84 research outputs found

    Differential profiling of breast cancer plasma proteome by isotope-coded affinity tagging method reveals biotinidase as a breast cancer biomarker

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    <p>Abstract</p> <p>Background</p> <p>Breast cancer is one of the leading causes of women's death worldwide. It is important to discover a reliable biomarker for the detection of breast cancer. Plasma is the most ideal source for cancer biomarker discovery since many cells cross-communicate through the secretion of soluble proteins into blood.</p> <p>Methods</p> <p>Plasma proteomes obtained from 6 breast cancer patients and 6 normal healthy women were analyzed by using the isotope-coded affinity tag (ICAT) labeling approach and tandem mass spectrometry. All the plasma samples used were depleted of highly abundant 6 plasma proteins by immune-affinity column chromatography before ICAT labeling. Several proteins showing differential abundance level were selected based on literature searches and their specificity to the commercially available antibodies, and then verified by immunoblot assays.</p> <p>Results</p> <p>A total of 155 proteins were identified and quantified by ICAT method. Among them, 33 proteins showed abundance changes by more than 1.5-fold between the plasmas of breast cancer patients and healthy women. We chose 5 proteins for the follow-up confirmation in the individual plasma samples using immunoblot assay. Four proteins, α1-acid glycoprotein 2, monocyte differentiation antigen CD14, biotinidase (BTD), and glutathione peroxidase 3, showed similar abundance ratio to ICAT result. Using a blind set of plasmas obtained from 21 breast cancer patients and 21 normal healthy controls, we confirmed that BTD was significantly down-regulated in breast cancer plasma (Wilcoxon rank-sum test, <it>p </it>= 0.002). BTD levels were lowered in all cancer grades (I-IV) except cancer grade zero. The area under the receiver operating characteristic curve of BTD was 0.78. Estrogen receptor status (<it>p </it>= 0.940) and progesterone receptor status (<it>p </it>= 0.440) were not associated with the plasma BTD levels.</p> <p>Conclusions</p> <p>Our study suggests that BTD is a potential serological biomarker for the detection of breast cancer.</p

    Decolorization of malachite green by cytochrome c in the mitochondria of the fungus Cunninghamella elegans

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    We studied the decolorization of malachite green (MG) by the fungus Cunninghamella elegans. The mitochondrial activity for MG reduction was increased with a simultaneous increase of a 9-kDa protein, called CeCyt. The presence of cytochrome c in CeCyt protein was determined by optical absorbance spectroscopy with an extinction coefficient (E\u2085\u2085\u2080\u2013\u2085\u2083\u2085) of 19.7 \ub1 6.3 mM-\ub9 cm-\ub9 and reduction potential of + 261 mV. When purified CeCyt was added into the mitochondria, the specific activity of CeCyt reached 440 \ub1 122 \u3bcmol min-\ub9 mg-\ub9 protein. The inhibition of MG reduction by stigmatellin, but not by antimycin A, indicated a possible linkage of CeCyt activity to the Qo site of the bc1 complex. The RT-PCR results showed tight regulation of the cecyt gene expression by reactive oxygen species. We suggest that CeCyt acts as a protein reductant for MG under oxidative stress in a stationary or secondary growth stage of this fungus.Peer reviewed: YesNRC publication: Ye

    A Newly Formed and Ruptured Atheromatous Plaque within Neointima after Drug-Eluting Stent Implantation: 2-Year Follow-Up Intravascular Ultrasound and Optical Coherence Tomography Studies

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    Late stent thrombosis (LST) which is a life threatening complication has emerged as a serious problem of drug-eluting stents (DES). Several studies have suggested that incomplete neointimal coverage of stent struts contributes to LST. Progressive atherosclerosis within the neointima is an another possible cause of LST, but this phenomenon has seldom been reported in DES. We present a case of LST following DES implantation after a period of 28 months due to ruptured atheromatous plaque, despite complete neointimal coverage of stent struts proven by optical coherence tomography

