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Dhanisha SS, Guruvayoorappan C. Pathological Implications of Mucin Signaling in Metastasis. Curr Cancer Drug Targets 2023; 23:585-602. [PMID: 36941808 DOI: 10.2174/1568009623666230320121332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 01/11/2023] [Accepted: 01/25/2023] [Indexed: 03/23/2023]
Abstract
The dynamic mucosal layer provides a selective protective barrier for the epithelial cells lining the body cavities. Diverse human malignancies exploit their intrinsic role to protect and repair epithelia for promoting growth and survival. Aberrant expression of mucin has been known to be associated with poor prognosis of many cancers. However, the emergence of new paradigms in the study of metastasis recognizes the involvement of MUC1, MUC4, MUC5AC, MUC5B, and MUC16 during metastasis initiation and progression. Hence mucins can be used as an attractive target in future diagnostic and therapeutic strategies. In this review, we discuss in detail about mucin family and its domains and the role of different mucins in regulating cancer progression and metastasis. In addition, we briefly discuss insights into mucins as a therapeutic agent.
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Affiliation(s)
| | - Chandrasekharan Guruvayoorappan
- Laboratory of Immunopharmacology and Experimental Therapeutics, Division of Cancer Research, Regional Cancer Centre, Medical College Campus, University of Kerala, Thiruvananthapuram, Kerala, 695011, India
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2
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Saad EA, Elsaid AM, Shoaib RMS, Megahed KF, Elsharawy AN. MUC7 VNTR polymorphism and association with bronchial asthma in Egyptian children. Sci Rep 2022; 12:18910. [PMID: 36344553 PMCID: PMC9640678 DOI: 10.1038/s41598-022-21631-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 09/29/2022] [Indexed: 11/09/2022] Open
Abstract
Overproduction of mucins in the airways donates largely to airway blockage in asthma patients. Glycoprotein MUC7 plays a role in the clearance of bacteria and has anti-candidacidal criteria. Our goal was to investigate the association between the MUC7 variable number of tandem repeats (VNTR) polymorphism and bronchial asthma among Egyptian children. The MUC7 VNTR polymorphism was investigated among 100 children with bronchial asthma and 100 healthy controls using polymerase chain reaction (PCR) method. Serum levels of immunoglobulin E (IgE), tumor necrosis factor-alpha (TNF-α), and transforming growth factor-beta1 (TGF-β1) were assessed by enzyme-linked immunosorbent assay (ELISA) technique. The frequencies of 6*5 genotype, 5*5 genotype, (6*5 + 5*5) genotypes, and MUC7*5 allele of the MUC7 VNTR variant were significantly lower among asthmatic patients than controls (p < 0.015, OR = 0.39, 95% CI = 0.19-0.81; p = 0.03, OR = 0.18, 95% CI = 0.04-0.86; p < 0.001, OR = 0.29, 95% CI = 0.15-0.58; p < 0.001, OR = 0.3, 95% CI = 0.17-0.55, respectively). The (6*5 + 5*5) genotypes of the MUC7 VNTR variant were not associated with the clinical manifestations and serum levels of IgE, TNF-α, and TGF-β1 among asthmatic patients (p ˃ 0.05). In conclusion, the (6*5 + 5*5) genotypes of the MUC7 VNTR variant may have a protective role for bronchial asthma in Egyptian children.
