxazole and 5-aryl-1,3-oxazole fragments via microwave (MW)-assisted cycloaddition of para-toluenesulfonylmethyl isocyanide (TosMIC) to imines and aldehydes. The compounds obtained were biologically evaluated in an AlphaScreen HIV-1 IN-LEDGF/p75 inhibition assay with six imidazole-based compounds (16c, 16f, 17c, 17f, 20a and 20d) displaying more than 50% inhibition at 10⯵M, with IC50 values ranging from 7.0 to 30.4⯵M. Additionally the hypothesis model developed predicts all active scaffolds except 20d to occupy similar areas as the N-heterocyclic (A) moiety and two aromatic rings (B and C) of previously identified inhibitor 5. These results indicate that the identified compounds represent a viable starting point for their use as templates in the design of next generation inhibitors targeting the HIV-1 IN and LEDGF/p75 protein-protein interaction. In addition, the in vitro antimicrobial properties of these fragments were tested by minimum inhibitory concentration (MIC) assays showing that compound 16f exhibited a MIC value of 15.6⯵g/ml against S. aureus, while 17f displayed a similar MIC value against B. cereus, suggesting that these compounds could be further developed to specifically target those microbial pathogens.
