Tumor-associated carbohydrate antigens of MUC1 - Implication in cancer development

Glycosylation of cancerous epithelial MUC1 protein is specifically altered in comparison to that which is presented by healthy cells. One of such changes is appearing tumor-associated carbohydrate antigens (TACAs) which are rare in normal tissues and are highly correlated with poor clinical outcomes and cancer progression. This review summarizes and describes the role of Tn, T antigens, their sialylated forms as well as fucosylated Lewis epitopes in different aspects of tumor development, progression, and metastasis. Finally, applications of MUC1 glycan epitopes as potential targets for therapeutic strategy of cancers are notified. One of the novelties of this review is presentation of TACAs as inherently connected with MUC1 mucin.

Effect of Dimeric Disintegrins Isolated from Vipera lebetina obtusa Venom on Glioblastoma Cellular Responses

Integrins play a fundamental role in the migration and invasiveness of glioblastoma (GBM) cells, making them suitable targets for innovative cancer therapy. The aim of this study was to evaluate the effect of the RGD homodimeric disintegrin VLO4, isolated from Vipera lebetina obtusa venom, on the adhesion, spreading, migration, and survival of LBC3, LN18, and LN229 cell lines. This disintegrin, as a potent antagonist for α5β1 integrin, showed pro-adhesive properties for these cell lines, the highest for LN229 and the lowest for LBC3. Glioblastoma cells displayed significant differences in the spreading on the immobilized VLO4 and the natural α5β1 integrin ligand, fibronectin. Solubilized VLO4 showed different cytotoxicity and pro-apoptotic properties among tested cell lines, with the highest against LN18 and none against LN229. Moreover, VLO4 revealed an inhibitory effect on the migration of LBC3 and LN18 cell lines, in contrast to LN229 cells, which were not sensitive to this disintegrin. However, LN229 migration was impaired by VLO5, a disintegrin antagonistic to integrin α9β1, used in combination with VLO4. A possible mechanism of action of VLO4 may be related to the downregulation of α5β1 integrin subunit expression, as revealed by Western blot. VLO4 also inhibited cell proliferation and induced caspase-dependent apoptosis in LBC3 and LN18 cell lines. These results indicate that targeting α5β1 integrin by related VLO4 compounds may be useful in the development of integrin-targeted therapy for glioblastoma.

Tiliroside Combined with Anti-MUC1 Monoclonal Antibody as Promising Anti-Cancer Strategy in AGS Cancer Cells

Specific changes in mucin-type O-glycosylation are common for many cancers, including gastric ones. The most typical alterations include incomplete synthesis of glycan structures, enhanced expression of truncated O-glycans (Tn, T antigens and their sialylated forms), and overexpression of fucosylation. Such altered glycans influence many cellular activities promoting cancer development. Tiliroside is a glycosidic dietary flavonoid with pharmacological properties, including anti-cancer. In this study, we aim to assess the effect of the combined action of anti-MUC1 and tiliroside on some cancer-related factors in AGS gastric cancer cells. Cancer cells were treated with 40, 80, and 160 µM tiliroside, 5 µg/mL anti-MUC1, and flavonoid together with mAb. Real-Time PCR, ELISA, and Western blotting were applied to examine MUC1 expression, specific, tumor-associated antigens, enzymes taking part in their formation, Gal-3, Akt, and NF-κB. MUC1 expression was significantly reduced by mAb action. The combined action of anti-MUC1 and tiliroside was more effective in comparison with monotherapy in the case of C1GalT1, ST3GalT1, FUT4, Gal-3, NF-κB, Akt mRNAs, and Tn antigen, as well as sialyl T antigen expression. The results of our study indicate that applied combined therapy may be a promising anti-gastric cancer strategy.

