MT-4 Cells Research Articles

Structural optimization of N1-aryl-benzimidazoles for the discovery of new non-nucleoside reverse transcriptase inhibitors active against wild-type and mutant HIV-1 strains

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are recommended components of preferred combination antiretroviral therapies used for the treatment of human immunodeficiency virus (HIV) infection. These regimens are extremely effective in suppressing virus replication. Recently, our research group identified some N1-aryl-2-arylthioacetamido-benzimidazoles as a novel class of NNRTIs. In this research work we report the design, the synthesis and the structure–activity relationship studies of new compounds (20–34) in which some structural modifications have been introduced in order to investigate their effects on reverse transcriptase (RT) inhibition and to better define the features needed to increase the antiviral activity. Most of the new compounds proved to be highly effective in inhibiting both RT enzyme at nanomolar concentrations and HIV-1 replication in MT4 cells with minimal cytotoxicity. Among them, the most promising N1-aryl-2-arylthioacetamido-benzimidazoles and N1-aryl-2-aryloxyacetamido-benzimidazoles were also tested toward a panel of single- and double-mutants strain responsible for resistance to NNRTIs, showing in vitro antiviral activity toward single mutants L100I, K103N, Y181C, Y188L and E138K. The best results were observed for derivatives 29 and 33 active also against the double mutants F227L and V106A. Computational approaches were applied in order to rationalize the potency of the new synthesized inhibitors.

Synthesis, Biological Evaluation, and Molecular Docking Studies of Novel 4-[4-Arylpyridin-1(4H)-yl]benzoic Acid Derivatives as Anti-HIV-1 Agents.

The structural similarities between N1 substituted 1,4-dihydropyridines and the known gp41 inhibitors, NB-2 and NB-64, were considered in the current research for the design of some novel anti-HIV-1 agents. A series of novel 4-[4-arylpyridin-1(4H)-yl]benzoic acid derivatives were synthesized and after a comprehensive structural elucidation were screened for in vitro anti-HIV-1 activity. Most of the tested compounds displayed moderate to good inhibitory activity against HIV-1 growth and were evaluated for in vitro cytotoxic activity using XTT assay at the concentration of 100 μm. Among the tested compounds, 1c, 1d and 1e showed potent anti-HIV-1 activity against P24 expression at 100 μm with inhibition percentage of 84.00%, 76.42% and 80.50%, respectively. All the studied compounds possessed no significant cytotoxicity on MT-2 cell line. The binding modes of these compounds to gp41 binding site were determined through molecular docking study. Docking studies proved 1a as the most potent compound and binding maps exhibited that the activities might be attributed to the electrostatic and hydrophobic interactions and additional H-bonds with the gp41 binding site. The Lipinski's 'rule of five' and drug-likeness criteria were also calculated for the studied compounds. All derivatives obeyed the Lipinski's 'rule of five' and had drug-like features. The findings of this study suggest that novel 4-[4-arylpyridin-1(4H)-yl]benzoic acid might be a promising scaffold for the discovery and development of novel anti-HIV-1 agents.

Discovery of Thiophene[3,2-d]pyrimidine Derivatives as Potent HIV-1 NNRTIs Targeting the Tolerant Region I of NNIBP.

Our previous studies led us to conclude that thiophene[3,2-d]pyrimidine is a promising scaffold for diarylpyrimidine (DAPY)-type anti-HIV agents with potent activity against resistance-associated human immunodeficiency virus (HIV) variants (J. Med. Chem. 2016, 59, 7991-8007; J. Med. Chem. 2017, 60, 4424-4443). In the present study, we designed and synthesized a series of thiophenepyrimidine derivatives with various substituents in the right wing region of the structure with the aim of developing new interactions with the tolerant region I of the binding pocket of the HIV-1 non-nucleoside reverse transcriptase (NNRTI), and we evaluated their activity against a panel of mutant HIV-1 strains. All the derivatives exhibited moderate to excellent potency against wild-type (WT) HIV-1 in MT-4 cells. Among them, sulfonamide compounds 9b and 9d were single-figure-nanomolar inhibitors with EC50 values of 9.2 and 7.1 nM, respectively. Indeed, 9a and 9d were effective against the whole viral panel except RES056. Notably, both compounds showed potent antiviral activity against K103N (EC50 = 0.032 and 0.070 μM) and E138K (EC50 = 0.035 and 0.045 μM, respectively). Furthermore, 9a and 9d exhibited high affinity for WT HIV-1 RT (IC50 = 1.041 and 1.138 μM, respectively) and acted as classical NNRT inhibitors (NNRTIs). These results are expected to be helpful in the design of thiophenepyrimidine-based NNRTIs with more potent activity against HIV strains with RT mutations.

