Mucin Secretion Research Articles

Synergic Laxative Effects of an Herbal Mixture of Liriope platyphylla, Glycyrrhiza uralensis, and Cinnamomum cassia in Loperamide-Induced Constipation of Sprague Dawley Rats.

Constipation is an acute or chronic illness attributed to various causes, ranging from lifestyle habits to side effects of a disease. To improve the laxative effects of some traditional medicines, herbal mixtures of Liriope platyphylla, Glycyrrhiza uralensis, and Cinnamomum cassia (LGC) were evaluated for their mechanism of action and therapeutic effects in loperamide (Lop)-induced constipated Sprague Dawley rats by examining alterations in excretion parameters, histological structure, mucin secretion, and related protein levels. Food intake and water consumption were constant for all animals. We observed that the Lop+LGC-treated group had significantly greater excretion of stool and urine than was observed in the Lop+Vehicle-treated group. Administration of LGC in the constipation model restored the intestinal transit ratio to normal levels, and increased the number of goblet cells, mucosal layer, and muscle thickness. Mucin secretion was greater in the Lop+LGC-treated group than in the Lop+Vehicle-treated group, and the expression of MUC2 and AQP8 genes were also increased. In addition, reverse transcription polymerase chain reaction and Western blot revealed an increase in the muscarinic acetylcholine receptors (mAChRs) in the Lop+LGC-treated group compared to the Lop+Vehicle-treated group. Furthermore, compared with the Lop+Vehicle-treated group, treatment with LGC reduced the phosphorylation of PKC and PI3K, and expression of Gα protein, but increased levels of IP3. Our results suggest that the traditional herbal mixture of LGC induces a potent laxative effect in Lop-induced constipation through mucosal tissue changes and mucin production. We also demonstrated that the laxative effect of LGC is closely related to the expression of mAChR and its downstream signals, suggesting the possibility of developing a constipation-laxative agent using LGC.

Different Munc18 proteins mediate baseline and stimulated airway mucin secretion.

Airway mucin secretion is necessary for ciliary clearance of inhaled particles and pathogens but can be detrimental in pathologies such as asthma and cystic fibrosis. Exocytosis in mammals requires a Munc18 scaffolding protein, and airway secretory cells express all 3 Munc18 isoforms. Using conditional airway epithelial cell-deletant mice, we found that Munc18a has the major role in baseline mucin secretion, Munc18b has the major role in stimulated mucin secretion, and Munc18c does not function in mucin secretion. In an allergic asthma model, Munc18b deletion reduced airway mucus occlusion and airflow resistance. In a cystic fibrosis model, Munc18b deletion reduced airway mucus occlusion and emphysema. Munc18b deficiency in the airway epithelium did not result in any abnormalities of lung structure, particle clearance, inflammation, or bacterial infection. Our results show that regulated secretion in a polarized epithelial cell may involve more than one exocytic machine at the apical plasma membrane and that the protective roles of mucin secretion can be preserved while therapeutically targeting its pathologic roles.

Effects of chlorogenic acid, epicatechin gallate, and quercetin on mucin expression and secretion in the Caco-2/HT29-MTX cell model.

Mucins are a family of large glycoproteins that represent the major structural components of the mucus and are encoded by 20 different mucin genes. Mucin expression can be modulated by different stimuli. In this study, we analyzed four mucins (MUC2, MUC3, MUC13, and MUC17) in coculture of Caco‐2/HT29‐MTX cells to demonstrate the variation in gene expression in the presence of antioxidant compounds like chlorogenic acid, epicatechin gallate, and quercetin (apple, tea, and coffee polyphenols, respectively). coculture of Caco‐2/HT29‐MTX cells was treated with polyphenols, and the expression of four mucins was determined by reverse‐transcriptase PCR. In addition, the secretion levels of MUC2 were established by enzyme‐linked immunoassay (ELISA) analysis. The results showed that each polyphenol compound induces different expression patterns of the mucin genes. Statistically significant up‐regulation of MUC17 was observed following incubation with epicatechin gallate and quercetin. ELISA results did not prove any significant differences in protein levels of MUC2 after treatment by the polyphenol compounds. The polyphenols considered in this study may influence mucin secretion and act on diverse salivary substrates to change the barrier properties of mucins for mucus secretion in different ways.

A Nanosensor Toolbox for Rapid, Label-Free Measurement of Airway Surface Liquid and Epithelial Cell Function.