    Percutaneous Cardiopulmonary Support-Supported Percutaneous Coronary Intervention: A Single Center Experience

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    BACKGROUND AND OBJECTIVES: Percutaneous cardiopulmonary support (PCPS) has proven to be a valuable technique in high-risk coronary patients undergoing percutaneous coronary intervention (PCI). However, there have been few studies on PCI associated with PCPS in Korea. We summarized our experience with PCPS-supported PCI. SUBJECTS AND METHODS: We retrospectively reviewed 19 patients with PCPS-supported PCI between August 2005 and June 2009. PCPS was used as an elective procedure for 10 patients with at least two of the following conditions: left-ventricular ejection fraction <35%, target vessel(s) supplying more than 50% of the viable myocardium, high risk surgical patients, and patients who refused coronary bypass surgery. In the remaining 9 patients PCPS was used as an emergency procedure, to stabilize and even resuscitate patients with acute myocardial infarction and cardiogenic shock, in order to attempt urgent PCI. RESULTS: Among the 19 patients who were treated with PCPS-supported PCI, 11 (57.9%) survived and 8 (42.1%) patients did not. ST elevation myocardial infarction with cardiogenic shock was more prevalent in the non-survivors than in the survivors (75% vs. 27.3%, p=0.04). The elective PCPS-supported PCI was practiced more frequently in the survivors than in the non-survivors (72.7% vs. 25%, p=0.04). In the analysis of the event-free survival curve between elective and emergency procedures, there was a significant difference in the survival rate (p=0.025). Among the survivors there were more patients with multi-vessel disease, but a lower Thrombolysis in Myocardial Infarction grade in the culprit lesions was detected in the non-survivors, before PCI. Although we studied high-risk patients, there was no procedure-related mortality. CONCLUSION: Our experience suggests that PCPS may be helpful in high risk patients treated with PCI, especially in elective cases. More aggressive and larger scale studies of PCPS should follow

    Network Clustering Revealed the Systemic Alterations of Mitochondrial Protein Expression

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    The mitochondrial protein repertoire varies depending on the cellular state. Protein component modifications caused by mitochondrial DNA (mtDNA) depletion are related to a wide range of human diseases; however, little is known about how nuclear-encoded mitochondrial proteins (mt proteome) changes under such dysfunctional states. In this study, we investigated the systemic alterations of mtDNA-depleted (ρ0) mitochondria by using network analysis of gene expression data. By modularizing the quantified proteomics data into protein functional networks, systemic properties of mitochondrial dysfunction were analyzed. We discovered that up-regulated and down-regulated proteins were organized into two predominant subnetworks that exhibited distinct biological processes. The down-regulated network modules are involved in typical mitochondrial functions, while up-regulated proteins are responsible for mtDNA repair and regulation of mt protein expression and transport. Furthermore, comparisons of proteome and transcriptome data revealed that ρ0 cells attempted to compensate for mtDNA depletion by modulating the coordinated expression/transport of mt proteins. Our results demonstrate that mt protein composition changed to remodel the functional organization of mitochondrial protein networks in response to dysfunctional cellular states. Human mt protein functional networks provide a framework for understanding how cells respond to mitochondrial dysfunctions

    Meta-analysis of genome-wide association studies in East Asian-ancestry populations identifies four new loci for body mass index

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    Recent genetic association studies have identified 55 genetic loci associated with obesity or body mass index (BMI). The vast majority, 51 loci, however, were identified in European-ancestry populations. We conducted a meta-analysis of associations between BMI and ∼2.5 million genotyped or imputed single nucleotide polymorphisms among 86 757 individuals of Asian ancestry, followed by in silico and de novo replication among 7488–47 352 additional Asian-ancestry individuals. We identified four novel BMI-associated loci near the KCNQ1 (rs2237892, P = 9.29 × 10−13), ALDH2/MYL2 (rs671, P = 3.40 × 10−11; rs12229654, P = 4.56 × 10−9), ITIH4 (rs2535633, P = 1.77 × 10−10) and NT5C2 (rs11191580, P = 3.83 × 10−8) genes. The association of BMI with rs2237892, rs671 and rs12229654 was significantly stronger among men than among women. Of the 51 BMI-associated loci initially identified in European-ancestry populations, we confirmed eight loci at the genome-wide significance level (P < 5.0 × 10−8) and an additional 14 at P < 1.0 × 10−3 with the same direction of effect as reported previously. Findings from this analysis expand our knowledge of the genetic basis of obesity