Galectin-3 and Epithelial MUC1 Mucin-Interactions Supporting Cancer Development

Aberrant glycosylation of cell surface proteins is a very common feature of many cancers. One of the glycoproteins, which undergoes specific alterations in the glycosylation of tumor cells is epithelial MUC1 mucin, which is highly overexpressed in the malignant state. Such changes lead to the appearance of tumor associated carbohydrate antigens (TACAs) on MUC1, which are rarely seen in healthy cells. One of these structures is the Thomsen-Friedenreich disaccharide Galβ1-3GalNAc (T or TF antigen), which is typical for about 90% of cancers. It was revealed that increased expression of the T antigen has a big impact on promoting cancer progression and metastasis, among others, due to the interaction of this antigen with the β-galactose binding protein galectin-3 (Gal-3). In this review, we summarize current information about the interactions between the T antigen on MUC1 mucin and Gal-3, and their impact on cancer progression and metastasis.

Anti-cancer effects of pyrazole-platinum(II) complexes combined with anti-MUC1 monoclonal antibody versus monotherapy in DLD-1 and HT-29 colon cancer cells

The membrane-bound MUC1 mucin is overexpressed and aberrantly glycosylated in many epithelium origin cancers. One of the promising strategies in cancer therapy is combining monoclonal antibodies against cancer related antigens, like MUC1, with chemotherapeutics. In the study we evaluated the potency of cisplatin (cisPt), two pyrazole-platinum(II) complexes PtPz4, PtPz6, and anti-MUC1 mAb applied as monotherapy, as well as the chemotherapeutics administrated with antibody, towards apoptotic response and cancer-related carbohydrate antigens (TACAs) in DLD-1 and HT-29 colon cancer cells. To assess the impact of the tested compounds on the examined factors flow cytometry, RT-PCR, Western blotting and ELISA were utilized. The combined therapy was more potent than monotherapy towards Bcl-2, Bid, caspases and TACAs of both cell lines. Combined therapy applied in DLD-1 cells induced apoptosis, was more effective than monotherapy in relation to p53, Bcl-xL, Bax, and Bim. In HT-29 cells, anti-MUC1 administrated with the drugs was more potent than monotherapy towards Bad. The proposed anti-MUC1/cisPt and pyrazole-platinum(II) complexes PtPz4, PtPz6 combined therapy may be promising anti-colon cancer therapy.

Anti-Cancer Potential of Afzelin towards AGS Gastric Cancer Cells

Afzelin demonstrates anti-inflammatory and anti-cancer properties. Our purpose was to assess its influence on apoptosis, Bax, caspases, MUC1, cancer-related carbohydrate antigens, enzymes participating in their formation, and galectin-3 in AGS gastric cancer cells. A total of 60 and 120 μM afzelin was used in all experiments. Flow cytometry was applied to determine apoptotic response. Western blotting and RT PCR were used to detect the expression of mentioned factors. Flavonoid at higher concentration revealed slight apoptotic respond. Bax, caspase-3, -8, -9 increased upon afzelin action. Stimulatory effect of the flavonoid on MUC1 cytoplasmic tail and extracellular domain in cell lysates and on MUC1 gene was revealed. MUC1 release into the culture medium was inhibited by the flavonoid. The 60 μM afzelin dose stimulated GalNAcTL5 protein expression and inhibited C1GalT1. ST6GalNAcT mRNA was inhibited by both flavonoid doses. ST3GalT was inhibited by 120 μM afzelin on protein and mRNA level. Lewisa/b protein was reduced by both afzelin concentrations. FUT3 and FUT4 mRNA was inhibited by 120 μM dose of afzelin. Galectin-3 protein increased in cell lysates and decreased in culture supernatant by 60 and 120 μM flavonoid. Galectin-3 gene expression was stimulated by two used concentrations of afzelin in comparison to control. We conclude that afzelin can be considered as the potential anti-cancer agent, supporting conventional cancer treatment.

MUC1 is an oncoprotein with a significant role in apoptosis (Review)

Mucin 1 (MUC1) is a membrane-bound, highly glycosylated protein that is overexpressed in all stages of malignant transformation. Overexpression of MUC1 together with loss of polarization and hypoglycosylation are associated with resistance to apoptosis, which is the process that results in efficient removal of damaged cells. Inhibition of the apoptotic process is responsible for tumor development, tumor progression and drug resistance. MUC1 is considered as an oncogenic molecule that is involved in various signaling pathways responsible for the regulation of apoptosis. Based on this, the aim of the present study was to discuss the involvement of MUC1 in the divergent mechanisms regulating programmed cell death.