Ciliated lung epithelial cells and the airway surface liquid (ASL) comprise one of the body's most important protective systems. This system is finely tuned, and perturbations to ASL rheology, ASL depth, ASL pH, the transepithelial potential, and the cilia beat frequency are all associated with disease pathology. Further, these apparently distinct properties interact with each other in a complex manner. For example, changes in ASL rheology can result from altered mucin secretion, changes in ASL pH, or changes in ASL depth. Thus, one of the great challenges in trying to understand airway pathology is that the properties of the ASL/epithelial cell system need to be assessed near-simultaneously and without perturbing the sample. Here, we show that nanosensor probes mounted on a scanning ion conductance microscope make this possible for the first time, without any need for labeling. We also demonstrate that ASL from senescence-retarded human bronchial epithelial cells retains its native properties. Our results demonstrate that by using a nanosensor approach, it is possible to pursue faster, more accurate, more coherent, and more informative studies of ASL and airway epithelia in health and disease.

Bisphenol A inhibits mucin 2 secretion in intestinal goblet cells through mitochondrial dysfunction and oxidative stress

AimsBisphenol A (BPA) can induce intestinal epithelial cell barrier dysfunction; however, its effects on the intestinal mucus barrier remain unclear. We used LS174T cells as a model to investigate the effects of BPA on the functions of intestinal goblet cells. Main methodsThis study used CCK-8, flow cytometry, ELISA and real-time PCR to investigate the effects of BPA on mitochondrial dynamics, oxidative stress and apoptosis in goblet cells. In addition, mucin synthesis and secretion were evaluated using PAS staining and a PAS assay, respectively. Key findingsOur results indicate that BPA reduced cell viability in a time- and concentration-dependent manner. BPA induced mitochondrial dysfunction, as indicated by the depolarization of the mitochondrial membrane potential, inhibition of mitochondrial respiratory chain complex enzyme activity and reduction of ATP production. Moreover, BPA caused oxidative stress by significantly increasing the accumulation of ROS, as well as oxidative stress products, and reducing the antioxidant capacity. Furthermore, BPA induced intestinal goblet cell apoptosis, accompanied by increased DNA fragmentation, caspase-3, -8, -9,-10 gene expression and enzyme activity. Additionally, BPA inhibited the synthesis and secretion of mucin 2. SignificanceOur data suggest that BPA affected the secretory function of intestinal goblet cells by inducing mitochondrial dysfunction, oxidative stress, and apoptosis.

Immunoresolvent Resolvin D1 Maintains the Health of the Ocular Surface.

The present review focuses on the role of one of the D-series resolvins (Rv) RvD1 in the regulation of conjunctival goblet cell secretion and its role in ocular surface health. RvD1 is the most thoroughly studied of the specialized proresolution mediators in the goblet cells. The anterior surface of the eye consists of the cornea (the transparent central area) and the conjunctiva (opaque tissue that surrounds the cornea and lines the eyelids). The secretory mucin MUC5AC produced by the conjunctival goblet cells is protective of the ocular surface and especially helps to maintain clear vision through the cornea. In health, a complex neural reflex stimulates goblet cell secretion to maintain an optimum amount of mucin in the tear film. The specialized pro-resolution mediator, D-series resolvin (RvD1) is present in human tears and induces goblet cell mucin secretion. RvD1 interacts with its receptors ALX/FPR2 and GPR32, activates phospholipases C, D, and A2, as well as the EGFR. This stimulation increases the intracellular [Ca2+] and activates extracellular regulated kinase (ERK) 1/2 to cause mucin secretion into the tear film. This mucin secretion protects the ocular surface from the challenges in the external milieu thus maintaining a healthy interface between the eye and the environment. RvD1 forms a second important mechanism along with activation of a neural reflex pathway to regulate goblet cell mucin secretion and protect the ocular surface in health.

Sodium channel TRPM4 and sodium/calcium exchangers (NCX) cooperate in the control of Ca2+-induced mucin secretion from goblet cells

Regulated mucin secretion is essential for the formation of the mucus layer that protects the underlying epithelial cells from foreign particles. Alterations in the quantity or quality of secreted mucins are therefore detrimental to airway and colon physiology. Based on various biochemical assays in several human cell lines, we report here that Na+/Ca2+ exchanger 2 (NCX2) works in conjunction with transient receptor potential cation channel subfamily M member 4 (TRPM4), and perhaps TRPM5, Na+ channels to control Ca2+-mediated secretion of both mucin 2 (MUC2) and MUC5AC from HT29-18N2 colonic cancer cells. Differentiated normal bronchial epithelial (NHBE) cells and tracheal cells from patients with cystic fibrosis (CFT1-LC3) expressed only TRPM4 and all three isoforms of NCXs. Blocking the activity of TRPM4 or NCX proteins abrogated MUC5AC secretion from NHBE and CFT1-LC3 cells. Altogether, our findings reveal that NCX and TRPM4/TRPM5 are both required for mucin secretion. We therefore propose that these two proteins could be potential pharmacological targets to control mucus-related pathologies such as cystic fibrosis.

