Microbial products alter the expression of membrane-associated mucin and antimicrobial peptides in a three-dimensional human endocervical epithelial cell model

Our understanding of the mechanisms that regulate tissue-specific mucosal defense can be limited by the lack of appropriate human in vitro models. The endocervix lies between the microbe-rich vaginal cavity and the relatively sterile endometrium and is a major portal of entry for Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, human immunodeficiency virus (HIV), and herpes simplex virus (HSV) infection in women. The endocervix is lined with a simple epithelium, and these cells produce mucus, which plays a key role in immune defense and reproduction. Here we describe the development of a human three-dimensional endocervical epithelial cell model generated by rotating wall vessel bioreactor technology. The model is composed of cellular aggregates that recapitulate major structural and barrier properties essential for the function and protection of the endocervix, including junctional complexes, microvilli, innate immune receptors, antimicrobial peptides, and mucins, the major structural component of mucus. Using this model, we also report, for the first time, that the membrane-associated mucin genes MUC1, MUC4, and MUC16 are differentially regulated in these aggregates by different bacterial and viral products. Differential induction of antimicrobial peptides was also observed with these products. Together these data define unique and flexible innate endocervical immune signatures that follow exposure to microbial products and that likely play a critical role in the outcome of pathogen challenge at this site.

Interleukin-22 and interleukin-22-producing NKp44+ natural killer cells in subclinical gut inflammation in ankylosing spondylitis

OBJECTIVE

The intestinal inflammation observed in patients with ankylosing spondylitis (AS) is characterized by an overexpression of interleukin-23 (IL-23). IL-23 is known to regulate IL-22 production through lamina propria NKp44+ natural killer (NK) cells, which are thought to be involved in protective mucosal mechanisms. This study was undertaken to evaluate the frequency of NKp44+ NK cells and the expression of IL-22 in the ileum of AS patients.

METHODS

Tissue NKp44+ NK cells, NKp46+ NK cells, and IL-22-producing cells were analyzed by flow cytometry. Quantitative gene expression analysis of IL-22, IL-23, IL-17, STAT-3, and mucin 1 (MUC-1) was performed by reverse transcriptase-polymerase chain reaction on ileal samples from 15 patients with AS, 15 patients with Crohn's disease (CD), and 15 healthy controls. NKp44, pSTAT-3, and IL-22 expression was analyzed by immunohistochemistry.

RESULTS

The frequency of NKp44+ but not NKp46+ NK cells was increased in the inflamed ileum of AS patients compared to CD patients and controls. The frequency of NKp46+ NK cells was significantly increased only in CD patients. Among CD4+ lymphocytes and NKp44+ NK cell subsets, the latter were the major source of IL-22 on lamina propria mononuclear cells from AS patients. Significant up-regulation of IL-22, IL-23p19, MUC-1, and STAT-3 transcripts in the terminal ileum of patients with AS was observed. Immunohistochemical analysis confirmed the increased IL-22 and pSTAT-3 expression in inflamed mucosa from AS and CD patients.

CONCLUSION

Our findings indicate that overexpression of IL-22, together with an increased number of IL-22-producing NKp44+ NK cells, occurs in the gut of AS patients, where it appears to play a tissue-protective role.

[Increased level of KL-6 in a BJP-λ-type multiple myeloma patient with poor prognosis]

A 63-year-old female with BJP-multiple myeloma (Durie-Salmon stage III B, International Staging System III) showed an increased level of KL-6, a sialylated carbohydrate antigen that is a MUC1 molecule expressed in type II pneumocytes and reflects activity of interstitial pneumonia. At the time of diagnosis, KL-6 was as high as 22,030 U/ml; however, surfactant protein D (SP-D) was normal, and stroma-related pneumonia was not indicated on CT images. Expression of KL-6 in multiple myeloma cells was detected by immunostaining and the patient was diagnosed with KL-6-positive multiple myeloma. Usually, MUC1 is encoded by chromosome 1q21, but the karyotypic analysis of the patient's bone marrow cells lacked chromosome 1. KL-6 increased as the disease progressed. The patient did not respond to chemotherapy, including bortezomib, showed an increase of pleural effusion, and died. For this patient, multiple myeloma with high KL-6 was refractory to chemotherapy, suggesting that new treatment strategies, including transplantation of hematopoietic stem cells, are required.

Utility of KL-6/MUC1 in the clinical management of interstitial lung diseases

Interstitial lung diseases (ILDs) are a diverse group of pulmonary disorders characterized by various patterns of inflammation and fibrosis in the interstitium of the lung. Because injury and/or regeneration of type II pneumocytes are prominent histological features of ILDs, substances derived from type II pneumocytes have been the focus of research investigating potential biomarkers for ILD. One important biomarker for ILD is the high-molecular-weight glycoprotein, Krebs von den Lungen-6 (KL-6). KL-6 is now classified as a human MUC1 mucin protein, and regenerating type II pneumocytes are the primary cellular source of KL-6/MUC1 in the affected lungs of patients with ILD. KL-6/MUC1 is detectable in the serum of patients with ILD, and extensive investigations performed primarily in Japan have revealed that serum KL-6/MUC1 is elevated in 70-100% of patients with various ILDs, including idiopathic interstitial pneumonias, collagen vascular disease-associated interstitial pneumonia, hypersensitivity pneumonia, radiation pneumonitis, drug-induced ILDs, acute respiratory distress syndrome, pulmonary sarcoidosis, and pulmonary alveolar proteinosis. The results from these various studies have supported the utility of KL-6/MUC1 as a serum biomarker for detecting these various ILDs. Moreover, KL-6/MUC1 serum levels have been demonstrated to be useful for evaluating disease activity and predicting the clinical outcomes of various ILD types. Based on these observations, we believe that KL-6/MUC1 is currently one of the best and most reliable serum biomarkers available for ILD management.

AP-1 transcription factors, mucin-type molecules and MMPs regulate the IL-11 mediated invasiveness of JEG-3 and HTR-8/SVneo trophoblastic cells

This study examines the IL-11 mediated activation of downstream signaling and expression of effector molecules to resolve the controversies associated with the IL-11 mediated regulation of the invasiveness of two commonly used trophoblastic cell models viz. JEG-3 and HTR-8/SVneo cells. It has been reported that IL-11 increases the invasiveness of JEG-3 cells while, reduces the invasiveness of HTR-8/SVneo cells. Invasion assay performed simultaneously for both the cell lines confirmed the above findings. In addition, HTR-8/SVneo cells showed a higher basal invasiveness than JEG-3 cells. Western blot showed the IL-11 mediated activation of STAT3(tyr705) and STAT1(tyr701) in both the cell lines. However, IL-11 activated the ERK1/2 phosphorylation in JEG-3 cells but, inhibited it in HTR-8/SVneo cells. Within 10 min of IL-11 treatment, p-STAT3(tyr705) was localized inside the nucleus of both the cell lines but, there was enhanced co-localization of protein inhibitor of activated STAT1/3 (PIAS1/3) and p-STAT3(tyr705) in HTR-8/SVneo cells and not in JEG-3 cells. This could be reason for the poor responsiveness of STAT3 responsive genes like mucin 1 (MUC1) in HTR-8/SVneo cells and not in JEG-3 cells. Further, microarray analysis of the IL-11 treated cells revealed differential responsiveness of JEG-3 as compared to HTR-8/SVneo cells. Several family of genes like activator protein-1 (AP-1) transcription factors (Jun and Fos), mucin-type molecules, MMP23B etc showed enhanced expression in IL-11 treated JEG-3 cells while, there was no response or decrease in their expression in IL-11 treated HTR-8/SVneo cells. Expression of these molecules was confirmed by quantitative RT-PCR. In addition, HTR-8/SVneo cells also showed a significant decrease in the expression of MMP2, MMP3 and MMP9 upon IL-11 treatment. Hence, IL-11 mediated differential activation of signaling and expression of effector molecules is responsible for the differential invasive response of JEG-3 and HTR-8/SVneo cells.

A novel survival-based tissue microarray of pancreatic cancer validates MUC1 and mesothelin as biomarkers

BACKGROUND

One-fifth of patients with seemingly 'curable' pancreatic ductal adenocarcinoma (PDA) experience an early recurrence and death, receiving no definable benefit from a major operation. Some patients with advanced stage tumors are deemed 'unresectable' by conventional staging criteria (e.g. liver metastasis), yet progress slowly. Effective biomarkers that stratify PDA based on biologic behavior are needed. To help researchers sort through the maze of biomarker data, a compendium of ∼2500 published candidate biomarkers in PDA was compiled (PLoS Med, 2009. 6(4) p. e1000046).

