First Evidence for a Role of Siglec-8 in Breast Cancer.

Sialic acid-binding immunoglobulin-like lectins (Siglecs) are involved in various immune cell-mediated diseases. Their role in cancer is poorly investigated, and research focusses on Siglec-expression on immune cells interacting with tumor cells. This study evaluates the role of Siglec-8 in breast cancer (BC). Siglec-8 expression was analyzed immunohistochemically on 235 primary BC cases and was correlated with clinical and pathological parameters and outcome. Cell culture experiments were performed with various BC cell lines. Siglec-8 was expressed in 215 BC cases and expression was lowest in triple-negative BC. It correlated with estrogen receptor-status, grading and the prognostic factors galectin (Gal)-7 and tumor-associated mucin-1 (TA-MUC1). However, Gal-7 and TA-MUC1 were only prognosticators for clinical outcome in the cohort expressing high (Immunoreactivity score IRS > 3) Siglec-8 levels but not in the low-expressing cohort. Siglec-8 knockdown led to a significantly reduced Gal-7 expression in MCF7 cells. All BC cell lines expressed low Siglec-8-levels, that could be elevated in MCF7 by Peroxisome proliferator-activated receptor (PPARγ)-stimulation. This study demonstrates that Siglec-8 is expressed in BC cells and correlates with known clinical and prognostic parameters. It is probably associated with Gal-7 and TA-MUC1 and might be regulated via PPARγ. Further analyses focusing on functional associations will clarify Siglec-8's eligibility as a possible therapeutic target.

JAK1/2 pathway inhibition suppresses M2 polarization and overcomes resistance of myeloma to lenalidomide by reducing TRIB1, MUC1, CD44, CXCL12, and CXCR4 expression.

Monocytes polarize into pro-inflammatory macrophage-1 (M1) or alternative macrophage-2 (M2) states with distinct phenotypes and physiological functions. M2 cells promote tumour growth and metastasis whereas M1 macrophages show anti-tumour effects. We found that M2 cells were increased whereas M1 cells were decreased in bone marrow (BM) from multiple myeloma (MM) patients with progressive disease (PD) compared to those in complete remission (CR). Gene expression of Tribbles homolog 1 (TRIB1) protein kinase, an inducer of M2 polarization, was increased in BM from MM patients with PD compared to those in CR. Ruxolitinib (RUX) is an inhibitor of the Janus kinase family of protein tyrosine kinases (JAKs) and is effective for treating patients with myeloproliferative disorders. RUX markedly reduces both M2 polarization and TRIB1 gene expression in MM both in vitro and in vivo in human MM xenografts in severe combined immunodeficient mice. RUX also downregulates the expression of CXCL12, CXCR4, MUC1, and CD44 in MM cells and monocytes co-cultured with MM tumour cells; overexpression of these genes is associated with resistance of MM cells to the immunomodulatory agent lenalidomide. These results provide the rationale for evaluation of JAK inhibitors, including MM BM in combination with lenalidomide, for the treatment of MM patients.

Smoking-associated increase in mucins 1 and 4 in human airways.

RATIONALE: Smoking-related chronic obstructive pulmonary disease (COPD) is associated with dysregulated production of mucus. Mucins (MUC) are important both for mucus secretion and epithelial defense. We have examined the distribution of MUC1 and MUC4 in the airway epithelial cells of never-smokers and smokers with and without COPD. METHODS: Mucosal biopsies and bronchial wash samples were obtained by bronchoscopy from age- and sex-matched COPD-patients (n = 38; GOLD I-II/A-B), healthy never-smokers (n = 40) and current smokers with normal lung function (n = 40) from the Karolinska COSMIC cohort (NCT02627872). Cell-specific expressions of MUC1, MUC4 and regulating factors, i.e., epithelial growth factor receptor (EGFR) 1 and 2, were analyzed by immunohistochemistry. Soluble MUC1 was measured by quantitative immunodetection on slot blot. RESULTS: The levels of cell-bound MUC1 expression in basal cells and in soluble MUC1 in bronchial wash were increased in smokers, regardless of airway obstruction. Patients with chronic bronchitis had higher MUC1 expression. The expression of MUC4 in cells with goblet cell phenotype was increased in smokers. The expression of EGFR2, but not that of EGFR1, was higher in never-smokers than in smokers. CONCLUSIONS: Smoking history and the presence of chronic bronchitis, regardless of airway obstruction, affect both cellular and soluble MUC1 in human airways. Therefore, MUC1 may be a novel marker for smoking- associated airway disease.

