vrx-480773 and HIV-Infections

The present work is an extension of our ongoing efforts towards the development and identification of new molecules with anti-HIV activity which have previously led to the discovery of arylazolylthioacetanilides as highly active NNRTIs. In this article, a series of 2-2-(3-(2-chlorophenyl)pyrazin-2-ylthio)-N-arylacetamide derivatives were synthesized and evaluated for in vitro anti-HIV activity. Most of the tested compounds exhibited moderate activities against wild-type HIV-1. Among them, compound 6k showed significant activity against wild-type HIV-1 with an EC(50) value of 1.7μM, along with moderate activity against wild-type reverse transcriptase (RT). The preliminary structure-activity relationship (SAR) and docking calculations of this new series of compounds were also investigated, which may help designing more potent molecules.

Topics: Anti-HIV Agents; Drug Design; HIV Infections; HIV Reverse Transcriptase; HIV-1; Humans; Models, Molecular; Structure-Activity Relationship; Thioacetamide

The development of novel HIV-1 NNRTIs offers the possibility of generating novel structures with increased potency. Based on the bioisosteric principle, a novel series of 2-(2-(2,4-dichlorophenyl)-2H-1,2,4-triazol-3-ylthio)-N-arylacetamide derivatives were designed, synthesized using a simple and efficient synthetic route, structurally confirmed by spectral analysis, evaluated for their anti-HIV activity in MT-4 cells and their inhibitory effect on HIV-1 RT. The results showed that some of the new compounds displayed low micromolar potency for inhibiting HIV-1 replication and promising activities against several selected resistant strains that confer resistance to current NNRTIs. However, all newly synthesized derivatives were not active against HIV-2 replication.

Topics: Acetamides; Anti-HIV Agents; Cell Line; HIV Infections; HIV Reverse Transcriptase; HIV-1; HIV-2; Humans; Reverse Transcriptase Inhibitors; Structure-Activity Relationship; Triazoles; Virus Replication

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.. 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 CC50 values 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.. 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.

Topics: Cell Line; Cells, Cultured; Enzyme Activation; Gene Products, gag; HIV Infections; HIV Protease; HIV-1; Humans; Leukocytes, Mononuclear; Nitriles; Reverse Transcriptase Inhibitors; Sulfonamides; Triazoles

A novel series of 1,2,3-thiadiazole thioacetanilide (TTA) derivatives have been designed, synthesized and evaluated for its anti-HIV activities in MT-4 cells. Some derivatives proved to be highly effective in inhibiting HIV-1 replication at nanomolar concentrations. Among them, 2-[4-(2,4-dichlorophenyl)-1,2,3-thiadiazol-5-ylthio]-N-(2-nitrophenyl)acetamide 7d2 was identified as the most promising compound (EC(50)=0.059+/-0.02 microM, CC(50)>283.25 microM, SI>4883). The structure-activity relationship (SAR) of these novel structural congeners is discussed.

Topics: Anti-HIV Agents; Biological Assay; Cell Line; Chemistry, Pharmaceutical; Drug Design; Drug Evaluation, Preclinical; HIV Infections; HIV Reverse Transcriptase; HIV-1; Humans; Models, Chemical; Reverse Transcriptase Inhibitors; Structure-Activity Relationship; Thiadiazoles; Virus Replication

Nonnucleoside reverse transcriptase (RT) inhibitors (NNRTIs) are important components of current combination therapies for human immunodeficiency virus type 1 (HIV-1) infection. However, their low genetic barriers against resistance development, cross-resistance, and serious side effects can compromise the benefits of the two current drugs in this class (efavirenz and nevirapine). In this study, we report a novel and potent NNRTI, VRX-480773, that inhibits viruses from efavirenz-resistant molecular clones and most NNRTI-resistant clinical HIV-1 isolates tested. In vitro mutation selection experiments revealed that longer times were required for viruses to develop resistance to VRX-480773 than to efavirenz. RT mutations selected by VRX-480773 after 3 months of cell culture in the presence of 1 nM VRX-480773 carried the Y181C mutation, resulting in a less-than-twofold increase in resistance to the compound. A virus containing the double mutation V106I-Y181C emerged after 4 months, causing a sixfold increase in resistance. Viruses containing additional mutations of D123G, F227L, and T369I emerged when the cultures were incubated with increasing concentrations of VRX-480773. Most of the resistant viruses selected by VRX-480773 are susceptible to efavirenz. Oral administration of VRX-480773 to dogs resulted in plasma concentrations that were significantly higher than those required for the inhibition of wild-type and mutant viruses. These results warrant further clinical development of VRX-480773 for the treatment of HIV infection in both NNRTI-naive and -experienced patients.

Topics: Administration, Oral; Alkynes; Animals; Anti-HIV Agents; Benzoxazines; Cell Line; Cyclopropanes; Dogs; Drug Resistance, Viral; HIV Infections; HIV-1; Humans; Mutation; Reverse Transcriptase Inhibitors; Triazoles