METHODS AND FINDINGS

Building on this compendium, we constructed a survival tissue microarray (termed s-TMA) comprised of short-term (cancer-specific death <12 months, n = 58) and long-term survivors (>30 months, n = 79) who underwent resection for PDA (total, n = 137). The s-TMA functions as a biological filter to identify bona fide prognostic markers associated with survival group extremes (at least 18 months separate survival groups). Based on a stringent selection process, 13 putative PDA biomarkers were identified from the public biomarker repository. Candidates were tested against the s-TMA by immunohistochemistry to identify the best markers of tumor biology. In a multivariate model, MUC1 (odds ratio, OR = 28.95, 3+ vs. negative expression, p = 0.004) and MSLN (OR = 12.47, 3+ vs. negative expression, p = 0.01) were highly predictive of early cancer-specific death. By comparison, pathologic factors (size, lymph node metastases, resection margin status, and grade) had ORs below three, and none reached statistical significance. ROC curves were used to compare the four pathologic prognostic features (ROC area = 0.70) to three univariate molecular predictors (MUC1, MSLN, MUC2) of survival group (ROC area = 0.80, p = 0.07).

CONCLUSIONS

MUC1 and MSLN were superior to pathologic features and other putative biomarkers as predicting survival group. Molecular assays comparing cancers from short and long survivors are an effective strategy to screen biomarkers and prioritize candidate cancer genes for diagnostic and therapeutic studies.

MUC1 expression is elevated in severe preeclamptic placentas and suppresses trophoblast cell invasion via β1-integrin signaling

CONTEXT

Preeclampsia is a pregnancy-specific disorder that features insufficient extravillous trophoblast (EVT) invasion. We have previously shown that MUC1 expression in human placenta increases with gestational age and inhibits choriocarcinoma cell invasion.

OBJECTIVE

Here, we studied whether MUC1 expression in preeclamptic placentas is dysregulated and the mechanism of EVT invasion regulated by MUC1.

DESIGN

MUC1 expression in severe preeclamptic placentas and gestational age-matched control placentas was analyzed by real-time RT-PCR, Western blot analysis, and immunohistochemistry. The effects of MUC1 expression on cell-matrix adhesion, invasion, and cell signaling were studied in HTR8/SVneo EVT cells.

RESULTS

We found that MUC1 mRNA and MUC1 protein were significantly up-regulated in severe preeclamptic placentas when compared with the gestational age-matched control placentas. Immunohistochemical analyses showed increased expression of MUC1 in the syncytiotrophoblast and EVT of severe preeclamptic placentas. In addition, MUC1 overexpression suppressed cell-matrix adhesion and invasion of EVT cells. Importantly, our data showed that MUC1 overexpression inhibited β1-integrin activity and phosphorylation of focal adhesion kinase, whereas the surface expression of β1-integrin was not significantly changed.

CONCLUSIONS

Our findings suggest that MUC1 is overexpressed in severe preeclamptic placentas and that MUC1 overexpression suppresses EVT invasion mainly via modulating β1-integrin signaling.

Intrinsic mitochondrial membrane potential and associated tumor phenotype are independent of MUC1 over-expression

We have established previously that minor subpopulations of cells with stable differences in their intrinsic mitochondrial membrane potential (Δψm) exist within populations of mammary and colonic carcinoma cells and that these differences in Δψm are linked to tumorigenic phenotypes consistent with increased probability of participating in tumor progression. However, the mechanism(s) involved in generating and maintaining stable differences in intrinsic Δψm and how they are linked to phenotype are unclear. Because the mucin 1 (MUC1) oncoprotein is over-expressed in many cancers, with the cytoplasmic C-terminal fragment (MUC1 C-ter) and its integration into the outer mitochondrial membrane linked to tumorigenic phenotypes similar to those of cells with elevated intrinsic Δψm, we investigated whether endogenous differences in MUC1 levels were linked to stable differences in intrinsic Δψm and/or to the tumor phenotypes associated with the intrinsic Δψm. We report that levels of MUC1 are significantly higher in subpopulations of cells with elevated intrinsic Δψm derived from both mammary and colonic carcinoma cell lines. However, using siRNA we found that down-regulation of MUC1 failed to significantly affect either the intrinsic Δψm or the tumor phenotypes associated with increased intrinsic Δψm. Moreover, whereas pharmacologically mediated disruption of the Δψm was accompanied by attenuation of tumor phenotype, it had no impact on MUC1 levels. Therefore, while MUC1 over-expression is associated with subpopulations of cells with elevated intrinsic Δψm, it is not directly linked to the generation or maintenance of stable alterations in intrinsic Δψm, or to intrinsic Δψm associated tumor phenotypes. Since the Δψm is the focus of chemotherapeutic strategies, these data have important clinical implications in regard to effectively targeting those cells within a tumor cell population that exhibit stable elevations in intrinsic Δψm and are most likely to contribute to tumor progression.

Androgen receptor regulates expression of the MUC1-C oncoprotein in human prostate cancer cells

BACKGROUND

The MUC1 heterodimeric oncoprotein is aberrantly overexpressed in human prostate cancers with more aggressive pathologic and clinical features. However, the signals that regulate MUC1 expression in prostate cancer cells are not well understood.

METHODS

MUC1 expression was studied in androgen-dependent and -independent prostate cancer cell lines by quantitative RT-PCR, immunoblotting and assessment of MUC1 promoter activation. Chromatin immunoprecipitation (ChIP) studies were performed to assess androgen receptor (AR) occupancy on the MUC1 promoter. Post-transcriptional regulation of MUC1 expression was assessed by miR-125b-mediated effects on activity of the MUC1 3' untranslated region (3'UTR).

RESULTS

The present studies demonstrate that AR occupies a consensus AR element on the MUC1 promoter in androgen-dependent LNCaP, but not in androgen-independent DU145 and PC3, prostate cancer cells. The results further show that AR downregulates MUC1 gene transcription. Stable introduction of exogenous AR in PC3 (PC3/AR) cells and then silencing of AR confirmed AR-mediated repression of the MUC1 promoter. AR signaling has also been shown to drive miR-125b expression. The present studies further demonstrate that miR-125b suppresses MUC1 translation in LNCaP cells and that an anti-sense miR-125b upregulates expression of MUC1 protein. In addition, stable expression of miR-125b in DU145 cells resulted in decreases in MUC1 levels.

CONCLUSIONS

These findings demonstrate that AR signaling regulates MUC1 expression by transcriptional and posttranscriptional mechanisms in prostate cancer cells.

A gold nanoparticle platform for protein-protein interactions and drug discovery

Gold nanoparticles hold great promise for studying protein-protein interactions because of their intrinsic optical properties. Pink when in a homogeneous suspension, the solution turns blue-gray when particles are drawn close together, for example, when immobilized proteins specifically interact with each other. However, the nanoparticle stability, size, and method of protein attachment contribute to the unreliable outcome of current assays. To overcome these hurdles, we developed novel and reliable methods first to synthesize homogenous particles of optimal diameter and second to apply a heterologous NTA-Ni-SAM coating for controlled orientation and optimal presentation of histidine-tagged proteins. Both methods were proven to greatly enhance assay sensitivity and specificity by increasing the signal and minimizing the nonspecific binding. Our assay reproducibly detected known protein-protein interactions and unambiguously identified small molecules that inhibited them. We believe our gold nanoparticle bioassay is a versatile and trustworthy new platform for analyzing protein-protein interactions and high-throughput screening of small-molecule inhibitors.

Mucin 1 C-terminal subunit oncoprotein is a target for small-molecule inhibitors

Mucin 1 (MUC1) is a heterodimeric protein that is overexpressed in diverse human carcinomas. The oncogenic function of the MUC1 C-terminal subunit (MUC1-C) subunit is dependent on the formation of dimers through its cytoplasmic domain; however, it is not known whether MUC1-C can be targeted with small-molecule inhibitors. In the present work, an assay using the MUC1-C cytoplasmic domain (MUC1-CD) was established to screen small-molecule libraries for compounds that block its dimerization. Using this approach, the flavone apigenin was identified as an inhibitor of MUC1-CD dimerization in vitro and in cells. By contrast, the structurally related flavone baicalein was ineffective in blocking the formation of MUC1-CD dimers. In concert with these results, apigenin, and not baicalein, blocked the localization of MUC1-C to the nucleus. MUC1-C activates MUC1 gene expression in an autoinductive loop, and apigenin, but not baicalein, treatment was associated with down-regulation of MUC1 mRNA levels and MUC1-C protein. The results also demonstrate that apigenin-induced suppression of MUC1-C expression is associated with apoptotic cell death and loss of clonogenic survival. These findings represent the first demonstration that the MUC1-C cytoplasmic domain is a target for the development of small-molecule inhibitors.

Enhanced induction of anti-tumor CTLs in vitro by a lentivirus-transduced dendritic cell vaccine expressing secondary lymphoid tissue chemokine and mucin 1

AIMS

Dendritic cell (DC)-based cancer immunotherapy requires an immunogenic tumor associated antigen (TAA) and an effective strategy for its presentation to lymphocytes. Here, we explored whether transduction of DCs with lentiviruses (LVs) expressing a fusion protein of secondary lymphoid tissue chemokine (SLC) and mucin 1 (MUC1) could stimulate antigen-specific cytotoxic T cells (CTLs) to human cancer cells in vitro.