Anti-cancer effect of combined action of anti-MUC1 and rosmarinic acid in AGS gastric cancer cells

MUC1 seems to be promising target in cancer cells due to its abundant and specifically altered expression as well as differential distribution pattern relative to normal tissues. Rosmarinic acid (RA) is a natural, polyphenolic compound with pharmacological activities, including anti-cancer. Herein, we aim to explore the effect of combined action of anti-MUC1 and RA on selected cancer-related factors in AGS gastric cancer cells. Cancer cells were treated with 100, 200 μM rosmarinic acid, 5 μg/ml anti-MUC1 and acid together with antibody. Western blotting, ELISA and RT-PCR were used to assess the expression of MUC1, selected sugar antigens, enzymes participating in protein glycosylation, Gal-3, p53, pro- and anti-apoptotic factors, and caspases-3,-8,-9 in cancer cells. MUC1 mRNA was significantly suppressed by combined action of anti-MUC1 and RA. Such treatment markedly inhibited expression of cancer-related Tn, T, sialyl Tn, sialyl T, and fucosylated sugar antigens as well as mRNA expression of enzymes participating in their formation: ppGalNAcT2, C1GalT1, ST6GalNAcT2, ST3GalT1 and FUT4. C1GalT1 was suppressed also on protein level. Gal-3, factor likely participating in metastasis, was significantly suppressed on mRNA level by RA administrated with anti-MUC1. Pro-apoptotic Bax protein and Bad mRNA were significantly induced, and anti-apoptotic Bcl-2 mRNA expression was inhibited by such treatment. Combined action of mAb and RA markedly increased caspase-9 mRNA expression. Results of the study indicate that combined action of anti-MUC1 and RA is more effective than monotherapy in relation to examined cancer related factors. Such treatment can be considered as new, promising strategy in gastric cancer therapy.

Luteolin alters MUC1 extracellular domain, sT antigen, ADAM-17, IL-8, IL-10 and NF-κB expression in Helicobacter pylori-infected gastric cancer CRL-1739 cells: A preliminary study

Luteolin is a natural flavonoid possessing certain beneficial pharmacological properties, including anti-oxidant, anti-inflammatory, anti-microbial and anti-cancer properties. The majority of types of gastric cancer with chronic gastritis are caused by infection with Helicobacter pylori (H. pylori). The present study evaluated the effect of luteolin on a number of selected factors that are potentially involved in gastric cancer development. The study was performed using gastric cancer CRL-1739 cells treated with 30 µM luteolin and H. pylori alone or combined. ELISA and reverse transcription PCR were used to assess the expression levels of MUC1, GalNAcα-R (Tn antigen) and NeuAcα2-3Galβ1-3GalNAc-R (sT antigen), ADAM-17, IL-8, IL-10 and NF-κB. H. pylori and luteolin independently and in combination significantly reduced the expression levels of the extracellular domain of MUC1 in gastric cancer cells compared with the untreated control cells. ADAM-17 expression was reduced by treatment with the pathogen and luteolin. Additionally, both factors reduced sT antigen expression. Treatment with 30 ≤M luteolin significantly induced IL-8 expression at the mRNA and protein level, and the mRNA expression levels of IL-10 and NF-κB compared with the control. Both H. pylori and luteolin induced IL-8 protein expression. The present preliminary results suggest that luteolin may be used to treat patients with gastric cancer.

