Several studies have reported that the citrus red mites Panonychus citri were an important allergen of citrus-cultivating farmers in Jeju Island. The aim of the present study was to purify and assess properties of a cysteine protease from the mites acting as a potentially pathogenic factor to citrus-cultivating farmers. A cysteine protease was purified using column chromatography of Mono Q anion exchanger and Superdex 200 HR gel filtration. It was estimated to be 46 kDa by gel filtration column chromatography and consisted of 2 polypeptides, at least. Cysteine protease inhibitors, such as trans poxy-succinyl-L-leucyl-amido (4-guanidino) butane (E-64) and iodoacetic acid (IAA) totally inhibited the enzyme activities, whereas serine or metalloprotease inhibitors did not affect the activities. In addition, the purified enzyme degraded human IgG, collagen, and fibronectin, but not egg albumin. From these results, the cysteine protease of the mites might be involved in the pathogenesis such as tissue destruction and penetration instead of nutrient digestion.
Animals ; Chromatography, Gel ; Chromatography, Ion Exchange ; Collagen/metabolism ; Cysteine Proteases/chemistry/*isolation & purification ; Cysteine Proteinase Inhibitors/metabolism ; Fibronectins/metabolism ; Humans ; Immunoglobulin G/metabolism ; Molecular Weight ; Protein Subunits/chemistry/isolation & purification ; Proteolysis ; Substrate Specificity ; Tetranychidae/*enzymology

This study was aimed to investigate the effect of proteasome inhibitor MG-132 at different doses on cultured K562 cell apoptosis. MTT assay was used to observe the activity of K562 cell proliferation inhibition rate after treating for 48 hours at different doses (0, 2, 4, 8, 16, 32 micromol/L). Immunocytochemistry was used to detect the NF-kappaB activity and glucocorticoid receptor (GR) expression. Flow cytometry was used to determine the K562 cell apoptosis. The results indicated that proliferation inhibition rate of K562 cells after treated for 48 hours showed dose-dependent, the inhibitory rates of cell proliferation in test groups were significant higher than that in control group, and the effect in 32 micromol/L test group was the most obvious (45.24 +/- 4.12)% (p < 0.05). The NF-kappaB activity and GR expression after treating for 48 hours showed dose-dependent. Compared with control group, the NF-kappaB activities in test groups were lower (p < 0.05), and the NF-kappaB activity in 32 micromol/L test group was the lowest (63.60 +/- 2.95); the GR expression in test groups was higher (p < 0.05), and the GR expression in 16 micromol/L test group was the highest (75.62 +/- 2.70). The K562 cell apoptosis rate after treating for 48 hours also showed dose-dependent. Compared with control group, the K562 cell apoptosis rates in test groups were higher (p < 0.05), the K562 cell apoptosis rate in 32 micromol/L test group was the highest (21.37 +/- 2.02)%. It is concluded that the MG-132 may induce K562 cell apoptosis and proliferation inhibition through up-regulation of NF-kappaB activity and down-regulation of GR expression both in dose-dependent manner.
Apoptosis ; drug effects ; Cell Proliferation ; drug effects ; Cysteine Proteinase Inhibitors ; pharmacology ; Humans ; K562 Cells ; Leupeptins ; pharmacology ; NF-kappa B ; metabolism ; Receptors, Glucocorticoid ; metabolism

OBJECTIVETo observe the effects of proteasome inhibitor MG-132 on hyperoxic lung injury in rats and explore the mechanism.

METHODSThirty SD rats were randomly divided into 3 groups, namely the normoxic group, hyperoxic group, and hyperoxic with MG-132 treatment group, and rat models of hyperoxic exposure-induced lung injury were established in the latter two groups. After pathological grading of the lung injury under optical microscope and determination of the wet/dry weight ratio of the lung tissue, the expressions of ubiquitin protein and nuclear factor-kappaB (NF-kappaB) p56 and the activity of proteasome 20S and myeloperoxidase (MPO) were detected. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) expressions in the lung tissue were also detected.

RESULTSThe rats with hyperoxic exposure showed obvious pulmonary edema and increased wet/dry weight ratio of the lung tissue (P<0.01), which were significantly alleviated with MG-132 treatment (P<0.01). Compared with the normoxic group, hyperoxic exposure resulted in significant lung pathologies (P<0.01), which was reduced after MG-132 treatment. Immunohistochemistry and Western blotting demonstrated increased expression of ubiquitin protein in the lung tissue after hyperoxic exposure (P<0.01), which was lowered by MG-132 treatment (P<0.01). Proteasome 20S activity was obviously enhanced in the hyperoxic group (P<0.01) but lowered by MG-132 treatment (P<0.01). Hyperoxic exposure also caused obviously enhanced MPO activity and expressions of NF-kappaB, TNF-alpha, and IL-6 (P<0.01), which were all reduced by MG-132 treatment (P<0.05).