MATERIALS AND METHODS

HLA-A2+ peripheral blood monocyte-derived DCs were transduced with recombinant lentiviruses LV at different multiplicities of infection (MOI), and MUC1, SLC or SLC-MUC1 mRNA and protein were detected by RT-PCR and Western blotting, respectively. Transduction efficiencies and phenotypes of DCs were evaluated by flow cytometry. Induction of T lymphocyte proliferation by DCs was examined with a Cell Count Kit-8 (CCK-8). CTL activities against tumor cells were analyzed by lactate dehydrogenase (LDH) cytotoxicity and enzyme-linked immunospot (ELISPOT) assays.

RESULTS

Stable expression of MUC1, SLC and SLC-MUC1 was obtained in DCs transduced with recombinant LVs, and the transduction efficiencies were dose-dependent. Transduction with LVs did not appreciably change the DC phenotype. CTL induced by LV MUC1 DCs potently and specifically lysed the HLA-A2+, MUC1+colon cancer cell line HCT-116. Moreover, this cytolytic activity against HCT-116 was enhanced with CTL stimulated by LV SLC-MUC1 DCs.

CONCLUSIONS

DCs transduced with MUC1 could induce effective cytolytic activity against tumor cells in an antigen-specific and HLA-restricted fashion in vitro, and SLC promoted MUC1-specific anti-tumor activity. The transduction of DCs with LV SLC- MUC1 may be a promising strategy in DC-based cancer immunotherapy.

Flow cytometry-based assay to evaluate human serum MUC1-Tn antibodies

Mucin-1 (MUC1) is a heavily O-glycosylated, transmembrane protein that is expressed on the apical surface of most secretory epithelia. In malignantly transformed epithelia, MUC1 has lost its apical distribution, is underglycosylated and is secreted into the circulation. Due to the underglycosylation of MUC1, cancer-specific MUC1-Tn/STn antigens, which are highly immunogenic, become exposed. We aimed at developing a system that allows detection of antibodies directed to the native form of MUC1 and the underglycosylated MUC1-Tn epitopes. To this end, we made use of the Chinese Hamster Ovary (CHO) ldlD cell line stably transfected with MUC1. This cell line has a glycosylation defect, which can be reversed by addition of different monosaccharides to the cell culture and enables the production of cells expressing the MUC1-Tn glycoforms. After validation with glycospecific antibodies, the CHO-ldlD MUC1 system was used to detect serum MUC1 and MUC1-Tn antibodies. Using this system, we could confirm the presence of MUC1-Tn antibodies in the serum of a patient vaccinated with a truncated MUC1 peptide. This indicates that the CHO-ldlD MUC1 system represents a flow cytometry-based technique to detect antibodies binding to the underglycosylated MUC1 protein. This cellular system is complementary to the previously published methods to detect MUC1 serum antibodies, since the antibodies to the native protein are evaluated and therefore it can be effectively used for MUC1 antibody monitoring in vaccination studies as well as for functional assays.

Role of mucins in the skin during benign and malignant conditions

Skin-related diseases comprise a major health challenge to the practicing physician, and constitute a significant psychological, social and financial burden to the society. Further, skin cancer, especially non-melanoma skin cancer is currently the leading type of malignancy in the Western world. Given the huge burden of skin diseases, there is growing emphasis on understanding their pathophysiology, and towards their early detection. Mucins are high-molecular weight O- and N-linked glycoproteins that have emerged in recent years as important molecules in maintaining health and in promoting or protecting against inflammation and cancer. They have also begun to emerge as highly specific diagnostic and prognostic markers and novel therapeutic targets in several malignant disorders. However, their role in cutaneous pathologies has remained largely obscured. The present review provides the expression patterns and proposed role of mucins in the healthy skin and various benign and malignant skin diseases. The review has immense clinical significance as the availability of highly specific reagents including monoclonal antibodies against mucins makes them extremely attractive targets for specific diagnosis and/or immunotherapy of benign and malignant cutaneous diseases.

MUC1 as a discriminator between endometrium from fertile and infertile patients with PCOS and endometriosis

CONTEXT

Endometrium of fertile women expresses progesterone-regulated Mucin 1 (MUC1) that carries selectin ligands recognized by the human blastocyst. Altered MUC1 expression at the time of implantation may contribute to endometrial infertility.

OBJECTIVE

The aim was to assess the expression of MUC1 in the endometrium from polycystic ovary syndrome (PCOS), endometriosis, and fertile women in comparison with other hormone-regulated proteins [hydroxysteroid dehydrogenase (HSD) 1, HSD2, estrogen receptor (ER) and progesterone receptor (PR)].

DESIGN AND PATIENTS

Endometrial samples were obtained from 33 fertile patients, 26 ovulatory PCOS patients, 15 anovulatory PCOS patients, and 25 endometriosis patients.

MAIN OUTCOME MEASURE

Immunohistochemistry assessed the expression of MUC1 subunits ER, PR, HSD1, and HSD2 in endometrial epithelium. Endometrial MUC1 expression was quantified by immunoblots and RT-PCR. HSD1 and HSD2 expression was assayed by RT-PCR.

RESULTS

MUC1ND expression was significantly higher in ovulatory PCOS than in fertile and anovulatory PCOS patients, even after progesterone stimulation. MUC1ND and -CD expression was lower in anovulatory PCOS than in fertile patients. Only MUC1CD expression was lower in endometriosis patients. Endometrial ER expression was significantly higher in PCOS and endometriosis patients, whereas PR expression was significantly higher in PCOS than in fertile patients. The expression of HSD1 was significantly higher in anovulatory PCOS than in fertile patients. Expression of HSD2 was significantly higher in PCOS patients and lower in endometriosis patients.

CONCLUSION

Expression of MUC1 subunits in the infertile endometrium is significantly different from fertile and appears to be a component of altered gene expression that potentially contributes to endometrial insufficiency.

Cigarette smoke induces epidermal growth factor receptor-dependent redistribution of apical MUC1 and junctional beta-catenin in polarized human airway epithelial cells

Cigarette smoke (CS) accounts for nearly 90% of lung cancer deaths worldwide; however, an incomplete understanding of how CS initiates preneoplastic changes in the normal airway hinders early diagnosis. Short-term exposure to CS causes aberrant activation of epidermal growth factor receptor (EGFR) and canonical Wnt/beta-catenin signaling pathways in human bronchial epithelial (HBE) cells. We hypothesize that this response is elicited through the disruption of spatially segregated cell membrane proteins in the polarized airway epithelium. Using an in vitro model of highly differentiated HBE cells, we observed membrane characteristics consistent with the native airway, including the presence of a membrane mucin, MUC1, at the apical cell pole, beta-catenin at the apical-lateral membrane, and EGFR at the basolateral membrane. Following exposure to smoke, intercellular spaces enlarge and cilia disappear. This histopathology is accompanied by molecular events that include perinuclear trafficking of basolateral EGFR, EGFR phosphorylation, pEGFR-mediated phosphorylation of MUC1's cytoplasmic tail (CT), loss of E-cadherin/beta-catenin complexes at the adherens junctions (AJs), intracellular formation and nuclear shuffling of beta-catenin/MUC1-CT complexes, and, ultimately, up-regulation and nuclear localization of Wnt nuclear effector, Lef-1. In the presence of EGFR inhibitor, AG1478, CS-induced histopathology and molecular events were inhibited. These data point to EGFR as a portal through which CS mediates its damaging effects on AJ-mediated cell polarity and activation of canonical Wnt/beta-catenin signaling.

MUC1 expression in Sjogren's syndrome, KCS, and control subjects

PURPOSE

To quantify and compare human mucin 1 (MUC1) protein and mRNA expression in tears and conjunctival epithelial cells collected from Sjogren's syndrome (SS), non-Sjogren's keratoconjunctivitus sicca (KCS) and non-dry eyed (NDE) control subjects.

METHODS

Seventy-six subjects were recruited for this study: 25 SS (confirmed via American-European Consensus Criteria 2002), 25 KCS (confirmed by symptoms and Schirmer scores < or = 10 mm) and 26 NDE. Tears were collected using an eye-wash technique. Impression cytology was used to gather protein and mRNA from conjunctival epithelial cells. Soluble and membrane bound MUC1 were quantified via western blotting and MUC1 mRNA was quantified by real time qPCR.

