Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to elucidate some of the factors that determine the characteristic expression of gangliosides in malignant melanoma and neuroblastoma the levels of ganglioside synthases (glycosyltransferases) were determined in a panel of cell lines from those tumors that exhibited a wide range of ganglioside composition. Sialyltransferases (GM3, GD3, GD1a, and GT1b synthases), N-acetylgalactosaminyltransferases (GM2 and GD2 synthases), and galactosyltransferase (GM1 and GD1b synthases) were analyzed in crude membrane preparations from these cells. The results confirmed the importance of GM3 and GD3 synthases in determining the prominence of the a (GM3 to GT1a) or b (GD3 to GQ1b) biosynthetic pathways. The overall ganglioside composition in cells was found to be dependent on the relative levels of specific enzymes acting sequentially or in competing pathways. In general, the pattern and levels of transferases correlated with the actual ganglioside content of the cell line, although several important discrepancies were noted. For example, in cell lines containing high amounts of GD2 ganglioside, the level of the preceding enzyme in the pathway (GD3 synthase) was unexpectedly low. Thus, the high GD2:GD3 ratios characteristic of most neuroblastomas result from low levels of GD3 synthase as well as high levels of GD2 synthase. In other cell lines, GD3 synthase was completely absent, resulting in the synthesis of GM2, but not GD2, by N-acetylgalactosaminyltransferase I, as would be expected. It was concluded that different glycosyltransferases play key roles in determining glycolipid expression in different cell types.
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PMID:Glycosylation pathways in the biosynthesis of gangliosides in melanoma and neuroblastoma cells: relative glycosyltransferase levels determine ganglioside patterns. 139 96

Human melanoma cells express high levels of GM3 and GD3 gangliosides whereas normal melanocytes have only low levels of GD3 but maintain their expression of GM3. In order to understand the basis for this difference, the levels of the sialyltransferase that converts GM3 to GD3 (CMP-N-acetylneuraminic acid:GM3 sialyltransferase or GD3 synthase, EC 2.4.99.8) were analyzed in melanoma and other cell lines. Enzyme levels were determined in vitro using membrane preparations and measuring the addition of [14C]-N-acetylneuraminic acid from CMP-[14C]-N-acetylneuraminic acid to GM3 in the presence of Triton CF-54. Sialyltransferase levels in 44 human cancer cell lines (including melanoma, neuroblastoma, astrocytoma, various carcinomas, and leukemias) and cultures of normal melanocytes and kidney epithelial cells were compared, and the products were identified by thin layer chromatography and fluorography. Melanoma cell lines exhibited the highest levels of incorporation and GD3 was found to be the major product. GM3 was also formed, apparently from endogenous lactosylceramide. Very low levels of GD3 synthase were found in normal melanocytes. Neuroblastoma and some astrocytoma cell lines also had significant levels of GD3 synthase. Some other cell lines incorporated high levels of radioactivity but the products did not correspond to GD3 and the major product was usually GM3. In general the levels of GD3 synthase correlated with the expression of GD3 in the various cell types. These results point to higher levels of GD3 synthase being directly responsible for the enhanced expression of GD3 in melanoma.
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PMID:Sialyltransferase levels and ganglioside expression in melanoma and other cultured human cancer cells. 280 71

