Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q86TM3 (cage)
 29,987 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MUC1 mucin is expressed by normal and malignant epithelial cells and is thought to function through cell-cell interactions and transmembrane signal transduction events. Secreted cancer-associated MUC1 is immunosuppressive and inhibits human T-cell proliferation. We report here that newly synthesized MUC1 is expressed on the surface of mitogen-activated human T cells and is also found in soluble form in the supernatants from cultures of mitogen-activated human T cells. After removal of the mitogenic stimulus from the T-cell cultures, MUC1 expression is downregulated. The addition of anti-MUC1 monoclonal antibody to mitogen-activated cultures partially inhibits the T-cell proliferative response. These data suggest that MUC1 serves an immunodulatory function for human T lymphocytes.
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PMID:Expression of MUC1 mucin on activated human T cells: implications for a role of MUC1 in normal immune regulation. 975 14

Synthetic peptides corresponding to the variable tandem repeat domain of the cancer-associated antigen MUC1 mucin are candidates for cancer vaccines. In our investigation mice were immunized via subcutaneous injection with poly(d,l-lactic-co-glycolic acid) (PLGA) microspheres containing a MUC1 mucin peptide. It was hypothesized that microencapsulation of the MUC1 mucin peptide would prime for antigen-specific Th1 responses while avoiding the need for traditional adjuvants and carrier proteins. Furthermore, an immunomodulator, monophosphoryl lipid A (MPLA), was incorporated into the peptide-loaded PLGA microspheres based on its ability to enhance Th1 responses. The results revealed T cell specific immune responses. The cytokine secretion profiles of the T cells consisted of high levels of interferon-gamma with undetectable levels of interleukin-4 and interleukin-10. Moreover, incorporation of MPLA in the MUC1 peptide-loaded PLGA microspheres resulted in an increase in interferon-gamma production. The antibody response was negative for IgM and IgG in the absence of MPLA; however, in the presence of MPLA antibody production was negative for IgM with a minimal IgG response consisting of IgG2a, IgG2b, and IgG3. Based on the antibody and cytokine profiles, it was concluded that MUC1 mucin peptide-loaded PLGA microspheres are capable of eliciting specific Th1 responses, which may be enhanced through the use of MPLA.
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PMID:Delivery of MUC1 mucin peptide by Poly(d,l-lactic-co-glycolic acid) microspheres induces type 1 T helper immune responses. 981

Seven ovarian and 33 breast high-risk stage II/III and stage IV cancer patients received high-dose chemotherapy followed by stem cell rescue. Thirty to 151 days after stem cell transplantation, the patients received their first immunotherapy treatment with Theratope STn-KLH cancer vaccine. Most patients developed increasing IgG anti-STn titers to a sustained peak after the fourth or fifth immunizations. Only one patient had elevated CA27.29 (MUC1 mucin) serum levels at trial entry. Five of the seven patients with preimmunotherapy elevated serum CA125 levels demonstrated decreasing CA125 levels during immunotherapy, consistent with an antitumor response. Evidence of STn antigen-specific T-cell proliferation was obtained from 17 of the 27 evaluable patients who received at least three immunotherapy treatments. Eleven of the 26 patients tested had evidence of an anti-STn TH1 antigen-specific T-cell response as determined by interferon-gamma, but not interleukin (IL)-4, production. After immunization, lytic activity of peripheral blood lymphocytes (PBLs) tested against a lymphokine activated killer (LAK)-sensitive cell line, a natural killer (NK)-sensitive cell line, and an STn-expressing cancer cell line (OVCAR) increased significantly. In vitro IL-2 treatment of the PBLs after vaccination greatly enhanced killing of the STn+ cancer cell line. Evidence of the development of OVCAR specific killing activity, over and above that seen due to LAK or NK killing, is presented. These studies provide the strongest evidence in humans of the development of an antitumor T-cell response after immunization with a cancer-associated carbohydrate antigen.
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PMID:Evidence of a cellular immune response against sialyl-Tn in breast and ovarian cancer patients after high-dose chemotherapy, stem cell rescue, and immunization with Theratope STn-KLH cancer vaccine. 992

