Partial characterization of sialoglycopeptides produced by cultured human melanoma cells and melanocytes

Abstract

The sialoglycopeptides produced by HM7 human melanoma and fetal uveal melanocyte cultures grown in the presence of [3H]glucosamine and [35S]sulfate were isolated from the Pronase digests of cells, spent media, and intracellular material. From the melanoma culture, six sialoglycopeptides, accounting for 43% of the total 3H radioactivity in the nondiffusible cell-associated glycopeptides, were purified. A major glycopeptide (GPIb) having an apparent molecular weight in the range 12 000-15 000 showed specific sialic acid dependent to interaction with wheat germ agglutinin (WGA). It was found to contain mainly O-glycosidically linked oligosaccharides having the structure (AcNeu) leads to 0-2[Gal leads to GalNAc]; some N-glycosidically linked saccharides were also present. A second WGA-binding glycopeptide (GPIa) was smaller and less anionic and had a higher proportion of N-glycosidically linked saccharides than GPIb. The normal fetal cultures yielded either no (iris) or markedly reduced (melanocytes) quantities of the WGA-binding glycopeptides. The four WGA-nonbinding sialoglycopeotides purified from melanoma were shown to have complex (N-acetyllactosaminly type) oligosaccharides linked via N-acetylglucosamine to asparagine with either no or insignificant amounts of O-glycosidically linked saccharides. The corresponding glycopeptides from melanocytes were of smaller molecular size and lower anionic charge, reflecting an overall lower degree of glycosylation.

Reduction of UDP-N-acetylglucosamine 2-Epimerase/N-Acetylmannosamine Kinase Activity and Sialylation in Distal Myopathy with Rimmed Vacuoles

“…3A). We used two lectins, WGA, which specifically recognizes a cluster structure of sialic acids (20), and SBA. WGA strongly stained the perinuclear region in control fibroblasts.…”

Effect of Amentoflavone on the Inhibition of Pulmonary Metastasis Induced by B16F-10 Melanoma Cells in C57BL/6 Mice

“…Blood was collected by heart puncture, and the serum was separated and used to estimate serum sialic acid and γ-glutamyl transpeptidase level. 27,28 Determination of the Effect of Amentoflavone on the Survival Rate of Metastatic Tumor-Bearing Animals Six animals from each group of the previous experiment were observed for their survival rate, and the percentage increase in life span (ILS) was calculated using the following formula: % ILS = T -C/C × 100, where T represents the number of survival days of the treated animals, and C represents the number of survival days of the control animals.…”

“…27 The serum was hydrolyzed using 0.2 N sulfuric acid. The hydrolysate was oxidized with periodic acid and incubated at 37°C for 30 seconds.…”

Structure and function of the Ca antigen

“…Treatment of the desialylated Ca antigen with D. pneumoniae endo-a-N-acetylgalactosaminidase (Umemoto et al, 1977) resulted in the release of 90% of the radioactivity as an oligosaccharide that co-chromatographed with on Bio-Gel P-4 and P-6 columns. Mild alkaline borohydride treatment (Bhavanandan et al, 1981) of the antigen released 95% of the radioactivity as oligosaccharides. Analysis of these oligosaccharides by high voltage paper electrophoresis and by chromatography on Bio Gel P-4 and P-6 columns revealed that the major components had mobilities identical with the tetrasaccharide [(NeuNac)2 -*Gal-+GalNac (OH)], the trisaccharide [NeuNac -+Gal-+GalNac (OH)] and the disaccharide [Gal -*GalNac (OH)] isolated from fetuin (Spiro & Bhoyroo, 1974).…”