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Query: UMLS:C0006142 (breast cancer)
 160,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The site-selective incorporation of two different fluorophores into a naturally occurring protein (lectin, a sugar-binding protein) has been successfully carried out using two distinct orthogonal chemical methods. By post-photoaffinity labeling modification, Con A, a glucose- and mannose-selective lectin, was modified with fluorescein in the proximity of the sugar binding site (Tyr100 site), and the controlled acylation reaction provided the site-selective attachment of coumarin at Lys114. In this doubly modified Con A, the fluorescein emission changed upon the binding to the corresponding sugars, such as the glucose or mannose derivatives, whereas the coumarin emission was constant. Thus, the doubly modified Con A fluorescently sensed the glucose- and mannose-rich saccharides in a ratiometric manner while retaining the natural binding selectivity and affinity, regardless of the double modification. On the benefit of the ratiometric fluorescent analysis using two distinct probes, the sugar trimming process of a glycoprotein can be precisely monitored by the engineered Con A. Furthermore, the doubly modified Con A can be used not only for the convenient fluorescent imaging of saccharides localized on a cell surface, such as the MCF-7, a breast cancer cell having rich high-mannose branch, but also for the ratiometric fluorescent sensing of the glucose concentration inside HepG2 cells. These results demonstrated that the semisynthetic lectin modified doubly by two distinct chemistries is superior to the singly modified one in function, and thus, it may be potentially useful in cell, as well as in test tube.
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PMID:Double-modification of lectin using two distinct chemistries for fluorescent ratiometric sensing and imaging saccharides in test tube or in cell. 1617 55

VVA-B4 lectin was used to investigate the differences in Tn antigen expression in tissues of different types of human breast cancer (benign lesions, carcinoma in situ, invasive carcinoma) and in normal tissues neighboring lobular carcinoma. Locations in which Tn antigen was expressed were identified using the avidin-biotin-peroxidase labeling system. Tissues collected during cosmetic procedures and classified as normal were completely negative, except for one case. Benign proliferative changes including fibroadenoma, apocrine and cylindrical metaplasia showed a very weak positive reaction, although strongly positive cells were also observed. The reaction in non-invasive cases of atypical hyperplasia was diversified depending on site. Intralobular hyperplasia was characterized by a particularly high percentage of labeled cells. A majority (up to 80%) of ductal and lobular carcinoma in situ showed very strong or moderate staining. In invasive cancers, there were conspicuous differences between stage of cancer development and tendency towards a decrease in intensely labeled cell count in the most advanced stages. In normal tissues in the direct neighborhood of carcinoma in situ, the cytoplasm of 40% of cells was strongly labeled. However, the findings for normal tissues in the close vicinity of invasive cancer were the most surprising, since there was either no or only very weak positive reaction. It can be concluded that glycosylation modifications during carcinogenesis, as demonstrated by the presence of Tn epitope, develop very early, before any destructive changes in proliferation/apoptosis or cell differentiation become discernible.
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PMID:Study of the expression of Tn antigen in different types of human breast cancer cells using VVA-B4 lectin. 1639 46

Lectins are naturally occurring, carbohydrate-binding molecules that can be isolated from diverse biological sources and used in the laboratory to investigate the presence of carbohydrate structures in or on cells, in much the same way as antibodies can be used to probe cells and tissues for the presence of specific antigens. As it is becoming increasingly apparent that subtle alterations in the glycosylation of cancer cells can profoundly influence their biological behavior (with consequent implications for patient outcome and prognosis), lectin histochemistry is a potentially useful modification of the more widely used technique of immunohistochemistry. This chapter provides an introductory background to lectins and their use in breast cancer research, and provides basic protocols for lectin histochemistry that highlight the important technical differences between this approach and immunohistochemistry. The methods given here are broadly applicable and can be modified to investigate virtually any glycosylation change of potential interest in breast cancer research.
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PMID:Detection of aberrant glycosylation in breast cancer using lectin histochemistry. 1649 3

If breast cancer patients are not cured, it is largely because of the fact that the cancer has spread beyond its primary site--the breast--to distant sites, such as, e.g., bone marrow, lung, brain, and/or liver. These secondary tumors are called metastases, and the underlying mechanisms leading to these secondary tumor deposits are complex and still ill understood. In this chapter, we report on how to develop clinically relevant human breast cancer cell line xenografts in severe combined immunodeficient mice. In severe combined immunodeficient mice, metastasizing human breast cancer cell lines were identified by their ability to bind the lectin Helix pomatia agglutinin, which was identified as a marker of metastasis in clinical studies. This model system was created to help to define the rate-limiting steps of the metastatic cascade.
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PMID:In vivo xenograft models of breast cancer metastasis. 1649 20

