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31.
Binding aspects of baicalein to HIV-1 integrase 总被引:8,自引:0,他引:8
Human immunodeficiency virus type 1 (HIV-1) integrase is an essential enzyme in the life cycle of the virus. It is responsible for catalyzing the insertion of the viral genome into the host cell chromosome. This integrase is an attractive target for the design of a HIV antiviral drug, because integrase has no human counterpart. In order to know the interaction mode of HIV-1 integrase with its inhibitor, we investigated the effect of the inhibitor, baicalein, on the conformation of the HIV-1 integrase catalytic domain [IN-(50-212/F185K)] using fluorescence and circular dichroism (CD) spectroscopy. We found that baicalein binds to the hydrophobic region of the HIV-1 integrase catalytic core domain. This binding of baicalein induces the conformational change of the enzyme. We also found that the binding ratio of baicalein to the HIV-1 integrase catalytic domain is 2:1. 相似文献
32.
Combinatory responses of proinflamamtory cytokines have been examined on the nitric oxide-mediated function in cultured mouse calvarial osteoblasts. Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) induced iNOS gene expression and NO production, although these actions were inhibited by L-NG-monomethylarginine (L-NMMA) and decreased alkaline phosphatase (ALPase) activity. Furthermore, NO donors, sodium nitroprusside (SNP) and NONOate dose-dependently elevated ALPase activity. In contrast, transforming-growth factor-β (TGF-β) decreased NO production stimulated by IL-1β, TNF-α and interferon-γ (IFN-γ). iNOS was expressed by mouse calvarial osteoblast cells after stimulation with IL-1β, TNF-α, and IFN-γ. Incubation of mouse calvarial osteoblast cells with the cytokines inhibited growth and ALPase activity. However, TGF-β-treatment abolished these effects of IL-1β, TNF-α and IFN-γ on growth inhibition and stimulation of ALPase in mouse calvarial osteoblast cells. In contrast, IL-1β, TNF-α, and IFN-γ exerted growth-inhibiting effects on mouse calvarial osteoblast cells which were partly NO-dependent. The results suggest that NO may act predominantly as a modulator of cytokine-induced effects on mouse calvarial osteoblast cells and TGF-β is a negative regulator of the NO production stimulated by IL-1β, TNF-α and IFN-γ. 相似文献
33.
34.
Bone marrow-derived mesenchymal stem cells (BMSCs) are of particular interest in the field of tissue engineering because of
their potential to differentiate into osteoblasts, chondrocytes, and neuronal cells. In order to promote the differentiation
of BMSCs into specific cell types, appropriate scaffold biomaterials and bioactive molecules that can support the differentiation
of BMSCs into specific cell types are needed. We hypothesized that β-mercaptoethanol (BME), which has been reported to induce
the differentiation of BMSCs into neural-like cells, promotes BMSCs to differentiate into neural-like cells when BME is added
to polymeric scaffolds containing the BMSCs. We fabricated biocompatible film shaped scaffolds composed of poly(lacti-co-glycolic)
acid (PLGA) and various concentrations of BME to confirm that BME-promoted differentiation of BMSCs is concentration-dependent.
Cell proliferation increased as the BME concentration in the films increased at the early stage, and the proliferation rate
remained similar on the PLGA films for 3 weeks following the BMSC seeding. The expression of neuronal markers in differentiated
BMSCs was assessed by RT-PCR. At 2- and 3-week time-points, mRNA expression of neurofilament and neuron specific enolase was
significantly increased in PLGA/BME films containing 400 μM BME compared to PLGA films. Thus, we have identified BMSC-seeded
PLGA/BME films with 200 μM and 400 μM BME as potentially useful candidates for neural tissue engineering applications by promoting
BMSC proliferation and differentiation towards neural-like cells. 相似文献
35.
Cascone T Morelli MP Morgillo F Kim WY Rodolico G Pepe S Tortora G Berrino L Lee HY Heymach JV Ciardiello F 《Journal of cellular physiology》2008,216(3):698-707
The proteasome plays a pivotal role in the turnover of regulatory transduction proteins induced by activated cell membrane growth factor receptors. The epidermal growth factor receptor (EGFR) pathway is crucial in the development and progression of human epithelial cancers. Proteasome inhibition may sensitize human cancer cell lines to EGFR inhibitors. We investigated the growth inhibitory and pro-apoptotic effects of the proteasome inhibitor bortezomib in combination with anti-EGFR drugs, such as gefitinib, vandetanib, and cetuximab in EGFR-expressing human cancer cell lines. Bortezomib determined dose-dependent growth inhibition in a nine cancer cell line panel (IC(50) values, range 6-42 nM). A significant synergistic growth inhibitory effect was observed with the combination of bortezomib and each EGFR inhibitor in all cell lines (combination index, CI, range 0.10-0.55), which was accompanied by a significant induction in apoptosis by the combined treatment with bortezomib, cetuximab and vandetanib. In HCT-116 colon cancer and A549 lung adenocarcinoma cells, bortezomib plus EGFR inhibitor treatment induced a more effective inhibition of EGFR-activated down-stream signals, including a marked suppression in activated, phosphorylated Akt (P-Akt). In contrast, overexpression of a constitutively active P-Akt protected A549 cells by cell growth inhibition and apoptosis following treatment with bortezomib and EGFR inhibitors. The combined treatment with bortezomib and EGFR inhibitors has a synergistic growth inhibitory and pro-apoptotic activity in different human cancer cells which possess a functional EGFR-dependent autocrine growth pathway through to a more efficient and sustained inhibition of Akt. 相似文献
36.