Rosmarinic acid influences collagen, MMPs, TIMPs, glycosylation and MUC1 in CRL-1739 gastric cancer cell line

Rosmarinic acid (RA) is a natural phenylpropanoid with numerous pharmacological activities. Because of limited studies of the effects of RA action in gastric cancer cells we examined how 100 and 200 μM acid influences MMPs, TIMPs, collagen, MUC1 and specific sugar antigens in gastric adenocarcinoma CRL-1739 cells. We revealed inhibitory effect of RA on MMP-9 activity what was correlated with increased collagen type I expression, main ECM substrate degraded by MMPs. Tissue inhibitor of MMPs, TIMP-1 but not TIMP-2 was significantly decreased on the protein level and increased on mRNA level by RA action what can suggest TIMP-1 independent inhibitory action of an acid on MMP-9 activity. Glycosylation of gastric cancer proteins was also effected by RA. ELISA tests revealed inhibitory effect of an acid on Tn antigen in cell lysates and culture supernatant and on T antigen in cell lysates. RA inhibited also sialylated Tn antigen in protein of culture supernatant and sialyl T in cell lysates. Extracellular domain of MUC1 mucin, main carrier of Tn and T antigens was significantly inhibited by higher dose of RA. The data suggest potential usefulness of RA as a complementary agent supporting chemotherapy in cancer treatment.

Lotus tetragonolobus, Ulex europaeus, Maackia amurensis, and Arachis hypogaea (peanut) lectins influence the binding of Helicobacter pylori to gastric carbohydrates

BACKGROUND

The carbohydrates of gastric mucins and other sugar structures are involved in interactions with Helicobacter pylori (H. pylori) adhesins. The binding of bacteria to mucins can protect the epithelium from direct contact with the pathogen and from developing infection because of a specific barrier created by the mucus. The pathogen also interacts with other carbohydrate structures of the epithelium. Direct contact between the bacteria and the epithelial cells facilitates infection development.

OBJECTIVES

The aim of this study was to assess the influence of Maackia amurensis (MAA), Lotus tetragonolobus (LTA), Ulex europaeus (UEA), and Arachis hypogaea (PNA) lectins on the binding of gastric carbohydrates with H. pylori adhesins.

MATERIAL AND METHODS

Three patients' gastric juices and 12 H. pylori strains were included in the study. An ELISA test was used to assess the presence of MUC1 and MUC5AC mucins and the sugar structures recognized by all examined lectins. The binding of the bacterium to the sugar structures was analyzed by the ELISA method with and without the gastric juices pretreated with lectins.

RESULTS

In the majority of the samples examined, MAA, LTA, UEA, and PNA lectins enhanced the binding of H. pylori to specific carbohydrate structures of gastric mucins.

CONCLUSIONS

Substances which influence the binding of the pathogen with specific carbohydrate receptors on gastric epithelial cells can favor inflammation development. However, if H. pylori binds with mucins, the bacterium can have difficulty reaching the epithelium and progressing with infection.

Lotus tetragonolobus and Maackia amurensis lectins influence phospho-IκBα, IL-8, Lewis b and H type 1 glycoforms levels in H. pylori infected CRL-1739 gastric cancer cells

PURPOSE

Attachment of Helicobacter pylori to the mucous epithelial cells and the mucous layer is said to be a crucial step for infection development. Sugar antigens of gastric mucins (MUC5AC, MUC1) can act as receptors for bacterial adhesins. The aim of the study was to investigate if Lotus tetragonolobus and Maackia amurensis lectins influence the level of MUC1, MUC5AC, Lewis b, H type 1, sialyl Lewis x, phospho-IκBα and interleukin 8 in Helicobacter pylori infected gastric cancer cells.

MATERIALS AND METHODS

The study was performed with one clinical H. pylori strain and CRL-1739 gastric cancer cells. To assess the levels of mentioned factors immunosorbent ELISA assays were used.

RESULTS

Coculture of cells with bacteria had no clear effect on almost all examined structures. After coculture with H. pylori and lectins, a decrease of the level of both mucins, Lewis b and H type 1 antigens was observed. Lectins addition had no effect on sialyl Lewis x. Maackia amurensis caused slight increase of phospho-IκBα while interleukin 8 level was decreased.

CONCLUSIONS

Lotus tetragonolobus and Maackia amurensis lectins can mediate in binding of Helicobacter pylori to gastric epithelium.