Embryo implantation evolved from an ancestral inflammatory attachment reaction.

The molecular changes that support implantation in eutherian mammals are necessary to establish pregnancy. In marsupials, pregnancy is relatively short, and although a placenta does form, it is present for only a few days before parturition. However, morphological changes in the uterus of marsupials at term mimic those that occur during implantation in humans and mice. We investigated the molecular similarity between term pregnancy in the marsupials and implantation in eutherian mammals using the gray short-tailed opossum (Monodelphis domestica) as a model. Transcriptomic analysis shows that term pregnancy in the opossum is characterized by an inflammatory response consistent with implantation in humans and mice. This immune response is temporally correlated with the loss of the eggshell, and we used immunohistochemistry to report that this reaction occurs at the materno-fetal interface. We demonstrate that key markers of implantation, including Heparin binding EGF-like growth factor and Mucin 1, exhibit expression and localization profiles consistent with the pattern observed during implantation in eutherian mammals. Finally, we show that there are transcriptome-wide similarities between the opossum attachment reaction and implantation in rabbits and humans. Our data suggest that the implantation reaction that occurs in eutherians is derived from an attachment reaction in the ancestral therian mammal which, in the opossum, leads directly to parturition. Finally, we argue that the ability to shift from an inflammatory attachment reaction to a noninflammatory period of pregnancy was a key innovation in eutherian mammals that allowed an extended period of intimate placentation.

From an increase in the number of tandem repeats through the decrease of sialylation to the downregulation of MUC1 expression level.

Enhanced glucose uptake by cancer cells was demonstrated in many studies in vitro and in vivo. Glycolysis is one of the main ways of obtaining energy in hypoxia conditions. However, in addition to energy exchange, carbohydrates are also necessary for the posttranslational modification of the protein molecules. Cancer cells are often characterized by an enhanced expression of different glycoproteides. Correct glycosylation defines the structure and activity of such molecules. We demonstrated that under the same cultivation conditions, the intensity of glycosylation does not depend on the total number of potential O-glycosylation sites in one molecule. As a model for the investigation, the tandem repeat region (region with variable number of tandem repeats) of the human mucin MUC1, in which each of the repeats carries four potential O-glycosylation sites, was used. An increase of the tandem repeat number in the recombinant protein did not lead to a proportional increase in the level of sLea glycosides. A consequence of this was a reduction in the number of recombinant proteins associated with the cytoplasmic membrane at an overall high expression level. Prolongation of the cultivation duration led to a reduction in the expression level of the recombinant proteins by up to 30% of the initial level, and the intensity of this reduction was in a direct ratio to the number of tandem repeats in the protein molecule.

MUC1-C drives MYC in multiple myeloma.

Multiple myeloma (MM) cell lines and primary tumor cells are addicted to the MYC oncoprotein for survival. Little is known, however, about how MYC expression is upregulated in MM cells. The mucin 1 C-terminal subunit (MUC1-C) is an oncogenic transmembrane protein that is aberrantly expressed in MM cell lines and primary tumor samples. The present studies demonstrate that targeting MUC1-C with silencing by clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 editing or with the GO-203 inhibitor is associated with downregulation of MYC messenger RNA and protein. The results show that MUC1-C occupies the MYC promoter and thereby activates the MYC gene by a ß-catenin/transcription factor 4 (TCF4)-mediated mechanism. In this way, MUC1-C (1) increases ß-catenin occupancy on the MYC promoter, (2) forms a complex with ß-catenin and TCF4, and, in turn, (3) drives MYC transcription. Analysis of MM cells using quantitative real-time reverse transcription polymerase chain reaction arrays further demonstrated that silencing MUC1-C is associated with downregulation of MYC target genes, including CCND2, hTERT, and GCLC Analysis of microarray data sets further demonstrated that MUC1 levels positively correlate with MYC expression in MM progression and in primary cells from over 800 MM patients. These findings collectively provide convincing evidence that MUC1-C drives MYC expression in MM.