High-grade non-small cell lung carcinoma: a comparative analysis of the phenotypic profile in small biopsies with the corresponding postoperative material.

The most recent classification of the lung cancer expanded the diagnostic criteria of its histological subtypes and included its immunophenotypic profile. We performed the study to compare the reliability of selected markers in high-grade non-small cell lung carcinoma (NSCLC) in the oligobiopsies with the matched postoperative samples. We evaluated expression of p40, p63, TTF1, cytokeratin 5/6, cytokeratin 7, napsin A, desmoglein 3, desmocollin 3 and mucin secretion as detected by mucicarmine staining. The study cohort included 123 cases of poorly-differentiated NSCLC. The tissue oligobiopsy material was available in 38 cases. Tissue microarrays (TMAs) from all postoperative cases were constructed. Comparing the immunophenotype between postsurgical samples and oligobiopsies we found an almost perfect agreement for most of performed IHC reactions. The highest concordance of results was found for desmoglein 3, CK7, and p40, whereas the lowest - for desmocollin 3. Immunoprofile of the oligobiopsies corresponded well to that in the resection specimens. The most useful markers in poorly differentiated ADs are: TTF1 and napsin A, and for non-keratinizing SCCs: p40, p63, CK5/6 and desmoglein 3.

Morphological characterization and molecular profiling of malignant pericardial effusion in patients with pulmonary adenocarcinoma.

Malignant pericardial effusions (MPCEs) is a common complication observed in advanced pulmonary adenocarcinoma. In such cases, investigating molecular alterations can have significant therapeutic implication in determining anticancer drugs. The objective was to evaluate the significance of cell block technique in the diagnosis of MPCE and further investigate the morphological and molecular profiles of MPCE in patients with pulmonary adenocarcinoma. Cytopathological and molecular profiles of 19 MPCE cases in patients with pulmonary adenocarcinoma were retrospectively analyzed. The control group consisted of 14 malignant pleural effusion (MPE) cases in patients with pulmonary adenocarcinoma. Anaplastic lymphoma kinase (ALK) and tyrosine-protein kinase Met (C-MET) expression was evaluated by fluorescence in situ hybridization (FISH). Epithelial growth factor receptor (EGFR) and K-Ras (KRAS) mutations were detected by ARMS real-time polymerase chain reaction (RT-PCR). Associations between MPCE and MPE were analyzed using Fisher's exact test. MPCE was found to have micropapillary and solid pattern predominant with mucin secretion compared to acinar patterns, as seen in MPE. Seventeen MPCE cases (89.5%) and all MPE cases (100%) underwent molecular analysis. Mutations in EGFR and KRAS, ALK rearrangement, and C-MET amplification were observed in MPCE and MPE with statistical differences. Additionally, two MPCE cases demonstrated EGFR T790M mutation and multiple insertions at L858. MPCE shows micropapillary and solid cytological patterns predominant with mucin secretion. MPCE are suitable to analyze oncogenic mutations and to develop targeted therapy for patients with pulmonary adenocarcinoma. Further molecular investigations may reveal novel molecular alterations.

Pancreatic Intraductal Papillary Mucinous Neoplasm With Elevated Pre-Operative Cystic Carcinoembryonic Antigen Level: A Histopathologic Correlation.

BackgroundTo study the relationship between carcinoembryonic antigen (CEA) level, intraductal papillary mucinous neoplasm (IPMN) subtype, and the presence of invasive carcinoma.MethodsCystic CEA level and the following pathologic variables: subtypes of IPMN, size of cystic lesion, presence of dysplasia or carcinoma, and main or branch duct involvement from 45 IPMN cases were analyzed.ResultsThere was a significant correlation between pre-operative cystic fluid CEA level and the intensity of luminal CEA staining. However, there was no correlation between CEA level and cystic mucinous secretions or mucinous epithelial cytoplasm CEA staining, mucin glycoprotein expression, size of lesion, grade of dysplasia or presence of invasive carcinoma. CEA level was neither sensitive nor specific for the presence of invasive carcinoma.ConclusionsCystic CEA level may not be a reliable determinant of the presence or absence of invasive carcinoma in IPMNs, and its use to assess risk of malignancy may be limited.

