Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.53 (sialidase)
 2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Low density lipoprotein receptor (LDL-R) is a membrane glycoprotein carrying both N- and O-linked oligosaccharides, processing of which is reflected in conversion from a precursor to mature form during its synthesis and intracellular transport. Treatment with brefeldin A (BFA) of mouse macrophage-like J774 cells, Chinese hamster ovary cells, and two human cancer cell lines (A431 and IMC-2) resulted in production of LDL-R with a molecular size 5-10 kDa smaller than that of the mature form in the control cells. Treatment with sialidase caused apparent reduction in the molecular size of LDL-R synthesized in all BFA-treated J774, Chinese hamster ovary, A431, and IMC-2 cell lines as observed for the mature form of the control cells. Thus, O-linked sugar chains of LDL-R were apparently sialylated in the BFA-treated cells. We also examined the effect of BFA on the processing of another membranous glycoprotein, epidermal growth factor receptor (EGF-R) carrying only N-linked oligosaccharides. EGF-R synthesized in the presence of BFA was found to have no response to sialidase treatment, suggesting that the drug blocks the sialylation of EGF-R. The results indicate that BFA causes different effects on the sialylation of LDL-R and EGF-R depending upon linkage types of their oligosaccharides.
 ...
PMID:Differential effects of brefeldin A on sialylation of N- and O-linked oligosaccharides in low density lipoprotein receptor and epidermal growth factor receptor. 221 29

Gastric and intestinal phenotypic expression in 223 surgically obtained primary gastric cancers and their histogenetic relationship to intestinal metaplasia in the surrounding gastric mucosa were studied by mucin histochemistry and pepsinogen (Pg) immunohistochemistry. Histochemical differentiation of mucins (paradoxical concanavalin A, the galactose oxidase-Schiff sequence and sialidase-galactose oxidase-Schiff) and immunohistochemical staining of Pgs I and II, allowed differentiation of gastric cancer cells from different histological categories into gastric elements including mucous neck cells, pyloric gland cells and surface mucous cells or intestinal elements including goblet cell and intestinal absorptive cell types. Of 122 papillary and tubular adenocarcinomas, 33 (27.1%) consisted mainly of gastric-type cells and 42 (34.4%) predominantly of intestinal-type cells. The remainder (38.5%) consisted of mixtures of gastric- and intestinal-type cells. Of 101 poorly differentiated adenocarcinomas, signet ring cell carcinomas and mucinous adenocarcinomas, 59 (58.4%) consisted mainly of gastric-type cells and 20 (19.8%) mainly of intestinal-type cells. Seven out of 35 papillary and tubular adenocarcinomas consisting mainly of gastric-type cancer cells were surrounded by mucosa with intestinal metaplasia. Conversely, 10 out of 40 papillary and tubular adenocarcinomas consisting mainly of intestinal-type cancer cells were observed in nonmetaplastic gastric mucosa. Thus no relationship as regards intestinal phenotypic expression was found between gastric cancers and surrounding gastric mucosa.
 ...
PMID:Gastric and intestinal phenotypic expression of human stomach cancers as revealed by pepsinogen immunohistochemistry and mucin histochemistry. 222 Mar 96

Asparagine-linked oligosaccharides were quantitatively released by hydrazinolysis from an alkaline phosphatase, Kasahara isozyme, which was purified from FL amnion cells. Almost all of the oligosaccharides (98%) were acidic components, all of which can be converted to neutral oligosaccharides upon sialidase digestion. Structural analysis of the oligosaccharides by sequential exoglycosidase digestion in combination with methylation analysis revealed that the alkaline phosphatase of FL cells contains sialylated mono-, bi-, tri-, and tetraantennary complex type sugar chains with the Gal beta 1----4GlcNAc beta 1---- outer chains. Some of the tetraantennary sugar chains contain a single Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4GlcNAc beta 1---- outer chain on their Man alpha 1----6 arm. Both fucosylated and nonfucosylated trimannosyl cores were found in the sugar chains. However, it is of interest that the core portion of monoantennary oligosaccharide was not fucosylated and that of the tetraantennary oligosaccharide with a tetrasaccharide outer chain was completely fucosylated.
Cancer Res 1990 Feb 15
PMID:Structures of the asparagine-linked oligosaccharides of an alkaline phosphatase, kasahara isozyme, purified from FL amnion cells. 229 56