Quercetin Inhibits Breast Cancer Stem Cells via Downregulation of Aldehyde Dehydrogenase 1A1 (ALDH1A1), Chemokine Receptor Type 4 (CXCR4), Mucin 1 (MUC1), and Epithelial Cell Adhesion Molecule (EpCAM).

BACKGROUND Quercetin, nature's most common flavonoid, possesses anticarcinogenic properties against various forms of cancer. The aim of this study was to investigate the effect of quercetin on breast cancer stem cells in the MDA-MB-231 cell line, and to elucidate the possible mechanisms for those effects. MATERIAL AND METHODS We evaluated breast cancer stem cell proliferation, clone generation, and mammosphere formation to determine the effect of quercetin treatment on breast cancer stem cells. RESULTS In our study, quercetin suppressed breast cancer stem cell proliferation, self-renewal, and invasiveness. It also lowered the expression levels of proteins related to tumorigenesis and cancer progression, such as aldehyde dehydrogenase 1A1, C-X-C chemokine receptor type 4, mucin 1, and epithelial cell adhesion molecules. CONCLUSIONS These results indicate that quercetin targets and destroys breast cancer stem cells, making it a potential novel drug in the fight against cancer.

Mucine-1 Is Related to Cell-Mediated Immunoexpression and Blood Pressure in Pulmonary Artery in Pulmonary Arterial Hypertension (PAH): Preliminary Results.

BACKGROUND AND AIM: Mucine-1 (MUC1) increases in primary lung disease; however, no data are available on pulmonary arterial hypertension (PAH). Our aim was to analyze MUC1 in PAH and a possible link with pulmonary artery pressure (PAPs), PaO2, PaCO2 and cell-mediated immunity. METHODS: We studied nine PAH patients (four males and five females, aged 52 ± 21 years). The control groups were nine patients with pulmonary hypertensions due to lung disease (PPH; five males and four females, aged 63 ± 18 years) and 14 patients with left heart disease (HPH; four males and ten females, aged 73 ± 13 years). All underwent arterial gas analysis and echocardiography. A serum sample was collected to determine MUC1 and CD40L values on ELISA. RESULTS: No differences were found for PAPs and CD40L. MUC1 resulted in comparable values between PAH and HPH but decreased when compared to PPH (16.46 ± 4.12 vs 116.6 ± 47.08 U/ml, p = 0.049). pO2 was higher in PAH (PAH 83.18 ± 1.77 vs PPH 62.75 ± 3.23 mmHg, p = 0.003; vs HPH 65.83 ± 6.94 mmHg, p = 0.036). pCO2 was lower compared to PPH (36.15 ± 2.19 vs 45.83 ± 3.00 mmHg, p = 0.026) but not compared to HPH. In PAH patients the MUC1 correlated with pO2 (r = -0.91), pCO2 (r = 0.80), PAPs (r = 0.82) and CD40L (r = 0.72) while it did not in PPH and HPH. CONCLUSIONS: These preliminary data show a possible mechanism of immune stimulation in PAH patients. This may imply an association between lung parenchyma, immunity and increase in vascular resistance. Additional studies are required to confirm these findings.

Bone marrow stroma protects myeloma cells from cytotoxic damage via induction of the oncoprotein MUC1.