The role of the glycosyl moiety of myricetin derivatives in anti-HIV-1 activity in vitro

BackgroundPlant extracts are sources of valuable compounds with biological activity, especially for the anti-proliferative activity against pathogens or tumor cells. Myricetin is a flavonoid found in several plants that has been described as an inhibitor of Human immunodeficiency virus type 1 (HIV-1) through its action against the HIV reverse transcriptase, but myricetin derivatives have not been fully studied. The aim of this study was to evaluate the anti-HIV-1 activity of glycosylated metabolites obtained from Marcetia taxifolia and derived from myricetin: myricetin rhamnoside and myricetin 3-(6-rhamnosylgalactoside).MethodsCompounds were obtained from organic extracts by maceration of aerial parts of M. taxifolia. All biological assays were performed in the MT4 cell line. Antiviral activity was measured as inhibition of p24 and reverse transcriptase with a fluorescent assay.ResultsBoth flavonoids have antiviral activity in vitro, with an EC50 of 120 µM for myricetin 3-rhamnoside (MR) and 45 µM for myricetin 3-(6-rhamnosylgalactoside) (MRG), both significantly lower than the EC50 of myricetin (230 µM). Although both compounds inhibited the reverse transcriptase activity, with an IC50 of 10.6 µM for MR and 13.8 µM for MRG, myricetin was the most potent, with an IC50 of 7.6 µM, and an inhibition greater than 80%. Molecular docking approach showed correlation between the free energy of binding with the assays of enzyme inhibition.ConclusionsThe results suggest that glycosylated moiety might enhance the anti-HIV-1 activity of myricetin, probably by favoring the internalization of the flavonoid into the cell. The inhibition of the HIV-1 reverse transcriptase is likely responsible for the antiviral activity.

Diagnostic performance of the indirect immunofluorescence test for the detection of antibodies against HTLV-1

The objective of the study was to determine the diagnostic yield of the indirect immunofluorescence (IFI) test for the detection of antibodies against HTLV-1. A diagnostic test evaluation study was performed. HTLV-1-infected MT2 cells and HTLV-1-uninfected K-562 cells were cultured; then these cells were impregnated and fixed in sheets for immunofluorescence and faced to Peruvian sera. A total of 155 sera (80 HTLV-1-positive sera and 75 sera positive for other diseases) from the Peruvian Instituto Nacional de Salud were used. In addition, the parameters of repeatability (intra-laboratory) and reproducibility (in laboratories of the Peruvian coast, mountains and jungle) of the test were evaluated. The IFI test detected the presence of antibodies against HTLV-1 reaching a sensitivity of 98.75% (95% CI: 95.69 - 100.00%), a specificity of 98.67% (95% CI: 95.40 - 100.00%) and the Kappa index was 0.975. There were no false positives or false negatives; however, one undetermined result and one non-specific result were obtained. The test showed 100% qualitative agreement when performing the repeatability and reproducibility. The results obtained are comparable to the reference test. Therefore, the IFI test had a good diagnostic performance and would be useful for the confirmation of HTLV-1.

A novel medium-throughput biological assay system for HTLV-1 infectivity and drug discovery.