CONCLUSIONMG-132 alleviates hyperoxic lung injury probably by inhibiting the NF-kappaB/inflammatory factor pathways.

Animals ; Animals, Newborn ; Cysteine Proteinase Inhibitors ; pharmacology ; Female ; Hyperoxia ; complications ; Interleukin-6 ; metabolism ; Leupeptins ; pharmacology ; Lung Injury ; etiology ; metabolism ; pathology ; Male ; NF-kappa B ; metabolism ; Peroxidase ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Tumor Necrosis Factor-alpha ; metabolism ; Ubiquitin ; metabolism

The inhibition of protein degradation through the ubiquitin-proteasome pathway is a recently developed approach to cancer treatment which extends the range of cellular target for chemotherapy. This therapeutic strategy is very interesting since the proteasomes carry out the regulated degradation of unnecessary or damaged cellular proteins, a process that is dysregulated in many cancer cells. Based on this hypothesis, the proteasome complex inhibitor Bortezomib was approved for use in multiple myeloma patients by FDA in 2003. Drug discovery programs in academy and the pharmaceutical industry have developed a range of synthetic and natural inhibitors of the 20S proteasome core particle that have entered human clinical trials as significant anti-cancer leads. The main results from the use of proteasome inhibition in cancer chemotherapy, the structure of several proteasome inhibitors and their synthesis is going to be reviewed in this paper.
Acetylcysteine ; analogs & derivatives ; chemical synthesis ; chemistry ; Antineoplastic Agents ; chemical synthesis ; classification ; therapeutic use ; Boronic Acids ; chemical synthesis ; chemistry ; therapeutic use ; Bortezomib ; Cysteine Proteinase Inhibitors ; chemical synthesis ; classification ; Dipeptides ; chemical synthesis ; chemistry ; Humans ; Multiple Myeloma ; drug therapy ; enzymology ; Peptides, Cyclic ; chemical synthesis ; chemistry ; Proteasome Endopeptidase Complex ; metabolism ; Proteasome Inhibitors ; Pyrazines ; chemical synthesis ; chemistry ; therapeutic use ; Ubiquitin ; antagonists & inhibitors ; metabolism

OBJECTIVETo investigate whether proteasome inhibitor MG-132 induces apoptosis of human erythroleukemia cell line K562 and possible mechanisms.

METHODSK562 cells were incubated with RPMI 1640 and exposed to 0, 1, 5, 10, 15 micromol/L of MG-132 for 24 hrs, respectively. The apoptosis of cells were detected by fluorescence microscope, DNA fragments and flow cytometry. The NF-kappaB mRNA expression was quantified by reverse transcription-polymerase chain reaction (RT-PCR). Expression of NF-kappaB and caspase-3 was semiquantitatively analyzed with SABC techniques. Caspase-3 activities were measured with a colorimetric method.

RESULTSThe growth of K562 cells was inhibited and the apoptosis of the cells increased after MG-132 treatment in a dose-dependent manner. After 24 hrs of 15 micromol/L MG-132 treatment, the percentage of apoptotic cells (26.5+/-0.6%) increased significantly when compared with the untreated controls (1.2+/-0.1%) (P<0.01). MG-132 treatment decreased the mRNA and protein expression of NF-kappaB, and increased the protein expression of caspase-3.

CONCLUSIONSMG-132 can induce apoptosis of human erythroleukemia cell line K562 through the down-regulation of NF-kappaB expression and up-regulation of caspase-3 expression.

Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Cysteine Proteinase Inhibitors ; pharmacology ; Dose-Response Relationship, Drug ; Humans ; K562 Cells ; Leupeptins ; pharmacology ; NF-kappa B ; Proteasome Inhibitors ; Reverse Transcriptase Polymerase Chain Reaction

Helminthic cysteine proteases are well known to play critical roles in tissue invasion, nutrient uptake, and immune evasion of the parasites. In the same manner, the sparganum, the plerocercoid of Spirometra mansoni, is also known to secrete a large amount of cysteine proteases. However, cysteine protease inhibitors regulating the proteolytic activities of the cysteine protease are poorly illustrated. In this regard, we partially purified an endogenous cysteine protease inhibitor from spargana and characterized its biochemical properties. The cysteine protease inhibitor was purified by sequential chromatographies using Resource Q anion exchanger and Superdex 200 HR gel filtration from crude extracts of spargana. The molecular weight of the purified protein was estimated to be about 11 kD on SDS-PAGE. It was able to inhibit papain and 27 kDa cysteine protease of spargana with the ratio of 25.7% and 49.1%, respectively, while did not inhibit chymotrypsin. This finding suggests that the cysteine protease inhibitor of spargana may be involved in regulation of endogenous cysteine proteases of the parasite, rather than interact with cysteine proteases from their hosts.
Animals ; Cystatins/pharmacology ; Cysteine Endopeptidases/metabolism ; Cysteine Proteinase Inhibitors/chemistry/*metabolism/*pharmacology ; Helminth Proteins/*metabolism/*pharmacology ; Spirometra/*metabolism

