Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously reported a hamster animal model of melanoma in which the tumor tissue expresses gangliosides GM3, GD3, and O-acetyl GD3. This ganglioside pattern is similar to that in human melanomas (Ren, S., A. Slominski, and R. K. Yu. 1989 Cancer Res. 49: 7051). In this study, we isolated and purified these gangliosides using chloroform-methanol extraction, Folch partition, chromatographies on DEAE-Sephadex A-25, and Iatrobeads columns. The yields of gangliosides GM3, GD3, and O-acetyl GD3 were 44.1 mg, 19.6 mg, and 9 mg per 100 g of Ma melanotic melanoma tissues, respectively. The structures of these gangliosides were characterized by periodate oxidation, gas chromatographic (GC) analysis, fast-atom bombardment-mass spectrometry (FAB-MS), and nuclear magnetic resonance (NMR) studies. The structure of hamster melanoma O-acetyl GD3 is different from the 9-O-acetyl GD3 previously reported in human melanoma. The major fatty acids of this ganglioside are C16:0, C18:0, C20:0, C22:0, and C24:0 and the long-chain base is C18-sphingosine.
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PMID:Characterization of a hamster melanoma-associated ganglioside antigen as 7-O-acetylated disialoganglioside GD3. 822 39

The expression of N-glycolylneuraminic acid (NeuGc)-containing gangliosides in human melanoma cells grown both in culture and as xenografts in athymic (nu/nu) mice was analyzed extensively with specific mouse monoclonal antibodies (MAbs). Three MAbs (GMR8, GMR14, and GMR3) specific for GM3(NeuGc), GM2(NeuGc), and GD3(NeuGc-NeuGc-), respectively, were used. Significant differences were observed in the ganglioside compositions between the cultured cells in vitro and the tumors grown in vivo. The major difference was that the cells cultured in serum-free medium did not express any NeuGc-containing gangliosides, whereas those grown in nude mice expressed a number of NeuGc-containing gangliosides, namely GM3(NeuGc), GM2(NeuGc), GD3(NeuAc-NeuGc-), GD3(NeuGc-NeuAc-), and GD3(NeuGc-NeuGc-). The structures of these gangliosides were also determined chemically. No activity of CMP-NeuAc hydroxylase was demonstrated either in the melanoma cells cultured in vitro or in those grown in nude mice, suggesting that these cells incorporated NeuGc-containing glycoconjugates from the mouse sera and converted them to other NeuGc-containing gangliosides. The mouse sera contained only GM2(NeuGc), but not the other NeuGc-containing gangliosides or any NeuAc-containing gangliosides.
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PMID:Characterization of ganglioside expression in human melanoma cells: immunological and biochemical analysis. 826 98

The fate of anti-tumor monoclonal antibodies (mAbs) after binding to the cell surface is one of the important factors for application of mAbs in therapy. For mAbs to remain on the cell surface for a long time is preferable character for complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC). On the other hand, quick internalization of mAbs into cytoplasm is advantageous for cytotoxic effects of toxins or cytotoxic drugs conjugated with mAbs. In this study we investigated the localization of anti-carbohydrate mAbs in vitro by immunocytochemical methods at the electron microscopic level. Anti-ganglioside GM3 mAb (mouse IgM) was localized both in cytoplasmic vesicles and on the cell surface membrane of mouse melanoma cells after incubation for 30 min at 37 degrees C. Anti-ganglioside GM2 mAb (mouse IgM), anti-ganglioside GD2 mAb (mouse IgG3) anti-ganglioside GD3 mAb (mouse IgG3) mainly existed on the cell surface of human small cell lung carcinoma cells, human neuroblastoma cells and human melanoma cells, respectively, after incubation for 30 min at 37 degrees C. On the other hand, anti-sialyl Lea mAb (mouse IgG1) was intensively incorporated into the cytoplasm of human colon tumor cells under the same conditions. Anti-ganglioside GD3 mAb and anti-sialyl Lea mAb were radiolabelled with 125Iodine and traced in in vitro culture. When the cells were incubated in the presence of the 125I-mAb for 90 min on ice, the ratio of intracellular counts to surface counts was 8/92 for anti-ganglioside GD3 mAb and 31/69 for anti-sialyl Lea mAb respectively. After the subsequent incubation for 60 min at 37 degrees C, the ratio altered to 13/87 for anti-ganglioside GD3 mAb and 54/46 for anti-sialyl Lea antigen mAb. This study suggested that internalization of anti-carbohydrate mAbs after the binding to the cell surface was different among the mAbs depending on the character of antigens. In conclusion, anti-ganglioside mAbs have beneficial characters for CDC or ADCC while anti-sialyl Lea mAb is suitable for immunoconjugates.
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PMID:Immunocytochemical study on internalization of anti-carbohydrate monoclonal antibodies. 829 35