RESULTS

The SS group demonstrated significantly higher concentrations of soluble MUC1 (0.12 +/- 0.11 [SS]; 0.013 +/- 0.02 [KCS; p=0.001]; 0.0023 +/- 0.0024 [NDE; p<0.001]) and MUC1 mRNA (3.18 +/- 1.44 [SS]; 1.79 +/- 1.18 [KCS; p<0.05]; 1.60 +/- 0.74 [NDE; p<0.05]) compared to both KCS and NDE groups. Soluble MUC1 expression was also higher in the KCS group compared to the NDE group (p=0.02), where as MUC1 mRNA expression was similar in both KCS and NDE groups. Membrane bound MUC1 expression differed only between the SS and NDE groups (0.005 +/- -0.003 [SS]; 0.003 +/- 0.002 [NDE; p=0.002]).

CONCLUSIONS

These results demonstrate that SS subjects express greater quantities of MUC1 protein and mRNA compared to both KCS and control subjects. Increased soluble MUC1 expression was also found in KCS subjects compared to controls. Membrane bound MUC1 was present in higher concentration in SS versus NDE only. These significant changes in MUC1 expression may represent compensatory or protective responses to chronic insult to the ocular surface.

miR-1226 targets expression of the mucin 1 oncoprotein and induces cell death

The MUC1 oncoprotein is aberrantly overexpressed in human carcinomas and hematologic malignancies. Micro-RNAs (miRNAs) have been implicated in the suppression and induction of oncogenesis. The present studies demonstrate that the MUC1 mRNA 3' untranslated region (3'UTR) contains a highly conserved motif for binding of a novel miRNA, miR-1226, that has no known targets. The results show that miR-1226 is expressed in human breast cancer cell lines and non-malignant mammary epithelial cells. We also show that miR-1226 interacts with the MUC1 mRNA 3'UTR and that miR-1226 downregulates endogenous MUC1 protein levels. Consistent with miR-1226-induced downregulation of MUC1 expression, the results demonstrate that miR-1226 induces i) an increase in reactive oxygen species, ii) loss of the mitochondrial transmembrane potential, and iii) a decrease in cell survival. These findings indicate that expression of the MUC1 oncoprotein is downregulated by miR-1226 and that miR-1226 thereby functions as a tumor suppressor by promoting the induction of cell death.

Temporal and spatial expression of Muc1 during implantation in sows

Recent evidence points to an important role for Muc1 in embryo implantation. In this study, Real-time PCR and immunohistochemistry were used to study mRNA and protein levels at, and between, the attachment sites of the endometrium of Day 13, 18 and 24 pregnant sows. The results indicate that Muc1 mRNA expression was higher between attachment sites than at attachment sites during implantation and this effect was significant on Day 13 (P < 0.01) and 24 (P < 0.01). Intense Muc1 immunostaining was observed in luminal epithelium and stroma and the staining between attachment sites was stronger than at attachment sites on Days 13 and 18. Collectively, these results suggest the crucial role of Muc1 in successful implantation and embryo survival.

Induction of antigen-specific CTL and antibody responses in mice by a novel recombinant tandem repeat DNA vaccine targeting at mucin 1 of pancreatic cancer

PURPOSE

Tandem repeat (TR) is the key epitope of mucin 1 (MUC1) for inducing cytotoxic T lymphocytes (CTL) to kill the tumor cells specifically. This study aimed to construct a new recombinant DNA vaccine based on single TR and to investigate the induced immune responses in mice.

MATERIALS AND METHODS

After the synthesis of a recombinant human TR(rhTR)and the construction of the recombinant plasmid pcDNA3.1-TR/Myc-his (+) A (pTR plasmid), C57BL/6 (H-2(b)) mice were immunized with it (TR group, n = 15). Mice inoculated with the empty vector (EV group, n = 15) and normal saline (NS group, n = 15) were used as vector and blank control, respectively. Cytotoxic assay was carried out to measure the CTL activity. And indirect enzyme-linked immunosorbent assay (ELISA) was used to detect anti-TR-specific antibodies.

RESULTS

TR group resulted in more efficient induction of CTL-specific cytolysis against TR polypeptide than both EV and NS groups (both P < 0.01). Vaccine-immunized mice had a higher equivalent concentration of anti-TR-specific antibodies (2,324 ± 238 μg/ml) than either of EV group (1,896 ± 533 μg/ml, P < 0.01) or NS group (1,736 ± 142 μg/ml, P < 0.01).

CONCLUSION

The novel recombinant TR DNA vaccine targeting at MUC1 of pancreatic cancer was constructed successfully, effectively expressing TR polypeptide in the transfected mammalian cells and inducing TR-specific CTL and antibody response.

Administration of vitamin D3 improves antimetastatic efficacy of cancer vaccine therapy of Lewis lung carcinoma

AIM

To analyze antitumor efficacy of experimental cancer vaccine therapy combined with introduction of vitamin D3 (VD3) for treatment of Lewis lung carcinoma (3LL).

MATERIALS AND METHODS

Cancer vaccines composed from recombinant murine beta-defensin-2 (mBD-2) and 3LL cell lysate, or DNA, coding for mBD-2-Muc1 fusion construct cloned in pcDNA3+ vector, were prepared and used for intradermal vaccination. Experimental cancer vaccines introduced i. d. at therapeutic and prophylactic regimens to 3LL-bearing C57Bl mice, were applied alone or in combination with VD3 (administered per os) and/or low-dose cyclophosphamide (CP, administered intraperitoneal). Efficacy of treatments was analyzed by primary tumor growth dynamics indexes and by metastasis rate in vaccinated animals.

RESULTS

As it has been shown, administration of the protein-based vaccine composed from mBD-2 and 3LL cell lysate in combination with VD3 and CP, but not in VD3 free setting, led to significant suppression of primary tumor growth (p < 0.005) and had significant antimetastatic effect. Introduction of VD3 with or without CP in the scheme of treatment with mBD- 2-Muc1-DNA vaccine at therapeutic regimen has led to significant suppression of primary tumor (p < 0.05) and metastasis volumes (p < 0.005), while in the groups of animals treated with DNA-vaccine + VD3 with or without CP at prophylactic regimen, significant antimetastatic effect (p < 0.05) and elevation of average life-span (p < 0.05) have been registered.

CONCLUSION

The results of this pilot study have shown promising clinical effects of VD3 administration in combination with cancer vaccinotherapy in vivo.

Effect of pro-inflammatory mediators on membrane-associated mucins expressed by human ocular surface epithelial cells

Membrane-associated mucins are altered on the ocular surface in non-Sjögren's dry eye. This study sought to determine if inflammatory mediators, present in tears of dry eye patients, regulate membrane-associated mucins MUC1 and -16 at the level of gene expression, protein biosynthesis and/or ectodomain release. A human corneal limbal epithelial cell line (HCLE), which produces membrane-associated mucins, was used. Cells were treated with interleukin (IL)-6, -8, or -17, tumor necrosis factor-alpha (TNF-alpha), and Interferon-gamma (IFN-gamma), or a combination of TNF-alpha and IFN-gamma, or IFN-gamma and IL-17, for 1, 6, 24, or 48 h. Presence of receptors for these mediators was verified by RT-PCR. Effects of the cytokines on expression levels of MUC1 and -16 were determined by real-time PCR, and on mucin protein biosynthesis and ectodomain release in cell lysates and culture media, respectively, by immunoblot analysis. TNF-alpha and IFN-gamma each significantly induced MUC1 expression, cellular protein content and ectodomain release over time. Combined treatment with the two cytokines was not additive. By comparison, one of the inflammatory mediators, IFN-gamma, affected all three parameters-gene expression, cellular protein, and ectodomain release-for MUC16. Combined treatment with TNF-alpha and IFN-gamma showed effects similar to IFN-gamma alone, except that ectodomain release followed that of TNF-alpha, which induced MUC16 ectodomain release. In conclusion, inflammatory mediators present in tears of dry eye patients can affect MUC1 and -16 on corneal epithelial cells and may be responsible for alterations of surface mucins in dry eye.

Are adenosquamous lung carcinomas a simple mix of adenocarcinomas and squamous cell carcinomas, or more complex at the molecular level?

Adenocarcinomas (AC), squamous cell carcinomas (SCC) and adenosquamous carcinomas (ASC) are three histological subtypes of non-small-cell lung carcinomas (NSCLC). ASC are morphologically mixed tumours that contain the two cell components AC and SCC. To understand if they are a "simple" mix of AC and SCC or if they present molecular specificities, as compared with the molecular characterization of both components, we performed a comparative transcriptome analysis on a series of nine ASC, five AC and five SCC induced in rats by radon exposure. We found that 72, 40 and 39 genes were differentially expressed when comparing AC_SCC, ASC_SCC and AC_ASC, respectively. Moreover, when classifying the three histological subtypes, using genes that discriminated AC and SCC, we observed that all ASC were classified as intermediate between the AC and SCC, some being closer to AC, others to SCC. These results indicated that, regarding gene expression, ASC could be considered as a mix of AC and SCC, both in various proportions. However, they also exhibit molecular specificities since we found specific genes discriminating ASC_SCC and AC_ASC. In conclusion, the ASC mixed lung tumours are more complex than simple mixes of AC and SCC components. Neuroendocrine differentiation and ERK proliferation pathways seemed preferentially deregulated in ASC compared to AC and SCC respectively, pathways that are worthy of being explored because they could partially explain the high clinical aggressiveness of ASC.

