Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0006142 (breast cancer)
 160,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to develop reagents that can detect the exposed core carbohydrate antigens of mucins, we have prepared monoclonal antibodies against partially deglycosylated LS174T human colon cancer mucin. The three monoclonal antibodies, 10F4, 15D3a, and 91S8, stained cancers of the colon, pancreas, stomach, breast, prostate, and lung to a greater extent than corresponding normal tissues. There was no staining of normal pancreas or breast, suggesting that these antibodies may be particularly useful for detecting cancers in these two organs. In homogenates of cultured cancer cells, antigen was detectable in three colon cancer cell lines, but not in a variety of other epithelial cancers. The epitope specificity of all three monoclonal antibodies appears to be for Tn antigen, i.e. GalNAc-alpha-Ser/Thr, based on their recognition of alpha-linked GalNAc, but not T antigen, sialyl Tn, or a range of other structures. However, the three anti-Tn antibodies differed in tissue staining specificity and in relative binding to different mucins. These monoclonal antibodies, prepared against deglycosylated colon cancer mucin, appear to be useful reagents for the immunohistochemical detection of epithelial cancers, especially pancreatic cancer and breast cancer.
 ...
PMID:Monoclonal antibodies against partially deglycosylated colon cancer mucin that recognize Tn antigen. 128 Oct 60

The breast cancer-associated epitope (mammary serum antigen or MSA) defined by monoclonal antibody (Mab) 3E1.2 is a neuraminidase-sensitive carbohydrate expressed on MUC-1-encoded molecules. However, the reactivity of Mab 3E1.2 is also reduced by protease treatment of the mucin, which suggests that 3E1.2 binds to multimers of the sialylated carbohydrate in a protein conformation-dependent manner. The common N-acetyl derivative of neuraminic acid (5-acetylneuraminic acid) is not involved in the epitope, since lectins specific for 5-acetylneuraminic acid (linked to GalNAc or Gal) are nonreactive with MSA-positive molecules. However, the N-glycolyl derivative, 5-glycolylneuraminic acid (Neu5Gc), forms a major part of the epitope since both free Neu5Gc and porcine stomach mucin (greater than 90% neuraminic acid as Neu5Gc) inhibit the binding of Mab 3E1.2, while bovine or ovine submaxillary mucins, fetuin, bovine gangliosides, and other carbohydrates do not. Indeed, the presence of Neu5Gc on human tumor mucin was confirmed by electrospray mass spectrometry. Neu5Gc is attached to an O-linked carbohydrate, since the expression of MSA by MCF-7 breast cancer cells is inhibited by the O-glycosylation inhibitor phenyl-N-acetyl-alpha-D-galactosaminide, but not by the N-glycosylation inhibitor tunicamycin, and the epitope is removed by treatment with O-glycanase but not N-glycanase F, endoglycosidase F, or endoglycosidase H, which are specific for N-linked glycans. This is likely to be a core glycan since 3E1.2 reacts after treatment of the mucin with trifluoromethanesulfonic acid, which removes most backbone and peripheral carbohydrates. Treatment with galactosidase or N-acetyl glucosaminidase enhances the binding of Mab 3E1.2, indicating that the Neu5Gc is not attached to galactose or N-acetyl galactosamine. Furthermore, the susceptibility of MSA to treatment with Arthrobacter urea-faciens neuraminidase [which is specific for alpha (2-6)-linked NeuNAc] and the loss in reactivity of GalNAc-specific lectins after periodate oxidation [alpha (2-3)-linked but not alpha (2-6)-linked NeuNAc protects GalNAc from periodate oxidation] indicate that the Neu5Gc may be attached alpha (2-6) to peptide-linked GalNAc. These results show that MSA is a Neu5Gc-containing O-linked core glycan, which represents a unique tumor-associated epitope not previously identified on human mucins.
 ...
PMID:The breast tumor-associated epitope defined by monoclonal antibody 3E1.2 is an O-linked mucin carbohydrate containing N-glycolylneuraminic acid. 171 85