beta-D-Xylosides are often used to competitively inhibit proteoglycan synthesis by serving as primers for free glycosaminoglycan (GAG) chain assembly. Quite unexpectedly, we found that when human melanoma cells and Chinese hamster ovary cells are labeled with [3H] galactose in the presence of 4-methyl umbelliferyl beta-D-xyloside (Xyl beta 4MU), a large portion of the labeled acceptor does not consist of the expected GAG chains, but of the novel GM3 ganglioside-like structure: Sia-alpha 2,3-[3H]Gal beta 1, 4Xyl beta 4MU. Moreover, formation of this derivative is associated with an inhibition of glycosphingolipid synthesis by up to 78% without affecting synthesis of other [3H]Gal-labeled glycoconjugates. Inhibition occurs rapidly and equally for all glycolipid species and is partially abrogated by brefeldin A. Inhibition requires the addition of a single galactose residue to the xyloside within the lumen of the Golgi apparatus. This addition appears to be carried out by galactosyl transferase I that normally synthesizes the core region of GAG chains. Although alpha-xyloside does not inhibit proteoglycan synthesis, it is galactosylated, but not sialylated, and is nearly as effective as a beta-xyloside at inhibiting glycolipid biosynthesis. Similar results were obtained for human macrophage U937, and differentiated or undifferentiated PC12 cells. However, in neuroblastoma cell line MR23, no low molecular weight xyloside products were made and glycolipid synthesis was not inhibited. These results suggest that some of the previously documented effects of beta-xylosides might result, in part, from their inhibition of glycolipid synthesis. The mechanism of inhibition is not a direct competition for glycolipid synthesizing enzymes; rather, it is an unexplained result of formation of Gal beta 1,4Xyl-1 (alpha or beta)4MU.
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PMID:Alpha- and beta-xylosides alter glycolipid synthesis in human melanoma and Chinese hamster ovary cells. 842 Sep 36

The ganglioside composition of 20 human malignant melanomas and 5 normal tissues (muscle, spleen, kidney, liver and brain) was analyzed by high-performance thin-layer chromatography (HPTLC) and immune HPTLC using a panel of antiganglioside monoclonal antibodies, and quantified by photodensitometry. The most prominent gangliosides were GM3 and GD3, present in all 20 melanomas; however these were expressed in the 5 normal tissues as well. GD2, GM2, GT3 and 9-O-Ac-GD3 were each expressed in at least 17 of 20 melanomas, but distribution on the normal tissues examined was largely restricted to brain. The detection of several additional glycolipids was studied. GMI was highly expressed in normal brain tissue, but was not detected in any melanoma biopsies, and SGPG was detected in neither. Fuc-GMI was identified in 3 melanoma specimens and a base-sensitive ganglioside, not previously identified in melanoma, was detected in 4 of 20 melanomas with the anti-GD2 MAb 3F8. This compound is most likely O-acetylated GD2. GD3 lactones were identified in 16 of 20 melanoma biopsies, however the proportion that are naturally occurring rather than artifacts of extraction is unclear. The total expression of the more restricted gangliosides (GM2, GD2, GT3 and 9-O-Ac-GD3) in these 20 melanomas ranged between 2.4 and 102.5 micrograms/g, representing 8 x 10(6) to 3 x 10(8) ganglioside molecules per cell. This number of tumor-surface antigens provides the rationale for a polyvalent anti-melanoma vaccine containing GM2, GD2, GT3 and 9-O-Ac-GD3.
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PMID:Ganglioside expression on human malignant melanoma assessed by quantitative immune thin-layer chromatography. 843 30