The effects of N- and O-glycosylation inhibitors on the expression of membrane proteins (MUC1 and some integrins) were evaluated in human endometrial (Ishikawa) and breast (MCF-7) cancer cells. Subconfluent cells were treated with 1-3 mg% concentration of tunicamycin and 2-10 mM of benzyl-N-acetyl-alpha-galactosaminide for 1-2 days, and used for flow cytometry, immunohistochemical staining, adhesion test and Western blotting. Benzyl-N-acetyl-alpha-galactosaminide inhibits MUC1 expression on the surface of breast more than endometrial cancer cells. Tunicamycin reduces MUC1 concentration on the cellular surface more than benzylglycoside, and greatly reduces glycosylation of glycoproteins, causing an increase in cell adhesion in both types of cancer cells. The expression of alpha2beta1 integrins on the surface of these cells was weak and decreased after treatment with inhibitors. Two different glycoforms of MUC1 proteins in endometrial cells and three in breast cancer cells were expressed and their molecular weights were reduced after treatment with glycosylation inhibitors. It was confirmed with lectin detection of carbohydrate epitopes (Tn and T) in MUC1 proteins. These observations show that glycosylation inhibitors altered the N- and O-glycan patterns in a sufficient manner, and positively modified the biological features of cancer cells.
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PMID:The influence of N- and O-glycosylation inhibitors on the glycosylation profile of cellular membrane proteins and adhesive properties of carcinoma cell lines. 1652 26

The objective of this randomised, multicentre, double-blind clinical trial was to investigate the impact of PS76A2, an aqueous mistletoe extract standardised to mistletoe lectins, on quality of life (QoL) in breast cancer patients. A total of 352 patients were randomly allocated to 2 groups receiving PS76A2 (15 ng mistletoe lectin/0.5 ml) or matching placebo twice weekly for 4 to 6 cycles of CMF (cyclophosphamide, methotrexate, fluorouracil) chemotherapy followed by 2 months follow-up. The primary efficacy end-point was the change from baseline of 3 FACT-G subscales (physical, emotional and functional well-being) during the fourth CMF cycle. Secondary measures included GLQ-8 (8 linear analogue self-assessment scales), Spitzer's uniscale and haematological variables. The main variables of safety analysis were adverse events, including injection site reactions and clinical laboratory tests. The results showed that physical, emotional and functional well-being improved upon PS76A2, but deteriorated following placebo. The treatment differences were statistically significant for the 3 subscales as well as for the summary score FACT-G, which was analysed as O'Brien's rank sum of its 3 subscales: The total score increased by 4.40 +/- 11.28, indicating a higher QoL after PS76A2, but decreased by 5.11 +/- 11.77 with placebo (p<0.0001). The GLQ-8 sum of 8 LASA scales was analysed as a summary score of GLQ-5 (sum of item nos. 1, 5, 6, 7, 8) and GLQ-3 (sum of item nos. 2, 3, 4). GLQ-5 characterises typical aspects of QoL, while GLQ-3 consists of 3 side-effects of CMF (feeling sick, numbness or pins and needles, loss of hair). GLQ-5 decreased by 42.9 +/- 125.0 upon PS76A2, indicating an improvement in QoL, but increased by 60.3 +/- 94.0 upon placebo (p<0.0001). GLQ-3 deteriorated in both groups (PS76A2: 13.9 +/- 52.4; placebo: 34.5 +/- 57.0), but the differences in favour of PS76A2 were, nevertheless, statistically significant (p=0.0007). The total score GLQ-8 improved by 28.9 +/- 154.6 after PS76A2 and deteriorated by 94.8 +/- 141.1 after placebo (p<0.0001). Spitzer's uniscale improved by 12.2 +/- 30.7 upon PS76A2 and deteriorated by 10.8 +/- 26.1 with placebo (p<0.0001). After follow-up without chemotherapy, a significant treatment difference in favour of PS76A2 was determined by means of FACT-G, GLQ-8 and Spitzer's uniscale. PS76A2 was well tolerated in this trial, with the exception of slight local reactions in 17.6% of the PS76A2 group. In conclusion, PS76A2 (15 ng mistletoe lectin/0.5 ml twice weekly) was shown to be safe and effective in improving QoL in breast cancer patients during chemotherapy and follow-up.
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PMID:Quality of life is improved in breast cancer patients by Standardised Mistletoe Extract PS76A2 during chemotherapy and follow-up: a randomised, placebo-controlled, double-blind, multicentre clinical trial. 1661 67

Aberrant carbohydrate expression frequently occurs in breast cancer and may endow cells with metastatic potential. Here we first studied the relationship between expression of Vicia villosa agglutinin (lectin) (VVA)-binding carbohydrates and aggressive breast cancer. We then investigated the molecular characteristics of these glycoproteins and compared them with those of glycoproteins recognized by the mouse anti-Tn monoclonal antibody (MAb) HB-Tn1. Histochemical studies of samples from 322 cases of invasive ductal carcinoma demonstrated that VVA-binding carbohydrate expression correlated with tumor stage, lymphatic invasion, and lymph node metastasis (p=0.0385, p=0.0019, and p=0.0430. respectively). Western blotting analysis of frozen materials from 39 cases, under denaturing and reducing conditions, revealed that the major cancer cell-specific VVA-binding proteins were molecules of about 30, 33, and >200 kDa. Cases expressing the approximately 33 kDa molecule had significant lymphatic invasion more frequently than did cases not expressing this molecule (p=0.0076). Binding of VVA to the approximately 30 and approximately 33 kDa molecules was completely lost by preincubation of VVA with 1 mM Tn antigen (N-acetylgalactosamine alpha1-O-serine). The VVA-binding molecules appeared to react with VU-3C6 anti-MUC1 MAb. Expression of HB-Tn1 in breast cancer cells showed significant correlation with expression of VVA-binding carbohydrate(s) (p<0.0001) but HB-Tn1 reactivity was not clearly related to breast cancer aggressiveness. Because anti-Tn MAbs bound to Tn antigen clusters, we concluded that atypical MUC1 bearing the noncluster form of Tn antigen is implicated in aggressive growth of primary breast cancer cells, particularly in lymphatic metastasis.
Breast Cancer Res Treat 2006 Jul
PMID:Expression of Vicia villosa agglutinin (VVA)-binding glycoprotein in primary breast cancer cells in relation to lymphatic metastasis: is atypical MUC1 bearing Tn antigen a receptor of VVA? 1675 27