According to the amino acids sequence of OC-IdeltaD86 gene and Escherichia coli codon usage, we synthesized this gene by overlap extension PCR method with 7 oligonucleotides DNA fragments. The PCR fragment was inserted into pGEM-T-easy vector and the recombined plasmid was named pGEM-T-OC-IdeltaD86. Two oligonucleotides into which the BamH I and Xho I sites were introduced were designed and synthesized based on pGEM-T-OC-IdeltaD86 and pet21b, and the PCR fragment into which the BamH I and Xho I sites were introduced was obtained. After digesting it with BamH I and Xho I, OC-IdeltaD86 gene was cloned into the corresponding sites of pet21b and obtained prokaryotic expression vector pet21b-OC-IdeltaD86. OC-IdeltaD86 gene was expressed in E. coli (BL21(DE3)plysS) after IPTG(Isopropyl beta-D-1-thiogalactopyranoside) inducement for 5 hours. The fusion protein of OC-IdeltaD86:6His gene accounted for 11.4% of total protein and 16.4% of soluble protein, which had been successfully purified by Ni-NTA and concentrated by PEG20000. This protein can effectively inhibit papain activity in vitro and may be used in anti-nematode research in vivo.
Cloning, Molecular ; Cystatins ; biosynthesis ; genetics ; Cysteine Endopeptidases ; metabolism ; Cysteine Proteinase Inhibitors ; genetics ; Escherichia coli ; genetics ; metabolism ; Genes, Plant ; genetics ; Mutation ; Oligonucleotides ; chemical synthesis ; genetics ; Oryza ; genetics ; Papain ; antagonists & inhibitors ; Prokaryotic Cells ; metabolism ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; metabolism

BACKGROUND: Human telomerase reverse transcriptase (hTERT) is a catalytic enzyme that is required for telomerase activity (TA) and cancer progression. Telomerase inhibition or inactivation increases cellular sensitivity to UV irradiation, DNA-damaging agents, the tyrosine kinase inhibitor, imatinib, and pharmacological inhibitors, such as BIBR1532. hTERT is associated with apoptosis. Some patients show drug-resistance during anti-cancer drug treatment and the cancer cell acquire anti-apoptotic mechanism. Therefore, we attempted to study correlation between hTERT and drug-resistance. METHODS: To study the correlation between protein level and activity of hTERT and drug-resistance, Western blotting and telomerase repeat amplification protocol (TRAP) assays were performed. To investigate whether hTERT contributes to drug resistance in tumor cells, we transiently decreased hTERT levels using small interfering RNA (siRNA) in T24/R2 cells. RESULTS: hTERT knockdown increased Bax translocation into the mitochondria and cytochrome C release into the cytosol. Caspase inhibitors, especially Z-VAD-FMK, rescued this phenomenon, suggesting that the stability or expression of hTERT might be regulated by caspase activity. CONCLUSIONS: These data suggest that hTERT might be a target molecule for drug-resistant tumor therapy.
Amino Acid Chloromethyl Ketones/pharmacology ; Antineoplastic Agents/*pharmacology ; Caspases/antagonists & inhibitors/metabolism ; Cell Line, Tumor ; Cisplatin/*pharmacology ; Cysteine Proteinase Inhibitors/pharmacology ; Cytochrome c Group/metabolism ; Drug Resistance, Neoplasm/genetics ; Humans ; Neoplasms/therapy ; RNA, Small Interfering ; Telomerase/*antagonists & inhibitors/genetics/metabolism ; bcl-2-Associated X Protein/metabolism

OBJECTIVETo investigate the effect of z-DEVD-fmk, a caspase-3 inhibitor on the neuronal apoptosis in ischemia-reperfusion region (IRR) of rat cerebral cortex.

METHODSRats prepared by middle cerebral artery occlusion and reperfusion were used as the research model. The animals were divided into A group (untreated), B group (DMSO control) and C group (treated with z-DEVD-fmk). Before reperfusion, z-DEVD-fmk (7 microg/kg) was injected into the ischemic side of ventriculus cerebri of C group rats. The expression and activation of caspase-3, expression and cleavage of poly (ADP-ribose) polymerase (PARP), and apoptotic neurons in the temporal-parietal cortex IRRs (SPAB method) of all the rats were studied using Western blotting, in situ apoptotic detection (TUNEL method) and immunohistochemistry.