The patterns of acidic and neutral glycosphingolipids (GSLs) were examined in a syngeneic tumour system in Balb/c mice consisting of closely related cell lines with different colonisation potentials directed to the murine lungs (in vivo selected highly metastatic sublines of L1-fibrosarcoma cells and their WGA-resistant mutants with low metastatic potential). GSLs were analysed by high-performance thin-layer chromatography and structurally identified by fast atom bombardment mass spectrometry combined with compositional analyses and exo-glycosidase digestion. The results suggest that highly metastatic sublines L1-LM and L1-LM12 derived by in vivo selection from mouse fibrosarcoma cells (cell line L1) exhibit a drastic increase of polar ganglioside expression and a restriction to globo-series GSLs. Contrasting with this the low metastatic mutant cells (L1-LM13WGA) express a reduced portion of acidic GSLs and exhibit a shift to less polar ganglioside components. Total cellular and plasma membrane-integrated GSLs were demonstrated to exhibit largely identical patterns. Concomitant with a significant decrease in LacCer expression a substantial reduction of GM2 and a complete lack of GM3 expression can be assigned to the highly metastatic sublines of L1-cells. On the other hand, the more polar gangliosides GM1a and, to an even greater extent, GD1a (exceeding 70% of total gangliosides) accumulate on L1-LM and their clonal sublines. The shift to acidic GSLs of higher polarity is less pronounced on the low metastatic WGA-resistant mutant cells (L1-LM13WGA) showing a preponderance of GM1a. The portion of GD1a within the fractions of acidic GSLs does not correspond to the cellular activities of CMP-NeuAc/GM1 (alpha 2-3) sialyltransferase measured for high and low metastatic cell variants. Total sialic acid content of the various cell lines differs, but is not associated with the metastatic potential. Gangliosides on L1-cells exhibit a significant substitution of N-glycolyl for N-acetylneuraminic acid (13%) compared to their metastatic sublines and to mutant cells (less than 1%). A conversion of surface exposed GD1a to GM1a on membranes of metastatic cells by in situ treatment with Vibrio cholerae sialidase is associated with a significant reduction of tumour cell colonisation directed to the murine lungs.
Br J Cancer 1990 Jun
PMID:Glycosphingolipid expression on murine L1-fibrosarcoma cells: analysis of clonal in vivo and in vitro selected sublines with different lung colonisation potential. 237 82

Sialidase activity has been studied in the human erythroleukemia K 562 cell line grown in vitro. The total sialidase activity was determined using disialoganglioside GD1a and fetuin as exogenous substrates. The enzymatic activity was stimulated by 0.08% Triton X-100 and reached the highest level at pH 4.0. Results obtained showed that gangliosides are hydrolysed more extensively than glycoproteins by K 562 sialidases. This finding could suggest that endogenous gangliosides may be the main source of metabolically available sialic acid in K 562 cell line. After treatment of K 562 cells by Adriamycin (40 nM), a potent anticancer drug, sialidase activity decreased by 40% as compared to control cells. This decrease occurs early during the first day of incubation with Adriamycin. This inhibition of sialidase activity could explain previous results obtained in our laboratory which show an enhanced sialylation of the membrane glycoconjugates after Adriamycin treatment.
Cancer Biochem Biophys 1986 Dec
PMID:Evidence for sialidase activity in K 562 cells: inhibition by adriamycin treatment. 243 12