Objective(s):Here, a reporter cell line containing two reporter vectors were developed, in order to monitor the Human T-Lymphotropic Virus type1(HTLV-1) infectivity and the cell viability simultaneously.Materials and Methods:The reporter cell line was constructed by stably transfected baby hamster’s kidney cell line (BHK-21), with the genomes expressing two different reporters in separate plasmids. The first reporter gene is transactivated by the HTLV-1 tax protein, while the second reporter is continuously expressed when introduced into a mammalian cell. In order to show its functionality, the effect of the drug mix on HTLV-1 was assayed by this system and was compared to the results obtained by other methods.Results:HTLV-1 reporter cell line was found to produce high level of luciferase when co-cultured with MT-2 and Hut-102 cells but not with Jurkat cell. Moreover, the combination therapy against HTLV-1 can reduce luciferase expression of the cell when co-cultured with MT-2 and Hut-102 comparable to the ELISA (R=0.932, P-value =0.002). In addition, the results revealed the superiority of the present system over the molecular methods.Conclusion:The results demonstrated that the biological assay system is a beneficial tool for the medium-throughput anti-HTLV-1 drug screening and inhibitory effect.

Identification of novel bifunctional HIV-1 reverse transcriptase inhibitors.

The increasing prevalence of mutations in HIV-1 reverse transcriptase (RT) that confer resistance to existing NRTIs and NNRTIs underscores the need to develop RT inhibitors with novel mode-of-inhibition and distinct resistance profiles. Biochemical assays were employed to identify inhibitors of RT activity and characterize their mode of inhibition. The antiviral activity of the inhibitors was assessed by cell-based assays using laboratory HIV-1 isolates and MT4 cells. RT variants were purified via avidin affinity columns. Compound A displayed equal or greater potency against many common NNRTI-resistant RTs (K103N and Y181C RTs) relative to WT RT. Despite possessing certain NNRTI-like properties, such as being unable to inhibit an engineered variant of RT lacking an NNRTI-binding pocket, we found that compound A was dependent on Mg2+ for binding to RT. Optimization of compound A led to more potent analogues, which retained similar activities against WT and K103N mutant viruses with submicromolar potency in a cell-based assay. One of the analogues, compound G, was crystallized in complex with RT and the structure was determined at 2.6 Å resolution. The structure indicated that compound G simultaneously interacts with the active site (Asp186), the highly conserved primer grip region (Leu234 and Trp229) and the NNRTI-binding pocket (Tyr188). These findings reveal a novel class of RT bifunctional inhibitors that are not sensitive to the most common RT mutations, which can be further developed to address the deficiency of current RT inhibitors.

Mutations Located outside the Integrase Gene Can Confer Resistance to HIV-1 Integrase Strand Transfer Inhibitors

ABSTRACTResistance to the integrase strand transfer inhibitors raltegravir and elvitegravir is often due to well-identified mutations in the integrase gene. However, the situation is less clear for patients who fail dolutegravir treatment. Furthermore, most in vitro experiments to select resistance to dolutegravir have resulted in few mutations of the integrase gene. We performed an in vitro dolutegravir resistance selection experiment by using a breakthrough method. First, MT4 cells were infected with human immunodeficiency virus type 1 (HIV-1) Lai. After integration into the host cell genome, cells were washed to remove unbound virus and 500 nM dolutegravir was added to the cell medium. This high concentration of the drug was maintained throughout selection. At day 80, we detected a virus highly resistant to dolutegravir, raltegravir, and elvitegravir that remained susceptible to zidovudine. Sequencing of the virus showed no mutations in the integrase gene but highlighted the emergence of five mutations, all located in the nef region, of which four were clustered in the 3′ polypurine tract (PPT). Mutations selected in vitro by dolutegravir, located outside the integrase gene, can confer a high level of resistance to all integrase inhibitors. Thus, HIV-1 can use an alternative mechanism to develop resistance to integrase inhibitors by selecting mutations in the 3′ PPT region. Further studies are required to determine to what extent these mutations may explain virological failure during integrase inhibitor therapy.

