Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.4.99.6 (sialyltransferase)
 1,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The MAT-B1 and MAT-C1 ascites sublines of the 13762 rat mammary adenocarcinoma differ in morphology, agglutinability with concanavalin A, and xenotransplantability. Both cell lines contain a major mucin-type glycoprotein, but the MAT-C1 (xenotransplantable) subline contains a 3-fold-greater content of sialic acid on the glycoprotein than does the MAT-B1 (nonxenotransplantable) subline. The present work indicates that whole cells of both lines incorporate radioactivity from labeled CMP-sialic acid into a component which comigrates with the major glycoprotein by sodium dodecyl sulfate polyacrylamide gel electrophoresis, and that label incorporated by MAT-B1 cells is released by alkaline-borohydride treatment. Sialyltransferase can be purified from 250- to 400-fold by chromatography of a Triton X-100 extract of microsomes on CDP-agarose. The purified fraction of both cell lines has a Km for CMP-sialic acid of 0.40 +/- 0.10 mM with asialofetuin as the acceptor, and gives 35 to 40% of the activity with the acceptor asialotransferrin as with asialofetuin. When assayed with a variety of acceptors, the MAT-C1 extract showed higher sialyltransferase activity at a pH below 6.5 than did the MAT-B1 extract. Analysis of the products following incubation with lactose yields only 3'-sialyllactose for both cell lines. The results indicate that the differences in MAT-B1 and MAT-C1 sialyltransferase when assayed with glycoprotein acceptors are not large enough to account for the differences in sialic acid content of the two cell lines.
Cancer Res 1984 Mar
PMID:Sialyltransferase of the 13762 rat mammary ascites tumor cells. 669 99

Copper, ceruloplasmin and sialyltransferase activity were measured in serum of 25 patients with lymphoreticular malignancies, in an attempt to study the sialyltransferase activity and correlation if any with the activity of the disease and ceruloplasmin. All 3 parameters were elevated in active disease but no definite correlation between sialyltransferase activity and copper or ceruloplasmin could be found. We conclude that plasma sialyltransferase activity is increased in lymphomas.
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PMID:Role of sialyltransferase in hypercupraemia of non-Hodgkin's lymphoma. 670 69

The specific activities of UDP-galactose : GM2 galactosyltransferase and CMP-NAN : GM1 sialyltransferase were measured in total particulate fractions of individual hepatocellular carcinomas (hepatomas) and hepatic nodules, induced in the rat by a carcinogenic diet of 0.05% N-2-fluorenylacetamide alternating with a low protein basal diet. In all tumors except the smallest nodules, galactosyltransferase specific activities were increased compared to those of control livers from rats fed only basal diet. When relative specific activities were related to wet weight of nodules larger than 0.1 g were in two populations. Specific activities of nodules in one population overlapped those of poorly differentiated hepatomas whereas specific activities of the second population those of well differentiated hepatomas. Specific activities of the sialyltransferase were also increased above those in control livers but not with the same frequency or to the same extent as for the galactosyltransferase. As with galactosyltransferase, nodules were found in two major populations when specific activities were related to nodule wet weight. The data suggest that increased specific activities of galactosyltransferase and sialyltransferase in hepatic nodules may provide an early phenotypic indicator of diverging differentiation in hepatocarcinogenesis.
Cancer Biochem Biophys 1980
PMID:Gangliosides of liver tumors induced by N-2 fluorenylacetamide III. Galactosyl and sialyl transferases in single carcinomas and nodules. 677 33