By selection for plastic adhesiveness we have previously established a variant tumor line (ESb-MP) from the metastatic murine lymphoma ESb. In contrast to the parental line, the adhesion variant is significantly decreased in malignancy and is altered in the capacity to bind soybean agglutinin (SBA) lectin. Here we show biochemically that the major SBA-binding cell-surface component of ESb-MP cells is the T200 glycoprotein. In ESb cells, T200 antigens bind SBA only after sialidase treatment. Enzymatic studies suggested that glycans detected by the lectin with or without sialidase treatment are different. Inhibition of N-glycosylation by tunicamycin and biosynthetic labeling revealed two T200 chains for ESb-MP cells that were larger in size than the single chain detected in ESb cells. Studies on the biosynthesis revealed that ESb-MP cells expressed two precursor chains for T200 whereas ESb cells displayed only one. There was no size difference detectable in the mature T200 molecules of ESb and ESb-MP cells. Our data suggest that the molecules differ in expression of O-linked glycans that can be recognized by SBA. Additional O-linked sugars on ESb-MP T200 molecules seem to be expressed in particular after trimming of the second T200 precursor chain.
 ...
PMID:Structural basis for altered soybean agglutinin lectin binding between a murine metastatic lymphoma and an adhesive low malignant variant. 244 94

Free alpha subunit (PU alpha) was extracted and purified from the urine of normal term pregnant women, and examined for molecular weight, electric charge, affinity to lectins (ConA, RCA and PNA) and the ability to combine with hCG beta in comparison with hCG alpha dissociated from hCG in vitro. The molecular weight of PU alpha was greater than that of hCG alpha in gel chromatography, but smaller in SDS-PAGE. However the free alpha subunits from the urine of patients with cancer were estimated to be larger than those of hCG alpha by both methods. In isoelectric focusing, while hCG alpha exhibited a neutral charge, PU alpha exhibited a negative charge. After treatment with sialidase, both hCG alpha and PU alpha were shifted to the basic region, indicating that they contained terminal sialic acid residues. The affinity to lectins indicated that PU alpha may contain both asparagine-linked and O-linked oligosaccharides, while hCG alpha contains asparagine-linked oligosaccharide only. PU alpha scarcely showed any combining activity with hCG beta, whereas hCG alpha combined actively. The O-linked oligosaccharide, which is not present in hCG alpha, may cause PU alpha to fail to combine with hCG beta.
 ...
PMID:[The characterization of free alpha subunit purified from the urine of normal term pregnant women]. 244 2

We collected a total of 78 tissue specimens, including primary colorectal carcinoma, normal colonic mucosa, and liver metastases of colon carcinoma, to examine whether the extracts of these tissues inhibited the binding of a monoclonal antibody FH6, specific for sialyl-dimeric LeX antigen. The results of inhibition assays demonstrated that: (a) contents of FH6-reactive molecules were greater in carcinoma tissues than in normal colonic mucosa; (b) metastatic foci in livers contained more FH6-reactive molecules than primary tumors; (c) primary tumors from Dukes' stage B1 patients contained less FH6-reactive molecules than primary tumors from Dukes' stage D patients. The inhibitory activity of these tumor tissue extracts against the binding of a monoclonal antibody FH6 to cultured colon carcinoma cells was eliminated by prior treatment of the extracts with sialidase, confirming that the FH6-reactive materials were sialyl-dimeric LeX antigen. Electrophoretic separation of tumor tissue extracts on 3% polyacrylamide gels followed by direct staining with monoclonal antibody FH6 revealed that very high molecular weight glycoproteins, presumably mucins, contained sialyl-dimeric LeX antigen.
Cancer Res 1989 Dec 15
PMID:Increased expression of sialyl-dimeric LeX antigen in liver metastases of human colorectal carcinoma. 257 22