Reduced expression of E-cadherin and increased sialylation level in clear cell renal cell carcinoma

Cancer cells are characterized by an aberrant increase in protein N-glycosylation and by disruption of E-cadherin-mediated adherens junctions. However, the relationship between alterations in N-glycosylation process and loss of E-cadherin adhesion in cancer remains unclear. The mechanisms of altered expression of adhesive glycoproteins in cancer cells have not been fully elucidated. Thus, the aim of this study was to examine the expression of E-cadherin and sialyl Lewis^a/^x, NeuAcα2-3Gal, NeuAcα2-6Gal/GalNAc structures in the normal renal tissue and intermediate and cancerous tissues from patients with clear cell RCC. Moreover, we attempted to correlate the E-cadherin expression with some specific sugar residues of renal cancer tissue glycoproteins. The expression of E-cadherin was analysed using ELISA test and immunoblotting. Oligosaccharide structures and sialylation level were detected with ELISA test using specific biotinylated lectins or antibodies. A significant decrease of E-cadherin expression as well as a significant increase in sialylated oligosaccharides level in intermediate zone and renal cancer tissue in comparison to normal renal tissue are reported. Significant decrease in expression of cadherins and increase in sialylation of oligosaccharide structures in renal cancer tissue in comparison to normal renal tissue, and in renal cancer tissue in comparison to intermediate zone of renal tissue, are important for the future research concerning detection and quantification of cadherins and sialylated oligosaccharide structures in urine and cells of urinary sediment as possible non-invasive marker of early RCC.

Changes of the expression of Lewis blood group antigens in glycoproteins of renal cancer tissues

Sialic acid and sialyl Lewisa/x are found on N- and O-glycans of many human malignant cells. Carbohydrate antigens can be used as tumor markers, and an increase of their levels in cancer cells is associated with tumor progression. The aim of this study was to assess the level of some Lewis blood group antigens on glycoproteins in tumor (cancer tissue), intermediate zone (adjacent to tumor tissue), and normal renal cortex/medulla (uninvolved by tumor). The study was performed on tissues taken from 30 patients. Relative amounts of sugar structures of proteins with molecular masses above 30 kDa were determined by ELISA-like test with biotinylated lectins: MAA (Maackia amurensis), SNA (Sambucus nigra), and monoclonal antibodies anti-sialyl Lewisa/x.∙ Higher expression of all examined structures was revealed in cancer tissues. Significant increases were observed for sialic acid linked α 2-3 in cancer tissues when compared to healthy ones and also among intermediate and healthy tissues. The sialic acid linked α 2-6 and sialyl Lewisx structures were significantly increased in cancerous cells when compared to normal and intermediate renal tissue. In case of sialyl Lewisa antigen, a significant difference was discovered between normal and intermediate tissue. Our results confirm that the examined Lewis antigens can be involved in tumor development. Their increase in cancer tissues can suggest their specific role in the process.

Changes of the expression of Lewis blood group antigens in glycoproteins of renal cancer tissues

Sialic acid and sialyl Lewisa/x are found on N- and O-glycans of many human malignant cells. Carbohydrate antigens can be used as tumor markers, and an increase of their levels in cancer cells is associated with tumor progression. The aim of this study was to assess the level of some Lewis blood group antigens on glycoproteins in tumor (cancer tissue), intermediate zone (adjacent to tumor tissue), and normal renal cortex/medulla (uninvolved by tumor). The study was performed on tissues taken from 30 patients. Relative amounts of sugar structures of proteins with molecular masses above 30 kDa were determined by ELISA-like test with biotinylated lectins: MAA (Maackia amurensis), SNA (Sambucus nigra), and monoclonal antibodies anti-sialyl Lewisa/x.∙ Higher expression of all examined structures was revealed in cancer tissues. Significant increases were observed for sialic acid linked α 2-3 in cancer tissues when compared to healthy ones and also among intermediate and healthy tissues. The sialic acid linked α 2-6 and sialyl Lewisx structures were significantly increased in cancerous cells when compared to normal and intermediate renal tissue. In case of sialyl Lewisa antigen, a significant difference was discovered between normal and intermediate tissue. Our results confirm that the examined Lewis antigens can be involved in tumor development. Their increase in cancer tissues can suggest their specific role in the process.