Multiple myeloma (MM) is a lethal haematological malignancy that arises in the context of a tumour microenvironment that promotes resistance to apoptosis and immune escape. In the present study, we demonstrate that co-culture of MM cells with stromal cells results in increased resistance to cytotoxic and biological agents as manifested by decreased rates of cell death following exposure to alkylating agents and the proteosome inhibitor, bortezomib. To identify the mechanism of increased resistance, we examined the effect of the co-culture of MM cells with stroma cells, on expression of the MUC1 oncogene, known to confer tumour cells with resistance to apoptosis and necrosis. Co-culture of stroma with MM cells resulted in increased MUC1 expression by tumour cells. The effect of stromal cell co-culture on MUC1 expression was not dependent on cell contact and was therefore thought to be due to soluble factors secreted by the stromal cells into the microenvironment. We demonstrated that MUC1 expression was mediated by interleukin-6 and subsequent up-regulation of the JAK-STAT pathway. Interestingly, the effect of stromal cell co-culture on tumour resistance was partially reversed by silencing of MUC1 in MM cells, consistent with the potential role of MUC1 in mediating resistance to cytotoxic-based therapies.

Development of an in vitro model to study uterine functions and early implantation using rat uterine explants.

This study was conducted to develop an in vitro model using rat uterine explants to explore complex uterine functions. Rat uterine explants (1-2 mm) were isolated, cultured and further characterized. Steroid hormone treatment of cultured explants showed that both Muc1 and Pr were significantly up-regulated (P < 0.05) by E2. Areg was significantly up-regulated (P < 0.05) by P4 and Igfbp1 was significantly up-regulated (P < 0.05) by the combination of E2 and P4, although, in rat, Igfbp1 is E2-dependent. In vitro decidualization of cultured explants was induced and two potential markers of decidualization, Prl8a2 and Bmp2, were examined. Real-time quantitative PCR data revealed that both Prl8a2 and Bmp2 were significantly up-regulated (P < 0.05) in MPA- and db-cAMP-treated explants compared to the control group of explants. Then, an individual hatched blastocyst and cultured explant was placed in a 96-well (round-bottom U-shaped) plate. Co-culture results showed that stable attachments were observed after 48 h, where embryos were stably attached to the explants and could not be dislodged after mild shaking and/or pipetting. The rates of attachment of embryos to the explants were increased significantly in the P4-treated group (63.6%) compared to the control group (35.5%), after steroid hormone treatment. The rates of attachment were reduced significantly in the E2-treated group (0.0%), where no stable attachments were observed. Despite the necessity of comprehensive investigation, our results suggest that the cultured rat uterine explants can be a useful in vitro model to study uterine functions and early implantation.

Innate immune defense in the inner ear - mucines are expressed by the human endolymphatic sac.

The human endolymphatic sac has been shown recently to have immunological capacities and has thus been proposed as the main entity protecting the inner ear from pathogen invasion, equivalent to mucosa-associated lymphoid tissue (MALT). Although the sac expresses molecules of the innate immune system, the potential expression of members of the important mucin family has not been detailed. Thus, this paper explores endolymphatic sac expression of a number of mucins and mucin precursors. Twelve fresh tissue samples from the human endolymphatic sac were obtained during translabyrinthine surgery. The expression of Mucin 1, 2, 5B/AC and 16, as well as the core structure elements (mucin precursors) T-antigen, Tn-antigen and Sialyl-Tn-antigen was investigated by immunohistochemistry. The endolymphatic sac epithelium expressed MUC1 (both apically towards the endolymphatic sac (ES) lumen and basally towards the capillary network), MUC 16 and Tn-antigen. There was no labeling after incubation with antibodies against T-antigen, sialyl-Tn-antigen, MUC2 and MUC5B/AC. We conclude that the human endolymphatic sac epithelium expresses a number of mucin molecules, which supports the hypothesis of the sac as the primary immunological tissue structure of the inner ear, equivalent to MALT in other organs. The mucins may also play a role in the formation and continuous homeostasis of the inner ear fluids, as well as the pathogenesis of Meniere's disease.

Critical roles of mucin-1 in sensitivity of lung cancer cells to tumor necrosis factor-alpha and dexamethasone.

