Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024623 (gastric cancer)
 36,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

GDP-L-Fuc:N-acetyl-beta-D-glucosaminide:alpha1-6 fucosyltransferase (alpha1-6 FucT), which catalyzes the transfer of fucose from GDP-Fuc to N-linked type complex glycopeptides, was purified from a culture supernatant of human gastric cancer cell line MKN45. The purification procedures included chromatographies on Q-Sepharose Fast Flow, synthetic GDP-hexanolamine-Sepharose, and GnGn-bi-Asn-Sepharose columns. SDS-PAGE of the purified enzyme gave a major band corresponding to an apparent molecular mass of 60 kDa. The enzyme was recovered in a 12% final yield with an approximately 4,600-fold increase in specific activity. The pH optimum was 7.5, and the enzyme was fully active in the presence of 5 mM EDTA and did not require divalent cations, Mg2+ and Ca2+. Oligonucleotide primers designed from partial amino acid sequences were used to amplify and clone alpha1-6 FucT cDNA from a cDNA library of MKN45 cells. The cDNA encodes 575 amino acids in length, and contains the predicted N-terminal and internal amino acid sequences derived on lysyl endopeptidase digestion. The homology to porcine brain alpha1-6 FucT is 92.2% at the nucleotide level and 95.7% at the amino acid level. No putative N-glycosylation sites were found in the predicted amino acid sequence of the human MKN45 cell enzyme or that of porcine brain. Thus, the enzyme is distinct from other fucosyltransferases which catalyze alpha1-2, alpha1-3, and alpha1-4 fucose addition.
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PMID:Purification and cDNA cloning of GDP-L-Fuc:N-acetyl-beta-D-glucosaminide:alpha1-6 fucosyltransferase (alpha1-6 FucT) from human gastric cancer MKN45 cells. 913 35

The aim of this project was to determine the cytotoxic components from the venom of king cobra, Ophiophagus hannah. Venom was purified by a combination of gel-filtration, ion-exchange and reversed-phase chromatographic steps. The biochemical properties of the cytotoxic component were consistent with those of L-amino acid oxidase. The molecular weight of the enzyme was estimated to be 150,000 by gel filtration and 70,000 under the denaturing conditions of SDS-PAGE, indicating a dimer. It has an isoelectric point of 4.5 and is a glycoprotein. The N-terminal sequence of L-amino acid oxidase from the king cobra venom was determined to be SVINLEESFQEPEYE. The cytotoxicity of L-amino acid oxidase was observed in stomach cancer, murine melanoma, fibrosarcoma, colorectal cancer and Chinese hamster ovary cell lines. Cytotoxicity resulted in the loss of ability in attachment and inhibition of cell proliferation. The cytotoxic protein decreased the level of cell proliferation by 74% according to [3H]thymidine uptake assay. The mechanism of enzyme action may be related to the inhibition of thymidine incorporation and an interaction with DNA.
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PMID:Characterization and cytotoxicity of L-amino acid oxidase from the venom of king cobra (Ophiophagus hannah). 930 6

Helicobacter pylori is a bacterial pathogen, estimated to infect half the world's population. The bacterium is the aetiological cause of gastritis, the common precursor for peptic ulcer disease and gastric cancer. Immunisation of at-risk individuals is the most cost-effective means of dealing with such a widespread pathogen. Potential vaccine candidates need to be identified and characterised. Conventional silver staining is commonly used for the sensitive detection of bacterial protein components separated by SDS-PAGE. Modified silver stains employing periodate oxidation have also been developed for the analysis of purified bacterial lipopolysaccharide. By using these methods in parallel, as a dual silver stain, bacterial fractions can be characterised in terms of protein and LPS content. Strain differences can also be readily identified by comparing protein and LPS profiles. When combined with differential immunoblotting, the dual silver stain is a useful analytical tool for characterising potential vaccine candidate antigens.
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PMID:Dual silver staining to characterise Helicobacter spp. outer membrane components. 944 30

SC142-reactive antigen are highly glycosylated glycoproteins expressed on tissues of gastric and colon cancers but not on normal tissues. Murine SC142 antibody specific for the SC142-reactive antigen has been produced by immunisation with SNU16 stomach cancer cells. However, SC142 antibody has several potential problems such as high immunogenicity and poor tumour penetration owing to their large size. To improve tumour penetration potential in vivo, recombinant single-chain fragments have been produced using the original hybridoma cells as a source of variable heavy- and variable light-chain-encoding antibody genes. The use of the polymerase chain reaction, expression cloning technology and gene expression systems in E. coli has led to the production of SC142 single-chain fragments, which was similar in activity to the SC142 parent antibody confirmed by immunohistochemistry. Analysis by DNA sequencing, SDS-PAGE and Western blotting has demonstrated the integrity of the single-chain fragments. Competitive ELISA showed that SC142 single-chain fragments originated from parent SC142 antibody. BIAcore biosensor binding experiments showed that the SC142 single-chain fragments had an ideal dissociation rate constant as a tumour imaging reagent. These results illustrate the potential application of these novel products as an immunodiagnostic and further immunotherapeutic reagent.
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PMID:Production and characterisation of a recombinant scFv reactive with human gastrointestinal carcinomas. 1217 77

