Human cytomegalovirus induces stage-specific embryonic antigen 1 in differentiating human teratocarcinoma cells and fibroblasts.

Cell surface expression of stage specific embryonic antigen 1 (SSEA-1), or Lex (III3 FucnLC4), was induced in differentiated human teratocarcinoma cells and in human diploid fibroblasts 3-6 d after infection with human cytomegalovirus (HCMV). In parallel, fucosylated lactoseries glycolipids bearing the SSEA-1/Lex epitope were readily detected in the infected cells but not in the uninfected cells. HCMV infection also results in altered expression of several glycosyltransferases. SSEA-1/Lex induction is probably a consequence of both increased expression of beta 1----3N-acetylglucosaminyltransferase, which catalyzes the rate-limiting step in lactoseries core chain synthesis, and subtle alterations in the relative competition for common precursor structures at key points in the biosynthetic pathway. Since SSEA-1 has been suggested to play a role in some morphogenetic cell-cell interactions during embryonic development, the induction of this antigen at inappropriate times might provide one mechanism whereby intrauterine infection with HCMV can damage the developing fetal nervous system

Glycotope structures and intramolecular affinity factors of plant lectins for Tn/T antigens

B

Characterization of a glycosphingolipid antigen defined by the monoclonal antibody MBr1 expressed in normal and neoplastic epithelial cells of human mammary gland

The antigen defined by a monoclonal antibody, MBr1, was found to be expressed in normal human mammary gland epithelia and human mammary carcinoma cells (Menard, S., Tagliabue, E., Canevari, S., Fossati, G., and Colnaghi, M. I. (1983) Cancer Res. 43, 1295-1300). The antigen has been isolated from breast cancer cell line MCF-7, which was used as immunogen, and its structure was determined by methylation analysis, NMR spectroscopy, direct probe mass spectrometry, and enzymatic degradation as identified below. Fuc alpha 1----2Gal beta 1----3GalNAc beta 1----3Gal alpha 1----4Gal beta 1----4Glc beta 1----1Cer The antibody cross-reacted weakly with fucosylasialo-GM1 (IV2FucGg4), which shares the same terminal sequence, Fuc alpha 1----2Gal beta 1----3GalNAc, with this antigen. However, various other structures, including lacto-series H structure (Fuc alpha 1----2 Gal beta 1----4/or 3GlcNAc beta 1----3Gal), did not show any reactivity with this antibody. Therefore, this antigen represents a blood group H antigen with a globo-series structure which is abundant in human teratocarcinoma (Kannagi, R., Levery, S. B., Ishigami, F., Hakomori, S., Shevinsky, L. H., Knowles, B. B., and Solter, D. (1983) J. Biol. Chem. 258, 8934-8942), although its presence must be limited in normal adult human tissue

Expression of GD2 and GD3 gangliosides in human embryonic neural stem cells

NSCs (neural stem cells) are undifferentiated neural cells endowed with a high potential for proliferation and a capacity for self-renewal with retention of multipotency to differentiate into neurons and glial cells. It has been recently reported that GD3, a b-series ganglioside, is a marker molecule for identifying and isolating mouse NSCs. However, the expression of gangliosides in human NSCs is largely unknown. In the present study, we analysed the expression of gangliosides, GD2 and GD3, in human NSCs that were isolated from human brains at gestational week 17 in the form of neurospheres, which are floating clonal aggregates formed by NSCs in vitro. Employing immunocytochemistry, we found that human NSCs were strongly reactive to anti-GD2 antibody and relatively weakly reactive to anti-GD3 antibody. Treatment of these cells with an organic solvent such as 100% methanol, which selectively removes glycolipids from plasma membrane, abolished the immunoreactivity with those antibodies, indicating that the reactivity was due to GD2 and GD3, but not to GD2-/GD3-like glycoproteins or proteoglycans. The immunoreactivity of human NSCs to antibody against SSEA-1 (stage-specific embryonic antigen-1), a well-known carbohydrate antigen of NSCs, was not decreased by the treatment with 100% methanol, indicating that SSEA-1 is mainly carried by glycoproteins and/or proteoglycans in human NSCs. Our study suggests that GD2 and GD3 can be marker gangliosides for identifying human NSCs

Phenotypic changes in 3T3 cells associated with the change of sphingolipid synthesis by a ceramide analog, 2-decanoylamino-3-morpholino-1-phenylpropanol (compound RV538)