Seventy five prostatic specimens from cancer, BPH and normal controls were studied by light microscopic histochemical methods for the demonstration of complex carbohydrates and some proteins: 1) alcian blue (AB) (pH 1.0), 2) alcian blue (AB) (pH 2.5), 3) Periodic Acid-Schiff (PAS), 4) peroxidase labelled-Ricinus communis agglutinin-diaminobenzidine (PO-RCA-DAB), 5) Concanavalin A-peroxidase-diaminobenzidine (ConA-PO-DAB), 6) ConA-PO-DAB-periodic acid-m-aminophenol Fast black salt K (ConA-PO-DAB-PA-AP-FBK). For identifying individual acidic and neutral carbohydrates, following procedures of enzyme digestion were performed upon some tissue sections prior to the above histochemical staining: a) sialidase (prior to staining with AB at pH 2.5), b) streptomyces hyaluronidase (prior to staining with AB at pH 2.5), c) testicular hyaluronidase (prior to staining with AB at pH 1.0 or pH 2.5), d) chondroitinase ABC (prior to staining with AB at pH 1.0 or pH 2.5), e) chondroitinase AC (prior to staining with AB at pH 1.0 or pH 2.5), f) alpha-amylase (prior to staining with PAS). In addition, the tissue specimens from prostatic cancer were stained immunohistochemically for demonstration of prostatic acid phosphatase (PAP) and the serum PAP levels were also measured by radioimmunoassay. The histochemical differences in the prostatic tissue among normal control, BPH and cancer as follows. In the tissue of prostatic cancer, chondroitin sulfate A, C and hyaluronic acid were present in the interstitium. Chondroitin sulfate, hyaluronic acid and sialic acid were present in the cytoplasm of cancer cells. In the tissue of BPH chondroitin sulfate B and hyaluronic acid was present in the interstitium and hyaluronic acid was present in the cytoplasm of epitherial cells. In the epithelial basement membrane of the tissue from BPH, chondroitin B and hyaluronic acid were present. 1,2-Glycol groups of neutral complex carbohydrates in the interstitium of prostatic cancer were shown to exist in smaller amounts than in that of BPH. In the cytoplasm of cancer cells the intensity of both PO-RCA-DAB and ConA-PO-DAB staining could be divided into three groups: strong, moderate and weak. In the prostatic cancer there was a good correlation between the intensity of PO-RCA-DAB staining and tumor grade, and intensity of ConA-PO-DAB staining was correlated well with serum PAP level. The cytoplasm of cancer cells showed a positive reaction to PAP immunostaining and no appreciable difference was observed according to tumor grade.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:[The histochemistry of complex carbohydrates in the prostatic tumor]. 258 29

A human monoclonal antibody termed HMST-1 was produced by fusing lymphocytes from segments of human pelvic lymph nodes from an endometrial cancer patient with murine myeloma cells. The epitope recognized by HMST-1 was determined to be lacto-series type 1 chain-containing glycosphingolipid (Gal beta 1-3GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1Cer) by isolating the antigen from endometrial cancer cell line SNG-II and analyzing with fast atom bombardment mass spectrometry, permethylation analysis, and exoglycosidase treatment. By the immunohistochemical avidin-biotin-peroxidase complex method, no normal endometrium and benign endometrial hyperplasia were stained with HMST-1, but HMST-1 reacted with about 35% of endometrial cancer cases. These facts indicate that the rate of expression of the antigen increases along with the course of malignancy in the endometrium. By sialidase treatment of the section, the positive rate increased to 57% in endometrial cancers and to 13% in normal endometrium, indicating that the antigen was masked with sialic acid and exposed by neuraminidase treatment. Immunohistochemistry also revealed that the antibody reacted with human fetal alimentary tract epithelium and mesothelium, indicating the oncodevelopmental nature of Gal beta 1-3GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1Cer.
Cancer Res 1989 Nov 15
PMID:Human monoclonal antibody (HMST-1) against lacto-series type 1 chain and expression of the chain in uterine endometrial cancers. 268 63


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>