Two monoclonal antibodies, TKH1 and TKH2, directed toward the sialosyl-Tn structure (NeuAc alpha 2----6GalNAc alpha 1----O-Ser or Thr), which display a remarkable immunohistological tumor specificity, were generated by immunization with ovine submaxillary mucin. The reactivity of these antibodies was monitored by solid phase enzyme-linked immunosorbent assay with different native and glycosidase-treated mucins and glycoproteins. Binding of the antibody to ovine submaxillary mucin glycoprotein was strongly inhibited by the O-linked disaccharide NeuAc alpha 2----6GalNAc alpha 1----O-serine, less strongly by NeuAc alpha 2----6GalNAc beta 1----O-propyl, and weakly by the monosaccharide GalNac. The reactivity was compared with previously established anti-Tn antibodies B72.3, NCC-Lu-35, and NCC-Lu-81. The antibody B72.3 was prepared previously after immunization with metastatic breast adenocarcinoma and its epitope was claimed to be GalNAc alpha 1----O-Ser (or - Thr) by Springer and associates [Springer, G.F., et al. In: T. Dao, et al. (eds.), Tumor Markers and Their Significance in the Management of Breast Cancer, pp. 47-70. New York: A.R. Liss, 1986]. The antibody was found to show very similar reactivity as that of TKH1/TKH2, and its reactivity to ovine submaxillary mucin was inhibited specifically by NeuAc alpha 2----6GalNAc alpha 1----O-serine, indicating that the antibody is clearly directed to sialosyl-Tn antigen. Immunohistological study of the distribution of this antigen in various normal human tissues and carcinomas by TKH1/TKH2 antibodies, as well as B72.3 and monoclonal antibodies NCC-Lu-35/81, which are directed to GalNAc alpha 1----O-Ser or Thr (Tn), was performed. The sialosyl-Tn antigen was not found in normal tissue except for a weak expression in Leydig cells of the testis, goblet cells of the colon, and parietal cells of the stomach. In contrast, the sialosyl-Tn antigen was strongly expressed in a large number of adenocarcinomas. As expected from the specificity studies, B72.3 shows the same reactivity as TKH1 and TKH2. Thus, both sialosyl-Tn (NeuAc alpha 2----6GalNAc alpha 1----O-Ser/Thr) and Tn (GalNAc alpha 1----O-Ser/Thr) are good tumor markers, and combined use of antibodies directed to these structures might be useful in the screening and classification of cancer.
 ...
PMID:Preparation and characterization of monoclonal antibodies directed to the tumor-associated O-linked sialosyl-2----6 alpha-N-acetylgalactosaminyl (sialosyl-Tn) epitope. 245 Jun 49

1. In previous studies we have isolated and characterized mucin-type glycopeptides from mouse and human melanoma cells. 2. These glycopeptides have clusters of oligosaccharides of the type (NeuNAc)0-2----[Gal----GalNAc] linked to serine and or threonine suggesting an apparent similarity to glycophorin. 3. We now report the interaction of polyclonal anti-glycophorin antibodies with various cultured cells. Antisera to highly purified glycophorin A were raised in rabbits. 4. Human melanoma cells (HM7), human breast cells (HBL-100) and two lines of human breast cancer cells (MCF-7 and MDA-MB-231) showed medium to very strong cell surface fluorescence pattern after staining with rabbit anti-glycophorin F(ab')2 and FITC-conjugated goat anti-rabbit F(ab')2. 5. Immunodiffusion, immunoelectrophoresis and affinity chromatography on anti-glycophorin IgG-Sepharose 4B of detergent extracts of metabolically labeled cultured cells gave further evidence for the presence of glycophorin-like components in these cells. 6. Glycoproteins of MCF-7 cells interacting with anti-glycophorin antibodies were affinity purified and partially characterized.
 ...
PMID:Detection of glycophorin A-like glycoproteins on the surface of cultured human cells. 250 71

Lymph node lymphocytes from patients with primary lung cancer were immortalized with Epstein-Barr virus, and culture supernatants were screened for cell-surface reactivity against allogeneic cancer cell lines. The percentage of wells containing detectable antibodies in initial screening ranged from 1 to 17%, but the vast majority of the cultures lost antibody activity on subsequent expansion. Two antibody-secreting clones, J309 and D579, derived from separate individuals and reactive with anaplastic lung cancer cell lines, were successfully expanded and fused with the NS-1 mouse myeloma cell line. The antibodies produced by these clones exhibited identical restricted serologic reactivity against cultured cell lines and detected a carbohydrate antigen present in the neutral glycolipid fraction of MCF-7 breast cancer cells. Serologic, immunochemical, and chemical analyses revealed that the antigen recognized by antibodies J309 and D579 is galactosylgloboside [Gal(beta 1----3)GalNAc(beta 1----3)Gal(alpha 1----4)Gal(beta 1----4)- GlcCer]. Conclusions regarding the significance of these findings with respect to the biology of lung cancer await further information concerning the distribution of galactosylgloboside in normal and malignant tissues and the frequency of antibodies to this structure in normal and tumor-bearing individuals.
 ...
PMID:Recognition of galactosylgloboside by monoclonal antibodies derived from patients with primary lung cancer. 283 67