Significance of mucin expression in pancreatobiliary neoplasms

Mucins are high molecular weight glycoproteins that play important roles in carcinogenesis and tumor invasion. We have described, for the first time, that pancreatic ductal adenocarcinomas (PDACs) with an aggressive behavior and a poor outcome expressed MUC1 (pan-epithelial membrane-associated mucin) but did not express MUC2 (intestinal-type secreted mucin), whereas intraductal papillary mucinous neoplasms (IPMNs) with indolent behavior and a favorable outcome did not express MUC1 but did express MUC2. These expression profiles of MUC1 and MUC2 related to the prognoses of the patients were also observed in biliary neoplasms such as intrahepatic cholangiocarcinoma (ICC)-mass-forming type (MF), mucin-producing bile duct tumor (MPBT), and extrahepatic bile duct carcinoma (EHBDC). We also found recently that high expression of MUC4 (tracheobronchial membrane-associated mucin) in PDACs, ICCs-MF, and EHBDCs was a new independent poor prognostic factor, although MUC4 was not expressed in normal pancreatobiliary tissue. High de novo expression of MUC5AC (gastric-type secreted mucin) was observed in many types of pancreatobiliary neoplasms, including all grades of pancreatic intraepithelial neoplasia (PanIN) and biliary intraepithelial neoplasia (BilIN), and all types of IPMNs and MPBTs, as well as PDACs and ICCs-MF, although MUC5AC was not expressed in normal pancreatobiliary tissue. The combined status of MUC1, MUC2, MUC4, and MUC5AC expression may be useful for the early detection of pancreatobiliary neoplasms and evaluation of their malignancy. In regard to the mechanism of mucin expression, we have recently reported that MUC1, MUC2, MUC4, and MUC5AC gene expression is regulated by epigenetics (DNA methylation and histone H3 lysine 9 modification) in cancer cell lines, including PDAC cells. Translational research of mucin gene expression mechanisms, including epigenetics, in pancreatobiliary neoplasms may give us new tools for the early and accurate detection of these neoplasms.

A double-regulated oncolytic adenovirus with improved safety for adenocarcinoma therapy

Safety and efficiency are equally important to be considered in developing oncolytic adenovirus. Previously, we have reported that ZD55, an oncolytic adenovirus with the deletion of E1B-55K gene, exhibited potent antitumor activity. In this study, to improve the safety of ZD55, we utilized MUC1 promoter to replace the native promoter of E1A on the basis of ZD55, and generated a double-regulated adenovirus, named MUD55. Our data demonstrated that the expression of early and late genes of MUD55 was both reduced in MUC1-negative cells, resulting in its stricter glandular-tumor selective progeny production. The cytopathic effect of MUD55 was about 10-fold lower than mono-regulated adenovirus ZD55 or Ad.MUC1 in normal cells and not obviously attenuated in glandular tumor cells. Moreover, MUD55 showed the least liver toxicity when administrated by intravenous injection in nude mice. These results indicate that MUD55 could be a promising candidate for the treatment of adenocarcinoma.

[Construction of eukaryotic expressing vector of multiple myeloma mucin-1 and its expression in COS-7 cells in vitro]

In order to construct an eukaryotic expression vector for gene of multiple myeloma mucin1 (muc1-2vntr) gene and to express it in COS-7 cells in vitro, so to provide the basic material for further research of multiple myeloma DNA vaccine. muc1-2vntr coding gene was used as a research gene and a KOZAK sequence was inserted before the gene Hind III and XbaI restriction sites were inserted before and after the coding gene. Then the whole sequence was synthesized and inserted into pcDNA3.1/myc-his B vector, and the resulted recombinant vector was transformed into E.coil competent cells to get an engineering strain, the recombinant plasmid pcDNA3.1-2vntr/myc-his B identified by restriction analysis and DNA sequencing were transfected into COS-7 cells by liposome-mediated gene transfer method. Finally, fluorescent microscopy was used to assess GFP expression and Western blot analysis using muc1 monoclonal antibody was used to recognize vntr, confirming the expression of vntr. The results showed that the full length of synthesized muc1-2vntr gene, as expected, was 140 bp. Both restriction analysis and DNA sequencing demonstrated that pcDNA3.1-2vntr/myc-his B included the whole translation frame region and muc1-2vntr gene. Furthermore, the fluorescence microscopy proved that the recombinant plasmid had been successfully transfected into COS-7 cells. The expression of mucin-1 protein was observed both in the transfected cell and the cell supernatant by Western blot. It is concluded that the pcDNA3.1-2vntr/myc-his B has been successfully constructed and expressed in COS-7 cells in vitro, which provides the basic material for further researches of mucin-1 function and possible multiple myloma DNA vaccine.

MUC1 is a downstream target of STAT3 and regulates lung cancer cell survival and invasion

Signal transducer and activator of transcription 3 (STAT3) is aberrantly activated in human cancer including lung cancer and has been implicated in transformation, tumorigenicity, and metastasis. One putative downstream gene regulated by Stat3 is MUC1 which also has important roles in tumorigenesis. We determined if Stat3 regulates MUC1 in lung cancer cell lines and what function MUC1 plays in lung cancer cell biology. We examined MUC1 expression in non-small cell lung cancer (NSCLC) cell lines and found high levels of MUC1 protein expression associated with higher levels of tyrosine phosphorylated STAT3. STAT3 knockdown downregulated MUC1 expression whereas constitutive STAT3 expression increased MUC1 expression at mRNA and protein levels. MUC1 knockdown induced cellular apoptosis concomitant with reduced Bcl-XL and sensitized cells to cisplatin treatment. MUC1 knockdown inhibited tumor growth and metastasis in an orthotopic mouse model of lung cancer by activating apoptosis and inhibiting cell proliferation in vivo. These results demonstrate that constitutively activated STAT3 regulates expression of MUC1, which mediates lung cancer cell survival and metastasis in vitro and in vivo. MUC1 appears to be a cooperating oncoprotein with multiple oncogenic tyrosine kinase pathways and could be an effective target for the treatment of lung cancer.

Novel multi-peptide vaccination in Hla-A2+ hormone sensitive patients with biochemical relapse of prostate cancer

BACKGROUND

A phase I/II trial was conducted to assess feasibility and tolerability of tumor associated antigen peptide vaccination in hormone sensitive prostate carcinoma (PC) patients with biochemical recurrence after primary surgical treatment.

METHODS

Nineteen HLA-A2 positive patients with rising PSA without detectable metastatic disease or local recurrence received 11 HLA-A*0201-restricted and two HLA class II synthetic peptides derived from PC tumor antigens subcutaneously for 18 months or until PSA progression. The vaccine was emulgated in montanide ISA51 and combined with imiquimod, GM-CSF, mucin-1-mRNA/protamine complex, local hyperthermia or no adjuvant. PSA was assessed, geometric mean doubling times (DT) calculated and clinical performance monitored.

RESULTS

PSA DT of 4 out of 19 patients (21%) increased from 4.9 to 25.8 months during vaccination. Out of these, two patients (11%) exhibited PSA stability for 28 and 31 months which were still continuing at data cut-off. One patient showed no change of PSA DT during vaccination but decline after the therapy. Three patients had an interim PSA decline or DT increase followed by DT decrease compared to baseline PSA DT. Three of the responding patients received imiquimod and one the mucin-1-mRNA/protamine complex as adjuvant; both are Toll-like receptor-7 agonists. Eleven (58%) patients had progressive PSA values. The vaccine was well tolerated, and no grade III or IV toxicity occurred.

CONCLUSION

Multi-peptide vaccination stabilized or slowed down PSA progress in four of 19 cases. The vaccination approach is promising with moderate adverse events. Long-term stability delayed androgen deprivation up to 31 months. TLR-7 co-activation seems to be beneficial.

MUC1 oncoprotein promotes autophagy in a survival response to glucose deprivation

Tumor cells survive under conditions of nutrient deprivation by mechanisms that are not fully understood. The MUC1 oncoprotein is aberrantly overexpressed by most human carcinomas and blocks oxidative stress-induced death. The present studies show that MUC1 inhibits the induction of necrosis in response to the deprivation of glucose. MUC1 suppressed glucose deprivation-induced increases in reactive oxygen species (ROS) and thereby depletion of ATP and cell death. Cells respond to oxidative stress and energy depletion with the induction of autophagy. Our results demonstrate that MUC1 blocks depletion of ATP and sustains growth of glucose-deprived cells by a mechanism sensitive to the autophagy inhibitor, 3-methyladenine. Silencing expression of ATG7, a protein essential for the formation of autophagic vacuoles, also attenuated the MUC1-sustained increases in ATP and growth in response to glucose deprivation. Moreover, we found that MUC1 stimulates AMPK activation and thereby promotes lysosomal turnover of LC3-II, a marker of starvation-induced autophagic activity. These results indicate that MUC1 suppresses glucose deprivation-induced increases in ROS and thereby promotes ATP production and survival. The findings also indicate that the overexpression of MUC1 as found in human cancers could provide a survival advantage in microenvironments with low glucose levels.