1-Hydroxypyrido[2,3-d]pyrimidin-2(1H)-ones as novel selective HIV integrase inhibitors obtained via privileged substructure-based compound libraries

A small library containing 3-hydroxyquinazoline-2,4(1H,3H)-dione and 1-hydroxypyrido[2,3-d]pyrimidin-2(1H)-one scaffolds was obtained via the copper(I)-catalyzed azidealkyne cycloaddition (CuAAC) reaction and evaluated for their anti-HIV activity in MT-4 cells. Among the synthesized compounds, several 1-hydroxypyrido[2,3-d]pyrimidin-2(1H)-one derivatives showed remarkable anti-HIV potency with EC50 values ranging from 0.92 to 26.85µM. The most active one, IIA-2, also showed remarkable and selective potency against HIV type 1 integrase (IN). To the best of our knowledge, this is the first report showing that 1-hydroxypyrido[2,3-d]pyrimidin-2(1H)-ones are selective HIV IN inhibitors. Preliminary structure-activity relationship (SAR) studies suggested that the divalent metal ion chelators and the nature and position of substituents around the core are important for antiviral potency. Molecular modeling has been used to predict the binding site of the pyrido[2,3-d]pyrimidin-2(1H)-one core in HIV type 1 IN and suggestions are made for improvement of its inhibitory activity.

1H-Tetrazol-5-amine and 1,3-thiazolidin-4-one derivatives containing 3-(trifluoromethyl)phenyl scaffold: Synthesis, cytotoxic and anti-HIV studies

On the basis of recently reported biologically active 3-(trifluoromethyl)phenylthioureas, a series of diaryl derivatives incorporating 1H-tetrazol-5-yl (1a–11a, 1a’–11a’) and 1,3-thiazolidin-4-one (1b–11b) scaffolds were synthesized. The synthesis pathway was confirmed by an X-ray crystallographic studies of 3a’, 6a, 8a, 6b and 8b. The cytotoxicity against MT-4 cells and anti-HIV properties of new derivatives were evaluated. As compared to initial thiourea connections, the cyclisation reduced the cytotoxicity of compounds by 2–15 times. The most promising N-(4-nitrophenyl)-1H-tetrazol-5-amine 7a was found to be more active than the origin thiourea. Its cytotoxicity was evaluated on A549, HTB-140 and HaCaT cell lines using MTT assay. The compound shows significant influence on cancer, but not on normal cells. Obtained results can provide some constructive data for further designing of novel family of potentially bioactive analogs.

Synthesis, structural studies and biological activity of novel Cu(II) complexes with thiourea derivatives of 4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione

The new Cu(II) complexes of 1/2/3-(bromophenyl)-3-(1,7,8,9-tetramethyl-3,5-dioxo-4-azatricyclo[5.2.1.02,6]dec-8-en-4-yl)thiourea derivatives have been synthesized. The spectroscopic studies together with density functional theory calculations of Cu(II) complexes revealed that two parent ligands coordinate to the copper cation in bidentate fashion via thiocarbonyl S and deprotonated N atoms forming rarely observed four-membered chelate ring, with nearly planar [CuN2S2] moiety. In solid state, the mononuclear complex is formed for thiourea derivative with 3-bromophenyl, whereas for Cu(II) connection with 2- and 4-bromophenyl-thioureas the formation of dinuclear complexes is observed, the latter formed by the stacking of mononuclear complexes.The microbiological activity of novel compounds has been evaluated. The Cu(II) complex with 4-bromophenyl ring connected to the thiourea moiety showed significant inhibition against standard strains of S. aureus and S. epidermidis. The range of minimal inhibitory concentration values is 2–4μg/mL. That compound exhibited antibiofilm potency and effectively inhibited the formation of biofilm of methicillin-susceptive strain of S. epidermidis ATCC 12228. Moreover, the cytotoxicity against the MT-4 cells of all obtained complexes has been evaluated. The complexes turned out to be non-cytotoxic for exponentially growing MT-4.

