A large number of protease inhibitors have been found from leeches, which are essential in various physiological and biological processes. In the curret study, a novel elastase inhibitor was purified and characterized from the leech of Hirudinaria manillensis, which was named HMEI-A. Primary structure analysis showed that HMEI-A belonged to a new family of proteins. HMEI-A exerted inhibitory effects on elastase and showed potent abilities to inhibit elastase with an inhibition constant (K
Amino Acid Sequence ; Animals ; Leeches/chemistry* ; Pancreatic Elastase/antagonists & inhibitors* ; Protease Inhibitors/pharmacology* ; Proteins

Apoptosis ; drug effects ; Boronic Acids ; pharmacology ; Bortezomib ; Hepatic Stellate Cells ; cytology ; drug effects ; Protease Inhibitors ; pharmacology ; Pyrazines ; pharmacology

With the decrease in land resources, marine resources open a new path for drug development, among which sponge is one of important marine biological resources. In recent years, many anti-tumor active compounds in new structures have been extracted and isolated from sponges. Targeted anti-tumor drugs from sponge become a new trend during the development of innovative drugs of marine resources. This essay summarizes the anti-tumor mechanism of sponge's active compounds and its related synthetics on the basis of its various anti-tumor targets including cytoskeleton (microtubule and actin), protein kinases (cyclin dependent kinase and aurora kinase), DNA synthesis and relevant enzymeso, growth microenvironment for tumor tissues and the immune system. Additionally, it also briefs relevant clinical studies.
Animals ; Antineoplastic Agents ; chemistry ; pharmacology ; Cytoskeleton ; drug effects ; Humans ; Immunologic Factors ; chemistry ; pharmacology ; Porifera ; chemistry ; Protease Inhibitors ; chemistry ; pharmacology

The aim of this study was to explore the synergistic effect of arsenic trioxide and bortezomib on apoptosis of Raji cell line. The cells were treated with arsenic trioxide, bortezomib, low-dose arsenic trioxide combined with bortezomib, respectively. The cell viability and proliferative curve were estimated by trypan blue dye exclusion. The cell apoptosis and cell cycle status were analyzed by flow cytometry. The apoptosis related elements such as caspase-3, BCL-2, BAX, JNK2 and IkappaB-alpha, were measured with Western blot. The results showed that compared with cells treated with mentioned above drugs alone, the proliferative potential of cells in combination group was significantly inhibited (p < 0.01), and apoptosis rate markedly increased (p = 0.001), while obvious cell cycle arrest was not observed. On the protein level, the expression of Caspase-3, BAX and IkappaB-alpha increased, while the expression of BCL-2, and JNK2 decreased. It is concluded that low-dose arsenic trioxide combined with bortezomib synergistically induced apoptosis in Raji cell line which may be mediated by inhibiting NK-kappaB and JNK2 signaling.
Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Arsenicals ; pharmacology ; Boronic Acids ; pharmacology ; Bortezomib ; Burkitt Lymphoma ; pathology ; Cell Line, Tumor ; Drug Synergism ; Humans ; Oxides ; pharmacology ; Protease Inhibitors ; pharmacology ; Pyrazines ; pharmacology

OBJECTIVEFrequency, type and clinical implications on protease and reverse transcriptase drug resistance mutations were investigated and phylogenetic analysis in antiretroviral drug-naïve AIDS patients was carried out in Henan province.

METHODS45 plasma samples were separated from the anticoagulatory whole blood, from which reverse transcription-polymerase chain reaction technique was used to amplify the partial pol gene. The sequences were analysed for genotypic antiretroviral resistance and phylogenetic relation through landing the websites http://hivdb.stanford.edu and http://hiv-web.lanl.gov, under BioEdit and DNAClub software.

RESULTSPartial pol sequences of 36 samples were successfully amplified. The major mutation rate of resistance to protease was 8.3% (3/36), including types D30A, V32A, G73C and V82A. Minor mutation rate of resistance was 100%, including types of L63PS (36/36), I93L (35/36), V77IL (34/36), A71IVT (10/36) and D60E (2/36). The mutation rate of resistance to reverse transcriptase was 38.9% (14/36). Mutation-scoring and clinical implication clewed drug resistance rates were 5.6% (2/36) and 22.2% (8/36) to protease inhibitors and reverse transcriptase inhibitors respectively, while 1 sample was potentially low-level resistant to all of the protease inhibitors and 3 samples to part of the reverse transcriptase inhibitors. Phylogenetic analysis revealed that the pol gene of 36 samples were highly homologous and having a near relative to B.US.83.RF ACC M17451. 36 samples seemed to have the same infection source while their resistance mutations were not due to drug-resistant virus infection but to the evolving of virus in vivo.