A potent, imaging adenoviral vector driven by the cancer-selective mucin-1 promoter that targets breast cancer metastasis

PURPOSE

With breast cancer, early detection and proper staging are critical, and will often influence both the treatment regimen and the therapeutic outcome for those affected with this disease. Improvements in these areas will play a profound role in reducing mortality from breast cancer.

EXPERIMENTAL DESIGN

In this work we developed a breast cancer-targeted serotype 5 adenoviral vector, utilizing the tumor-specific mucin-1 promoter in combination with the two-step transcriptional amplification system, a system used to augment the activity of weak tissue-specific promoters.

RESULTS

We showed the strong specificity of this tumor-selective adenovirus to express the luciferase optical imaging gene, leading to diagnostic signals that enabled detection of sentinel lymph node metastasis of breast cancer. Furthermore, we were able to target hepatic metastases following systemic administration of this mucin-1 selective virus.

CONCLUSIONS

Collectively, we showed that the amplified mucin-1 promoter-driven vector is able to deliver to and selectively express a desirable transgene in metastatic lesions of breast tumors. This work has strong clinical relevance to current diagnostic staging approaches, and could add to targeted therapeutic strategies to advance the fight against breast cancer.

Mucin 1 (MUC1) is a novel partner for MAL2 in breast carcinoma cells

BACKGROUND

The MAL2 gene, encoding a four-transmembrane protein of the MAL family, is amplified and overexpressed in breast and other cancers, yet the significance of this is unknown. MAL-like proteins have trafficking functions, but their molecular roles are largely obscure, partly due to a lack of known binding partners.

METHODS

Yeast two-hybrid screening of a breast carcinoma cDNA expression library was performed using a full-length MAL2 bait, and subsequent deletion mapping experiments were performed. MAL2 interactions were confirmed by co-immunoprecipitation analyses and confocal microscopy was employed to compare protein sub-cellular distributions. Sucrose density gradient centrifugation of membranes extracted in cold Triton X-100 was employed to compare protein distributions between Triton X-100-soluble and -insoluble fractions.

RESULTS

The tumor-associated protein mucin 1 (MUC1) was identified as a potential MAL2 partner, with MAL2/MUC1 interactions being confirmed in myc-tagged MAL2-expressing MCF-10A cells using co-immunoprecipitation assays. Deletion mapping experiments demonstrated a requirement for the first MAL2 transmembrane domain for MUC1 binding, whereas the MAL2 N-terminal domain was required to bind D52-like proteins. Confocal microscopy identified cytoplasmic co-localisation of MUC1 and MAL2 in breast cell lines, and centrifugation of cell lysates to equilibrium in sucrose density gradients demonstrated that MAL2 and MUC1 proteins were co-distributed between Triton X-100-soluble and -insoluble fractions. However co-immunoprecipitation analyses detected MAL2/MUC1 interactions in Triton X-100-soluble fractions only. Myc-MAL2 expression in MCF-10A cells was associated with both increased MUC1 detection within Triton X-100-soluble and -insoluble fractions, and increased MUC1 detection at the cell surface.

CONCLUSION

These results identify MUC1 as a novel MAL2 partner, and suggest a role for MAL2 in regulating MUC1 expression and/or localisation.

[Detecting MUC-1 mRNA for diagnosing peripheral blood micro-metastasis in non-small cell lung cancer patients]

BACKGROUND & OBJECTIVE

Mucins, including MUC-1, are generally considered to be products of epithelial tissues and epithelial tumors. Theoretically, MUC-1 mRNA in peripheral blood with interstitial origin indicates metastasis. This study was to explore the feasibility of MUC-1 mRNA as a molecular marker in detecting peripheral blood micro-metastasis in patients with non-small cell lung cancer (NSCLC).

METHODS

Nested reverse transcription-polymerase chain reaction (RT-PCR) was used to detect MUC-1 gene expression in peripheral blood samples from 60 patients with NSCLC, 15 patients with benign pulmonary disease, and 20 healthy subjects. MUC-1 gene expression in K562 and HL-60 cells with non-epithelial origin, and A549 and MCF-7 cells with epithelial origin was also detected by nested RT-PCR.

RESULTS

The positive rates of MUC-1 mRNA were 80.0% in NSCLC group, 60.0% in benign pulmonary disease group, and 65.0% in healthy group. MUC-1 mRNA was also detected in K562, HL-60, A549 and MCF-7 cells.

CONCLUSION

MUC-1 mRNA can not be a reliable detection marker for peripheral blood micro-metastasis in NSCLC patients.

Dietary induction of colonic tumors in a mouse model of sporadic colon cancer

A defined rodent "new Western diet" (NWD), which recapitulates intake levels of nutrients that are major dietary risk factors for human colon cancer, induced colonic tumors when fed to wild-type C57Bl/6 mice for 1.5 to 2 years from age 6 weeks (two-thirds of their life span). Colonic tumors were prevented by elevating dietary calcium and vitamin D(3) to levels comparable with upper levels consumed by humans, but tumorigenesis was not altered by similarly increasing folate, choline, methionine, or fiber, each of which was also at the lower levels in the NWD that are associated with risk for colon cancer. The NWD significantly altered profiles of gene expression in the flat colonic mucosa that exhibited heterogeneity among the mice, but unsupervised clustering of the data and novel statistical analyses showed reprogramming of colonic epithelial cells in the flat mucosa by the NWD was similar to that initiated by inheritance of a mutant Apc allele. The NWD also caused general down-regulation of genes encoding enzymes involved in lipid metabolism and the tricarboxylic acid cycle in colonic epithelial cells before tumor formation, which was prevented by the supplementation of the NWD with calcium and vitamin D(3) that prevented colon tumor development, demonstrating profound interaction among nutrients. This mouse model of dietary induction of colon cancer recapitulates levels and length of exposure to nutrients linked to relative risk for human sporadic colon cancer, which represents the etiology of >90% of colon cancer in the United States and other Western countries.

MUC1 oncoprotein promotes growth and survival of human multiple myeloma cells

The MUC1 oncoprotein is aberrantly expressed in human multiple myeloma cells by mechanisms that are not understood. Moreover, the functional role of MUC1 in multiple myeloma is not known. The present studies demonstrate that the MUC1 gene locus is amplified in multiple myeloma cell lines and in primary cells from patients. The KMS28PE multiple myeloma cell line, which was found to have MUC1 gene amplification, was stably silenced for MUC1 using different siRNAs. Silencing MUC1 was associated with a decrease in nuclear beta-catenin levels, consistent with the function of MUC1 in stabilizing beta-catenin. MUC1 is also known to activate the IKKbeta-->NF-kappaB pathway and KMS28PE cells silenced for MUC1 were found to have downregulation of IKKbeta and IkappaBalpha phosphorylation, and decreased nuclear targeting of NF-kappaB p65. The results also demonstrate that MUC1: i) contributes to KMS28PE cell proliferation, and ii) protects against apoptosis and loss of self-renewal in the response to melphalan and dexamethasone. These findings indicate that MUC1 activates the beta-catenin and NF-kappaB pathways in multiple myeloma cells and contributes to their growth and survival.

Does the pre-operative value of serum CA15-3 correlate with survival in breast cancer?

INTRODUCTION

CA15-3 is a well-known tumour marker for breast cancer. Currently it is not recommended for screening or diagnosis of breast cancer and its main application is in monitoring response to treatment in women with metastatic breast cancer. The aim of this study was to correlate serum CA15-3 at presentation with the stage of disease and overall survival in women with breast cancer in the University Malaya Medical Centre.

METHODS

This is a retrospective study of 437 women who had CA15-3 levels determined at initial presentation of breast cancer to UMMC between Jan 1999 and Oct 2003.

RESULTS

Of those patients who were adequately staged, CA15-3 was found to be elevated (defined as >51 U/ml) in 0% of Stage 1, 7.9% of Stage 2, 36.7% of Stage 3 and 68.6% of Stage 4 cases. In a subset of 331 patients with survival data, patients with normal CA15-3 had a 85% five year overall survival rate compared to 38% in their counterparts with elevation of the tumor marker. The level of elevation was also significantly related to survival; patients with values more than 200 U/ml exhibited only a 28% five year survival. The association of elevated CA15-3 at initial presentation with poor outcome was maintained over univariate and multivariate analyses.

CONCLUSION

Estimation of CA15-3 at presentation of breast cancer is important as it is an independent prognostic indicator and may prompt the physician to investigate for metastases if elevated.