Localization of secretory mucins MUC5AC and MUC5B in normal/healthy human airways

Localization of secretory mucins MUC5AC and MUC5B in normal/healthy human airways

Cytopathologic Features of Secretory Carcinoma of Salivary Gland: Report of Two Cases.

Secretory carcinoma of the salivary gland (SC) is a newly introduced rare salivary gland tumor that shares histological, immunohistochemical, and genetic characteristics with secretory carcinoma of the breast. Here, we report the cytologic features of two cases of SC confirmed by surgical resection. In these two cases, SC was incidentally detected in a 64-year-old female and a 56-yearold male. Fine needle aspiration cytology revealed nests of tumor cells with a papillary or glandular structure floating in mucinous secretions. The tumor cells demonstrated uniform, round, smooth nuclear contours and distinct nucleoli. Multiple characteristic cytoplasmic vacuoles were revealed. Singly scattered tumor cells frequently showed variable sized cytoplasmic vacuoles. The cytopathologic diagnosis of SC should be considered when characteristic cytological findings are revealed. Further immunohistochemistry and gene analyses are helpful to diagnose SC.

Histochemical evaluation of an epithelial layer of the cardiac part gastroesophageal junction mucosa in the different periods of a prenatal ontogenesis of human (part 2)

In order to study the quantitative and qualitative composition of mucins of the gastroesophageal zone (GEZ) epithelium during the stages of embryonic and fetal periods of ontogenesis, we conducted morphometric and histochemical studies of the epithelial differon of the gastroesophageal junction (GEJ). The early embryonic period of 5–6 weeks was established to have been observing a gradual increase of neutral and acid mucins secretion in the gastric parts of the GEJ epithelial differon whereas the embryo-fetal or non-fetal period from 7 to 9 weeks was characterized by changing and the structural rearrangement of the epithelial differon and sulfomucins appearance in gastric epithelium and gradual decrease in the production of acid mucins. The early fetal period (10–28 weeks) is characterized by disappearance of acid sialomucins in the enterocytes of the GEZ from 10 to 18 weeks and an increase to 7.65±0.18% of neutral mucins with a drop in their level in the 18-20 week period and a decrease to 24±0.10% at 28 weeks (p<0.001). The late fetal period, from 28 to 38 weeks, was characterized by a complete structural rearrangement of the epithelial differon of the GEZ with the formation of a simple columnar epithelium of the cardiac part of the stomach with incomplete histochemical cytological differentiation of the GEZ gastric epithelium. It was evidenced by the presence of residual acid mucins (sialomucins) that are not typical for mature gastric epithelium.

Disease-related responses induced by cadmium in an in vitro human airway tissue model

Cadmium (Cd) is found at high concentrations in tobacco smoke due to its volatility when tobacco is burned. Inhaled Cd is linked to smoking-related respiratory diseases, such as chronic obstructive pulmonary disease and lung cancer. Alterations in mucociliary clearance, squamous metaplasia, and carcinoma are commonly observed in the respiratory tract of animals exposed to Cd. In vitro cell models widely used to study mechanisms underlying Cd toxicity are not suitable for studying its effects on mucociliary clearance and airway tissue remodeling. Herein we assess Cd-induced functional and structural changes in a well-differentiated human air-liquid-interface (ALI) airway tissue model. Acute treatments with Cd induced aberrant expression and secretion of mucins, impaired cilia functions, and squamous differentiation, and produced persistent oxidative stress and enhanced release of pro-inflammatory cytokines and matrix metalloproteinases. Accumulation of intracellular Cd was associated with sustained oxidative stress and inflammation, which, in turn, may have initiated squamous differentiation in ALI cultures. These observations demonstrate that ALI airway tissue models can recapitulate the functional and structural alterations in Cd-exposed animals, suggesting their potential application for studying tissue responses related to respiratory toxicants like those present in tobacco smoke.