Lung cancer is the leading cause of death from cancer. Mucins are glycoproteins with high molecular weight, responsible for cell growth, differentiation, and signaling, and were proposed to be correlated with gene heterogeneity of lung cancer. Here, we report aberrant expression of mucin genes and tumor necrosis factor receptors in lung adenocarcinoma tissues compared with normal tissues in GEO datasets. Mucin-1 (MUC1) gene was selected and considered as the target gene; furthermore, the expression pattern of adenocarcinomic cells (A549, H1650, or H1299 cells) was validated under the stimulation with tumor necrosis factor-alpha (TNFα) or dexamethasone (DEX), separately. MUC1 gene interference was done to A549 cells to show its role in sensitivity of lung cancer cells to TNFα and DEX. Results of our experiments indicate that MUC1 may regulate the influence of inflammatory mediators in effects of glucocorticoids (GCs), as a regulatory target to improve therapeutics. It shows the potential effect of MUC1 and GCs in lung adenocarcinoma (LADC), which may help in LADC treatment in the future.

IL-22/IL-22R1 signaling regulates the pathophysiology of chronic rhinosinusitis with nasal polyps via alteration of MUC1 expression.

BACKGROUND: IL-22 is an IL-10-family cytokine that regulates chronic inflammation. We investigated the role of IL-22 and its receptor, IL-22R1, in the pathophysiology of chronic rhinosinusitis with nasal polyps (CRSwNP). METHODS: IL-22 and IL-22R1 protein and mRNA expression in NP and in uncinate tissues (UT) from CRS and non-CRS patients was examined using immunohistochemistry and real-time PCR, respectively. Dispersed NP and UT cells were cultured with the Staphylococcus aureus exotoxins, staphylococcal enterotoxin B and alpha-toxin, following which exotoxin-induced IL-22 levels and their association with clinicopathological factors were analyzed. Effects of IL-22 on MUC1 expression and cytokine release in NP cells were also determined. RESULTS: IL-22 and IL-22R1 in NP were mainly expressed in infiltrating inflammatory cells and in epithelial cells, respectively. IL-22 mRNA levels in NP were significantly higher than those in UTs from non-CRS patients whereas IL-22R1 levels were conversely lower in NPs. NP cells produced substantial amounts of IL-22 in response to exotoxins. Exotoxin-induced IL-22 production by NP cells significantly and negatively correlated with the degree of local eosinophilia and postoperative computed tomography (CT) score, whereas conversely it positively correlated with the forced expiratory volume in 1s (FEV1)/forced vital capacity (FVC) ratio. IL-22 significantly enhanced MUC1 mRNA expression in NP cells. IL-22-induced MUC1 mRNA levels were significantly and positively correlated with IL-22R1 mRNA levels in NPs. CONCLUSIONS: These data suggest that imbalance of IL-22/IL-22R1 signaling regulates the pathogenesis of CRSwNP, including local eosinophilia, via alteration of MUC1 expression.

Micro-RNAs miR-29a and miR-330-5p function as tumor suppressors by targeting the MUC1 mucin in pancreatic cancer cells.

MUC1 is an oncogenic mucin overexpressed in several epithelial cancers, including pancreatic ductal adenocarcinoma, and is considered as a potent target for cancer therapy. To control cancer progression, miRNAs became very recently, major targets and tools to inhibit oncogene expression. Inhibiting MUC1 using miRNAs appears thus as an attractive strategy to reduce cancer progression. However, potent miRNAs and associated mechanisms regulating MUC1 expression remain to be identified. To this aim, we undertook to study MUC1 regulation by miRNAs in pancreatic cancer cells and identify those with tumor suppressive activity. MiRNAs potentially targeting the 3'-UTR, the coding region, or the 5'-UTR of MUC1 were selected using an in silico approach. Our in vitro and in vivo experiments indicate that miR-29a and miR-330-5p are strong inhibitors of MUC1 expression in pancreatic cancer cells through direct binding to MUC1 3'-UTR. MUC1 regulation by the other selected miRNAs (miR-183, miR-200a, miR-876-3p and miR-939) was found to be indirect. MiR-29a and miR-330-5p are also deregulated in human pancreatic cancer cell lines and tissues and in pancreatic tissues of Kras(G12D) mice. In vitro, miR-29a and miR-330-5p inhibit cell proliferation, cell migration, cell invasion and sensitize pancreatic cancer cells to gemcitabine. In vivo intra-tumoral injection of these two miRNAs in xenografted pancreatic tumors led to reduced tumor growth. Altogether, we have identified miR-29a and miR-330-5p as two new tumor suppressive miRNAs that inhibit the expression of MUC1 oncogenic mucin in pancreatic cancer cells.