No evidence of association of MUC-1 genetic polymorphism with embryo implantation failure

Pregnancy loss can be caused by several factors involved in human reproduction. Although up to 50% of cases remain unexplained, it has been postulated that the major cause of failed pregnancy is an error of embryo implantation. Transmembrane mucin-1 (MUC-1) is a glycoprotein expressed on the endometrial cell surface which acts as a barrier to implantation. The gene that codes for this molecule is composed of a polymorphic tandem repeat of 60 nucleotides. Our objective was to determine if MUC-1 genetic polymorphism is associated with implantation failure in patients with a history of recurrent abortion. The study was conducted on 10 women aged 25 to 35 years with no history of successful pregnancy and with a diagnosis of infertility. The control group consisted of 32 patients aged 25 to 35 years who had delivered at least two full-term live children and who had no history of abortions or fetal losses. MUC-1 amplicons were obtained by PCR and observed on agarose and polyacrylamide gel after electrophoresis. Statistical analysis showed no significant difference in the number of MUC-1 variable number of tandem repeats between these groups (P > 0.05). Our results suggest that there is no effect of the polymorphic MUC-1 sequence on the implantation failure. However, the data do not exclude MUC-1 relevance during embryo implantation. The process is related to several associated factors such as the mechanisms of gene expression in the uterus, specific MUC-1 post-translational modifications and appropriate interactions with other molecules during embryo implantation.

[Prokaryotic expression, purification of HSP65-MUC1 VNTR2 fusion protein and primary research on its tumoricidal effect]

AIM

To express the HSP65-MUC1 VNTR(2) in E.coli and to evaluate its activity of inhibiting tumor growth in vivo.

METHODS

HSP65 and MUC1 VNTR(2) were generated by PCR method and sub-cloned to pET28a(+) to construct the recombinant expression vector HSP65-MUC1 VNTR(2)-pET28a(+). E.coli BL21(DE3) bearing the plasmid was induced with IPTG for protein production. Target protein was characterized by Western blot with monoclonal antibody and purified by Q-Sepharose ion-exchange chromatography and gel filtration. The murine cancer cell linejB16 that transfected by human gene MUC1 was utilized to construct the model of carcinoma, and the tumor growth inhibition activities of HSP65-MUC1VNTR(2) was evaluated in mice C57BL/6.

RESULTS

The gene HSP65 and MUC1 VNTR(2) confirmed by sequence analysis matched respectively with BCG HSP65 and human gene MUC1 VNTRs in GenBank exactly. The reconstructed vector HSP65-MUC1 VNTR(2)-pET28a could express target protein stably in the soluble fraction of bacterial extract. The purity of HSP65-MUC1 VNTR(2) protein could be above 95% after purification by Q ion-exchange chromatography and gel filtration. The result of Western blot with monoclonal antibody showed positive. The results of prophylactic immunization with HSP65-MUC1 VNTR(2) fusion protein showed that experiment all groups had significantly higher tumor inhibition rates than that of control group.

CONCLUSION

In summary, HSP65-MUC1 VNTR(2) fusion protein was solubly expressed in prokaryotic expression system and its tumor growth inhibition activity was evaluated primarily. The result indicated that the fusion protein could inhibit the MUC1 positive tumor growth significantly. It can be used in the future research as the cancer vaccine.

[Human mucin 1 promoter drives human sodium/iodide symporter gene targeting expression in pancreatic carcinoma cells]

OBJECTIVE

To clone human mucin 1 (MUC1) gene promoter and apply to drive human sodium/iodide symporter (hNIS) gene targeting expression in pancreatic carcinoma cells.

METHODS

Human Mucin1 (MUC1) promoter was cloned from the 5' flanking region of the MUC1 gene by two-step nest PCR from human pancreatic carcinoma cells of the line CAPAN-I, II and then linked to pDC316 plasmid (pDC316-MUC1). Subsequently, a recombinant plasmid containing MUC1 and hNIS was constructed (pDC316-MUC1/hNIS). The recombinant plasmid pDC316-MUC1/hNIS, pD316-mCMV/NIS plasmid, and pDC316-mCMV/hNIS plasmid were transfected into the CAPAN-II cells, human pancreatic carcinoma cells of the line PANC-1, and human cervical carcinoma cells of the line HeLa respectively as experimental group, positive control group, and negative control group. 48 h after the transfection RT-PCR and immunofluorescence were used to confirm the expression of hNIS mRNA and hNIS protein. Then the cells were cultured in solution with 125I. The 125I uptake in the cells was measured by gamma-counting.

RESULTS

The sequence data of regulatory element in MUC1 promoter genes was corresponded to those of reference report. The hNIS protein expression level was high in the MUC1 positive cells, as CAPAN-II cells and PANC-1 cells, but very low in the MUC1 negative cells, such as the HeLa cells. Two days after the transfection, the CAPAN-II cells and PANC-1 cells showed a high level of 125I uptake after transfection with pDC316-MUC1/hNIS, and the CAPAN-II cells, PANC-1 cells, and HeLa cells showed a high level of 125I uptake after transfection with pDC316-MCMV/hNIS. A7-12-fold increase in 125I uptake was observed in the pDC316-MUC1/hNIS transfected cells compared with the pDC316-MUC1 transfected cells.

CONCLUSION

MUC1 promoter cloned from CAPAN-2 cells can be used to drive NIS genes expression in MUC1 positive pancreatic carcinoma cells. Therefore, this strategy can be used as a novel and potent gene-targeting therapy in the MUC1 positive pancreatic carcinoma in vivo.

MUC1 cell surface mucin is a critical element of the mucosal barrier to infection

Cell surface mucin glycoproteins are highly expressed by all mucosal tissues, yet their physiological role is currently unknown. We hypothesized that cell surface mucins protect mucosal cells from infection. A rapid progressive increase in gastrointestinal expression of mucin 1 (Muc1) cell surface mucin followed infection of mice with the bacterial pathogen Campylobacter jejuni. In the first week following oral infection, C. jejuni was detected in the systemic organs of the vast majority of Muc1(-/-) mice but never in Muc1(+/+) mice. Although C. jejuni entered gastrointestinal epithelial cells of both Muc1(-/-) and Muc1(+/+) mice, small intestinal damage as manifested by increased apoptosis and enucleated and shed villous epithelium was more common in Muc1(-/-) mice. Using radiation chimeras, we determined that prevention of systemic infection in wild-type mice was due exclusively to epithelial Muc1 rather than Muc1 on hematopoietic cells. Expression of MUC1-enhanced resistance to C. jejuni cytolethal distending toxin (CDT) in vitro and CDT null C. jejuni showed lower gastric colonization in Muc1(-/-) mice in vivo. We believe this is the first in vivo experimental study to demonstrate that cell surface mucins are a critical component of mucosal defence and that the study provides the foundation for exploration of their contribution to epithelial infectious and inflammatory diseases.

Reversal of drug resistance in breast carcinoma cells by anti-mdr1 ribozyme regulated by the tumor-specific MUC-1 promoter

Multidrug resistance (MDR) is a serious obstacle for cancer chemotherapy. The aim of this study was to reverse MDR of breast carcinoma cells specifically by degrading mdr1 mRNA with anti-mdr1 ribozyme. Our strategy was to limit the expression of ribozyme to only breast-derived cells, but not other type of cells. The results showed the recombinant ribozyme pEGFP-RZmuc was expressed in two kinds of breast carcinoma cells, but not in non-breast-derived cancer cells. Evaluation of chemosensitivity showed that a 15-fold reduction in drug resistance for Adriamycin and a 32-fold reduction in drug resistance for Vinblastine were observed in the transfected cells. Our results demonstrate the efficacy and selectivity of pEGFP-RZmuc to reverse MDR in drug resistant breast carcinoma cells in vitro.

In vivo radioiodide imaging and treatment of pancreatic cancer xenografts after MUC1 promoter-driven expression of the human sodium-iodide symporter

INTRODUCTION AND AIMS

Mucin 1 (MUC1) is a transmembrane glycoprotein that is overexpressed in many tumor types, including breast, pancreatic, and ovarian cancer. The aim of this study was to create a construct containing sodium-iodide symporter (NIS) under the control of the 0.8-kb MUC1 promoter to infect pancreatic cancer cells both in vitro and in vivo, to investigate the potential for radioiodide imaging and ablation of this disease.

METHODOLOGY

We amplified the 797-bp MUC1 promoter by two-step nested PCR. Subsequently, a replication-deficient adenoviral construct was created containing the MUC1 promoter followed by the human NIS gene. Iodide uptake assays and immunofluorescence were used to confirm NIS expression and function. Pancreatic cancer xenografts in mice were infected with Ad/MUC1/NIS and then imaged and treated using radioiodide.