The glycosyl nature of the receptor for the peptide hormone calcitonin has been investigated in a human breast cancer cell line, T 47D. Studies have been carried out to assess the ability of various lectins and of the antibiotic tunicamycin to inhibit specific binding of calcitonin to the cells, to reduce cross-linking of photoactive calcitonin to a macromolecular receptor component and to influence calcitonin stimulation of cyclic AMP. Pre-incubation of cells with low concentrations of tunicamycin for 72 h resulted in a reduction of total specific binding by approx. 80% and a 40% reduction in calcitonin-stimulated adenylate cyclase; formation of the cross-linked receptor component was also inhibited. Wheat-germ lectin showed the most marked inhibition of total specific binding and cyclic AMP production. However, cross-linking of photoactive calcitonin to receptor component was totally inhibited by this lectin. Soya-bean lectin brought about very little reduction in total specific binding but had more profound effects on calcitonin-stimulated cyclic AMP production and cross-linking of photoactive calcitonin. Concanavalin A and lentil lectin showed some inhibition of all parameters. The data indicate that the calcitonin receptor in T 47D cells is associated with glycosyl moieties, the major contributors of which are N-acetyl-D-glucosamine residues, but N-acetyl-D-galactosamine and mannose residues are also associated.
 ...
PMID:The calcitonin receptor on T 47D breast cancer cells. Evidence for glycosylation. 630 49

Several investigators have shown that the expression of the sialyl-Tn (STn) epitope on cancer associated mucins is associated with a poor prognosis in several human cancers suggesting that STn may have functional significance in metastasis. We postulate that antibodies against the STn-epitope can inhibit metastasis. We generated a synthetic "mimic", NANA alpha (2-->6)GalNAc alpha-O-Crotyl (STn-crotyl), of the natural O-linked epitope on mucins, NANA alpha (2-->6)GalNAc alpha-O-Serine (STn-serine). STn-crotyl was conjugated to the carrier protein KLH through the crotyl linker arm and a "vaccine" containing STn-KLH plus Detox adjuvant was formulated. The immunogenicity of the vaccine was evaluated in BALB/c mice and in metastatic breast cancer patients. The specificity and titres of IgG antibodies were evaluated by ELISA on ovine submaxillary mucin (OSM) solid phases. OSM is a convenient source of repeating, natural O-linked STn-serine structures. Mice immunized three times with as little as 0.25 microgram of STn-KLH produced a median IgG titre of over 1:5000 on solid phase OSM. Anti-OSM IgG monoclonal antibodies generated from these mice were completely inhibited in their binding to solid phase OSM equally well by STn-serine and STn-crotyl synthetic haptens but not by several other closely related synthetic haptens. Breast cancer patients immunized 2-8 times with 25 or 100 micrograms of the same vaccine produced median peak IgG titres 1:1280 measured on STn-HSA and 1:80 on OSM. Once again, hapten inhibition experiments with the human sera demonstrated the specificities of the IgG antibodies for STn-crotyl and STn-serine, but not against several other related synthetic haptens. We found little or no evidence that the artificial linker arm (crotyl linker) contributed significantly to either the titre or affinity of the antibodies generated in either mice or human breast cancer patients. This suggests that the antibodies recognized the cancer-associated disaccharide NANA alpha (2-->6)GalNAc. Evidence of a clinical response was noted in several of the immunized breast cancer patients with other patients showing prolonged disease stability.
 ...
PMID:Specificity of the IgG response in mice and human breast cancer patients following immunization against synthetic sialyl-Tn, an epitope with possible functional significance in metastasis. 752 78

The Tn determinant (GalNAc alpha-O-Ser/Thr) is expressed by about 90% of human carcinomas, but is cryptic in most normal human tissues. A murine monoclonal antibody (MAb) 83D4, developed following immunization with human breast carcinoma cells, reacts with a Tn-related epitope. In the present study we characterized the glycoprotein antigen identified by 83D4 in the human breast carcinoma cell line MCF-7. We further showed that the 83D4 antigenic determinant is masked in human milk fat globule membranes (HMFGM), and can be exposed upon mild m-periodate treatment after desialylation. Western-blot analysis resolved the 83D4 antigen from MCF-7 into two main components of 120-190 kD and > 500 kD respectively. Non equilibrium pH gradient electrophoresis/SDS PAGE revealed the acidic nature of the reactive glycoproteins (pI 4.43-4.70). 83D4 antigenic activity resolved by CsCl gradient ultracentrifugation layered on a wide range of densities (1.30-1.46 g/ml) including typical densities of mucin-like glycoproteins but also lower densities. The amino acid composition of the antigen, relatively rich in serine but poor in threonine and proline, confirmed the divergence from other mucin-like carcinoma-associated glycoproteins. Dicarboxylic amino acids were abundant, accounting in part for the acidic nature of the molecules. ELISA and Western-blot analysis of the subcellular fractions from MCF-7 cells revealed that the 83D4 antigen is mainly contained in plasma membranes (85%) from which it may be resolved into two broad bands (slow and fast migrating components). These results provide information on a group of breast carcinoma associated glycoproteins related to but different from typical mucins, and provide data on alteration of O-glycosylation in tumor cells.
Breast Cancer Res Treat 1994
PMID:Analysis of a heterogeneous group of human breast carcinoma associated glycoproteins bearing the Tn determinant. 753 64

