Dimerization inhibitors of HIV-1 reverse transcriptase, protease and integrase: A single mode of inhibition for the three HIV enzymes?

The genome of human immunodeficiency virus type 1 (HIV-1) encodes 15 distinct proteins, three of which provide essential enzymatic functions: a reverse transcriptase (RT), an integrase (IN), and a protease (PR). Since these enzymes are all homodimers, pseudohomodimers or multimers, disruption of protein-protein interactions in these retroviral enzymes may constitute an alternative way to achieve HIV-1 inhibition. A growing number. of dimerization inhibitors for these enzymes is being reported. This mini review summarizes some approaches that have been followed for the development of compounds that inhibit those three enzymes by interfering with the dimerization interfaces between the enzyme subunits. (c) 2006 Elsevier B.V. All rights reserved

Selective killing of human immunodeficiency virus infected cells by non-nucleoside reverse transcriptase inhibitor-induced activation of HIV protease

<p>Abstract</p> <p>Background</p> <p>Current antiretroviral therapy against human immunodeficiency virus (HIV-1) reduces viral load and thereby prevents viral spread, but it cannot eradicate proviral genomes from infected cells. Cells in immunological sanctuaries as well as cells producing low levels of virus apparently contribute to a reservoir that maintains HIV persistence in the presence of highly active antiretroviral therapy. Thus, accelerated elimination of virus producing cells may represent a complementary strategy to control HIV infection. Here we sought to exploit HIV protease (PR) related cytotoxicity in order to develop a strategy for drug induced killing of HIV producing cells. PR processes the viral Gag and Gag-Pol polyproteins during virus maturation, but is also implicated in killing of virus producing cells through off-target cleavage of host proteins. It has been observed previously that micromolar concentrations of certain non-nucleoside reverse transcriptase inhibitors (NNRTIs) can stimulate intracellular PR activity, presumably by enhancing Gag-Pol dimerization.</p> <p>Results</p> <p>Using a newly developed cell-based assay we compared the degree of PR activation displayed by various NNRTIs. We identified inhibitors showing higher potency with respect to PR activation than previously described for NNRTIs, with the most potent compounds resulting in ~2-fold increase of the Gag processing signal at 250 nM. The degree of enhancement of intracellular Gag processing correlated with the compound's ability to enhance RT dimerization in a mammalian two-hybrid assay. Compounds were analyzed for their potential to mediate specific killing of chronically infected MT-4 cells. Levels of cytotoxicity on HIV infected cells determined for the different NNRTIs corresponded to the relative degree of drug induced intracellular PR activation, with CC₅₀values ranging from ~0.3 μM to above the tested concentration range (10 μM). Specific cytotoxicity was reverted by addition of PR inhibitors. Two of the most active compounds, VRX-480773 and GW-678248, were also tested in primary human cells and mediated cytotoxicity on HIV-1 infected peripheral blood mononuclear cells.</p> <p>Conclusion</p> <p>These data present proof of concept for targeted drug induced elimination of HIV producing cells. While NNRTIs themselves may not be sufficiently potent for therapeutic application, the results provide a basis for the development of drugs exploiting this mechanism of action.</p

Current state-of-the-art in preclinical and clinical development of novel non-nucleoside HIV-1 reverse transcriptase inhibitors

In spite of the tremendous advance in our understanding of the HIV-1 life cycle and of the molecular mechanisms underlying its pathogenesis, it is still not possible to fully control the HIV-1 infection for long periods of time, not to mention eradicate it. However, as it is still unclear whether an effective vaccine could be developed in a short time, therapeutic approaches based on the combination of different potent antiviral drugs are now thought to be the best option for the control of HIV-1 infection in patients. For this reason, development of novel molecules that are safer, more potent and less sensitive to drug resistance than available drugs is mandatory. Among the currently exploited anti-HIV drugs, non-nucleoside reverse transcriptase inhibitors play a major role. This review will summarise the most recent advances and evolutionary trends for this class of anti-HIV drugs