A SEA-antibody single chain Fv (SEA-scFv) fusion protein was produced by bacterial expression system in this study. SEA-scFv has both staphylococcal enterotoxin A (SEA) effects and antibody activity directed at the epithelial mucin core protein MUC1, a cancer associated antigen. It was expressed mostly in the cytoplasm as an insoluble form. The gene product was solubilized by guanidine hydrochloride, refolded by conventional dilution method, and purified using metal-chelating chromatography. The resulting SEA-scFv fusion protein preparation was found to react with MUC1 and MHC class II antigens and had the ability to enhance cytotoxicity of lymphokine activated killer cells with a T cell phenotype against a human bile duct carcinoma cell line, TFK-1, expressing MUC1. This genetically engineered SEA-scFv fusion protein promises to be an important reagent for cancer immunotherapy.
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PMID:SEA-scFv as a bifunctional antibody: construction of a bacterial expression system and its functional analysis. 1006 51

The MUC1 epithelial mucin, which is overexpressed and aberrantly glycosylated in breast and other carcinomas, is also expressed on the apical surface of most normal glandular epithelial cells. Since clinical trials evaluating the efficacy of MUC1-based vaccines have been initiated in breast cancer patients, it is important to address the question of whether an effective immune response to the cancer associated mucin can be generated without inducing autoimmunity. Since non-classic cytotoxic T lymphocyte (CTL) responses to MUC1 have been reported, it is also relevant to examine the role of costimulatory molecules in the effective presentation of MUC1 based antigens. We have therefore looked at the effect of expressing B7.1 on the tumorigenicity of a MUC1 expressing mammary epithelial cell line (410.4) in a transgenic mouse expressing MUC1 on its normal glandular epithelial tissues. Coexpression of B7.1 with MUC1 in 410. 4 cells resulted in a dramatic inhibition of tumour growth which depended on the activity of CD4+ and CD8+ T cells. The epithelial tissues in the transgenic mice able to reject the B7.1, MUC1-expressing tumours showed no evidence of degeneration and the mice survived their normal life span. The results demonstrate that an immune response to the MUC1 antigen can be induced in MUC1 transgenic mice and that presentation of the antigen, whether directly or by cross-priming, is markedly enhanced by coexpression of B7.1.
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PMID:Expression of B7.1 in a MUC1-expressing mouse mammary epithelial tumour cell line inhibits tumorigenicity but does not induce autoimmunity in MUC1 transgenic mice. 1045 19

The MUC1 membrane mucin was first identified as the molecule recognised by mouse monoclonal antibodies directed to epithelial cells, and the cancers which develop from them. Cloning the gene showed that the extracellular domain is made up of highly conserved repeats of 20 amino acids, the actual number varying between 25 and 100 depending on the allele. Each tandem repeat contains five potential glycosylation sites, and between doublets of threonines and serines lies an immunodominant region which contains the epitopes recognised by most of the mouse monoclonal antibodies. The O-glycans added to the mucin produced by the normal breast are core 2 based and can be complex, while the O-glycans added to the breast cancer mucin are mainly core 1 based. This means that some core protein epitopes in the tandem repeat which are masked in the normal mucin are exposed in the cancer associated mucin. Since novel carbohydrate epitopes are also carried on the breast cancer mucin, the molecule is antigenically distinct from the normal breast mucin. (Changes in glycosylation in other epithelial cancers have been observed but are not so well documented.) Immune responses to MUC1 have been seen in breast and ovarian cancer patients and clinical studies have been initiated to evaluate the use of antibodies to MUC1 and of immunogens based on MUC1 for immunotherapy of these patients. The role of the carbohydrates in the immune response and in other interactions with the effector cells of the immune system is of particular interest and is discussed.
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PMID:MUC1 and cancer. 1057 Oct 20

MUC1 mucin is a target protein for many monoclonal antibodies. Human MUC1 detected by a murine anti-KL-6 monoclonal antibody that recognizes a sialylated carbohydrate chain has been designated KL-6/MUC1. Given the heterogeneous antigenicity of KL-6/MUC1, we established a new murine monoclonal antibody, H9, that reacts with epitope DTRP (Asp-Thr-Arg-Pro) peptides within the immunodominant region of the tandem repeat of MUC1 mucin. The reactivity of the H9 antibody differs from that of other previously reported antibodies that recognize the tandem repeat region of MUC1. Immunohistochemical experiments indicate that the reactivity of the H9 antibody is similar to that of other antibodies directed against MUC1 core proteins. A new cancer-associated protein detected by a sandwich assay using the H9 antibody as a catcher and the KL-6 antibody as a tracer is designated HK9. Serum HK9 levels showed a high expression level in lung cancer: 51% (19/37 cases) for adenocarcinoma, 39% (11/28 cases) for squamous cell carcinoma, and 67% (10/15 cases) for small cell carcinoma. The HK9 expression in lung cancer increased with cancer progression. These findings suggest monoclonal antibody H9 to be a novel antibody that reacts with an epitope within the tandem repeat region of MUC1, and that the cancer-associated antigen HK9 may have useful tumor-associated properties.
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PMID:A novel monoclonal antibody, H9, directed against the core protein of MUC1 mucin. 1067 62