The Tn determinant (GalNAc-O-Ser/Thr) is one of the most specific human tumor markers. In normal cells Tn is a cryptic structure in the peptide core of mucin type O-glycoproteins, and it is detected in an unmasked form in most human carcinomas evaluated by immunohistochemistry. Scarce data are available regarding the characteristics of soluble Tn bearing glycoproteins. We herein report the first comparative characterization of soluble Tn glycoproteins derived from different kinds of human tumors (breast, colon, gastric, ovarian and liver). Considerable heterogeneity was observed in the physicochemical properties of Tn soluble glycoproteins from all the tumor-associated effusions evaluated. In SDS-PAGE analysis Tn glycoproteins from liver and colon effusions migrated as a broad single major component (>500 kDa), while several components of >200 kDa were identified in samples from breast, ovarian, and gastric cancer. The results of perchloric acid (PCA) treatment and CsCl gradient ultracentrifugation indicated that the Tn glycoproteins in effusion fluids correspond predominantly to mucin-like glycoproteins. However, in samples from patients with colon and liver cancer, a fraction of Tn glycoproteins formed part of the immune complexes that precipitated in PCA, suggesting that the anti-Tn immune response in vivo could modify their physicochemical properties. The four apomucins evaluated (MUC1, MUC2, MUC5AC and MUC6) carried Tn epitopes in each of the effusions, indicating that soluble apomucin detection may reflect the abnormal expression of MUC genes inherent to these tumors. Taking together, these results indicate that apomucin expression profile is responsible, at least in part, for the high heterogeneity of soluble Tn glycoproteins, and suggest that the identification of Tn determinant on the different soluble apomucins could be useful for the development of new diagnostic tools as well as to evaluate the anti-tumor immune response in patients with cancer.
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PMID:Biochemical characterization of soluble Tn glycoproteins from malignant effusions of patients with carcinomas. 1288 44

All human immunoglobulins are glycosylated. The changes in IgG glycosylation are associated with autoimmune disorders and pregnancy. Little is known about IgG glycosylation in patients with cancer. A lectin enzyme-linked immunosorbent assay (LELISA) based method was developed for measuring the Concanavalin A - positive IgG in the serum. Its rationale is as follows: PtA was used as a capture agent for binding IgG via the Fc fragment. Then IgG and the ConA-positive glycans on the IgG were detected using an anti-human IgG-F(ab)2 alkaline phosphatase conjugate or biotinylated ConA, respectively. The index ConA binding/total IgG was calculated. Serum samples from patients with gastric carcinoma (n=53) and healthy blood transfusion donors (n=24) were analysed. The protein A-agarose and ConA-sepharose affinity chromatography was applied to the purification of IgG, ConA-positive IgG, and Fab fragments. The LELISA, SDS-PAGE and Western blot methods were used to analyse the purified IgG and Fab fragments. A significantly higher ConA binding to IgG was found in patients with cancer compared to that of blood donors (ConA index = 1.07+/-0.08 (95% CI) and 0.81+/-0.08, respectively; P=0.0002). In donors, a significant correlation between the level of IgG bound to PtA and the ConA binding (r=0.85; p<0.001) was observed. Patients with gastric cancer showed a less pronounced, though significant correlation (r=0.33; P=0.02). Only the Fd fragment of the Fabs derived from both total serum IgG and ConA-positive fraction of IgG contained the ConA-positive glycans. The comparison of the purified IgG and Fab fragments derived from healthy blood donors and patient with gastric cancer showed no difference in either SDS-PAGE, immunoblotting or LELISA pattern. The LELISA is simple, reproducible and suitable for the evaluation of IgG glycosylation changes. The level of ConA positive serum IgG was found to be increased in patients with cancer. No convincing evidence of the presence of asymmetrically glycosylated F(ab)2 fragments was found. A trend towards a better survival of patients with a lower level of the ConA-positive IgG was observed suggesting a possible blocking effect of the latter on tumor immunity.
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PMID:An increased level of the Concanavalin A-positive IgG in the serum of patients with gastric cancer as evaluated by a lectin enzyme-linked immunosorbent assay (LELISA). 1823 53