Kui bioloog kohtab keemikut: HIV-1 inhibiitorite otsingul

Väitekirja elektrooniline versioon ei sisalda publikatsioone.HIV-1 on pandeemiline viirus ning nakatatud inimeste arv maailmas suureneb pidevalt. Vaktsiin selle vastu puudub, kuid nakatatud patsientide raviks on kliinilise kasutuse loa saanud ligi 30 erinevat ühendit. Erinevatesse klassidesse kuuluvate inhibiitorite kombineeritud kasutamine (ART) on kujunenud HIV-ga nakatunud patsientide ravimise aluseks. ART ravi kõige olulisemaks puuduseks on ravimite toksilised kõrvaltoimed ning uute resistentsete viiruse tüvede teke. Antud väitekirja põhieesmärgiks oli leida efektiivseid mittetoksilisi ühendeid, mis suruvad maha HIV-1 replikatsiooni (nii metsik-tüüpi viiruse kui ka resistentsete tüvede oma) keskendudes eelkõige pöördtranskriptaasi inhibiitoritele. Kolm gruppi keemilisi ühendeid testiti antiretroviirus-vastase toime suhtes: atsüklilised tümidiini nukleosiidi analoogid, bimorfoliinid ja nende derivaadid ning sahariidhüdrasoonid. Samuti tõestati eksperimentaalselt eelneva in silico skriiningu käigus saadud tulemusi. Käesoleva töö tulemusena töötati välja meetod HIV-1 inhibiitorite skriinimiseks ViraPower lentiviiruse ekspressioonisüsteemi (Invitrogen) põhjal. Meetod on kiire, lihtne, usaldusväärne ning on kõlblik kasutamiseks väljaspool kõrgenenud ohutustasemega laborit (BSL3). Kõige tugevam toime meie laboris uuritud ühenditest oli mitte-nukleosiidsel pöördtranskriptaasi inhibiitoril (NNRTI), mis omas tuntud ravimi Nevirapiiniga sarnast aktiivsust, kuid oli kahjuks mitteaktiivne viiruse resistentsete vormide vastu. Antud ühend leiti ratsionaalse ravimidisaini strateegiat kasutades. Antud töö tulemused võimaldasid täiustada olemasolevat in silico skriiningu meetodit, mis võimaldab tulevikus kavandada uusi ning efektiivsemaid HIV-1 inhibiitoreid.HIV-1 is a pandemic virus and the numbers of infected people are constantly increasing all over the world. There is no vaccine available, but about 30 compounds have been approved by FDA for the treatment of HIV-infected patients. ART (antiretroviral therapy) consists of a combination of at least 3 inhibitors with different mechanism of action. The main drawback of such treatment is side effects of the drugs and the appearance of new resistant forms of the virus. The aim of this work was to find non-toxic compounds which can effectively suppress HIV-1 replication (both wild-type and resistant forms of the virus). We focused our efforts mostly on the discovery of novel reverse transcriptase inhibitors. Three groups of compounds were tested for their antiretroviral activity (acyclic thymine nucleoside analogues, bimorpholines and their derivatives, and saccharide hydrazones); also we experimentally verified the results of the previous in silico screening. As a result of this work, we developed an assay for HIV-1 inhibitors′ screening. This assay is based on ViraPower Lentiviral Expression System (Invitrogen) and is simple, fast, reliable and can be used outside BSL3 facilities. The most potent compound, found by us so far, acts as a non-nucleoside reverse transcriptase inhibitor (NNRTI) and has activity comparable to the activity of a known NNRTI nevirapine, but is unfortunately inactive against the resistant forms of the virus. This compound was found using ration drug design strategy. Most importantly, the results of this work allowed us to improve the existing in silico screening method, which could result in more potent HIV-1 inhibitors in the future

Putative HIV-1 reverse transcriptase inhibitors: design, synthesis, in vitro evaluation and in silico analysis.