CONCLUSIONMost of the antiretroviral drug-naïve AIDS patients in Henan province were sensitive to the currently available antiviral medicine, but antiviral treatment must be in accordance with the strict procedure and to keep better adherence, to avoid the epidemics caused by drug-resistant virus.

Acquired Immunodeficiency Syndrome ; genetics ; Adult ; Anti-HIV Agents ; pharmacology ; China ; Drug Resistance, Viral ; genetics ; Female ; Genes, pol ; genetics ; Genotype ; HIV Protease ; genetics ; HIV Protease Inhibitors ; pharmacology ; Humans ; Male ; Mutation ; Phylogeny ; RNA-Directed DNA Polymerase ; genetics ; Reverse Transcriptase Inhibitors ; pharmacology

BACKGROUND: The objective of this study was to evaluate the role of proteases on the degradation of parathyroid hormone (PTH) in blood samples. METHODS: Protease inhibitors with specificity against serine proteases (aprotinin), cysteine proteases (E-64), serine and cysteine proteases (leupeptin), metalloproteases (EDTA), or a protease inhibitor cocktail with a broad spectrum of inhibitory activity were added to blood samples. After storage at room temperature (0-48 hr), PTH levels were measured. RESULTS: PTH levels in samples with the protease inhibitor cocktail did not change significantly after 48 hr of storage at room temperature, but the average PTH levels decreased by 40.7% and 20.1%, in samples stored at room temperature and stored at 4degrees C without protease inhibitors, respectively. PTH levels in samples with leupeptin were stable for up to 24 hr. After 48 hr, the mean PTH levels decreased by 17.1%, 16.0%, 26.2%, and 32.1%, with 500 KIU/mL aprotinin, 100 micro mol/L leupeptin, 10 micro mol/L E-64, and 10 micro mol/L EDTA, respectively, in the samples stored at room temperature. CONCLUSIONS: The decrease in PTH levels in blood samples seemed to be due to the degradation of PTH by proteases. Various proteases, including especially serine proteases, would act together to degrade PTH in blood specimen. The PTH degradation may be inhibited in blood specimen with protease inhibitor cocktail.
Aprotinin/pharmacology ; Blood Specimen Collection ; Edetic Acid/pharmacology ; Female ; Humans ; Leucine/analogs & derivatives/pharmacology ; Leupeptins/pharmacology ; Male ; Parathyroid Hormone/*blood/metabolism ; Protease Inhibitors/*pharmacology ; Time Factors

The aim of this study was to prepare tandem multimeric proteins of BmSPI38, a silkworm protease inhibitor, with better structural homogeneity, higher activity and stronger antifungal ability by protein engineering. The tandem multimeric proteins of BmSPI38 were prepared by prokaryotic expression technology. The effects of tandem multimerization on the structural homogeneity, inhibitory activity and antifungal ability of BmSPI38 were explored by in-gel activity staining of protease inhibitor, protease inhibition assays and fungal growth inhibition experiments. Activity staining showed that the tandem expression based on the peptide flexible linker greatly improved the structural homogeneity of BmSPI38 protein. Protease inhibition experiments showed that the tandem trimerization and tetramerization based on the linker improved the inhibitory ability of BmSPI38 to microbial proteases. Conidial germination assays showed that His₆-SPI38L-tetramer had stronger inhibition on conidial germination of Beauveria bassiana than that of His₆-SPI38-monomer. Fungal growth inhibition assay showed that the inhibitory ability of BmSPI38 against Saccharomyces cerevisiae and Candida albicans could be enhanced by tandem multimerization. The present study successfully achieved the heterologous active expression of the silkworm protease inhibitor BmSPI38 in Escherichia coli, and confirmed that the structural homogeneity and antifungal ability of BmSPI38 could be enhanced by tandem multimerization. This study provides important theoretical basis and new strategies for cultivating antifungal transgenic silkworm. Moreover, it may promote the exogenous production of BmSPI38 and its application in the medical field.
Animals ; Antifungal Agents/pharmacology* ; Escherichia coli/metabolism* ; Proteins/metabolism* ; Protease Inhibitors/chemistry* ; Bombyx/chemistry* ; Saccharomyces cerevisiae/metabolism* ; Peptide Hydrolases

OBJECTIVETo establish fluorescence resonance energy transfer (FRET) assay method of detecting proteolytic activity of non-structural protein 3-4A (NS3-4A) serine protease of hepatitis C virus (HCV) for high throughput screening inhibitors against HCV in vitro.

