Expression of Gal beta 1,4GlcNAc alpha 2,6-sialyltransferase and alpha 2,6-linked sialoglycoconjugates in normal human and rat tissues.

Abstract

We performed histochemical studies on normal human and rat tissues using anti-GalP1,4GlcNAc a2,6-~ialyItransferase (a2,6-ST) antibody and Sambucusnigra agglutinin (SNA). a2,6-ST and its products were detected in almost all tissues examined. However, the staining intensities varied significantly with di&rent cell types. Some seaetory epithelial cells, such as hepatocytes and choroid plexus cells, were vividly stained with either anti-aZ.6-ST or SNA. In several cell types the intensity of a2,6-ST staining did not always correlate with SNA stainability. Neurons and gastrointestinal epithelia were rarely stained with SNA, even though they were positive for a2,6-ST. In contrast, the endothelial cells of blood vessels strongly reacted with SNA despite their weak a2,6-ST expression. The precise physiological roles played by a2,6-linked sialylated glycoconjugates have been unclear. However, the fmdiags desaibed here lend fiuther support to their important role in cell growth and difkrentiation, since immature blood cells, including megakaryocytes in bone marrow, were intensely stained with anti-al,dST and SNA, and SNA reaction praducts were primarily observed in the basal and suprabasal layers of the stratified epithelia rather than in the more a e n t i a t e d upper layers. In view of the vivid reactivity ofantLa2,CST io the decidual cells of the placenta, it seem likely that a2,6-ST expression is under hormonal control. (J I l i s t d e m C y t d e m 43945-954, 1995)

Differential Expression of β-Galactoside α2,6 Sialyltransferase and Sialoglycans in Normal and Cirrhotic Liver and Hepatocellular Carcinoma

“…Kupffer cells, endothelial cells, and oval cells are positive for both ligands in the cytoplasm. The fact that these cells (found to be negative for ST6Gal I staining) nonetheless express ␣2,6 sialoglycans has also been observed by other groups (Kaneko et al, 1995;Dall'Olio et al, 2000). This could be explained by small amounts of active ST6Gal I enzyme below the threshold of mAb recognition, by an as yet unidentified ␣2,6-sialylating sialyltransferase, or by more complex mechanisms regulating ␣ 2,6 sialylation (Keppler et al, 1999).…”

“…Binding sites of plant lectins such as SNA and MAA recognizing ␣ 2,6-sialylated and ␣2,3-sialylated glycans in normal liver and HCC have been described in previous studies (Cao et al, 1996(Cao et al, , 1999Kaneko et al, 1995). In contrast to CD22 and sialoadhesin, these lectins may have a wider range of carbohydrate reactivities.…”

“…Hepatocytes express ST6Gal I in considerable quantities (Kaneko et al, 1995) as a key enzyme for the ␣2,6 sialylation of plasma glycoproteins. ST6Gal I expression is induced as part of the acute phase response (Dalziel et al, 1999).…”

An Oncogenic Protein Golgi Phosphoprotein 3 Up-regulates Cell Migration via Sialylation

“…Enhanced expression of ␣2,6-linked sialylation on N-glycans often correlates with human cancer progression, metastatic spread, a poor prognosis, and stem cell markers (7,9,10). Increased expression has been reported in carcinomas of the colon (11), breast (12), cervix (13), and ovary (9) and in some brain tumors (14). The expression level of the ␣2,6-sialyltransferase-I (ST6GAL1) gene is up-regulated by the Ras oncogene (15,16).…”

Altered Expression of Sialylated Glycoproteins in Breast Cancer Using Hydrazide Chemistry and Mass Spectrometry

“…By existing as terminal sugars on glycans attached to proteins and lipid moieties, sialic acids play critical roles in intermolecular interactions and the formation of cellular characteristics (4). Altered expression of sialylated glycoproteins has been discovered in many carcinomas such as colon, acute myeloid, leukemia, cervix, and brain tumors (5)(6)(7)(8)(9)(10)(11)(12)(13)(14). Furthermore, partial removal of sialic acids on cell surface has also been shown to increase both cell adhesion and aggregation in the pancreatic cancer cells (15), which confirmed that sialylation indeed contributes to cell metastasis.…”