A culture of BALB/c 3T3 cells grown in the presence of 40 [mu]M of the ceramide analog compound RV538 (2-decanoylamino-3-morpholino-1-phenylpropanol) for several passages caused a substantial decrease in the level of all glycosphingolipids and an accumulation of ceramide and sphingomyelin. Associated with these chemical changes of sphingolipid composition and metabolism, the following phenotypic changes were observed: (i) loss of the cobblestone appearance at cell density saturation and development of fibroblastic appearance with partial overlapping of cells; (ii) reduction of cell growth rate; (iii) enhanced production of lactic acid; (iv) enhanced rate of glucose transport; and (v) higher incidence of large colony formation with infiltrating appearance in soft agar. Cell morphology changes, lactate pruduction, and enhanced sugar uptake were reversed by co-culturing cells with gangliosides, particularly trisialogangliosides. Thus, these phenotypic changes mimicking those of oncogenically transformed cells are closely related to the blocked synthesis of glycolipids in these cells, whereas other changes may be caused by an accumulation of ceramide and sphingomyelin.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27183/1/0000186.pd

Effects of the glucolipid synthase inhibitor, P4, on functional and phenotypic parameters of murine myeloma cells

This study describes the effects of the glucolipid synthase inhibitor P4, (DL-threo-1-phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol), on various functional and phenotypic parameters of 5T33 murine myeloma cells. Cell recovery was reduced by >85% following incubation of the cells for 3 days in the presence of 4 μM P4 (the IC50 concentration). Both cytostatic and cytotoxic inhibition was observed with tumour cell metabolic activity and clonogenic potential reduced to 42% and 14% of controls, respectively, and viability reduced to 52%. A dose-dependent increase in cells undergoing apoptosis (from 7% to 26%) was also found. P4 induced a decrease in the number of cells expressing H-2 Class I and CD44, and a large increase in cells expressing H-2 Class II and the IgG2b paraprotein. It did not affect surface expression of CD45 or CD54 (ICAM-1). Based on these alterations in tumour cell growth, adhesion molecule expression and potential immunogenicity, it is anticipated that P4 will provide a novel therapeutic approach for the treatment of multiple myeloma. In addition, given that essentially all tumours rely heavily on overexpressed or abnormal glucosphingolipids for growth, development and metastasis, glucolipid synthase inhibitors may prove to be universally effective anti-cancer agents. © 1999 Cancer Research Campaig

Lewis X antigen mediates adhesion of human breast carcinoma cells to activated endothelium. Possible involvement of the endothelial scavenger receptor C-Type lectin

Lewis x (Lex, CD15), also known as SSEA-1 (stage specific embryonic antigen-1), is a trisaccharide with the structure Galβ(1–4)Fucα(1–3)GlcNAc, which is expressed on glycoconjugates in human polymorphonuclear granulocytes and various tumors such as colon and breast carcinoma. We have investigated the role of Lex in the adhesion of MCF-7 human breast cancer cells and PMN to human umbilical endothelial cells (HUVEC) and the effects of two different anti-Lex mAbs (FC-2.15 and MCS-1) on this adhesion. We also analyzed the cytolysis of Lex+-cells induced by anti-Lex mAbs and complement when cells were adhered to the endothelium, and the effect of these antibodies on HUVEC. The results indicate that MCF-7 cells can bind to HUVEC, and that MCS-1 but not FC-2.15 mAb inhibit this interaction. Both mAbs can efficiently lyse MCF-7 cells bound to HUVEC in the presence of complement without damaging endothelial cells. We also found a Lex-dependent PMN interaction with HUVEC. Although both anti-Lex mAbs lysed PMN in suspension and adhered to HUVEC, PMN aggregation was only induced by mAb FC-2.15. Blotting studies revealed that the endothelial scavenger receptor C-type lectin (SRCL), which binds Lex-trisaccharide, interacts with specific glycoproteins of Mr␣∼␣28 kD and 10 kD from MCF-7 cells. The interaction between Lex+-cancer cells and vascular endothelium is a potential target for cancer treatment.Fil: Elola, Maria Teresa. Fundación Instituto Leloir; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Capurro, Mariana Isabel. University of Toronto; CanadáFil: Barrio, Maria Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Investigación, Docencia y Prevención del Cáncer; ArgentinaFil: Coombs, Peter J.. Imperial College London; Reino UnidoFil: Taylor, Maureen E.. Imperial College London; Reino UnidoFil: Drickamer, Kurt. Imperial College London; Reino UnidoFil: Mordoh, Jose. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Investigación, Docencia y Prevención del Cáncer; Argentin