Mature circulating endothelial cells (CECs) are novel cellular markers of endothelial damage/dysfunction. The two main techniques of CEC enumeration are flow cytometry (FC) and immunomagnetic bead (IB) isolation. Both quantify CECs accurately, but a direct comparison of both methods has not been reported. We sought to assess the agreement between the two methods in two patient populations, and a group of healthy subjects, with emphasis given to methodological issues. We included 34 patients with acute coronary syndrome (ACS), 60 patients with primary breast cancer (PBC) and 30 healthy controls (HC). We quantified CECs using the IB method [CD146 and FITCUlex europaeus lectin-1] and FC [CD45, CD34 and CD146]. Bland-Altman plots suggested reasonable agreement (<5% of events >2 standard deviations from the mean) between FC and the IB methods for CEC quantification in whole blood in the two disease groups (ACS and PBC), but not among the HCs. There were no statistically significant differences in CEC levels by the two methods amongst all three patient groups. There is reasonable agreement between the FC and the IB methods for mature CEC quantification in whole blood, especially amongst disease groups. The agreement between the two methods appears to weaken in healthy controls, and at lower and higher absolute CEC counts.
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PMID:Detection and quantification of mature circulating endothelial cells using flow cytometry and immunomagnetic beads: a methodological comparison. 1680 50

Galectin-9, a member of the beta-galactoside-binding animal lectin family, is involved in various cellular biological events, including aggregation and apoptosis, adhesion of cancer cells, and dendritic cell maturation. We recently reported the relationship between galectin-9 expression in tumor tissue and distant metastasis in breast cancer. Tumors in 42 of the 84 patients were galectin-9-positive, and tumors in 19 of the 21 patients with distant metastasis were galectin-9-negative, assessed by immunohistochemistry. The cumulative distant metastasis-free survival ratio for galectin-9-positive patients was better than for the galectin-9-negative group (p < 0.0001). Multivariate analysis revealed that galectin-9 status influenced distant metastasis independent of and much more than lymph node metastasis. MCF-7 subclones with a high level of galectin-9 expression formed tight clusters during proliferation in vitro, whereas a subclone (K10) with the lowest level of galectin-9 expression did not. However, K10 cells stably transfected with a galectin-9 expression vector aggregated in nude mice as well as in culture. Ectopic expression of galectin-9 also reduced MCF-7 cell adhesion to extracellular matrix proteins.
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PMID:Galectin-9, a novel prognostic factor with antimetastatic potential in breast cancer. 1695 1

Gelatinase B (MMP-9) and galectin-3 are widely known to participate in tumor cell invasion and metastasis. Glycans derived from MMP-9 expressed in MCF-7 breast cancer and THP-1 myeloid leukemia cells were compared with those from MMP-9 expressed in natural neutrophils. The many O-linked glycans of neutrophil gelatinase B presented a cluster of mainly galactosylated core II structures, 46% of which were ligands for galectin-3; 11% contained two to three N-acetyllactosamine repeating units that are high-affinity ligands for the lectin. The glycan epitopes thus provide MMP-9 with both high-affinity and (presumably) high-avidity interactions with galectin-3. In contrast, the O-glycans released from MMP-9 expressed in MCF-7 and THP-1 cells were predominantly sialylated core I structures. Only 10% of MCF-7 and THP-1 gelatinase B O-glycans were ligands for galectin-3 and contained only a maximum single N-acetyllactosamine repeat. Consistent with the glycan analysis, surface plasmon resonance binding assays indicated that the cancer-associated glycoforms of MMP-9 bound galectin-3 with an affinity and avidity significantly reduced compared with those of the natural neutrophil MMP-9. Galectin-3 exists as a multimer that also binds laminin, providing a means of localizing neutrophil MMP-9 in the extracellular matrix (ECM). The analytical data presented here suggest that MMP-9 glycoforms secreted by tumor cells are unlikely to be tethered at the site of secretion, thus promoting more extensive cleavage of the ECM and providing a rationale for the contribution that gelatinase B makes to cancer cell metastasis.
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PMID:Cancer-associated glycoforms of gelatinase B exhibit a decreased level of binding to galectin-3. 1717 47


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