37.
Molecular basis of the differences between normal and tumor tissues of gastric cancer 总被引:1,自引:0,他引:1
Yang S Shin J Park KH Jeung HC Rha SY Noh SH Yang WI Chung HC 《Biochimica et biophysica acta》2007,1772(9):1033-1040
To be able to describe the differences between the normal and tumor tissues of gastric cancer at a molecular level would be essential in the study of the disease. We investigated the gene expression pattern in the two types of tissues from gastric cancer by performing expression profiling of 86 tissues on 17K complementary DNA microarrays. To select for the differentially expressed genes, class prediction algorithm was employed. For predictor selection, samples were first divided into a training (n=58), and a test set (n=28). A group of 894 genes was selected by a t-test in a training set, which was used for cross-validation in the training set and class (normal or tumor) prediction in the test set. Smaller groups of 894 genes were individually tested for their ability to correctly predict the normal or tumor samples based on gene expression pattern. The expression ratios of the 5 genes chosen from microarray data can be validated by real time RT-PCR over 6 tissue samples, resulting in a high level of correlation, individually or combined. When a representative predictor set of 92 genes was examined, pathways of 'focal adhesion' (with gene components of THBS2, PDGFD, MAPK1, COL1A2, COL6A3), 'ECM-receptor interaction' pathway (THBS2, COL1A2, COL6A3, FN1) and 'TGF-beta signaling' (THBS2, MAPK1, INHBA) represent some of the main differences between normal and tumor of gastric cancer at a molecular level. 相似文献
38.
Free Flow Electrophoresis (FFE) is a liquid-based isoelectric focusing method. Unlike conventional in-gel fractionation of proteins, FFE can resolve proteins in their native forms and fractionation of subcellular compartments of the cell is also possible. To test the efficacy of the FFE method, the native cytosol proteome of a bacterium, Pseudomonas putida KT2440 was fractionated by FFE and the spectrum of protein elutes was characterized in association with 2-dimentional gel electrophoresis (2-DE). Major native proteins of P. putida KT2440 were eluted in the range of pH 4.8 approximately 6.0 in FFE, whereas the denatured proteome of P. putida KT2440 was widely distributed in the rage of pH 4 approximately 10 in the 2-DE analysis. In addition, one of the three FFE major fractions, which was eluted at pH 5.0, was further analyzed using 2-DE/MS-MS. Then, the pH range of identified proteins eluted in 2-DE/MS-MS was 4.72 approximately 5.89, indicating that observed pi values of native cytosolic proteomes in FFE were narrower than those of denatured cytosolic proteome. These results suggest that FFE fractionation and 2-DE/MS analysis may be useful tools for characterization of native proteomes of P. putida KT2440 and comparative analysis between denatured and native proteomes. 相似文献
39.
A cDNA clone, MT-c, encoding metalloprotease was isolated from snake (Agkistrodon halys brevicadus) venom gland cDNA library. Deduced amino acid sequence indicated that MT-c is composed of a signal sequence, amino-terminal propeptide, a central metalloprotease domain, and a Lys-Gly-Asp (KGD) disintegrin domain. The partial cDNA encoding metalloprotease and disintegrin domain was subcloned and expressed in E. coli. The expressed MT-c protein was purified and successfully refolded into functional form retaining the enzyme activity. Analyses of the purified recombinant protease activity revealed that the enzyme hydrolyzes extracellular matrix proteins including type I gelatin, type IV and type V collagen, while type I, II, III collagens and fibronectin were insensitive to the proteolytic digestion. The recombinant enzyme was also able to degrade fibrinogen by specifically cleaving A alpha chain of the protein. 相似文献
40.
Kim CH Pennisi P Zhao H Yakar S Kaufman JB Iganaki K Shiloach J Scherer PE Quon MJ LeRoith D 《American journal of physiology. Endocrinology and metabolism》2006,291(2):E298-E305
Most rodent models of insulin resistance are accompanied by decreased circulating adiponectin levels. Adiponectin treatment improves the metabolic phenotype by increasing fatty acid oxidation in skeletal muscle and suppressing hepatic glucose production. Muscle IGF-I receptor (IGF-IR)-lysine-arginine (MKR) mice expressing dominant-negative mutant IGF-IRs in skeletal muscle are diabetic with insulin resistance in muscle, liver, and adipose tissue. Adiponectin levels are elevated in MKR mice, suggesting an unusual discordance between insulin resistance and adiponectin responsiveness. Therefore, we investigated the metabolic actions of adiponectin in MKR mice. MKR and ob/ob mice were treated both acutely (28 microg/g) and chronically (for 2 wk) with full-length adiponectin. Acute hypoglycemic effects of adiponectin were evident only in ob/ob mice but not in MKR mice. Chronic adiponectin treatment significantly improved both insulin sensitivity and glucose tolerance in ob/ob but not in MKR mice. Adiponectin receptor mRNA levels and adiponectin-stimulated phosphorylation of AMPK in skeletal muscle and liver were similar among MKR, wild-type, and ob/ob mice. Thus MKR mice are adiponectin resistant despite normal expression of adiponectin receptors and normal AMPK phosphorylation in muscle and liver. MKR mice may be a useful model for dissecting relationships between insulin resistance and adiponectin action in regulation of glucose homeostasis. 相似文献