Masters Degree. University of KwaZulu-Natal, Durban.One of the most significant treatments for HIV-1 infection has been the combination of drugs targeting the HIV life cycle with the aim of preventing further destruction of the host immune system. This study addresses the design, synthesis, in vitro evaluation, and in silico analysis of putative HIV-1 reverse transcriptase (RT) inhibitors. The inhibitors comprise two structurally diverse components which are intended to bind separately to the enzyme allosteric site and to a location at, or close to, the polymerase active site. Therefore, the hydrophobic N-tritylated phalo-DL-phenylalanine derivatives (fluoro, chloro, bromo, iodo) have been coupled to 8-(6- aminohexyl) amino-adenosine-3',5'-cyclic monophosphate through N-hydroxysuccinimidecarbodiimide chemistry. Compounds were characterized by thin layer chromatography, UV spectroscopy, MALDI-TOF mass spectrometry and proton NMR spectrometry. A reverse transcriptase colorimetric assay kit, which features a sandwich ELISA protocol, based on biotin-avidin and digoxygenin-anti DIG interactions, was used for quantitative determination of the inhibitory effect of synthesized compounds on recombinant HIV-1 reverse transcriptase activity in vitro. Molecular docking simulations of the chimeric inhibitors within the allosteric site of HIV-1 RT, were performed using AutoDock Vina. The predicted binding associations were compared with laboratory findings on HIV-1 RT inhibition. Two dimensional representations of protein-ligand interactions were generated using LigPlot. The non-halogenated N-trityl-L-phenylalanine-8-(6-aminohexyl)amino-adenosine-3',5'-cyclic monophosphate derivative (4a) inhibited RT activity down to 57 % at 10-4 M, while the Ntrityl-para-fluoro-DL-phenylalanine-8-(6-aminohexyl)aminoadenosine-3′,5′-cyclic monophosphate derivative (4b) was the strongest RT inhibitor reducing RT activity to 69 % at 10-7 M (IC50 = 29.2 μM). In the same assay, Nevirapine, a first-line anti-retroviral drug, showed a decline in RT activity down to 43% at 10-5 M (IC50 = 3.03 μM). Ranking of inhibitors according to estimated docking energies obtained from in silico docking was in excellent agreement with potencies calculated from experimental studies. The docking score of N-trityl-para-fluoro-DL-phenylalaline-8-(6-aminohexyl)amino-adenosine-3',5'-cyclic monophosphate was -8.8 kcal/mol, while that of Nevirapine was -9.9 kcal/mol. The benzene rings of the N-trityl-fluoro-DL-phenylalanine-8-(6-aminohexyl) amino-adenosine-3',5'-cyclic monophosphate derivative formed hydrophobic interactions with hydrophobic, non-aromatic amino acid residues Pro176 and Val179 in the allosteric site. Nevirapine, on the other hand showed strong van der Waals interactions with Val106 ,Val179 and Tyr188 due to the aromatic properties of the pyridine ring. Possible π-π stacking between phenyl rings of Nevirapine and Tyr 181/Tyr188 aromatic side chains may also be present. Other HIV-1 RT large subunit residues in the allosteric site common to the binding of Nevirapine and the active para-fluoro derivative include Lys101, Tyr318, Leu 100, Trp229 and Phe227. Apparent binding to the allosteric site suggests that compounds may be acting primarily as non-nucleoside reverse transcriptase inhibitors (NNRTIs)