METHODSHCV recombinant plasmid pMAL~c2/NS3-4A was transformed into the E.coli strain K12TB1. Maltose-binding-protein (MBP) NS3-4A fusion protein expression was induced by adding isopropyl-β-D-thiogalacto-pyranoside (IPTG) and purified by affinity chromatography. The proteolytic activity of MBP-NS3-4A protease was analyzed by FRET with the special protease substrate. The reaction system in this model was optimized, and the reliability of the model was evaluated.

RESULTSHigh throughput screening model for HCV NS3-4A protease inhibitors was established, and the best concentrations of enzyme and substrate were optimized. In the model, the Km value of protease was 4.74 μmol/L, Z factor was up to 0.80, and coefficient of variation (CV) was 1.91%. BILN 2061, one of the known HCV protease inhibitors, was measured with the Ki of 0.30 nmol/L.

CONCLUSIONThe assay model using FRET method for HCV NS3 4A serine protease is stable and reliable, and the model is suitable for high throughput screening for HCV NS3 4A protease inhibitors.

Antiviral Agents ; pharmacology ; Drug Evaluation, Preclinical ; Fluorescence Resonance Energy Transfer ; Hepacivirus ; enzymology ; High-Throughput Screening Assays ; methods ; Protease Inhibitors ; pharmacology ; Viral Nonstructural Proteins ; antagonists & inhibitors ; genetics

OBJECTIVETo investigate the effects of various HIV protease inhibitors on the function of pancreatic beta-cells.

METHODSRat insulinoma INS-1 cells were incubated with different concentrations of ritonavir or amprenavir for 48 h and stimulated with 20 mmol/L D-glucose for 30 min. The rate of insulin release was measured in the supernatant by ELISA, normalized to cellular DNA contents. Cells were counted with trypan blue and MTT test were determined to evaluate the effect of protease inhibitors on cell viability.

RESULTRitonavir treatment significantly decreased baseline insulin release and glucose-stimulated insulin release in a dose-dependent manner (r=-0.861, -0.839, both P<0.01). For 10 micromol/L of ritonavir, the decrease rate of baseline insulin secretion and glucose-stimulated insulin secretion was 46% and 47%, respectively. Amprenavir had no effect on the rate of insulin release.

CONCLUSIONVarious HIV protease inhibitors present different effect on the insulin release of pancreatic beta-cells.

Animals ; Carbamates ; pharmacology ; HIV Protease Inhibitors ; pharmacology ; Insulin ; secretion ; Insulinoma ; metabolism ; pathology ; Islets of Langerhans ; metabolism ; Pancreatic Neoplasms ; metabolism ; pathology ; Rats ; Ritonavir ; pharmacology ; Sulfonamides ; pharmacology

This study was aimed to investigate the effects of proteasome inhibitor bortezomib (Velcade, PS-341) on the activation of NF-kappaB and the expression of intercellular adhesion molecule-1 (ICAM-1) in K562 cells. The K562 cells were incubated in the culture of RPMI 1640 with 10% calf serum in 12-well plates and exposed to 0, 10, 20, 30, 50 and 100 nmol/L of bortezomib for 6 hours. The activation of NF-kappaB was analyzed by SP immunohistochemistry, meanwhile RT-PCR was performed to detect expression of ICAM-1. The results showed that the activation of NF-kappaB and the expression of ICAM-1 in K562 cells decreased significantly after bortezomib treatment. The inhibitory effect on ICAM-1 was probably related with the activity suppression of NF-kappaB. It is concluded that proteasome inhibitor bortezomib downregulates the expression of K562 cell ICAM-1 by inhibiting the activity of NF-kappaB, which provides a new way for the target therapy in acute leukemia.
Boronic Acids ; pharmacology ; Bortezomib ; Humans ; Intercellular Adhesion Molecule-1 ; metabolism ; K562 Cells ; NF-kappa B ; metabolism ; Protease Inhibitors ; pharmacology ; Pyrazines ; pharmacology