    Overexpression of Reactive Cysteine-Containing 2-Nitrobenzoate Nitroreductase (NbaA) and Its Mutants Alters the Sensitivity of <i>Escherichia coli</i> to Reactive Oxygen Species by Reprogramming a Regulatory Network of Disulfide-Bonded Proteins

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    The effects of redox-sensitive proteins on <i>Escherichia coli</i> were investigated by overexpressing <i>Pseudomonas</i> 2-nitrobenzoate nitroreductase (NbaA) and its mutants. Overexpression of wild-type and mutant NbaA proteins significantly altered the sensitivity of <i>E. coli</i> to antibiotics and reactive oxygen species regardless of the enzyme activity for reduction of 2-nitrobenzoic acid. The overexpressed proteins rendered cells 100–10000-fold more sensitive to superoxide anion (O<sub>2</sub><sup>•–</sup>)-generating paraquat and 10–100-fold more resistant to H<sub>2</sub>O<sub>2</sub>. A significant increase in intracellular levels of O<sub>2</sub><sup>•–</sup>, but not H<sub>2</sub>O<sub>2</sub>, was observed during expression of wild-type and truncated (Δ65–74, Δ193–216, and Δ65–74Δ193–216) NbaA. From two-dimensional nonreducing/reducing sodium dodecyl sulfate–polyacrylamide gel electrophoresis and mass spectrometry analyses, 29 abundant proteins in the cytoplasm were identified to form interchain disulfide bonds, when cells were exposed to polymyxin B. Of them, down-regulation and modifications of SodB, KatE, and KatG were strongly associated with elevated cellular O<sub>2</sub><sup>•–</sup> levels. Western blotting showed up-regulation of cell death signal sensor, CpxA, and down-regulation of cytoplasmic superoxide dismutase, SodB, with ∼2-fold up-regulation of heterodimeric integration host factor, Ihf. Activity gel assays revealed significant reduction of glyceraldehyde-3-phosphate dehydrogenase with constant levels of 6-phosphogluconate dehydrogenase. These changes would support a high level of NADPH to reduce H<sub>2</sub>O<sub>2</sub>-induced disulfide bonds by forced expression of thioredoxin A via thioredoxin reductase. Thus, overexpression of wild-type and truncated NbaA partially compensates for the lack of KatE and KatG to degrade H<sub>2</sub>O<sub>2</sub>, thereby enhancing disulfide bond formation in the cytoplasm, and modifies a regulatory network of disulfide-bonded proteins to increase intracellular O<sub>2</sub><sup>•–</sup> levels

    Regulation of protein function by native metastability

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    In common globular proteins, the native form is in its most stable state. In contrast, each native form exists in a metastable state in inhibitory serpins (serine protease inhibitors) and some viral membrane fusion proteins. Metastability in these proteins is critical to their biological functions. Mutational analyses and structural examination have previously revealed unusual interactions, such as side-chain overpacking, buried polar groups, and cavities as the structural basis of the native metastability. However, the mechanism by which these structural defects regulate protein functions has not been elucidated. We report here characterization of cavity-filling mutations of α(1)-antitrypsin, a prototype serpin. Conformational stability of the molecule increased linearly with the van der Waals volume of the side chains. Increasing conformational stability is correlated with decreasing inhibitory activity. Moreover, the activity loss appears to correlate with the decrease in the rate of the conformational switch during complex formation with a target protease. These results strongly suggest that the native metastability of proteins is indeed a structural design that regulates protein functions
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