Early growth response gene-1 regulates host cell autophagy in HTLV-1 infection

Objective To investigate the influence of early growth response gene-1 (EGR1) on the autophagy of host cells following infection with human T cell leukemia virus type 1 (HTLV-1). Methods A HTLV-1-positive cell line MT2 was co-cultured with HeLa cells for 24 h to construct the virus early infection model. Immunoblotting assay was used to detect the expression of HTLV-1 core protein p19 and EGR1. Luciferase reporter gene analysis was used to detect the transcriptional activity of 5′-regulatory sequence of EGR1 at different time points after co-culturing. An effective small interfering RNA (siRNA) targeting EGR1 was screened out and transfected into HeLa cells by Lipofectamine 2000. Then the transfected HeLa cells were co-cultured with the HTLV-1-positive cell line MT2 for 24 h. Immunoblotting assay was used to detect HTLV-1 core protein p19, EGR1 and autophagy-related protein LC3. Real-time PCR was performed to detect viral load. Autophagosome was analyzed by immunofluorescence after co-culturing. Results The expression of EGR1 and the transcriptional activity of pEGR1-luc gradually increased after co-culturing HeLa cells with MT2 cells for 8 h (P<0.01). The expression of EGR1 was positively correlated with host cell autophagy following HTLV-1 infection. The effective siRNA for silencing the expression of EGR1 was obtained and named as siE2. The viral load, the expression of HTLV-1 core protein p19 and the proportion of LC3B/LC3A in the co-culture model were markedly down-regulated by RNA interference with siE2, which was concomitant with a persistent decrease of intracellular autophagosome (P<0.01). Conclusion EGR1 is associated with host cell autophagy and viral replication in HTLV-1 infection. Key words: Early growth response gene-1; Human T-cell leukemia virus type 1; Autophagy; Virus replication

Polymorphic Nature of Human T-Cell Leukemia Virus Type 1 Particle Cores as Revealed through Characterization of a Chronically Infected Cell Line

Human T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-1 cell-to-cell transmission is dependent on the release of infectious virus particles into the virological synapse. The HTLV-1 particle structure is still poorly understood, and previous studies analyzed viruses produced by transformed lymphocytic cell lines chronically infected with HTLV-1, particularly the MT-2 cell line, which harbors truncated proviruses and expresses aberrant forms of the Gag protein. In this study, we demonstrate that the chronically infected SP cell line harbors a relatively low number of proviruses, making it a more promising experimental system for the study of the HTLV-1 particle structure. We first identified the genomic sites of integration and characterized the genetic structure of the gag region in each provirus. We also determined that despite encoding a truncated Gag protein, only the full-length Gag protein was incorporated into virus particles. Cryo-transmission electron microscopy analyses of the purified virus particles revealed three classes of particles based upon capsid core morphology: complete cores, incomplete cores, and particles without distinct electron densities that would correlate with the capsid region of a core structure. Observed cores were generally polygonal, and virus particles were on average 115 nm in diameter. These data corroborate particle morphologies previously observed for MT-2 cells and provide evidence that the known poor infectivity of HTLV-1 particles may correlate with HTLV-1 particle populations containing few virus particles possessing a complete capsid core structure.IMPORTANCE Studies of retroviral particle core morphology have demonstrated a correlation between capsid core stability and the relative infectivity of the virus. In this study, we used cryo-transmission electron microscopy to demonstrate that HTLV-1 particles produced from a distinct chronically infected cell line are polymorphic in nature, with many particles lacking organized electron densities that would correlate with a complete core structure. These findings have important implications for infectious HTLV-1 spread, particularly in the context of cell-to-cell transmission, a critical step in HTLV-1 transmission and pathogenesis.