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Affiliation(s)
- Entsar A. Saad
- grid.462079.e0000 0004 4699 2981Chemistry Department, Faculty of Science, Damietta University, Damietta, 34517 Egypt
| | - Afaf M. Elsaid
- grid.10251.370000000103426662Genetics Unit, Children Hospital, Mansoura University, Mansoura, Egypt
| | - Rasha M. S. Shoaib
- grid.510451.4Food and Dairy Sciences and Technology Department, Faculty of Environmental Agricultural Sciences, Arish University, Arish, North Sinai Egypt
| | - Khaled F. Megahed
- grid.10251.370000000103426662Department of Pediatrics, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Amal N. Elsharawy
- grid.462079.e0000 0004 4699 2981Chemistry Department, Faculty of Science, Damietta University, Damietta, 34517 Egypt
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3
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Su W, Feng B, Hu L, Guo X, Yu M. MUC3A promotes the progression of colorectal cancer through the PI3K/Akt/mTOR pathway. BMC Cancer 2022; 22:602. [PMID: 35655161 PMCID: PMC9161576 DOI: 10.1186/s12885-022-09709-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/27/2022] [Indexed: 12/17/2022] Open
Abstract
AbstractMucin 3A (MUC3A) is overexpressed in colorectal cancer (CRC) and associated with poor prognosis, but the related mechanism remains unclear. Our study found that MUC3A promotes the progression of CRC by activating the PI3K/Akt/mTOR signaling pathway. Knockout of MUC3A significantly inhibited the proliferation of CRC cells and induced G1 phase arrest by upregulating p21 protein, an important cell cycle regulator. Moreover, knockout of MUC3A significantly inhibited invasion ability and enhanced the sensitivity to the chemotherapeutic agent 5-FU. Furthermore, we found that knockout of MUC3A repressed the PI3K/Akt/mTOR pathway through RNA-seq. Treatment with the PI3K/Akt/mTOR pathway inhibitor rapamycin successfully eliminated the difference in proliferation, invasion and chemoresistance between MUC3A knockout cells and control cells. Our study suggests that MUC3A is a potential oncogene that promotes the proliferation, invasion, and chemotherapy resistance of CRC. Moreover, CRC patients with high expression of MUC3A may benefit from rapamycin treatment.
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Whole Exome Sequencing Identifies Two Novel Mutations in a Patient with UC Associated with PSC and SSA. Can J Gastroenterol Hepatol 2021; 2021:9936932. [PMID: 34545326 PMCID: PMC8449715 DOI: 10.1155/2021/9936932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 08/24/2021] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Patients diagnosed with ulcerative colitis (UC) associated with primary sclerosis cholangitis (PSC) and sessile serrated adenoma (SSA) are rare. The present study aimed to identify the potential causative gene mutation in a patient with UC associated with PSC and SSA. METHODS DNA was extracted from the blood sample and tissue sample of SSA, followed by the whole exome sequencing (WES) analysis. Bioinformatics analysis was utilized to predict the deleteriousness of the identified variants. Multiple sequence alignment and conserved protein domain analyses were performed using online software. Sanger sequencing was used to validate the identified variants. Expression and diagnostic analysis of identified mutated genes was performed in the GSE119600 dataset (peripheral blood samples of PSC and UC) and GSE43841 dataset (tumor samples of SSA). RESULTS In the present study, a total of 842 single nucleotide variants (SNVs) in 728 genes were identified in the blood sample. Two variants, integrin beta 4 (ITGB4) (c.C2503G; p.P835A) and a mucin 3A (MUC3A) (c.C1019T; p.P340L), were further analyzed. MUC3A was associated with inflammatory bowel disease. Sanger sequence in blood revealed that the ITGB4 mutation was fully cosegregated with the result of WES in the patient. Additionally, a variant, tumor protein p53 gene (TP53) (c.86delA; p.N29Tfs ∗ 15) was identified in the tissue sample of SSA. Compared to that in normal controls, ITGB4 was upregulated in both UC and PSC, MUC3A was, respectively, upregulated and downregulated in PSC and UC, and TP53 was downregulated in SSA. ITGB4 and TP53 had a potential diagnostic value for UC, PSC and SSA. CONCLUSIONS The present study demonstrated that the ITGB4 (c.C2503G; p.P835A) and MUC3A (c.C1019T; p.P340L) mutations may be the potential causative variants in a patient with UC associated with PSC and SSA. TP53 (c.86delA; p.N29Tfs ∗ 15) mutation may be associated with SSA in this patient.
