Transcriptional Regulation of α1,3-Galactosyltransferase in Embryonal Carcinoma Cells by Retinoic Acid

Abstract

Treatment of mouse teratocarcinoma F9 cells with alltrans-retinoic acid (RA) causes a 9-fold increase in steady-state levels of mRNA for UDP-Gal:␤-D-Gal ␣1,3-galactosyltransferase (␣1,3GT) beginning at 36 h. Enzyme activity rises in a similar fashion, which also parallels the induction of laminin and type IV collagen. Nuclear run-on assays indicate that this increase in ␣1,3GT in RA-treated F9 cells, like that of type IV collagen, is transcriptionally regulated. Differentiation also results in increased secretion of soluble ␣1,3GT activity into the growth media. The major ␣-galactosylated glycoprotein present in the media of RA-treated F9 cells, but not of untreated cells, was identified as laminin. Differentiation of F9 cells is accompanied by an increase in ␣-galactosylation of membrane glycoproteins and a decrease in expression of the stage-specific embryonic antigen, SSEA-1 (also known as the Lewis X antigen or Le X ), which has the structure Gal␤1-4(Fuc␣1-3)GlcNAc␤1-R. However, flow cytometric analyses with specific antibodies and lectins, following treatment of cells with ␣-galactosidase, demonstrate that differentiated cells contain Le X antigens that are masked by ␣-galactosylation. Thus, RA induces ␣1,3GT at the transcriptional level, resulting in major alterations in the surface phenotype of the cells and masking of Le X antigens.

Down-regulation of nucleophosmin/B23 during retinoic acid-induced differentiation of human promyelocytic leukemia HL-60 cells

“…One hundred percent represents the nucleophosmin/B23 protein levels of uninduced cells without dilution tained ability to reduce nitrobluetetrazolium during RA treatment, as compared to the sense oligomertransfected or untransfected HL-60 cells (Table 2). There were decreases of expression of di erentiation marker CD15 during RA-induced di erentiation (Figure 8), as previously reported in RA-induced F9 cells (Cho et al, 1996). The decrease of the expression of CD15 was enhanced by nucleophosmin/B23 antisense oligomer treatment in RA-induced differentiation.…”

Implications of galactocerebrosidase and galactosylcerebroside metabolism in cancer cells

“…1,2,4,5 Glycosphingolipids are known to be increased upon the surface of cancer cells and play an important role in inhibition of cellular adhesion and apoptosis. [6][7][8][9][10][11][12][13] There is currently little explanation for increased levels of glycosphingolipids within the cellular membrane of cancer cells, except one finding of transcriptional repression of the GALC gene in head and neck squamous cell carcinoma (HNSCC), and an increased utilization of ceramide to glycosylated forms in cancer cells stimulated by antineoplastic drugs. [14][15][16] Our article intends to illuminate the mechanisms of GALC suppression as well as other ways of GalCer accumulation and their impact on tumor pathology.…”

A Soluble Form of α1,3-Galactosyltransferase Functions within Cells to Galactosylate Glycoproteins

“…Clonal cell lines were derived from the G418 (400 g/ml)-resistant transfectant population using cloning cylinders. Flow cytometric analyses were performed (27), and a representative clonal line that stably expresses cell surface ␣-galactosylated glycoconjugates was selected and designated fl-␣1,3GT-1.…”

“…The ␣1,3GT is expressed in a variety of mammalian species, but it is not expressed in Old World monkeys, apes, and humans (34,35). The expression of the ␣1,3GT in murine F9 teratocarcinoma cells is transcriptionally up-regulated by retinoic acid induction, but most of the newly synthesized enzyme is eventually secreted into the culture media of the cells (27). The ␣1,3GT is secreted by many cell types, since we have detected soluble forms of the ␣1,3GT in the culture media of all cell lines expressing the enzyme, and we have found enzyme activity in the sera of different animals expressing the functional ␣1,3GT gene (28).…”

“…One enzyme that has recently been shown to be secreted from cultured cells is the murine ␣1,3-galactosyltransferase (␣1,3GT) 1 (27,28), which is responsible for the synthesis of terminal ␣-Gal sequences in Gal␣1 3 3Gal␤1 3 4GlcNAc-R. The murine (29), bovine (30), porcine (31,32), and New World monkey (33) cDNA encoding for ␣1,3GT have been identified.…”