The effect of hyperthermia (42°C) on the anti-tumoral effect of bromelain, N-acetyl cysteine, chemotherapeutic agents and their combinations - an in vitro evaluation

Bromelain, N-acetyl cysteine and their combinations show cytotoxicity at 37°C. Similarly, their combinations with common chemotherapeutic agents (gemcetabine, Mitomycin C, oxaliplatin and 5-FU) show enhanced cytotoxicity. Since, hyperthermia (42°C) inhibits cellular proliferation, we set out to determine if it would further enhance the effect of these agents. Tumour cells (pancreatic and colorectal) were grown in a 96 well plate and treated to various agents and their combinations at 37° and 42°C. The survival of cells at 72 hours was evaluated with sulfhordamine assay. Colony formation assay was performed to evaluate development of resistance to these agents and finally PAS staining was carried out to determine the effect of bromelain, Nacetylcysteine (NAC), oxaliplatin and their combinations on mucin secretion in ASPC-1 (pancreatic) cancer cells. Hyperthermia (42°C) enhanced cytotoxicity of certain agents or their combinations in some of the cell lines. It also showed the absence or a reduction of effect, with certain agents. Hyperthermia reduced colony formation in CFPAC cells and with agents (bromelain + NAC, gemcitabine, NAC + gemcitabine, Bromelain + NAC + Gemcitabine). A similar effect with 5FU, 5FU + NAC and 5FU + bromelain was observed. Hyperthermia reduced mucin secretion in ASPC-1 cells, with bromelain and its combinations with NAC and oxaliplatin. NAC as a single agent increased mucin with hyperthermia. The effect of hyperthermia on cytotoxicity of bromelain, NAC and their combinations with chemotherapeutic agents varied with agents, their combinations and cell types, showing an increase, null effect or a decrease. However, hyperthermia reduced colony formation and mucin secretion.

Resolvin D1, but not resolvin E1, transactivates the epidermal growth factor receptor to increase intracellular calcium and glycoconjugate secretion in rat and human conjunctival goblet cells

PurposeTo identify interactions of the epidermal growth factor receptor (EGFR) with the pro-resolving mediator receptors for RvD1 and RvE1 to stimulate an increase in intracellular [Ca2+] ([Ca2+]i) and mucin secretion from cultured human and rat conjunctival goblet cells. MethodsGoblet cells from human and rat conjunctiva were grown in culture using RPMI media. Cultured goblet cells were pre-incubated with inhibitors, and then stimulated with RvD1, RvE1, EGF or the cholinergic agonist carbachol (Cch). Increase in [Ca2+]i was measured using fura-2/AM. Goblet cell secretion was measured using an enzyme-linked lectin assay with UEA-1. Western blot analysis was performed with antibodies against AKT and ERK 1/2. ResultsIn cultured human conjunctival goblet cells RvE1 -stimulated an increase in [Ca2+]i. RvD1-, but not the RvE1-, stimulated increase in [Ca2+]i and mucin secretion was blocked by the EGFR inhibitor AG1478 and siRNA for the EGFR. RvD1-, but not RvE1-stimulated an increase in [Ca2+]i that was also inhibited by TAPI-1, an inhibitor of the matrix metalloprotease ADAM 17. Inhibition of the EGFR also blocked RvD1-stimulated increase in AKT activity and both RvD1-and RvE1-stimulated increase in ERK 1/2 activity. Pretreatment with either RvD1 or RvE1 did not block the EGFR-stimulated increase in [Ca2+]i. ConclusionsWe conclude that in cultured rat and human conjunctival goblet cells, RvD1 activates the EGFR, increases [Ca2+]i, activates AKT and ERK1/2 to stimulate mucin secretion. RvE1 does not transactivate the EGFR to increase [Ca2+]I and stimulate mucin secretion, but does interact with the receptor to increase ERK 1/2 activity.

Secreted Mucins on the Ocular Surface.

Mucins, which play important roles on the ocular surface in wettability, lubrication, and barrier function, are classified into two categories: secreted mucins and membrane-associated mucins. The most important secreted mucin on the ocular surface is MUC5AC, which is secreted by the conjunctival goblet cells. In the human conjunctiva, goblet cells are present in higher concentrations in the fornix, inferior nasal bulbar, and the lid wiper on the lid margin. The number of conjunctival goblet cells and MUC5AC expression/secretion are decreased in a patient with dry eye. In Japan, drugs that stimulate mucin secretion or increase the number of conjunctival goblet cells are commercially available. A P2Y2 receptor, diquafosol, stimulates tear fluid secretion from conjunctival epithelial cells and promotes mucin secretion from conjunctival goblet cells. Rebamipide was marketed originally as an oral therapeutic drug to treat gastritis in Japan. Topical rebamipide increases numbers of goblet cells in the bulbar conjunctiva and the lid wiper area of palpebral conjunctiva. Many researchers have reported decreases in the ocular surface mucin expression including MUC5AC secreted by goblet cells in patients with dry eye. However, it is unknown whether changes in mucin expression on the ocular surface cause or result from dry eye. Further study is needed to determine the true mechanism of dry eye disease.