The melanoma-associated disialogangliosides 9(7)-O-acetyl-GD3 and 9(7)-O-acetyl-GD2 have been structurally well characterized. However, the compartmentalization and sequence of action of the biosynthetic activities responsible for synthesizing these molecules remain obscure. Here, we have studied the spatial and temporal interrelationships among the activities responsible for the later stages of ganglioside biosynthesis and those for O-acetylation in cultured human melanoma cells. First, brefeldin A treatment was used to separate biosynthetic steps into compartments distal or proximal to the transport block imposed by the drug. In keeping with prior reports, GM2/GD2 synthase was consistently rendered inaccessible to its acceptors GM3 and GD3. In contrast, the effect on GD3 biosynthesis was cell line-specific. Synthesis of GD3 was nearly abrogated in two lines, while it accumulated in a third line. This indicates that the spatial organization of ganglioside processing activities can vary even between similar cell lines. However, in all cell lines studied, the ratio of 9(7)-O-acetyl-GD3 to GD3 was not changed by brefeldin A, indicating that the majority of ganglioside O-acetyltransferase activity is co-localized with GD3 biosynthetic activity in the same Golgi subcompartment(s). As an alternative approach, Golgi-enriched fractions from melanoma cells were incubated with radiolabeled and nonlabeled nucleotide sugars or acetyl-CoA. In these preparations, biosynthesis is dependent upon the co-localization of appropriate sugar nucleotide transporters, glycosyltransferases, and acceptors that are endogenously present within intact topologically correct compartments. Incubations with CMP-Neu5Ac and acetyl-CoA corroborated the results with brefeldin A, co-localizing ganglioside O-acetyltransferase activity in compartments where GD3 biosynthesis takes place. Analyses with CMP-Neu5Ac and UDP-GalNAc showed that GD2 and GD3 synthesis occur in partially overlapping compartments. Labeling with acetyl-CoA and UDP-GalNAc indicated that although labeled acetate can be transferred from acetyl-CoA directly to GD2, ganglioside O-acetyltransferase activity does not substantially overlap with the biosynthetic compartment(s) for GD2. Instead, O-acetyl-GD3 appears to be co-localized with the compartment of GD2 biosynthesis and serves as an acceptor for GD2 synthase. Thus, both 9-O-acetyl-GD3 and GD2 can be precursors of 9-O-acetyl-GD2, but apparently in distinct compartments.
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PMID:Kinetic and spatial interrelationships between ganglioside glycosyltransferases and O-acetyltransferase(s) in human melanoma cells. 848 86

In vitro immunization of human B-lymphocytes was performed with liposomes containing the monosialoganglioside GM3, with or without either complete tetanus toxoid or a synthetic T helper epitope derived from tetanus toxin (determinant 830-843). The immunized B-cells were Epstein-Barr virus transformed and the human anti-ganglioside antibody response was evaluated using an indirect ELISA against different mono- and disialogangliosides. Clones producing antigen-specific human antibodies of the IgM isotype against the ganglioside GM3 used as the immunogen were selected and one clone, IM-11, was further characterized. In addition, a method of positive selection using GM3-coated magnetic beads has been developed which allowed us to rescue unstable clones. The binding of the human antibody IM-11 to a large panel of glycosphingolipids separated on thin-layer plates was studied. The human MAb IM-11 was found to bind strongly to NeuAcGM3, IV3 NeuAcnLc4 and sulfate containing glycosphingolipids and weakly to NeuGcGM3. Immunohistological staining of melanoma and breast cancer biopsy sections showed a selective reactivity of IM-11 with tumor cells which varied among different tumors.
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PMID:Antigen-specific primary immune response of human B-lymphocytes after in vitro immunization with GM3 ganglioside. 859 25