Immunobiology and immunosurveillance in patients with intraductal papillary mucinous neoplasms (IPMNs), premalignant precursors of pancreatic adenocarcinomas.

Premalignant lesions for many cancers have been identified, and efforts are currently directed toward identification of antigens expressed on these lesions that would provide suitable targets for vaccines for cancer prevention. Intraductal papillary mucinous neoplasms (IPMNs) are premalignant pancreatic cysts of which a subset has the potential to progress to cancer. Currently, there are no validated predictive markers for progression to malignancy. We hypothesized that the presence or absence of immune surveillance of these lesions would be one such factor. Here we show that the tumor antigen MUC1, which is abnormally expressed on pancreatic cancer and is a target for cancer immunosurveillance, is also abnormally expressed on premalignant IPMN. We show that some IPMN patients make MUC1-specific IgG. Moreover, we show evidence of CD4 and CD8 T cell infiltration into IPMN areas of high dysplasia suggesting an ongoing immune response within the lesions. We also found, however, increased levels of circulating myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs) in some IPMN patients as well as evidence of T cell exhaustion. Further studies correlating immunosurveillance or immunosuppression with IPMN progression to malignancy will help define the immune response as a biomarker of risk, leading potentially to a vaccine to boost spontaneous immunity and prevent progression to cancer.

Species variation and spatial differences in mucin expression from corneal epithelial cells.

Mucins are large glycoproteins expressed by epithelial cells of both the conjunctiva and cornea, and principle components of the glycocalyx. They are thought to play an important role in determining the interactions between the cornea/conjunctiva and the overlying tear film. The purpose of this study was to characterize the membrane-associated corneal mucin expression pattern from multiple species commonly used in ophthalmic research and drug development to better define the biochemical attributes of the ocular surface. Humans, rhesus macaques and dogs were found to have a very similar pattern of mucin expression, with mucin 16 (MUC16) being the most prevalent mucin transcript. In contrast, the rabbit had a unique mucin expression pattern with all mucin transcripts expressed at relatively similar levels. To determine if there were spatial differences in expression, peripheral and central corneal epithelium were individually isolated and evaluated for mucin expression. In all species examined, MUC1, MUC4 and MUC16 had higher peripheral corneal expression when compared with central, which reached statistical significance in MUC1 (rhesus and dog). The data demonstrated variation in corneal epithelial membrane-associated mucin expression between species, with the rabbit having a distinct expression pattern. These differences may be reflective of the environment, pathogen exposure or tear film dynamics of the respective species. The species differences, as well as regional mucin expression patterns, characterized in this study further define the biochemical composition of the ocular surface and may play an important role in tear film stability.

Differential expression and clinical relevance of MUC1 in renal cell carcinoma metastasis.

PURPOSE: To determine the differential expression patterns and prognostic relevance of Mucin-1 (MUC1) expression in clear cell renal cell carcinoma (RCC) metastasis. METHODS: Tissue microarrays (TMA) from samples of 151 RCC metastases, 61 primary RCCs and corresponding benign renal tissues were immunohistochemically stained for MUC1 and semi-quantitatively evaluated by immunoreactivity scores (IRS). MUC1 differential expression in metastasis, primary RCC and normal tissue were comparatively analyzed. Patient characteristics and clinical follow-up for patients with metastatic RCC (mRCC) were recorded. Correlations of MUC1 expression with mRCC survival were determined. RESULTS: Median cytoplasmic expression was highest in benign tissue (IRS = 1.04). Primary RCC (0.50) and metastasis (0.12) showed significantly lower cytoplasmic staining intensity. Membranous expression in benign tissue was, however, significantly lower (0.21) compared with primary RCC (0.59) and metastasis (0.57). Notable differences of MUC1 cytoplasmic and membranous expression were observed between different metastasis sites. Significantly higher (P = 0.014) membranous expression was observed in pulmonary versus non-pulmonary lesions, while no significant differences of cytoplasmic MUC1 expression were observed. The prognostic relevance of MUC1 expression in metastatic RCC was limited. CONCLUSIONS: MUC1 is differentially expressed in benign renal tissue, primary RCC and RCC metastasis. Membranous MUC1 expression was significantly elevated in pulmonary metastases compared to non-pulmonary lesions, which may reflect individual biology and putative response to MUC1-based anti-cancer therapy.