GD3 Synthase (alpha 2,8sialyltransferase) (EC 2.4.99.8) cDNA has been cloned by eukaryotic cell expression cloning. Using this cDNA as a probe, the expression level of the gene in human cancer cell lines was analysed by Northern blotting and RT-PCR, then correlated with the ganglioside expression and enzyme activity. Melanoma cell lines showed extremely strong bands in Northern blot and RT-PCR/Southern analysis. The enzyme activity was also very high in melanomas as expected. Neuroblastoma and astrocytoma lines showed relatively low levels of the gene expression, whereas they expressed high levels of GD2. Although the mRNA level of the GD3 synthase gene and enzyme activity in individual cell lines correlated positively, some cell lines showed much higher activity than expected from the mRNA level. Among leukaemia lines, adult T cell leukaemia-associated (HTLV-I+) lines showed fairly high levels of the mRNA. On the other hand, T-ALL lines showed very low levels. In addition, GD3 and GD2 expression and mRNA level of the gene during T lymphocyte activation were analysed. Only GD3 expression was induced by any of the stimulatory reagents used, and corresponding up-regulation of the GD3 synthase gene was shown in RT-PCR/Southern analysis.
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PMID:Expression of alpha 2,8-sialyltransferase (GD3 synthase) gene in human cancer cell lines: high level expression in melanomas and up-regulation in activated T lymphocytes. 874 67

Gangliosides have attracted particular attention in the field of brain research, since they were found not only to be abundant in neural tissue but also to have intricate structures in synaptic membranes. A murine neuroblastoma cell line, Neuro2a, expresses negligible amounts of GM3 and b-series gangliosides, but significant amounts of a-series gangliosides (GM1 and GD1a). With the transfection of cDNA encoding GD3 synthase, the de novo synthesis and expression of GD3 and b-series gangliosides occurred, and, furthermore, it induced the growth of axon-like neurites and cholinergic differentiation of Neuro2a cells. On the other hand, with the transfection of an alpha 1,2-fucosyltransferase, the axon-like neurite outgrowth was suppressed and dendrite-like neurites were outgrowth. These observations directly demonstrate the primary importance of the gene expression of a glycosyltransferase, and of the subsequent biosynthesis of gangliosides and their expression on the cell surface for neural cell development and differentiation.
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PMID:New evidence for the occurrence of a glycolipid-mediated signal transduction system. 890 74

The mouse Sia alpha 2,3Gal beta 1, 4GalNAc alpha 2,8-sialyltransferase (ST8Sia III) genomic gene, whose transcripts are only expressed in fetal and newborn brain and testis, was isolated and its 5'-flanking region was analyzed. The gene was found to span about 8 kb and to be composed of only four exons. The genomic ST8Sia III gene is much smaller and its organization much simpler than other sialyltransferase genes so far reported, which span more than 25 kb and comprise seven or more exons. In particular, the sialyl motif L of ST8Sia III, which is a highly conserved region in all cloned sialyltransferases, was in one exon. In contrast, this motif is encoded by discrete exons in the other sialyltransferases. The ST8Sia III gene was highly expressed in the mouse brain and gave rise to at least three transcripts (2.1 kb, 2.4 kb, and 6.5 kb), which differed in the length of their 3'-untranslated regions through the alternative use of different polyadenylation sites. Primer extension and S1 nuclease protection analyses of mRNA prepared from newborn brain revealed that ST8Sia III gene expression started from a unique site at 382 nt upstream of ATG. Although the promoter region lacked an apparent TATA or CCAAT box and potential regulatory motifs, a transfection experiment involving neuroblastoma cells expressing ST8Sia III demonstrated the minimal promoter activity exhibited by the proximal region 418 bp upstream from the ATG codon, which suggests the presence of tissue-specific enhancer elements.
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PMID:Unique genomic structure and expression of the mouse alpha 2,8-sialyltransferase (ST8Sia III) gene. 892 52