Glycosylation of proteins in healthy and pathological human renal tissues

Cancer development is associated with the improper glycosylation of proteins. There are alterations in the synthesis and expression of sugar structures. These changes can be important not only in the early stages of tumour development, but also in the next stages connected with cancer invasiveness and its ability to form metastases. Oligosaccharide structures of glycans in tumours deviate from normal cells. Relatively increased degrees of branching and sialylation of N-glycans, enhanced presentation of short-chain mucin-type O-glycans with sialylation, and alterations in the expression of blood group ABO and Lewis epitopes can be observed. The main aim of our study was to assess changes in the glycosylation of proteins in clear cell renal cell carcinoma. This study was performed on tissues taken from 15 patients. The relative amounts of sugar structures of proteins with molecular mass above 30 kDa in tumour (cancer tissue), intermediate zone i.e. tumour-adjacent tissue, and normal tissue uninvolved by tumour, were determined by ELISA-like test with biotinylated lectins highly specific to examined sugar antigens. A higher expression of all examined structures was revealed in cancer tissue. Increased levels of sialic acid, fucose, T and Tn antigens, compared to healthy renal tissue, were characteristic for clear cell renal cell carcinoma.

Are Lewis b and H type 1 on Helicobacter pylori involved in binding of bacteria to MUC1 mucin?

BACKGROUND

Helicobacter pylori is responsible for gastroduodenal diseases such as chronic gastritis, gastric and duodenal ulcers and also gastric malignances. During an infection, gastric mucins, especially secretory MUC5AC, are said to participate in interactions with bacterial adhesins. Recently, epithelial MUC1 mucin has also been proposed to be engaged in infection development. H. pylori surface possesses lipopolisaccharides with Lewis antigens whose role in interactions with gastric mucins has not been elucidated thoroughly so far.

OBJECTIVES

To check the involvement of Lewis b and H type 1 structures of H. pylori in adhesion of bacteria to MUC1 mucin.

MATERIAL AND METHODS

The study was performed on gastric juices taken from 10 clinical patients and 4 H. pylori strains. Bacteria were assessed for the presence of Lewis b and H type 1 structures by ELISA test. Interactions of H. pylori with MUC1 were analyzed by sandwich ELISA method with bacteria pretreated or not with Lewis b - HSA or H type 1 - HSA glycoconjugates.

RESULTS

In the majority of the patients, the slight increase of adhesion of H. pylori to MUC1, after pretreatment of bacteria with H type 1 glycoconjugate was observed. A statistically significant difference was revealed in one strain with a dose of conjugate 50µg/mL (P = 0.05). The influence of Lewis b on adhesion is considered to be contradictory.

CONCLUSIONS

H type 1 antigens are suggested to be involved in carbohydrate - carbohydrate interactions of H. pylori with MUC1 mucin.

[The role of gastric mucins in interactions with Helicobacter pylori]

Helicobacter pylori is a Gram-negative bacterium which colonizes the stomach of over 50% of the world's population. The pathogen is responsible for many diseases including gastritis, ulcers and also gastric cancers. It is said that adherence of bacteria to epithelial cells plays a key role in infection development. Two gastric mucins, components of mucus, are assumed to have an important role in protection against adhesion and in this way in progression of infection. These are a secretory MUC5AC mucin, produced by mucous epithelial cells, and a membrane-bound MUC1 mucin, expressed by epical surfaces of epithelial cells. Interactions with bacteria occur between carbohydrate antigens of mucins and specific adhesins of the Helicobacter pylori surface. In this paper we present the latest knowledge about these intriguing interactions of both mucins and their interplay with the pathogen providing protection against infection.