The expression of complex carbohydrates recognised by Helix pomatia lectin (HPA, nominal monosaccharide binding specificity alpha-GalNAc) has been shown to predict unfavourable prognosis in breast and other cancers. It has been suggested that the prognostic significance of HPA binding may be through recognition of either Tn epitope (alpha-GalNAc-O-serine/threonine) or blood group A antigen (terminal alpha-1-->3GalNAc attached to the basic H-antigen, Fuc-alpha-1-->2-Gal-beta-1-->4(or 3) GlcNAc-->R). In this study, the expression of glycoproteins terminating in alpha-GalNAc residues was investigated immunohistochemically using HPA and two monoclonal antibodies--BRIC 66 (anti-alpha-GalNAc) and BRIC 111 (anti-Tn). In paraffin sections, 74/87 (85%) of breast cancers expressed HPA-binding ligands, while 28/87 (32%) were positive for BRIC 66 binding and 25/87 (29%) expressed Tn. Distribution of staining patterns were distinctive and different with the three markers. BRIC 66, BRIC 111 and HPA binding to glycoproteins derived from breast cancer homogenates and to blood group A and Tn positive glycoproteins in Western blots confirmed the immunohistochemistry data. The results suggest that the prognostic significance of HPA binding in breast cancer is unlikely to be simply through recognition of blood group A antigen or Tn epitope on cancer cells. Breast cancers may express a complex profile of related but distinct glycans sharing similar terminal immunodominant sugar GalNAc, which may be implicated in aggressive biological behaviour.
 ...
PMID:Expression of alpha-GalNAc glycoproteins by breast cancers. 753 16

mAb BW835 (IgG1) has been generated to breast cancer cell lines by alternating injections of MCF-7 or SW-613 cells and has been demonstrated to be of value in the serodiagnosis of mammary carcinoma. BW835 defines a carbohydrate epitope on integrated or secreted MUC1 glycoforms from carcinoma cells and human milk. To identify BW835-reactive glycopeptides on MUC1, proteolytic fragments of the mucin obtained by digestion with the Gly-C-specific endopeptidase IV from papaya corresponding to low molecular mass fragments (< 10 kilodaltons) of the tandem repeat domain were screened. A glycosylated fragment (glycopeptide 17) containing the mAb HMFG-2-defined epitope was highly reactive to BW835 antibody, while nonglycosylated tandem repeat peptide TAP25 or its in vitro-glycosylated N-acetylgalactosamine (GalNAc) derivatives were unreactive. Glycopeptide 17 bound to peanut agglutinin and to a Thomsen-Friedenreich antigen (TF alpha)-specific mAb (A78-G/A7). Binding of BW835 to glycopeptide 17 or to MUC1 was competitively inhibited by peanut agglutinin and by the synthetic glycopeptides TF alpha Ser or TF alpha Thr but not by their beta-anomers. Evidence for site specificity of binding by BW835 to glycopeptide 17 was revealed by demonstrating nonreactivity of the antibody to other TF alpha-expressing glycoproteins with peptide moieties lacking MUC1-specific motifs at putative glycosylation sites. The epitope of BW835 was localized to threonine within the VTSA-peptide motif by site-specific enzymatic beta-galactosylation of the synthetic tandem repeat peptide TAP25-GalNAc1 TAPPAHGVT(-O-alpha GalNAc)SAPDTRPAPGSTAPPA. This is the first report on a TF alpha-specific mAb that shows a strict peptide sequence dependency of binding.
 ...
PMID:Monoclonal antibody BW835 defines a site-specific Thomsen-Friedenreich disaccharide linked to threonine within the VTSA motif of MUC1 tandem repeats. 754 84


1 2 3 4 5 6 7 8 Next >>