It was reported recently by our group that the transfection of GD3 synthase cDNA into Neuro2a cells, a neuroblastoma cell line, caused cell differentiation with neurite sprouting (Kojima et al., 1994; J. Biol. Chem., 269, 30451-30456). To further explore this phenomenon in detail, we applied tetracycline-regulated system to control the expression of GD3 synthase cDNA in Neuro2a cells. Under this system, the process of Neuro2a cell differentiation was rather slow, about 3 weeks of cell culturing in the absence of tetracycline was required for most cells to extend the neurite-like structures. The RNase protection assay indicated that the mRNA of GD3 synthase gene was first detected between 4 h and 8 h after the gene was activated and kept at approximately the same level through the process. Furthermore, time-course analysis of total ganglioside expressions has shown that GD3 and GT1b gangliosides appeared on the cell surface early in the process and reached the maximum level around day 6. We also found that the amounts of GD3 and GT1b on the cell surface started to decrease after day 6 and returned gradually to the basal values after 3 weeks. On the other hand, GQ1b and GD1b were started to be synthesized at early stage and the amounts were continuously to increase through the whole Neuro2a morphological change process. In addition, time-course analysis by flow cytometry method for GD3 and GQ1b suggested that the conversions of simple gangliosides to more complex gangliosides may be required to induce the Neuro2a differentiation. Our results indicated that the combination of cDNA transfection and regulated gene expression is a powerful tool to study the function of glycolipids and should have a general application to the glycobiology field.
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PMID:Regulated expression system for GD3 synthase cDNA and induction of differentiation in Neuro2a cells. 945 7

Most human neuroblastoma tumors are characterized by the high expression of GD2 (or GD2 and/or GM2) gangliosides, whereas melanomas characteristically express GD3 ganglioside. The molecular basis for these patterns was investigated by examining the relationship between ganglioside levels, glycosyltransferase (GM2/GD2 synthase and GD3 synthase) activity, and corresponding mRNA levels in a panel of human neuroblastoma and melanoma cell lines. In general, the ganglioside patterns could be explained by the levels of the transferases and their mRNA, indicating control at the level of transcription. A key role was noted for GD3 synthase. Notably, it was found that neuroblastoma cell lines with high GD2 ganglioside levels had low levels of GD3, its synthase, and mRNA for the enzyme even though this step provides the substrate for GD2 synthesis. The key role for GD3 synthase was also examined by stably transfecting GD3 synthase cDNA into a neuroblastoma cell line (SH-SY5Y) not expressing GD3 and GD2. The resulting cell line had high levels of GD2 ganglioside and altered morphology and growth characteristics.
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PMID:Relationship of glycosyltransferases and mRNA levels to ganglioside expression in neuroblastoma and melanoma cells. 993 Jul 22

Recently, we showed that transfection of GD3 synthase cDNA into Neuro2a cells, a mouse neuroblastoma cell line, causes cell differentiation with neurite sprouting. In a search for the genes involved in this ganglioside-induced Neuro2a differentiation, we used a tetracycline-regulated GD3 synthase cDNA expression system combined with differential display PCRs to identify mRNAs that were differentially expressed at four representative time points during the process. We report here the identification of 10 mRNAs that are expressed highly at the Neuro2a differentiated stage. These cDNAs were named GDAP1-GDAP10 for (ganglioside-induced differentiation-associated protein) cDNAs. It is interesting that in retinoic acid-induced neural differentiated mouse embryonic carcinoma P19 cells, GDAP mRNA expression levels were also up-regulated (except that of GDAP3), ranging from three to >10 times compared with nondifferentiated P19 cells. All the GDAP genes (except that of GDAP3) were developmentally regulated. The GDAP1, 2, 6, 8, and 10 mRNAs were expressed highly in the adult mouse brain, whereas all the other GDAP mRNAs were expressed in most tissues. Our results suggested that these GDAP genes might be involved in the signal transduction pathway that is triggered through the expression of a single sialyltransferase gene to induce neurite-like differentiation of Neuro2a cells.
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PMID:Isolation of 10 differentially expressed cDNAs in differentiated Neuro2a cells induced through controlled expression of the GD3 synthase gene. 1021 54