The sera of 40 patients with gastric cancer and 11 patients as the control group were studied for the detection of matrix metalloproteinases. The malignant behavior of tumor cells mainly depends on the capability of invasion and the metastasis of cancer cells. After the components of the extracellular matrix (ECM) are degraded, tumor cells invade the surrounding tissue and the vascular or lymphatic vessels to form metastasis colonies at distant sites. Extracellular proteolytic enzymes implicate the invasion and metastasis of cancer. Proteolytic enzymes from tumors lead to the breakdown of basement membranes and the ECM, thereby, facilitating cancer cell invasion into the surrounding normal tissue. Proteinase activity is overexpressed in the serum of stage 3 and 4 tumors compared to stage 1 and 2 tumors. ProMMP-9 was detected in the serum of patients of gastric cancer by SDS polyacrylamide gel electrophoresis (SDS-PAGE) and SDS-PAGE zymography, with its molecular mass of 92 kDa. MMP-9 in serum plays an important role in the progression of gastric cancer.
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PMID:Relation of matrix metalloproteinase-9 to different stages of tumors in the serum of gastric cancer. 1871 98

Helicobacter pylori is one of the most common pathogens affecting humans and is the major environmental factor in the development of gastric cancer increasing from 4 to 6 folds the risk of its development. Variations in cancer risk among H. pylori infected individuals may correlate to difference in H. pylori strains, variable host characteristics and specific interactions between host and microbial determinants. To determine the effect of different strains of H. pylori on cellular apoptosis this study was designed an in vitro model using AGS and HEF cell lines. After specified time intervals total cell proteins was extracted and subjected to SDS-PAGE and immunoblotting using anti poly ADP-ribose polymerase (PARP) antibody. Decrease in densitometric value of PARP was indicative of higher level of apoptosis. The ability of apoptosis induction in AGS and HEF cell lines by wild type (cagA+/vacA+), cagA-/vacA+, vacA-/cagA+ and double negative (cagA-/vacA-) strains were significantly different. The assessed apoptosis in AGS cell line co-cultured with wild type strain was 3.22 +/- 0.2 in 24 h, 2.8 +/- 0.1 in 48 and 2.1 +/- 0.09 in 72 h of incubation time. Similar assessment with cagA-/vacA+ strains in AGS cells was 4.17 +/- 1.49 in 24 h, 3.32 +/- 0.45 in 48 h and 2.32 +/- 0.61 in 72 h incubation. A variation in apoptotic potential between the H. pylori strains on two cells (AGS and HEF) was observed. Based on present results, it is concluded that H. pylori strains as well as target cell types are important in pathogenesis and induction of apoptosis during a specified time interval.
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PMID:Evaluation of apoptosis induction using PARP cleavage on gastric adenocarcinoma and fibroblast cell lines by different strains of Helicobacter pylori. 1909 Feb 86

Helicobacter pylori is recognized as a major case of gastritis and peptic ulcer and a key factor in the development of gastric cancer, gastric lymphoma, and non-ulcerative dyspepsia in man. The detection of antibodies specific for strains of H. pylori has demonstrated the value of serology for providing evidence of infection. The present study was conducted to detect the antigenic proteins of excretory antigen of H. pylori with Western blotting and examine whether anti-H. pylori IgG and IgA antibodies from H. pylori positive patients cross-react with antigens from other common bacterial pathogens. By using SDS-PAGE, 20 different proteins were found in the excretory antigen. By Western blotting and absorption studies, there were indications that anti-H. pylori IgA antibodies directed against 54 kDa, 50 kDa and 27 kDa cross-reacted with antigens from other bacteria, and that H. pylori proteins of 99 kDa, 88 kDa and 81 kDa possibly shared similar epitope with antigens of other pathogens not tested in the absorption studies. The cross-reactivity occurred in this study was not significantly affect the performance of the in-house ELISA.
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PMID:Antibody response to Helicobacter pylori excretory antigen and the cross reaction study. 1911 3

Early detection and rational therapy for gastric cancer are crucial. In this study we undertook comparative proteomics for identification of gastric carcinoma biomarkers using pooled laser capture microdissected GA cells and matched nonmalignant gastric mucosa epithelial cells. The method involved separation of total proteins by 1D SDS-PAGE, trypsin digestion, and postdigest (18)O/(16)O labeling followed by nano-HPLC-MS/MS for peptide identification and relative quantification. A total of 78 differentially expressed proteins were identified, among these proteins, 42 proteins were up-regulated in GA and 36 proteins were down-regulated. Some differentially expressed proteins were further validated by western blot analysis.
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PMID:Identification of human gastric carcinoma biomarkers by differential protein expression analysis using 18O labeling and nanoLC-MS/MS coupled with laser capture microdissection. 1933 Apr 69


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