Mechanism and action characteristics studies of a quinoxalinone compound against HIV-1 replication / 药学学报

This study is to investigate the mechanism and action characteristics of 6-chloro-3-methyl-4-(2-methyoxycarbonylthiophene-3-sulfonyl)-3, 4-dihydroquinoxa-lin-2-(1 H)-one (XU07011) against HIV-1 replication. XU07011 anti-HIV activity was tested by using VSVG/HIV pseudotype viral system and confirmed by HIV-1 live viruses' infectious assay. Time of addition was used to test HIV-1 reverse transcription process. RNA-dependent DNA polymerase activity and RNase H activity were tested by using enzyme linked immunoabsorbent assay and fluorescence method. Wild type and nine NNRTIs-resistant reverse transcriptase enzymatic models and cell-based pharmacological models were used to evaluate XU07011 bio-characteristics. The results showed that XU07011 inhibited HIV-1 replication with IC50 of (0.057 +/- 0.01) micromol x L(-1) which was comparable to nevirapine [IC50: (0.046 +/- 0.01) micromol x L(-1)]. Mechanism study data indicated that XU07011 blocked HIV-1 reverse transcription process through acting on reverse transcriptase RNA-dependent DNA polymerase with IC 50 of (1.1 +/- 0.3) micromol x L(-1). The compound showed no effect on RNase H activity. XU07011 exhibited better activities comparing with nevirapine on K103N mutated NNRTIs-resistant HIV-1 strains. This study could provide a theoretical basis for novel anti-HIV reagents development.

Shizukaol F: a new structural type inhibitor of HIV-1 reverse transcriptase RNase H / 药学学报

This study is to investigate the mechanism of action of lindenane disesquiterpenoid shizukaol F on HIV-1 replication. Real time quantity PCR, ELISA assay and fluorescence methods were used to test HIV-1 reverse transcription process, RNA-dependent DNA polymerase activity, and RNase H activity, respectively. It showed that shizukaol F inhibited LTR/Gag production of HIV-1 reverse transcription with an IC50 of 9.11 micromol x L(-1). This result is consistent with its inhibitory effect on HIV-1 replication (IC50 of 6.12 micromol x L(-1)). Mechanism studies showed that compound shizukaol F inhibited HIV-1 RT-RNase H with IC50 of 26.4 micromol x L(-1), but had no effect on HIV-1 RT RNA-dependent DNA polymerase activity. In conclusion, shizukaol F is a new structural type HIV-1 RNase H inhibitor. This discovery will provide a clue for new type of reverse transcriptase inhibitors development.

Establishment of a cell-based 2009 H1N1 influenza neuraminidase inhibitors evaluation system / 药学学报

This study is to establish a cell-based model targeting to neuraminidase (NA) of the 2009 H1N1 influenza A virus. NA is an influenza virus structural protein with enzymatic activity of the cleavage of HA-sialic acid interaction to release new viral particles from cells. A model of HIV-1 (pNL4-3.Luc.R(-)E(-)) based pseudovirions packed with HA [hemagglutinin, A/VietNam/1203/2004 (H5N1)] and NA [A/California/04/2009 (H1N1)] was established to evaluate compounds activities on NA function. The viral release can be blocked by neuraminidase inhibitors, oseltamivir and oseltamivir carboxylate, with IC50 of (61 +/- 31) nmol L(-1) and (5.5 +/- 2.9) nmol L(-1) respectively. A point mutation of H275Y on NA leads oseltamivir-resistance. This corresponding mutation was introduced into the system which was also confirmed by oseltamivir and oseltamivir carboxylate.

Establishment of pharmacological evaluation system for non-nucleoside reverse-transcriptase inhibitors resistant HIV-1 / 药学学报

Consistent non-nucleoside reverse-transcriptase inhibitors (NNRTIs) resistant HIV-1 strains occurred due to the clinical use for more than ten years of efavirenz (EFV), nevirapine (NVP), and delavirdine (DLV). In this study, we established nine cell-based pharmacological models according to most NNRTIs-resistant clinical tested strains, Resistant mutations were introduced into vector, pNL4-3.Luc.R-E-, by overlapping PCR. Then, pseudovirions were produced by co-transfection of VSV-G plasmid and pNL4-3.Luc.R-E- -mut. All nine recombinant VSVG/HIV-mut pseudovirions (VSVG/HIV-wt, VSVG/HIV(-K103N), VSVG/HIV(-Y181C), VSVG/HIV(-L100I,K103N), VSVG/HIV(-Y188L), VSVG/HIV(-K103N,Y181C), VSVG/HIV(-K103N,P225H), VSVG/HIV(-K103N,Y188L), VSVG/HIV(-K103N,G109A) and VSVG/HIV(-K103N,V108I)) had high efficient infectivity. Furthermore, they all showed resistant characteristics to EFV and NVP with IC50 changes consisting with clinical reports, not to nucleoside reverse-transcriptase inhibitors (AZT and d4T). This series safe cell-based model, which could be carried out in BSL-2 laboratory, can be used for evaluating NNRTIs candidates.

Screening of HIV-1 replication inhibitors by using pseudotyped virus system / 药学学报

This study is to establish a cell-based pharmacological model targeting HIV-1 replication for compounds screening and to screen compounds randomly selected from compounds library by using this pseudotyped viral system. The cell-based HIV-1 replication pharmacological model was set up by HIV-1 core packed with vesicular stomatitis virus glycoprotein. The level of HIV-1 replication was presented by reporter genes expression (luciferase activity or percentage of GFP positive cells). When a compound has inhibitory effect on VSVG/HIV model, VSVG/MLV model would be used to test for specificity. Vesicular stomatitis virus glycoprotein can efficiently mediate HIV core into a wide range of host cells. Expression level of reporter genes showed dose-dependent manner with virion dilution. Among 500 compounds, three compounds dose-dependently inhibit HIV-1 replication, but not MLV replication. VSVG/HIV pseudotyped viral system can be used as a pharmacological model for HIV-1 replication inhibitor screening. Compounds 2-methylthio-5-(4-methylbenzo)amido-l,3,4-thiadiazole, N-(3-hydroxyphenyl)-2-(4-isobutylphenyl) propionamide, and N-(4-picolyl)-4-methylbenzenesulfonamide can specifically inhibit HIV-1 replication with IC50 of 1.92, 5.38, and 3.39 micromol L(-1) respectively.