RESULTS

A 23- and 15.5-fold increase in iodide uptake was observed in Ad/MUC1/NIS-infected MUC1-positive Capan-2 and SW1990 cells with no significant increase observed in MUC1-negative Hela cells or in cells infected with the control virus. The in vivo study showed a clear image of Ad/MUC1/NIS-infected tumor xenografts using (125)I. Administration of a therapeutic dose of (131)I resulted in a regression in size to 76 +/- 15% of their original volume, whereas control tumors continued to increase in size to >200% of their original volume.

CONCLUSIONS

These results show that the 0.8-kb MUC1 promoter was successfully used to drive human NIS-targeted expression in pancreatic cancer cells, and Ad/MUC1/NIS-mediated radiotherapy can make pancreatic cancer xenografts in mice shrinking. This could potentially have applications for both imaging and therapy in other MUC1-positive tumors.

Cutting edge: transgenic expression of human MUC1 in IL-10-/- mice accelerates inflammatory bowel disease and progression to colon cancer

Epithelial cell MUC1 is aberrantly expressed on human epithelial adenocarcinomas where it functions as a regulator of immune responses and an oncogene. Normally expressed at low levels in healthy colonic epithelium, MUC1 was reported to be overexpressed in human inflammatory bowel disease (IBD) and thus may be expected to play an important role in regulating chronic inflammation and its progression to colitis-associated colon cancer. Studies in the immunobiology and pathology of IBD and colitis-associated colon cancer have been done in various mouse models but none could properly address the role of MUC1 due to low homology between the mouse and the human molecule. We report that IL-10(-/-) mice, a widely accepted mouse model of IBD, crossed to human MUC1-transgenic mice, develop MUC1(+) IBD characterized by an earlier age of onset, higher inflammation scores, and a much higher incidence and number of colon cancers compared with IL-10(-/-) mice.

Cancer immunotherapy: phase II clinical studies with TG4010 (MVA-MUC1-IL2)

Vaccines are well known in the context of prevention of diseases caused by infectious agents. Current research is now aimed at using vaccines to manipulate the immune system to eliminate established diseases, including cancer. Several such immunotherapeutic vaccines are now in clinical trials and are beginning to show clinical benefit. TG4010 is one such vaccine. It incorporates the MUC1 antigen, which is overexpressed in the majority of cancers, into a non-propagative pox viral vector, MVA. A second gene, interleukin-2 is also incorporated into TG4010 as an immune stimulus. The vaccine has been tested in breast, kidney, prostate and lung cancers with encouraging results.

In vivo bioluminescence visualization of antitumor effects by human MUC1 vaccination

Recently, the use of a cancer deoxyribonucleic acid (DNA) vaccine encoding tumor-associated antigens has emerged as an immunotherapeutic strategy. In this study, we monitored tumor growth inhibition by pcDNA3-hMUC1 immunization in mice using optical imaging. To determine the anti-hMUC1-associated immune response generated by pcDNA3.1 or pcDNA3-hMUC1, we determined the concentration of interferon-gamma (IFN-gamma) protein and CD8+IFN-gamma cell numbers among lymphocytes from the draining lymph nodes of mice immunized with pcDNA3.1 or pcDNA3-hMUC1. After subcutaneously injecting CT26/hMUC1-Fluc into mice immunized with pcDNA3-hMUC1, we monitored in vivo tumor growth inhibition using an optical imaging method. The concentration of IFN-gamma protein in pcDNA3-hMUC1 was higher than that of the pcDNA3.1 group (2.7 < or = 0.08 ng/mL and 1.6 +/- 0.07 ng/mL, respectively, p < .001. The number of hMUC1-associated CD8+IFN-gamma cells in pcDNA3-hMUC1-immunized animals was 30-fold higher than in the pcDNA3.1 group. Bioluminescent images showed tumor growth inhibition in pcDNA3-hMUC1 immunized animals up to 25 days after immunization. A good correlation (r2 = .9076: pcDNA3/hMUC1 group; r2 = .7428: pcDNA3.1 group) was observed between bioluminescence signals and tumor weights in two mice in each group. We conclude that optical bioluminescent imaging offers a useful means of monitoring the antitumor effects of cancer DNA immunization in living animals.

Evolution of the human MUC1 oncoprotein

The mucin (MUC) family consists of secreted and membrane-bound forms. The transmembrane mucin 1 (MUC1) is a heterodimer that is aberrantly overexpressed by diverse human carcinomas and certain hematologic malignancies. The MUC1 N-terminal (MUC1-N) and C-terminal (MUC1-C) subunits are generated by autocleavage within a SEA domain. The MUC1 cytoplasmic domain (MUC1-CD) located downstream of the SEA domain is sufficient for the induction of anchorage-independent growth and tumorigenicity; however, no information is available regarding the origin of these transforming sequences. Previous work demonstrated that, except for the SEA domain, MUC1 has no sequence homology with other membrane-bound mucins. The present results demonstrate that MUC1-CD evolved from repeat regions in the MUC5B secreted mucin. We also show that MUC1 sequences upstream to the SEA domain emerged from MUC5B. These findings indicate that both the MUC1-N and MUC1-C subunits evolved from secreted gel-forming mucins and that the MUC1-CD oncogenic function emerged by diversification after evolution from MUC5B.

Evaluation of serum tumour markers concentrations in patients with homozygous β-thalassaemia in relation to demographical, clinical and biochemical parameters

Increased life expectancy in patients with homozygous beta-thalassaemia consequently increases the risk for neoplastic diseases. This study was conducted to assess the levels of five common tumour markers in thalassaemic patients and to investigate possible correlations to demographical, clinical and laboratory data. Eighty-five patients (44 female and 41 male) with homozygous beta-thalassaemia (mean age = 27.92 +/- 12.5), on regular blood transfusions and adequate chelation treatment, and 60 sex and age- matched healthy controls were enrolled in the study. Blood samples for the determination of carcinoma antigen (CA) 15.3, CA 125, CA 19.9, carcinoembryonic antigen (CEA) and alpha-fetoprotein (a-FP) were collected from every subject. Results showed that 69% of the thalassaemic patients had abnormal levels of CA 15.3, whereas only sporadic cases had increased levels of CA 125 and CA 19.9. On the contrary, all controls had normal levels of CA 15.3, CA 19.9 and CA 125. CEA and a-FP were within reference ranges both in the thalassaemic and in the control group. Levels of CA 15.3 were significantly lower in patients aged less than 20 years compared to older patients. Male patients had significantly increased levels of CA 15.3 compared to female patients. Relatively recent studies show an increased expression of CA 15.3 on progenitor cells of the erythroid lineage and increased amounts of circulating progenitor cells even in well-transfused thalassaemic patients. However, it seems that there are also other factors contributing to this phenomenon. In conclusion, our results indicate that CA 15.3 seems to be an unreliable marker of occult malignancy in patients with beta-thalassaemia. However, more studies are needed to support these preliminary results.

Characterization of the MUC1.Tg/MIN transgenic mouse as a model for studying antigen-specific immunotherapy of adenomas

A bigenic MUC1.Tg/MIN mouse model was developed by crossing Apc/(MIN/+) (MIN) mice with human MUC1 transgenic mice to evaluate MUC1 antigen-specific immunotherapy of intestinal adenomas. The MUC1.Tg/MIN mice developed adenomas at a rate comparable to that of MIN mice and had similar levels of serum MUC1 antigen. A MUC1-based vaccine consisting of MHC class I-restricted MUC1 peptides, a MHC class II-restricted pan-helper peptide, unmethylated CpG oligodeoxynucleotide and GM-CSF caused flattening of adenomas and significantly reduced the number of large adenomas. Immunization was successful in generating a MUC1-directed immune response evidenced by increased MUC1 peptide-specific anti-tumor cytotoxicity and IFN-gamma secretion by lymphocytes.

MUC1 is a promising therapeutic target for prostate cancer therapy

Prostate cancer (CaP) is one of the most common malignancies in men, and the incidence of CaP is increasing. Because of the limitations of current therapeutic approaches, many patients die of secondary disease (metastases). Mucins are used as diagnostic markers as well as therapeutic targets due to their aberrant and unique expression pattern during cancer progression. There is a growing interest in mucins as treatment targets in human malignancies, including CaP. So far, 21 mucin genes have been identified. Of these, MUC1 has been investigated most extensively. In neoplastic tissues, MUC1 is underglycosylated compared with that in normal tissues. The reduced glycosylation permits the immune system to access the peptide core of the tumor-associated underglycosylated MUC1 antigen (uMUC1) and reveal epitopes that are masked in the normal cell. This feature makes it possible to design an antibody that discriminates between normal and adenocarcinoma cells and target tumor-associated MUC1 with toxins or radionuclides, or use a vaccine targeting tumor-associated MUC1 antigen. The results from our recent study have shown that over-expression of MUC1 plays a very important role in CaP progression and MUC1 is an ideal target for targeted therapy to control micrometastases and hormone refractory disease. This review will cover our current understanding of the structure and functions of MUC1, summarize its expression on human CaP tissues and focus on the MUC1-based immunotherapy for control of metastatic CaP.