Commercial Porcine Gastric Mucin Preparations, also Used as Artificial Saliva, are a Rich Source for the Lectin TFF2: In Vitro Binding Studies.

Mucous gels (mucus) cover internal body surfaces. The secretory mucins MUC5AC and MUC6 and the protective peptide TFF2 are characteristic constituents of gastric mucus; TFF2 is co-secreted with MUC6. Herein, we investigated two commercial mucin preparations by FPLC and proteomics, because they are model systems for studying the rheology of gastric mucins. One preparation is also used as a saliva substitute, for example, after radiation therapy. We show that both preparations contain TFF2 (≈0.6 to 1.1 %, w/w). The majority of TFF2 is strongly bound noncovalently to mucin in a manner that is resistant to boiling in SDS. First overlay assays with 125 I-labeled porcine TFF2 revealed that mucin binding is modulated by Ca2+ and can be blocked by the lectin GSA-II and the antibody HIK1083, both recognizing the peripheral GlcNAcα1→4Galβ1→R moiety of MUC6. TFF2 binding was also inhibited in the presence of Me-β-Gal but less so by the α anomer. TFF2 may play a role in the oligomerization and secretion of MUC6, the rheology of gastric mucus, and the adherence of gastric microbiota. TFF2 in artificial saliva may be of benefit. TFF2 might also interact with the sugar moiety of various receptors.

Reconsidering the central role of mucins in dry eye and ocular surface diseases.

Mucins are key actors in tear film quality and tear film stability. Alteration of membrane-bound mucin expression on corneal and conjunctival epithelial cells and/or gel-forming mucin secretion by goblet cells (GCs) promotes in ocular surface diseases and dry eye disease (DED). Changes in the mucin layer may lead to enhanced tear evaporation eventually contributing to tear hyperosmolarity which has been associated with ocular surface inflammation. Inflammatory mediators in turn may have a negative impact on GCs differentiation, proliferation, and mucin secretion. This sheds new light on the position of GCs in the vicious circle of DED. As contributor to ocular surface immune homeostasis, GC loss may contribute to impaired ocular surface immune tolerance observed in DED. In spite of this, there are no tools in routine clinical practice for exploring ocular surface mucin deficiency/dysregulation. Therefore, when selecting the most appropriate treatment options, there is a clear unmet need for a better understanding of the importance of mucins and options for their replacement. Here, we comprehensively revisited the current knowledge on ocular surface mucin biology, including functions, synthesis, and secretion as well as the available diagnostic tools and treatment options to improve mucin-associated homeostasis. In particular, we detailed the potential link between mucin dysfunction and inflammation as part of the uncontrolled chronic inflammation which perpetuates the vicious circle in DED.

Establishment of a Mucin Secreting Cell Line Cx-03 from an Uterine Carcino Sarcoma.

The identification of novel cell lines which combine the most important properties of mucosal membranes in terms of drug absorption, transmembrane transport and mucus secretion can help to establish improved and meaningful test systems for pharmacological and infectiological studies. We have established a novel mucus secreting tumor cell line (Cx-03) derived from a female patient who underwent radical hysterectomy after diagnosis of a large malignant carcino sarcoma (Muellerian mixed tumor). Via xenotransplantation in SCID beige mice, recultivation and subcloning a stable cell line was established from primary tumor cells. Human origin and novelty of the cell line was determined by karyotype analysis and STR fingerprint. During growth cells produce considerable amounts of a PAS positive viscoelastic mucus. Immunostaining revealed expression of mucins and the mucin modifier CLCA1. We demonstrate in initial electrophysiological experiments that confluent, polarized monolayers of Cx-03 are formed (on PCF-filter supports) that exhibit stable electrical resistance (> 600Ω cm2). Confluent Cx-03 monolayers express barrier-forming tight junction proteins claudin-1 and -4 which co-localize with zonula occludens protein-1 (ZO-1) at cell-cell contacts. Mucus secretion is a rare property among mammalian cell lines. In combination with its ability to form polarized monolayers Cx-03 might contribute as a novel cell based model for drug absorption, transport and barrier studies.