Design, synthesis and anti-HIV evaluation of novel diarylpyridine derivatives as potent HIV-1 NNRTIs

As a continuation of our efforts to discover and develop “me-better” drugs of DAPYs, novel diarylpyridine derivatives were designed, synthesized and evaluated for their anti-HIV activities in MT-4 cells. The majority of these compounds showed high activity against wild-type HIV-1 strain (IIIB) with EC50 values in the range of 0.04–4.41 μM. Among them, compound 5b2 (EC50 = 0.04 μM, SI = 3963) was the most potent. This compound showed anti-HIV-1IIIB activity superior than of Nevirapine but still inferior than of Etravirine. Selected compounds were also evaluated for the activity against reverse transcriptase (RT), and most of the compounds exhibited submicromolar IC50 values indicating they are specific RT inhibitors. Preliminary structure-activity relationships and modeling studies of these new analogues provide valuable avenues for future molecular optimization.

Synthesis, crystal structure, anti-HIV, and antiproliferative activity of new pyrazolylthiazole derivatives

The development of new HIV-1 non-nucleoside reverse transcriptase inhibitors offers the possibility of generating novel structures of increased potency. Based on the bioisosteric principle, new series of N′-benzylidene-2-(5-(4-chlorophenyl)-3-phenyl-4,5-dihydropyrazol-1-yl)thiazole-4-carbohydrazide schiff bases 5a–x containing 1,3-thiazole clubbed with 2-pyrazoline was synthesized and characterized by spectroscopic techniques. The structure of the synthesized compounds was unambiguously confirmed by single-crystal X-ray diffraction analysis of compound 5k. All the new analogs were evaluated in vitro for antiviral activity against the replication of HIV-1 and HIV-2 in MT4 cells using MTT assay. The results showed that only compounds 5n, and 5r possess potent activity against HIV-1 replication (IC50 = 0.50, 0.45 μM, SI = 3 and 5), respectively. None of the compounds are active against HIV-2. Furthermore, compounds 5a, 5i, 5n, and 5r were evaluated for their antiproliferative activity against two solid tumor-derived cell lines consisting MCF-7 (breast cancer) and Hep-G2 (human hepatocarcinoma).

Synthesis, X-ray structure, in vitro HIV and kinesin Eg5 inhibition activities of new arene ruthenium complexes of pyrimidine analogs

Three new ruthenium(II)-arene complexes of the general formula [{(η6-p-cymene)Ru(L)}2](Cl)2), where L are monastrol (L1), ethyl 4-(3-hydroxyphenyl)-6-methyl-2-thioxo-pyrimidine-5-carboxylate (L2) or its 4-bromophenyl analog (L3), have been synthesized and characterized by elemental analysis, 1H, 13C, and 2-D NMR spectroscopy. The X-ray diffraction study of complex 1 showed the presence of a dicationic diruthenium complex where two thioxopyrimidines act as tridentate μ,κN:κ2S ligand, bridging two Ru ions through the pyrimidine nitrogen and sulfur atoms. All new complexes were evaluated in vitro for their antiviral activity against the replication of HIV-1 and HIV-2 in MT-4 cells using MTT assay. Additionally, complexes 1–3 were screened for their inhibitory activity against the ATPase enzyme and the motor-protein Kinesin Eg5. Complex 1 was found to inhibit microtubule-stimulated ATPase activity of kinesin of IC50 = 30 μM (monastrol, IC50 = 10 μM).

Anti-HIV-1 and cytotoxicity of a new dimeric thiazepine alkaloid isolated from Ixora undulata Roxb. leaves

The crude alkaloidal extract of Ixora undulata Roxb. leaves recorded a cytotoxicity of IC50 = 125 µg/mL against EL4 and revealed a reduction with CC50 = 47 µg/mL in the viability of MT-4 cells, beside a 50% protection with EC50 > 47 µg/mL against HIV-1IIIB. Bioassay guided fractionation of the crude alkaloidal extract of I. undulata leaves led to the isolation of a new dimeric thiazepine alkaloid, together with the monomer and its glycoside. The isolated alkaloids were structurally elucidated based on extensive nuclear magnetic resonance spectroscopy, infrared, and HRESI/MS. The isolated alkaloids were evaluated for their anti-HIV-1 and cytotoxic activities, while the obtained results revealed promising activity with structure-based relationship, which is discussed briefly.