The release of galactosyltransferase, sialyltransferase, and several glycosidase activities into the growth media from several normal and transformed cell lines was examined. Six of the seven cell lines released galactosyltransferase into their culture media. Only the human leukemia CCRF-CEM cells failed to release demonstrable galactosyltransferase activity. Release of galactosyltransferase activity into the media closely paralleled the growth curves for all but the BHKpy cells. These cells continued to release peak levels of galactosyltransferase activity into the culture media after their growth had plateaued. Media galactosyltransferase activity was unaffected by Triton X-100 treatment had remained in the supernatant fraction of a 100,000 X g, 12-hr centrifugation, suggesting that the cells release galactosyltransferase in a soluble form. In contrast to galactosyltransferase activity, only one of the cell lines (L1210) released sialyltransferase activity in appreciable amounts. Even this level of activity was 20-fold less than that observed for galactosyltransferase in the media from L1210 cells. Of the nine glycosidase activities assayed, only N-acetylglucosaminidase was observed in significant amounts in the media from all but the CCRF-CEM cells. However, N-acetylglucosaminidase release did not correlate closely with cell growth. These findings suggest a relatively specific release of galactosyltransferase and N-acetylglucosaminidase activities by cells in tissue culture. Moreover, the release of galactosyltransferase closely parallels cell growth. The significance of these released enzymes, especially to cell growth, has yet to be determined.
Cancer Res 1981 Jul
PMID:Release of glycosyltransferase and glycosidase activities from normal and transformed cell lines. 678 58

The correlation between levels of sialic acid and sialic acid-containing glycolipids (gangliosides) in tumors and serum with the growth characteristics of the tumors was investigated in transplantable hepatomas and squamous cell carcinomas initiated with the carcinogen N-2-fluorenylacetamide and propagated in vivo and in tissue culture. Tumor lines varied in histologic classification, growth rate, and ability to form pulmonary metastases. There was neither a correlation between growth rate and histologic classification nor between either of these two parameters and the ability to metastasize. Total and ganglioside sialic acid levels were elevated in carcinogen-treated liver and in transplantable hepatomas when contrasted with normal liver. Levels of sialic acid showed a weak correlation with the growth rate of hepatomas. Gangliosides from nonmetastatic hepatoma lines exhibited less N-acetylneuraminic acid--galactose--glucose-N--acylsphingosine (GM3) and an increased ratio of total monosialogangliosides to disialogangliosides than did metastatic lines. Ganglioside patterns of metastatic hepatoma lines more closely resembled the ganglioside patterns of normal liver than did those of the nonmetastatic lines. Concomitant elevations of total and ganglioside sialic acid levels were observed in sera of animals bearing subcutaneous implants. Serum levels of total sialic acid did correlate with total sialic acid levels found in the tumor tissues. The levels of serum sialic acid were not correlated directly with levels of serum sialyltransferase activity. Elevations of both tissue and serum ganglioside sialic acid were consistent features of liver tumorigenesis in the rat after N-2-fluorenylacetamide administration. They appeared, furthermore, to be early events not directly related to tumor cell differentiation or metastasis.
J Natl Cancer Inst 1980 Jun
PMID:Characteristics of transplantable tumors induced in the rat by N-2-fluorenylacetamide: elevations in tissue and serum sialic acid. 692 77

A murine melanoma variant (B16-F10ir6), resistant to lymphocytic cytolysis, has been shown previously to produce lower numbers of tumor nodules in the lung of C57BL/6J mice following i.v. inoculations. These differences found in tumor implantation and lymphocyte recognition may be due to changes in surface properties of this cell line. Therefore, membrane-bound sialic acid (released by Vibrio cholerae neuraminidase treatment), ectosialyltransferase activity, and total cellular glycosidase levels were measured in this cell line and compared with levels in its parent melanoma tumor cell line, B16-F10, which was selected for its enhanced ability to form tumor nodules. The results of these studies indicate a correlation between the degree of lung implantation and the amount of tumor cell sialic acid accessible to neuraminidase cleavage, tumor cell surface sialyltransferase activity, and several cellular glycosidase activities. These results are consistent with the idea that membrane structural changes in the glycocalyx may account for the ability of a tumor cell to implant and metastasize.
Cancer Res 1981 Jun
PMID:A correlation between cell surface sialyltransferase, sialic acid, and glycosidase activities and the implantability of B16 murine melanoma. 723 26