[Nutritional habits of female students of the Medical University of Bialystok depending on the socioeconomic situation]

The aim of the study was the estimation of the selected nutritional habits of female students of the Medical University of Bialystok related to the socio-economic situation of families (SES). The investigation included 251 female students (18% of a higher SES, 56.5% students of an average SES and 25.5% students of a lower SES). The highest percentage of female students consumed four meals a day independently on the socio-economic status. Lunch and afternoon snack were the most frequently omitted meals. The socio-economic situation of families did not differ significantly the consumption frequency of selected groups of food products among the studied students. The diets analysed in this study were characterized by low intake of whole meal bread, coarse-grained barley, milk and dairy products, fish, raw vegetables and fruit.

Glycosylation of mucins present in gastric juice: the effect of helicobacter pylori eradication treatment

It is suggested that gastric mucins, and in particular some specific glycan structures that can act as carbohydrate receptors, are involved in the interactions with Helicobacter pylori adhesins. The main aim of our study was to evaluate glycosylation pattern of glycoproteins of gastric juice before and at the end of eradication therapy. Gastric juices were taken from 13 clinical patients and subjected to analysis. Pooled fractions of the void volume obtained after gel filtration were subjected to ELISA tests. To assess the relative amounts of carbohydrate structures, lectins and monoclonal antibodies were used. Changes in the level of MUC 1 and MUC 5AC mucins and of carbohydrate structures, which are suggested to be receptors for Helicobacter pylori adhesins, were observed by the end of the eradication treatment. Our results support the idea about the involvement of MUC 5AC and MUC 1 with some specific sugar structures in the mechanism of Helicobacter pylori infection.

Assessment of interactions between mucins of gastric juice and Helicobacter pylori--preliminary study

BACKGROUND/AIMS

Helicobacter pylori resides primarily in the gastric mucus layer composed of carbohydrate-rich glycoproteins, mucins. Carbohydrates of the secretory MUC 5AC mucin are one of the proved receptors for H. pylori adhesins. A participation of the membrane-associated MUC 1 in the mechanism of infection is also suggested. The main aim of the study was to support the participation of the membrane associated MUC 1 mucin in the mechanism of infection.

METHODOLOGY

13 gastric juices were included in the study. The presence of MUC 5AC and MUC 1 mucins as well as H. pylori bindings were performed using ELISA tests.

RESULTS

MUC 1 and MUC 5AC mucins were present in all the examined juices. H. pylori adhered to both glycoproteins.

CONCLUSIONS

H. pylori bind to the secretory MUC 5AC mucin as well as to the epithelial MUC 1. This supports the idea that the membrane-associated mucin is involved in the mechanism of H. pylori infection.

The effect of Helicobacter pylori eradication treatment on the MUC 1 and Lewis antigens level in human gastric juice: a preliminary study

Helicobacter pylori is considered as a causative agent of gastritis, duodenal and gastric ulcers, and gastric cancer. During inflammation, association of the pathogen of gastric epithelial cells and mucins is considered important. It was postulated that Lewis b structures of secretory MUC 5AC mucin can be a receptor for the bacterium. Some authors also suggest that epithelial MUC 1 mucin may be implicated in the mechanism of infection. The main aim of our work was to support this last suggestion by evaluation of the possible changes in MUC 1 and Lewis a and b levels in gastric juice before and at the end of eradication treatment. The gastric juices of ten examined patients were chromatographed on a Sepharose 4 B column, electrotransferred on Immobilon P membranes, and assessed for MUC 1 and Lewis a and b structures using monoclonal antibodies. In 90% of examined patients, higher amounts of MUC 1 mucin were observed at the end of eradication treatment. Similar results for Lewis a and b structures were found. In the case of MUC 1 and Lewis b, the differences were statistically significant. Helicobacter pylori influences expression of the soluble form of MUC 1 mucin and Lewis a and b structures present in gastric juice.