Structure-Based Optimization of Thiophene[3,2-d]pyrimidine Derivatives as Potent HIV-1 Non-nucleoside Reverse Transcriptase Inhibitors with Improved Potency against Resistance-Associated Variants.

This work follows on from our initial discovery of a series of piperidine-substituted thiophene[3,2-d]pyrimidine HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTI) ( J. Med. Chem. 2016 , 59 , 7991 - 8007 ). In the present study, we designed, synthesized, and biologically tested several series of new derivatives in order to investigate previously unexplored chemical space. Some of the synthesized compounds displayed single-digit nanomolar anti-HIV potencies against wild-type (WT) virus and a panel of NNRTI-resistant mutant viruses in MT-4 cells. Compound 25a was exceptionally potent against the whole viral panel, affording 3-4-fold enhancement of in vitro antiviral potency against WT, L100I, K103N, Y181C, Y188L, E138K, and K103N+Y181C and 10-fold enhancement against F227L+V106A relative to the reference drug etravirine (ETV) in the same cellular assay. The structure-activity relationships, pharmacokinetics, acute toxicity, and cardiotoxicity were also examined. Overall, the results indicate that 25a is a promising new drug candidate for treatment of HIV-1 infection.

Influence of cellular autophagy on replication dynamics of human T cell leukemia virus typeI(HTLV-1) in HeLa cells

Objective To investigate the replication dynamics and cellular states of host cells with human T cell leukemia virus type 1 (HTLV-1) infection. Methods HTLV-1 positive cell line MT2 was co-cultured with HeLa cells for 4 to 36 hours to acquire the virus early infection model. Immunoblotting was used to detect HTLV-1 core protein p19, apoptosis-related proteins caspase-3/9 and autophagy-related protein LC3 at different time points. Real-time PCR was used to measure viral loads. Luciferase reporter gene assay was used to detect the enzymatic activities of caspase-3/7/9 and the transcriptional activities of 3′-LTR at different time points after co-culturing. Autophagosomes were analyzed by immunofluorescence after co-culturing. The HTLV-1 long terminal repeat reporter gene (pHTLV-1-LTR-luc) was transfected into HeLa cells by lipidosome 2000-mediated transfection and the luciferase activities at different time points were detected. Results The HTLV-1 infection model was successfully constructed by co-culturing MT2 cells with HeLa cells in vitro. Viral load and transcriptional activity of the 3′-LTR gradually increased at 4 to 16 h after virus infection (P 0.05), but the proportion of LC3B/LC3A showed a gradual increasing trend with the persistent increase of autophagosomes (P<0.01). Conclusion Viral replication dynamics of HTLV-1 is closely related to autophagy in host cells. Key words: Human T cell leukemia virus type 1; Replication dynamics; Apoptosis; Autophagy

New chalcones and thiopyrimidine analogues derived from mefenamic acid: microwave-assisted synthesis, anti-HIV activity and cytotoxicity as antileukemic agents

AbstractThe development of new HIV non-nucleoside reverse transcriptase inhibitors offers the possibility of generating structures of increased potency. To this end, coupling of mefenamic acid (4) with 4-amino-acetophenone (6) in the presence of dicyclohexylcarbodiimide and dimethylaminopyridine (DMAP) reagents afforded 4-(acetyphenyl)-2-((2,3-dimethylphenyl)amino)benzamide (7). Analogously, treatment of mefenamyl chloride (5) prepared from4with6under microwave irradiation (MWI) afforded7. A new series of substituted chalconyl-incorporated amide derivatives of mefenamic acid8–13were synthesized from condensation of7with various substituted benzaldehydes via the Claisen–Schmidt reaction. Treatment of8and11with thiourea in a basic medium afforded the thiopyrimidine analogues14and15, respectively. The newly synthesized compounds were assayed against HIV-1 and HIV-2 in MT-4 cells. Compounds9and11showed cytotoxicity values of 2.17 and 2.06 μm, respectively, against mock-infected MT-4 cells (C type adult T leukemia cells), which considered to be promising antileukemic agents.