Cachexia is rare in nude mice bearing human malignant tumors even when the transplanted tumors become as large as the body size of the host. In our series on heterotransplantation of a variety of human malignant tumors into nude mice, a malignant melanoma (SEKI) was found to induce severe body weight loss in the host at the early stage of transplantation. There was no electrolyte disturbance, hyper- or hypoadrenocorticism, hyperthyroidism, or destruction of cells of vital organs to account for the weight loss. Moreover, no evidence was obtained for concomitant infection with bacteria, Mycoplasma or fungi. These cachectic mice revealed remarkably increased levels of serum sialyltransferase and decreased liver catalase activity. The removal of tumor tissues from these mice resulted in prompt recovery of body weight, serum sialyltransferase, and liver catalase activity within 1 to 2 weeks. On the basis of the results obtained, the SEKI melanoma was thought to have produced a pathophysiological state in host nude mice which was very similar to that of cachexia in cancer patients. Nude mice bearing transplants of SEKI melanoma may provide a useful system for the study of cancer cachexia in humans.
Cancer Res 1981 Jul
PMID:Serum sialyltransferase and liver catalase activity in cachectic nude mice bearing a human malignant melanoma. 724 51

Sialic acid metabolism was investigated in control rat liver, in regenerating liver at 24 h and 48 h after partial hepatectomy and in the liver of sham-operated animals. High levels of membrane-bound neuraminidase, with no detectable changes in the soluble enzyme, were observed in regenerating rat liver. The neuraminidase activities in the liver of sham-operated rats were identical to those present in control liver. High levels of CMP-N-acetylneuraminic acid synthetase and sialyltransferase were observed both in regenerating liver as well as in the liver of sham-operated rats. The sialic acid content of regenerating rat liver, which was lower than that found in the liver of control and sham-operated rats at 24 h, returned to normal values 48 h after surgery.
Cancer Lett 1981 Sep
PMID:Sialic acid metabolism in regenerating rat liver. 730 57

Sodium butyrate and dimethylsulfoxide (DMSO) have marked effects on the growth, morphology, and biochemistry of two human colonic adenocarcinoma cell lines in culture. Doubling times were increased between 18% and 660% while cell viability was unaffected. Both cell lines formed colonies in soft agar in the absence of butyrate of DMSO, but no colonies were observed in the presence of these agents. However, no differences in in vivo tumorigenicities, when cells were implanted in athymic mice, were seen following treatment. Gross morphological alterations including cell enlargement, process formation, and cellular flattening occurred during culture in butyrate or DMSO. Acrylamide gel electrophoresis in sodium dodecyl sulfate revealed no change in membrane protein constituents, but autoradiographic analysis of membrane glycoproteins demonstrated differences between treated and untreated cells. Ganglioside compositions were altered, and a sialyltransferase required for the synthesis of GM3 ganglioside was elevated by butyrate. Although cytoplasmic aminooligopeptidase remained unaffected by butyrate or DMSO, brush border-associated activity was enhanced by butyrate. Alkaline phosphatase also rose dramiatically during culture in butyrate but was not enhanced by DMSO.
Cancer 1980 Mar 15
PMID:Effects of sodium butyrate and dimethylsulfoxide on biochemical properties of human colon cancer cells. 735 11

The observation that the activity of sialyltransferase (EC 2.4.99.1; serum glycoprotein:N-acetylneuraminic acid transferase) is often elevated in the serum of cancer patients necessitates an elucidation of the interrelationships of this serum enzyme with host tissues. Accordingly, the activity of this enzyme in serum, tumor, and liver was determined at various times after implantation of the R3230AC mammary carcinoma into Fischer rats. Results from samples obtained at numerous, sequential time points demonstrated that significant elevations in serum sialyltransferase enzyme activity occurred only in animals bearing large tumor burdens, i.e., greater than 20 g, or in animals with tumors present for longer than 21 days. In these tumor-bearing rats, the activity of sialyltransferase increased in liver tissue at 21 to 25 days concurrently with the increase in serum enzyme activity, suggesting that the liver may be a potential source of the serum enzyme. Sialyltransferase activity in tumor tissue was quite variable; the activity increased one week after tumor implantation and remained at the same level thereafter. When tumors were excised, the activity of the serum enzyme returned to control values within four days after surgery, suggesting that the half-life of serum sialyltransferase was two days. Serum enzyme levels were again elevated upon regrowth of the tumor. These results show that the serum sialyltransferase alters its activity in conjunction with changes in tumor burden.
Cancer Res 1980 Sep
PMID:Correlation of serum, tumor, and liver serum glycoprotein: N-acetylneuraminic acid transferase activity with growth of the R3230AC mammary tumor in rats and relationship of the serum activity to tumor burden. 742 28


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