Gangliosides such as GD3, GM2, and GD2 are abundantly expressed on the cell surfaces of various malignant cells, suggesting the potential for anti-ganglioside antibody therapy for tumors. Anti-ganglioside GD2 antibody treatment is currently undergoing clinical trials for melanoma and neuroblastoma. We previously reported high in vivo antitumor effects of anti-GM2 ganglioside antibody against lung cancer. To determine whether anti-GM2 antibody may be clinically indicated for gastrointestinal cancers, we evaluated the mRNA expression of alpha2,8 sialyltransferase, a GD3 synthase, and beta1,4 N-acetylgalactosaminyltransferase (beta1,4 GalNAc-T), a GM2/GD2 synthase, in gastrointestinal cancers. We performed modified semi-quantitative RT-PCR, which reduces complexity incidental to radiolabeling on samples taken from small surgically removed clinical specimens. Stomach (19/22) and colorectal (21/30) cancers showed decreased expression of alpha2,8 sialyltransferase as compared with respective normal tissues (P < 0.05). In contrast, increased expression of beta1,4 GalNAc-T was detected in both types of tumors. Clinicopathological analysis revealed significantly higher expression level of alpha2,8 sialyltransferase in the poorly differentiated than in the well-differentiated stomach cancer group (P < 0.05). Furthermore, the expression level of alpha2,8 sialyltransferase was significantly decreased in male as compared with female colorectal cancer patients (P < 0.05). These results suggest that expression level of GM2 ganglioside is elevated in gastrointestinal cancer, and that anti-GM2 antibody may be applicable to its treatment.
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PMID:Decreased expression of alpha2,8 sialyltransferase and increased expression of beta1,4 N-acetylgalactosaminyltransferase in gastrointestinal cancers. 1185 18

9-O-Acetylation is a common sialic acid modification, expressed in a developmentally regulated and tissue/cell type-specific manner. The relevant 9-O-acetyltransferase(s) have not been isolated or cloned; nor have mechanisms for their regulation been elucidated. We previously showed that transfection of the GD3 synthase (ST8Sia-I) gene into Chinese hamster ovary (CHO)-K1 cells gave expression of not only the disialoganglioside GD3 but also 9-O-acetyl-GD3. We now use differential display PCR between wild type CHO-K1 cells and clones stably expressing GD3 synthase (CHO-GD3 cells) to detect any increased expression of other genes and explore the possible induction of a 9-O-acetyltransferase. The four CHO mRNAs showing major up-regulation were homologous to VCAM-1, Tis21, the KC-protein-like protein, and a functionally unknown type II transmembrane protein. A moderate increase in expression of the FxC1 and SPR-1 genes was also seen. Interestingly, these are different from genes observed by others to be up-regulated after transfection of GD3 synthase into a neuroblastoma cell line. We also isolated a CHO-GD3 mutant lacking 9-O-acetyl-GD3 following chemical mutagenesis (CHO-GD3-OAc(-)). Analysis of the above differential display PCR-derived genes in these cells showed that expression of Tis21 was selectively reduced. Transfection of a mouse Tis21 cDNA into the CHO-GD3-OAc(-) mutant cells restored 9-O-acetyl-GD3 expression. Since the only major gangliosides expressed by CHO-GD3 cells are GD3 and 9-O-acetyl-GD3 (in addition to GM3, the predominant ganglioside type in wild-type CHO-K1 cells), we conclude that GD3 enhances its own 9-O-acetylation via induction of Tis21. This is the first known nuclear inducible factor for 9-O-acetylation and also the first proof that 9-O-acetylation can be directly regulated by GD3 synthase. Finally, transfection of CHO-GD3-OAc(-) mutant cells with ST6Gal-I induced 9-O-acetylation specifically on sialylated N-glycans, in a manner similar to wild-type cells. This indicates separate machineries for 9-O-acetylation on alpha2-8-linked sialic acids of gangliosides and on alpha2-6-linked sialic acids on N-glycans.
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PMID:Genes modulated by expression of GD3 synthase in Chinese hamster ovary cells. Evidence that the Tis21 gene is involved in the induction of GD3 9-O-acetylation. 1249 56


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