In breast cancer, the O-glycans added to the MUC1 mucin are core 1- rather than core 2-based. We have analyzed whether competition by the glycosyltransferase, ST3Gal-I, which transfers sialic acid to galactose in the core 1 substrate, is key to this switch in MUC1 glycosylation that results in the expression of the cancer-associated SM3 epitope. Of the three enzymes known to convert core 1 to core 2, by the addition of GlcNAc to GalNAc in core1 C2GnT1 is the dominant enzyme expressed in normal breast tissue. Expression of C2GnT1 is low or absent in around 50% of breast cancers, whereas expression of ST3Gal-I is consistently increased. Mapping of ST3Gal-I and C2GnT1 within the Golgi pathway showed some overlap. To examine functional competition, the enzymes were overexpressed in T47D cells, which normally make core 1-based structures, have no detectable C2GnT1 activity and express the SM3 epitope. Overexpression of C2GnT1 resulted in loss of binding of SM3 to MUC1, accompanied by a decrease in the GalNAc/GlcNAc ratio, indicative of a switch to core 2 structures. Transfection of a C2GnT1 expressing line with ST3Gal-I restored SM3 binding and reduced GlcNAc incorporation into MUC1 O-glycans. Thus, even when C2GnT1 is expressed, the O-glycans added to MUC1 become core 1-dominated structures, provided expression of ST3Gal-I is increased as it is in breast cancer.
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PMID:The relative activities of the C2GnT1 and ST3Gal-I glycosyltransferases determine O-glycan structure and expression of a tumor-associated epitope on MUC1. 1111 34

For the purpose of establishing a new adoptive immunotherapy for bile duct carcinoma (BDC), we have directed our attention to superantigens (SAgs), the most potent known activators of T lymphocytes. In our previous study, staphylococcal enterotoxin A (SEA) was conjugated chemically with MUSE11 mAb, which recognizes the MUC1 cancer-associated antigen, and shown to enhance the specific cytotoxic activity of T-LAK cells against MUC1-expressing BDC cells (TFK-1) in vitro and in vivo. However, it is probable that SEA might cause side-effects because of nonspecific binding to class II positive cells. In order to overcome these, we generated mutated SEA (mSEA) by changing Asp at position 227 of native SEA to Ala, which has reduced affinity to MHC class II molecules, but retains the potential for T cell activation. When mSEA-D227A was administered to rabbits to examine effects on blood pressure, 500 times more mSEA-D227A was tolerated than native SEA. This prompted us to construct a mSEA-D227A-conjugated mAb, reactive with MUC1. It augmented the antitumor activity of T-LAK cells significantly, and furthermore, mSEA-D227A could be conjugated to two bispecific antibodies, BsAb (anti-MUC1 x anti-CD3) and BsAb (anti-MUC1 x anti-CD28), which in combination had greater enhancing effects than mSEA-D227A-conjugated anti-MUC1 mAb, and combination of unconjugated BsAbs. These findings indicate a utility of mSEA-D227A-conjugated antibodies for targeted cancer immunotherapy.
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PMID:Mutated SEA-D227A-conjugated antibodies greatly enhance antitumor activity against MUC1-expressing bile duct carcinoma. 1177 76

The membrane epithelial mucin MUC1 is expressed at the luminal surface of most simple epithelial cells, but expression is greatly increased at lactation and in most breast carcinomas. The increase in level of expression of MUC1 in breast cancer is accompanied by changes in the profile of glycosyl transferases involved in the synthesis of the O-glycans attached to the MUC1 core protein. The cancer-associated mucin is therefore structurally different from the normal mucin, and expresses novel B cell epitopes. MUC1 antibodies are used for in vivo targeting of breast and ovarian tumors, and there is considerable interest in MUC1 as a possible target antigen for the immunotherapy of breast cancer. The different glycoforms can affect cell interactions differently, depending on whether specific interactions with lectins occur. In the absence of such lectin interactions, the long sialylated and negatively charged molecule can inhibit intercellular interactions between other cell surface molecules. The potential role of the different components of the immune system in MUC1 responses are discussed within the framework of how to develop logical strategies for designing clinical studies.
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PMID:MUC1 and the immunobiology of cancer. 1246 41


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