The influence of Helicobacter pylori patients' treatment on MUC 1 content in gastric juice

BACKGROUND/AIMS

Helicobacter pylori that resides in the gastric mucus layer is the major etiological factor in gastritis, gastric ulcers and carcinomas. Among others, carbohydrate structures of MUC 1 mucin are also considered by some authors as being important in the mechanism of infection. The main aim of our study was to establish whether Helicobacter pylori treatment has any influence on the level of soluble form of MUC 1 mucin in gastric juice.

METHODOLOGY

We examined two groups of Helicobacter pylori infected patients. The first group was treated with omeprazole (at the end of the therapy the bacterium was still present). The second group was treated with omeprazole and antibiotics, and the bacterium eradication was confirmed. MUC 1 mucin was determined by Western blotting technique.

RESULTS

Before the therapy, the level of MUC 1 was found to be low in almost all cases, while at the end of the treatment in both groups of patients an increase of MUC 1 mucin was observed.

CONCLUSIONS

Our results can confirm the thesis that Helicobacter pylori inhibits the expression of MUC 1 mucin on cell membranes.

Application of the 50% Hydrazine Solution Method for O-Glycans Release, their Chemical Labeling, and HPLC Separation

Mucins are high molecular mass glycoproteins with oligosaccharides O-bonded to the protein core. beta-elimination is the most popular method used for releasing of O-glycans. However to such released glycoforms it is difficult to introduce a label to amplify a signal for oligosaccharide detection.In our study we used a combination of the beta-elimination and hydrazinolysis methods. Released glycoforms were labeled with para-amino benzooic acid ethyl ester (ABBE) and fractionated on HPLC column.This combined procedure seems to be a good tool for O-glycans analysis.

MUC 1 mucin content in gastric juice of duodenal ulcer patients: effect of Helicobacter pylori eradication therapy

It has been suggested that Helicobacter pylori can interact via carbohydrate structures with gastric mucins. Particularly, the Lewis b structures of the secretory MUC 5AC mucin are considered to be putative receptors for bacterial adhesins. Also the epithelial MUC 1 mucin is implicated by some authors to have a major role in the mechanism of infection. The main objective of our study was to evaluate MUC 1 mucin levels in human gastric juice before and at the end of eradication therapy. Any possible changes could suggest the participation of MUC 1 in H. pylori infection. We assume that the amount of the soluble form of MUC 1 exfoliated to the juice correlates with MUC 1 expressed on epithelial cells. Gastric juice samples of 14 duodenal ulcer patients infected with H. pylori were assayed before and at the end of eradication. In all samples, DNA content was determined. Mucin fractions were isolated by gel exclusion chromatography. High molecular mass material containing MUC 1 was subjected to 4%-12% polyacrylamide gradient gels, electrotransfer to Immobilon P and immunodetection. In 12 infected patients (86%), the initial low level of MUC 1 mucin in gastric juice increased at the end of eradication. In comparison to the infected patients, neutral carbohydrate and DNA content in gastric juice diminished after treatment. Our results indicate that the bacterium affects the soluble form of MUC 1 mucin, thus suggesting a likely role of this mucin in the course of H. pylori infection.

Statistical evaluation of the isoform patterns of N-acetyl-beta-hexosaminidase from human renal cancer tissue separated by isoelectrofocusing

OBJECTIVES

Isoenzymes of HEX from human renal carcinoma and neighbouring macroscopically normal renal tissue can show different patterns on isoelectrofocusing gels. The aim of our work was to elaborate the method for statistical evaluation of differences.

DESIGN AND METHODS

Isoenzymes of N-acetyl-beta-hexosaminidase were separated from renal (control and cancerous) tissues of 15 patients. Isoenzymes were electrofocused in Multiphor II, with ampholine pH 3.5-9.0 (2%) and then evaluated densitometrically and analysed statistically.

RESULTS

A similar pattern in activity of isoforms of isoenzymes A and B in normal and cancerous renal tissue was observed.

CONCLUSIONS

The proposed method of statistical evaluation of differences in isoforms of N-acetyl-beta-glucosaminidase can also be adapted to estimate the isoforms of other enzymes in different tissues.