A BATTLE AGAINST AIDS: NEW PYRAZOLE KEY TO AN OLDER LOCK-REVERSE TRANSCRIPTASE

Objective: The reason for the failure of most of the anti-HIV drugs are their poor pharmacokinetics, the poor risk to benefit ratio and the drug resistance. With the objective of developing newer pyrazole scaffolds for effective treatment of HIV, binding mode analysis of designing ligands with the HIV-1RT protein and prediction of key ADME and toxicity parameters of the compounds was in an area of interest.Methods: In this study, molecular docking studies and ADME-T studies were carried out in designing of some novel pyrazole analogs. The protein (PDB ID: 1RT2) was prepared using the Protein Preparation Wizard (Schrodinger Glide 5.0). ADME parameters calculated by QikProp 3.0v and toxicity of designed analogs checked by using two different online software's namely Lazar and protox.Results: Most of the designed pyrazole analogs have good oral absorption as well as good binding affinity towards HIV-1 reverse transcriptase.Conclusion: Finally total 5 analogs (SGS-2, 3, 12, 13 and 14) from the 14 designed leads were found to be best on the basis of molecular docking and ADME-T studies

Current and Novel Inhibitors of HIV Protease

The design, development and clinical success of HIV protease inhibitors represent one of the most remarkable achievements of molecular medicine. This review describes all nine currently available FDA-approved protease inhibitors, discusses their pharmacokinetic properties, off-target activities, side-effects, and resistance profiles. The compounds in the various stages of clinical development are also introduced, as well as alternative approaches, aiming at other functional domains of HIV PR. The potential of these novel compounds to open new way to the rational drug design of human viruses is critically assessed

STRUCTURE-BASED DESIGN OF NOVEL RILPIVIRINE ANALOGUES AS HIV-1 NON-NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITORS THROUGH QSPR AND MOLECULAR DOCKING

Objectives: The aim of this research is to investigate the better biological activities from Rilpivirine analogues based on their Quantitative Structure-Property Relationship (QSPR) and pharmacophore study.Methods: In this study, we had designed six Rilpivirine analogues. The complementary aided-computational drug design and molecular docking was employed to find the best lead candidate. The drug-likeness properties of Rilpivirine analogues were defined by following the Rule of Five.Results: The drug-likeness properties of Rilpivirine derivatives (RVN 1-6) were defined by the Rule of Five (RO5), which RVN3 compound showed the best RO5 score among others. However, the log P value of RVN1 and RVN4 are lower than 5, while RVN2, RVN3, RVN5 and RVN6 have log P values greater than 5. Based on the solubility, RVN1 and RVN4 compounds are more soluble than other analogues including Rilpivirine prototype (RVN). The topological polar surface area (TPSA) score of RVN1 and RVN4 showed greater scores compared to others. On the other hand, the TPSA score of all Rilpivirine analogues are below 140 Ã…2. The absorption, distribution, metabolism, and excretion (ADME) properties of Rilpivirine analogues were determined, according to blood brain barrier penetration were found within the range of-1.2 to-2.2, which RVN4 showed the lowest value compared to others, while RVN showed the highest value. The percentage of human intestinal absorption was observed 100% to all compounds. The plasma protein binding percentages was obtained within the range 99.03-99.57%. Moreover, the hydrogen bond donor contribution of all compounds was in the range 2-4 bonds, while the acceptor hydrogen bond was found 6 bonds from all compounds. The mutagenicity properties showed all compounds could cause mutagenic effect in long-term administration. The carcinogenicity tests were done in mouse showed positive results to all compounds, while carcinogenicity test in rat showed negative results upon all compound, except RVN3 which gave positive result. From molecular docking result, RVN 1 and RVN 4 showed higher potential inhibition activities to Reverse Transcriptase Human Immunodeficiency Virus Type 1 (HIV-1 RT) compared other analogues.Conclusion: Non-nucleoside reverse transcriptase inhibitors (NNRTIs) have a great potential inhibition against HIV-1 RT. From high throughput computational approach, we suggested that RVN 1 and RVN 4 are the potential drug candidates which have better activity among other Rilpivirine derivatives

Guidelines for using antiretroviral agents among HIV-infected adults and adolescents: recommendations of the Panel on Clinical Practices for Treatment of HIV

