Linked Life Data

9841644

Source:http://linkedlifedata.com/resource/pubmed/id/9841644

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1999-1-28
pubmed:abstractText
Ammonia in animal cell cultures has been shown to specifically inhibit terminal sialylation of N- and O-linked oligosaccharides of glycoproteins. For example, we have previously shown that as little as 2.5 mM NH4Cl can decrease neural cell adhesion molecule (NCAM) polysialylation in both small cell lung cancer (SCLC) and Chinese hamster ovary (CHO) cells. Besides its potential involvement in SCLC metastasis, polysialic acid (PolySia) is a sensitive marker for measuring changes in sialylation. The role of UDP-N-acetylglucosamine (UDP-GlcNAc) in ammonia's inhibition of NCAM polysialylation was examined by adding glucosamine (GlcN) and uridine (Urd) to the cultures. This bypassed feedback inhibition of GlcN-6-P synthase and increased UDP-GlcNAc content by 25-fold in SCLC cells. After 3 days, PolySia levels were reduced to 10% of control with little effect on NCAM protein content. The extensive decrease in PolySia was confirmed in CHO cells. The effects of GlcN or Urd alone were less extensive, lending support to a specific role for UDP-GlcNAc in inhibition by ammonia. By comparison, 20 mM NH4Cl decreased PolySia content by 45% and increased UDP-GlcNAc in SCLC cells by 2-fold. The discrepancy between the ¿GlcN+Urd¿ and NH4Cl effects on UDP-GlcNAc and PolySia suggests that accumulation of UDP-GlcNAc is only partially responsible for decreased polysialylation in response to NH4Cl. In an attempt to increase NCAM polysialylation, N-acetylmannosamine and cytidine were added to cultures in order to circumvent the feedback inhibition of CMP-sialic acid synthesis. However, this only slightly increased PolySia levels and failed to counter ammonia's inhibition of NCAM polysialylation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
8756-7938
pubmed:author
pubmed:issnType
Print
pubmed:volume
14
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
834-44
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:9841644-Ammonia, pubmed-meshheading:9841644-Ammonium Chloride, pubmed-meshheading:9841644-Animals, pubmed-meshheading:9841644-CHO Cells, pubmed-meshheading:9841644-Carbohydrate Sequence, pubmed-meshheading:9841644-Carcinoma, Small Cell, pubmed-meshheading:9841644-Cricetinae, pubmed-meshheading:9841644-Cytidine, pubmed-meshheading:9841644-Hexosamines, pubmed-meshheading:9841644-Humans, pubmed-meshheading:9841644-Lung Neoplasms, pubmed-meshheading:9841644-Molecular Sequence Data, pubmed-meshheading:9841644-Neural Cell Adhesion Molecules, pubmed-meshheading:9841644-Nucleoside Diphosphate Sugars, pubmed-meshheading:9841644-Oligosaccharides, pubmed-meshheading:9841644-Sialic Acids, pubmed-meshheading:9841644-Tumor Cells, Cultured, pubmed-meshheading:9841644-Uridine Diphosphate N-Acetylglucosamine
pubmed:articleTitle
Role of nucleotide sugar pools in the inhibition of NCAM polysialylation by ammonia.
pubmed:affiliation
Department of Chemical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3120, USA. zanghi@biotech.biol.ethz.ch
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't