This paper describes the homeostasis of glycosphingolipid (GSL) on the cell surface as revealed for the first time by an application of endoglycoceramidase (EGCase) capable of hydrolyzing the linkage between the oligosaccharide and the ceramide of various GSLs. When cell-surface GSLs of B16 melanoma cells were hydrolyzed by the action of EGCase, the synthesis of GSLs was found to increase transiently, possibly due to activation of UDP-glucose:ceramide glucosyltransferase. As a result, the cell-surface GSL content was restored quickly to exactly the same level found without the EGCase treatment, if EGCase was removed from the cell culture. Treatment of erythrocytes with EGCase caused the suppression of de novo ceramide production, resulting in maintenance of the ceramide content of B16 cells at the same level even after EGCase treatment. The signal for homeostatic regulation could be the ceramide release found to mimic in part the action of EGCase; it suppressed de novo production of ceramide and was directly converted to GSL, NeuAc alpha 2,3GAl beta 1,4Glc beta 1,1 N-acetylsphingosine (C2-ceramide GM3). Our finding demonstrates a novel form homeostatic regulation coupled to the GSL-synthesizing system in mammalian cells for maintaining the contents of both cell-surface GSLs and free ceramide. Since many opportunistic pathogens were found to produce EGCase extracellularly, this restoration mechanism could also be present as a defense mechanism against microbial EGCase.
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PMID:Homeostasis of cell-surface glycosphingolipid content in B16 melanoma cells. Evidence revealed by an endoglycoceramidase. 864 78

Different approaches to generating human monoclonal antibodies (MAbs) against tumor-associated ganglioside antigens have been carried out in several laboratories. A specific goal addressed by our laboratory is to produce human MAbs to several ganglioside antigens of relevance as therapeutic targets, such as the GM2, GD2, GD3 and GM3 gangliosides in melanoma. In vitro immunization of human B lymphocytes from normal donors was performed using liposomes containing gangliosides as the immunizing antigen combined with either complete tetanus toxoid or a synthetic peptide corresponding to a T helper epitope to stimulate in vitro immunization. Specific human anti-ganglioside antibodies were obtained, indicating that the antibody response found in vitro was antigen-driven. To overcome the widely reported problems concerning stability of immunoglobulin production by the antibody-secreting cell lines, a method of positive selection using GM3-coated magnetic beads has been developed in order to rescue unstable clones. Development of new methods to reproducibly generate ganglioside-specific human MAbs will amplify the possibilities for diagnostic and therapeutic applications.
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PMID:Generation of human monoclonal antibodies against ganglioside antigens and their applications in the diagnosis and therapy of cancer. 867 58

Mouse monoclonal IgM antibody (MAb 202) can cause melanoma cell necrosis in vivo. We analysed its immune mechanism in three melanoma patients to whom MAb 202 was administered. After the MAb 202 administration, histopathological analysis showed necrosis of melanoma cells expressing only GM3 in two patients. Another patient carrying both GM3 and GD3 showed infiltration of lymphocytes within the tumor nest but no tumor cells or nest necrosis. Immunohistological examination using anti-mouse IgM antibody revealed MAb 202 bound on the surface of melanoma cells in two patients but not in the third (positive for both GM3 and GD3). In vitro, MAb 202 reacted with the melanoma cells of the same two patients, but not with any other tissues of these individuals. We found no reaction of MAb 202 to non-melanoma cells including normal melanocytes and glia cells. Our trials suggest, 1) MAb 202 reacts directly to monosialogangliosides on the melanoma cell surface and then leads to the cytotoxicity reaction, or 2) MAb 202 induces lymphocyte infiltration and possibly then promotes the secretion of some cytokines.
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PMID:Immunohistological reaction mechanism of anti-monosialoganglioside monoclonal antibody, MAb 202, showing predominant cytotoxicity for malignant melanoma. 869 82


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