Epithelial MUC1 promotes cell migration, reduces apoptosis and affects levels of mucosal modulators during acetylsalicylic acid (aspirin)-induced gastropathy.

MUC1 is a transmembrane mucin highly expressed in the stomach. Although extensive research has uncovered many of its roles in cancer, knowledge about the functions of MUC1 in normal tissues is limited. In the present study, we showed that acetylsalicylic acid (ASA; aspirin) up-regulated MUC1/Muc1 expression in the gastric mucosa of humans and wild-type (WT) mice. ASA induced mucosal injury in all mice to a similar extent; however, WT animals and those chimaeras with Muc1 on the epithelia recovered faster than Muc1-knockout (KO) mice and chimaeras carrying Muc1 on haemopoietic but not epithelial cells. MUC1 enhanced proliferation and migration of the human gastric cell line MKN-7 and increased resistance to apoptosis. The repeated treatment regime used caused a reduction in cyclo-oxygenase-1 (Cox-1) expression, though WT animals returned faster towards pre-treatment levels and had increased Cox-2 and vascular endothelial growth factor levels during recovery. Thus we found that epithelial Muc1 is more important for the healing process than haemopoietic Muc1 and Muc1/MUC1 facilitates wound healing by enhancing cell migration and proliferation, protecting against apoptosis and mediating expression of mucosal modulators. Thus MUC1 plays essential roles during wound healing and development of treatment modalities targeting enhanced expression of MUC1 may be beneficial to treat mucosal wounds.

Mucin 1 expression correlates with metastatic recurrence in postoperative patients with esophageal squamous cell cancer.

Mucin1 (MUC1) expression correlates with invasion and metastasis and poor survival in some cancers. The purpose of the study was to investigate the clinical significance of MUC1 expression and the risk of tumor metastatic recurrence in patients with esophageal squamous cell cancer (ESCC) after curative resection. A total of 108 ESCC patients were enrolled in this study. MUC1 expression was detected in ESCC tissues from 70 patients by immunohistochemistry (IHC). The expression of MUC1 in the cancerous tissue group was significantly higher than that in the paracancerous normal tissue group (65.4%:10.0%, p < 0.01). MUC1 expression correlated with pT (< 0.05), pN (p < 0.01) and pTNM stage (< 0.01). The 5-year survival rate of the patients was 39.8%. The 5-year tumor metastatic recurrence rate of the patients was 74.1%, and it was associated with pT (p < 0.01), pN (p < 0.01), pTNM stage (p < 0.01) and MUC1 expression (p < 0.01). Multivariate analysis confirmed that pN and MUC1 expression were independent predictive factors. In conclusion, MUC1 expression correlates with tumor metastatic recurrence in postoperative ESCC patients.

MUC1: a novel metabolic master regulator.

MUC1, a type I transmembrane protein, is significantly overexpressed and aberrantly glycosylated in tumors of epithelial origin. By virtue of its aberrant signaling due to loss of apical-basal polarity in cancer, MUC1 regulates the metabolite flux at multiple levels. Serving as a transcriptional co-activator, MUC1 directly regulates expression of metabolic genes. By regulating receptor tyrosine kinase signaling, MUC1 facilitates production of biosynthetic intermediates required for cell growth. Also, via direct interactions, MUC1 modulates the activity/stability of enzymes and transcription factors that directly regulate metabolic functions. Additionally, by modulation of autophagy, levels of reactive oxygen species, and metabolite flux, MUC1 facilitates cancer cell survival under hypoxic and nutrient-deprived conditions. This article provides a comprehensive review of recent literature on novel metabolic functions of MUC1.