Ganglioside inhibition of sup 125 I-plasmin binding to colorectal carcinoma cells
- IRSC-CNRS, Villejuif (France)
The pre-incubation of human colorectal carcinoma cells SW 1116 with 25 to 100 uM purified gangliosides resulted in 35-60% inhibition of specific {sup 125}I-plasmin binding to the cell surface. After 5 to 6 days in culture, tumor cells were pre-incubated at 4 degrees for 1 to 4 h followed by post-incubation with {sup 125}I-plasmin by techniques previously described. At 25 uM the capacity for inhibition of plasmin binding was GT1b greater than GQ1b greater than or equal to GD1a greater than GM1 less than or equal to GgOse 4Cer. Thus a terminal sialyl moiety appears to be necessary (p less than 0.05) although exogenous N-acetyl neuraminic acid was ineffective (p greater than 0.05), indicating a role for the lipid portion of the ganglioside. Other (glyco)lipids such as sphingosine, fucolipid H-1 and sulfatide were without significant effect. The inhibition could not be reversed by the presence of 10 mM Ca+2, EDTA, pre-treatment of the cell with carboxypeptidase or pretreatment of plasmin with neuraminidases. The inhibition was however reversed by post-incubation in control medium without exogenous ganglioside. Cell counts determined prior to, and after ganglioside incubation showed that the effect was not due to cell death or detachment from the culture surface. The dissociation constant for {sup 125}I-plasmin binding was 5.6 x 10(-8) M (700,000 sites/cell), but in the presence of trisialoganglioside (GT1b), Scatchard plots suggested diversification of binding sites with 280,000 sites/cell at Kd 2.6 x 10(-8) M and 820,000 sites/cell at Kd 2.1 x 10(-7) M. Another interpretation of the Scatchard plot in the presence of ganglioside was that the glycolipid imposed negative cooperativity on plasmin binding to the cell surface. These results suggest that certain gangliosides can affect tumor cell invasiveness by altering protease binding to the cell surface.
- OSTI ID:
- 5803066
- Journal Information:
- Journal of Receptor Research; (USA), Vol. 10:5-6; ISSN 0197-5110
- Country of Publication:
- United States
- Language:
- English
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FIBRINOLYSIN
BIOCHEMICAL REACTION KINETICS
GANGLIOSIDES
BIOLOGICAL FUNCTIONS
LARGE INTESTINE
CARCINOMAS
RECTUM
INHIBITION
IODINE 125
MAN
PEPTIDE HYDROLASES
TRACER TECHNIQUES
TUMOR CELLS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
CARBOHYDRATES
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DISEASES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
FIBRINOLYTIC AGENTS
FUNCTIONS
GASTROINTESTINAL TRACT
GLYCOLIPIDS
HEMATOLOGIC AGENTS
HYDROLASES
INTERMEDIATE MASS NUCLEI
INTESTINES
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIPIDS
MAMMALS
NEOPLASMS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PRIMATES
RADIOISOTOPES
REACTION KINETICS
SACCHARIDES
SERINE PROTEINASES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques
550901 - Pathology- Tracer Techniques