The availability of an increasing number of antiretroviral agents and the rapid evolution of new information has introduced substantial complexity into treatment regimens for persons infected with human immunodeficiency virus (HIV). In 1996, the Department of Health and Human Services and the Henry J. Kaiser Family Foundation convened the Panel on Clinical Practices for the Treatment of HIV to develop guidelines for clinical management of HIV-infected adults and adolescents (CDC. Report of the NIH Panel To Define Principles of Therapy of HIV Infection and Guidelines for the use of antiretroviral agents in HIV-infected adults and adolescents. MMWR 1998;47[RR-5]:1-41). This report, which updates the 1998 guidelines, addresses 1) using testing for plasma HIV ribonucleic acid levels (i.e., viral load) and CD4+ T cell count; 2) using testing for antiretroviral drug resistance; 3) considerations for when to initiate therapy; 4) adherence to antiretroviral therapy; 5) considerations for therapy among patients with advanced disease; 6) therapy-related adverse events; 7) interruption of therapy; 8) considerations for changing therapy and available therapeutic options; 9) treatment for acute HIV infection; 10) considerations for antiretroviral therapy among adolescents; 11) considerations for antiretroviral therapy among pregnant women; and 12) concerns related to transmission of HIV to others. Antiretroviral regimens are complex, have serious side effects, pose difficulty with adherence, and carry serious potential consequences from the development of viral resistance because of nonadherence to the drug regimen or suboptimal levels of antiretroviral agents. Patient education and involvement in therapeutic decisions is critical. Treatment should usually be offered to all patients with symptoms ascribed to HIV infection. Recommendations for offering antiretroviral therapy among asymptomatic patients require analysis of real and potential risks and benefits. Treatment should be offered to persons who have 55,000 copies/mL (by b-deoxyribonucleic acid [bDNA] or reverse transcriptase-polymerase chain reaction [RT-PCR] assays). The recommendation to treat asymptomatic patients should be based on the willingness and readiness of the person to begin therapy; the degree of existing immunodeficiency as determined by the CD4+ T cell count; the risk for disease progression as determined by the CD4+ T cell count and level of plasma HIV RNA; the potential benefits and risks of initiating therapy in an asymptomatic person; and the likelihood, after counseling and education, of adherence to the prescribed treatment regimen. Treatment goals should be maximal and durable suppression of viral load, restoration and preservation of immunologic function, improvement of quality of life, and reduction of HIV-related morbidity and mortality. Results of therapy are evaluated through plasma HIV RNA levels, which are expected to indicate a 1.0 log10 decrease at 2-8 weeks and no detectable virus (<50 copies/mL) at 4-6 months after treatment initiation. Failure of therapy at 4-6 months might be ascribed to nonadherence, inadequate potency of drugs or suboptimal levels of antiretroviral agents, viral resistance, and other factors that are poorly understood. Patients whose therapy fails in spite of a high level of adherence to the regimen should have their regimen changed; this change should be guided by a thorough drug treatment history and the results of drug-resistance testing. Because of limitations in the available alternative antiretroviral regimens that have documented efficacy, optimal changes in therapy might be difficult to achieve for patients in whom the preferred regimen has failed. These decisions are further confounded by problems with adherence, toxicity, and resistance. For certain patients, participating in a clinical trial with or without access to new drugs or using a regimen that might not achieve complete suppression of viral replication might be preferable. Because concepts regarding HIV management are evolving rapidly, readers should check regularly for additional information and updates at the HIV/AIDS Treatment Information Service website (http://www.hivatis.org).prepared by Mark Dybul, Anthony S. Fauci, John G. Bartlett, Jonathan E. Kaplan, Alice K. Pau.The material in this report was prepared for publication by the National Center for HIV, STD, and TB Prevention, and Division of HIV/AIDS Prevention \u2014 Surveillance and EpidemiologyIncludes bibliographical references (p. 26-34).Infectious DiseaseTreatment and InterventionSupersede