The specific release of sialyltransferase activity by human hepatoma cell lines

Liu, Chen-Kao; Schmied, Robert; Waxman, Samuel

doi:10.1016/0009-8981(79)90149-9

Cited by 6 publications

(7 citation statements)

References 14 publications

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“…The findings in this paper and previous reports [9,12,15] demonstrate that glycosyltransferases are released from cell cultures under normal conditions of growth in vitro. Such release may account for glycosyltransferases found in serum.…”

Section: Chromatographical Properties Of Medium Gtsupporting

confidence: 64%

“…However, it has been reported [19] that the release of GT is greater from virally transformed baby hamster kidney fibroblasts than from nontransformed fibroblasts. We have also found [9] that although hepatoma cells release larger amounts of ST compared to Chang cells, other neoplastic cells release only mini mal amounts of ST into the culture medium. Thus, increased release of ST or decreased release of GT from human hepatoma cells does not appear to be a general property of neoplastic cells.…”

Section: Chromatographical Properties Of Medium Gtmentioning

confidence: 58%

“…We have previously reported that some patients with hepatocellular carcinoma (hepintroduction Glycosyltransferases are a family of mem brane-associated enzymes found primarily in the endoplasmic reticulum and Golgi appara tus that catalyze sequential transfer of mono-atoma) elevated levels of serum sialyltransferase (ST) and a hypersialylated vitamin B12 binding protein [9], A cell line derived from a hepatoma of such a patient was found to uniquely release ST and vitamin Bn binding protein into the culture medium. In contrast, a cell line (Chang) derived from normal hu man liver contained and released little ST or B12 binding protein [2].…”

mentioning

confidence: 99%

“…In contrast, a cell line (Chang) derived from normal hu man liver contained and released little ST or B12 binding protein [2]. Other neoplastic cells were also found [9] to release minimal amounts of ST into the culture medium. In this paper, we have studied the content of and release from hepatoma and Chang cells of other glycosyltransferases in the hope of finding some protein markers for neoplastic diseases.…”

mentioning

confidence: 99%

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Characterization of Galactosyltransférase Released from Human Hepatoma Cells

Liu¹,

Schmied²,

Waxman³

1982

Enzyme

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A human hepatoma cell line (SK-H-MA) released a large amount of sialyltransferase (ST) and galactosyltransférase (GT) into the culture medium, whereas cells derived from normal human liver (Chang) released a large amount of GT but very little ST. The characteristics of hepatoma GT were studied since an abnormal GT isoenzyme has been associated with human gastrointestinal neoplasmas. Both hepatoma and Chang medium GT activities had an absolute requirement for MnC1(2) (25 mmol/1) and a broad optimal pH between 6.5 and 7.0, and were not affected by 0.1% Triton X-100. These two enzyme preparations were inhibited to the same extent by N-acetylglucosamine and N-acetylgalactosamine, while N-acetylglucosamine was 100 times more potent than N-acetylgalactosamine. Various nucleotides inhibited both enzyme activities equally well. Uracil-containing nucleotides were better inhibitors than thymine-containing nucleotides, and other nucleotides were only slightly inhibitory. The most effective inhibitor was UDP. More of the GT activity in hepatoma medium (65%) as compared to Chang medium (35%) bound to concanavalin A-Sepharose, and was eluted with 2.5% α-methylmannoside. These results suggest that the GTs from hepatoma and Chang media are not different in their enzymatic activity but may differ in their carbohydrate contents, which may be another manifestation of the neoplastic nature of the hepatoma cell line.

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Section: Chromatographical Properties Of Medium Gtsupporting

confidence: 64%

Section: Chromatographical Properties Of Medium Gtmentioning

confidence: 58%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Characterization of Galactosyltransférase Released from Human Hepatoma Cells

Liu¹,

Schmied²,

Waxman³

1982

Enzyme

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“…Assays. The method of assaying sialyltransferase has been reported (14). A typical reaction mixture contained: 10 ,ul of 0.25 M sodium phosphate buffer, pH 7.0, with 50 mM MgCl2; 10 ,ul of desialylated fetuin (50 mg/ml) (15); 50 ,ul of sample; and 30 nmol of CMP-["4C]sialic acid (5,000 cpm/ nmol).…”

Section: Methodsmentioning

confidence: 99%

12-O-Tetradecanoyl-Phorbol-13-Acetate Release of Glycosyltransferases from Human Blood Cells

Liu¹,

Schmied²,

Waxman³

1980

J. Clin. Invest.

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A B S T R A C T The mononuclear cells separated from human blood by Ficoll-Hypaque centrifugation contained and released sialyltransferase, galactosyltransferase, and fucosyltransferase. Granulocytes contained and released lesser amounts of glycosyltransferases, whereas platelets released more fucosyltransferase than sialyltransferase or galactosyltransferase. When mononuclear cells were incubated with 12-0-tetradecanoyl-phorbol-13-acetate (TPA), the release of these three glycosyltransferases increased two-to sixfold, and cell suspension glycosyltransferase activities decreased 10-50%. Mononuclear cells were fractionated into lymphocytes and monocytes using baby hamster kidney cells microexudate-coated flasks. TPA stimulated the release of glycosyltransferases from lymphocytes but not from monocytes. The release of glycosyltransferases by TPA-treated mononuclear cells was not further stimulated by reincubation with TPA and was not affected by puromycin, cAMP, or cGMP. Concanavalin A, a mitogenic stimulator of lymphocytes, also stimulated the release of glycosyltransferases from mononuclear cells, but to a lesser extent. TPA did not stimulate the release of 5'-nucleotidase or decrease its activity on the cell pellet. Triton X-100 (0.2%) stimulated the release of glycosyltransferases to the same extent as TPA, but also caused the release of 5'-nucleotidase. [3H]TPA bound specifically and reversibly to mononuclear cells. The possible relationship between glycosyltransferase release and TPA effect on the plasma membrane is discussed.

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