RESULTSIn the cerebral IRRs of A, B, C groups reperfused for 1 h and 24 h, the quantities of caspase-3 precursor were 16.7 +/- 3.0, 11.5 +/- 3.0 and 47.5 +/- 3.5, and 76.1 +/- 3.5, 71.3 +/- 6.4 and 88.2 +/- 5.5, respectively; the caspase-3 fragments (12,000) 8.2 +/- 2.3, 9.4 +/- 1.2 and 4.3 +/- 1.6, and 59.0 +/- 6.3, 60.5 +/- 7.2 and 17.3 +/- 2.8, respectively; the PARP 12.6 +/- 3.0, 13.9 +/- 2.0 and 53.7 +/- 4.1, and 67.5 +/- 8.6, 61.1 +/- 6.6 and 93.6 +/- 4.1, respectively; the PARP fragments (24,000) 6.0 +/- 0.7, 6.6 +/- 1.2, 3.6 +/- 1.1, and 27.4 +/- 2.6, 25.8 +/- 3.2, 12.1 +/- 2.8 (relative quantity, x+/- s); the densities of apoptotic neurons 83.3 +/- 7.5, 84.3 +/- 5.7 and 45.7 +/- 4.0, and 197.4 +/- 11.8, 185.2 +/- 11.2 and 99.1 +/- 5.8 (cell number/0.1 mm(2), x+/- s). These results showed that in the cerebral IRRs of both A and B groups, all caspase-3 expression and activation, PARP expression and cleavage, and neuronal apoptosis were increased relevantly along with prolongation of the reperfusion time (P < 0.05 - 0.001). At each time point of the reperfusion, caspase-3 activation, PARP cleavage and neuronal apoptosis in the cerebral IRR of C group were significantly less than those of the former two groups (P < 0.05 - 0.001). The variations of the 5 parameters of A, B and C groups correlated positively with one another (r = 0.630 - 0.942, P < 0.01). The cells expressing PARP were mainly neurons in the cerebral IRRs of all the animals, but the difference of their number was not distinct among the 3 groups.

CONCLUSIONSIt is an important mechanism resulting in apoptosis of the injured neurons in the cerebral IRR that caspase-3 expression and activation abnormally increased by the reperfusion have more PARP rapidly inactivated by over-cleavage. z-DEVD-fmk may decrease PARP cleavage by inhibiting activity and auto-activation of caspase-3, and prevent the injured neurons from apoptosis.

Animals ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Caspase Inhibitors ; Cerebral Cortex ; drug effects ; metabolism ; pathology ; Cysteine Proteinase Inhibitors ; pharmacology ; Infarction, Middle Cerebral Artery ; complications ; Male ; Neurons ; drug effects ; Oligopeptides ; pharmacology ; Poly(ADP-ribose) Polymerases ; metabolism ; Random Allocation ; Rats ; Rats, Wistar ; Reperfusion Injury ; etiology ; metabolism ; physiopathology

Because of the complexity of the cathepsin B-like (CBL) family, an information on the biological and biochemical characteristics of individual CBL genes is lacking. In this study, we investigated the degradative effects of the recombinant HC58 protein isolated from Haemonchus contortus parasites on protein substrates over a broad pH range in vitro. This protein, which hydrolyzed the synthetic peptide substrates Z-FR-AMC and Z-RR-AMC, had characteristics of the cysteine protease class of proteins. In the acidic pH range, the isolated protein actively degraded hemoglobin (Hb), the heavy chain of goat immunoglobulin G, and azocasein. By contrast, it degraded fibrinogen in the alkaline pH range. These activities were strongly inhibited in the presence of the cysteine protease inhibitor E-64. While the protein digested Hb, it did not induce the agglutination of erythrocytes from its natural host. These results suggest that the HC58 protein may play a role in the nutrition of this parasite.
Animals ; Caseins/metabolism ; Cathepsin B/antagonists&inhibitors/*genetics/isolation & purification/*metabolism ; Cysteine Proteinase Inhibitors/pharmacology ; DNA, Complementary/genetics ; Goat Diseases/*parasitology ; Goats ; Haemonchiasis/parasitology/*veterinary ; Haemonchus/*enzymology/genetics/isolation & purification ; Hemagglutination Tests/veterinary ; Hemoglobins/metabolism ; Hydrogen-Ion Concentration ; Immunoglobulin G/metabolism ; Leucine/analogs & derivatives/pharmacology ; RNA, Helminth/chemistry/genetics ; Recombinant Proteins/genetics/metabolism ; Reverse Transcriptase Polymerase Chain Reaction/veterinary