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5
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Sun Y, Sun X, You C, Ma S, Luo Y, Peng S, Tang F, Tian X, Wang F, Huang Z, Yu H, Xiao Y, Wang X, Zhang J, Gong Y, Xie C. MUC3A promotes non-small cell lung cancer progression via activating the NFκB pathway and attenuates radiosensitivity. Int J Biol Sci 2021; 17:2523-2536. [PMID: 34326691 PMCID: PMC8315024 DOI: 10.7150/ijbs.59430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 05/20/2021] [Indexed: 11/20/2022] Open
Abstract
Mucin 3A (MUC3A) is highly expressed in non-small cell lung cancer (NSCLC), but its functions and effects on clinical outcomes are not well understood. Tissue microarray of 92 NSCLC samples indicated that high levels of MUC3A were associated with poor prognosis, advanced staging, and low differentiation. MUC3A knockdown significantly suppressed NSCLC cell proliferation and induced G1/S accumulation via downregulating cell cycle checkpoints. MUC3A knockdown also inhibited tumor growth in vivo and had synergistic effects with radiation. MUC3A knockdown increased radiation-induced DNA double strain breaks and γ-H2AX phosphorylation in NSCLC cells. MUC3A downregulation inhibited the BRCA-1/RAD51 pathway and nucleus translocation of P53 and XCRR6, suggesting that MUC3A promoted DNA damage repair and attenuated radiation sensitivity. MUC3A knockdown also resulted in less nucleus translocation of RELA and P53 in vivo. Immunoprecipitation revealed that MUC3A interacted with RELA and activated the NFκB pathway via promoting RELA phosphorylation and interfering the binding of RELA to IκB. Our studies indicated that MUC3A was a potential oncogene and associated with unfavorable clinical outcomes. NSCLC patients with a high MUC3A level, who should be more frequent follow-up and might benefit less from radiotherapy.
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Affiliation(s)
- Yingming Sun
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Department of Radiation and Medical Oncology, Affiliated Sanming First Hospital of Fujian Medical University, Sanming, China
| | - Xiaoge Sun
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Department of Radiation Oncology, The Affiliated Hospital of Inner Mongolia Medical University, Hohhot, China
| | - Chengcheng You
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Department of Pathology, China Three Gorges University Medical College, Yichang, China
| | - Shijing Ma
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yuan Luo
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Shan Peng
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Fang Tang
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Xiaoli Tian
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Feng Wang
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Zhengrong Huang
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Hongnv Yu
- Central Laboratory of Xinhua Hospital of Dalian University, Department of Medical Oncology, Xinhua Hospital of Dalian University, Dalian, China
| | - Yu Xiao
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, China.,Tumor Precision Diagnosis and Treatment Technology and Translational Medicine, Hubei Engineering Research Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Xiaoyong Wang
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Key Laboratory of Tumor Biological Behaviors, Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Junhong Zhang
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Key Laboratory of Tumor Biological Behaviors, Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yan Gong
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, China.,Tumor Precision Diagnosis and Treatment Technology and Translational Medicine, Hubei Engineering Research Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Conghua Xie
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Key Laboratory of Tumor Biological Behaviors, Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
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6
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Luo Y, Ma S, Sun Y, Peng S, Zeng Z, Han L, Li S, Sun W, Xu J, Tian X, Wang F, Wu Q, Xiao Y, Zhang J, Gong Y, Xie C. MUC3A induces PD-L1 and reduces tyrosine kinase inhibitors effects in EGFR-mutant non-small cell lung cancer. Int J Biol Sci 2021; 17:1671-1681. [PMID: 33994852 PMCID: PMC8120466 DOI: 10.7150/ijbs.57964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 03/30/2021] [Indexed: 12/31/2022] Open
Abstract
The immune checkpoint ligand programmed death-ligand 1 (PD-L1) and the transmembrane mucin (MUC) 3A are upregulated in non-small cell lung cancer (NSCLC), contributing to the aggressive pathogenesis and poor prognosis. Here, we report that knocking down the oncogenic MUC3A suppresses the PD-L1 expression in NSCLC cells. MUC3A is a potent regulator of epidermal growth factor receptor (EGFR) stability, and MUC3A deficiency downregulates the activation of the PI3K/Akt and MAPK pathways, which subsequently reduces the expression of PD-L1. Furthermore, knockdown of MUC3A and tyrosine kinase inhibitors (TKIs) in EGFR-mutant NSCLC cells play a synergistic effect on inhibited proliferation and promoted apoptosis in vitro. In the BALB/c nude mice xenograft model, MUC3A deficiency enhances EGFR-mutated NSCLC sensitivity to TKIs. Our study shows that transmembrane mucin MUC3A induces PD-L1, thereby promoting immune escape in NSCLC, while downregulation of MUC3A enhances TKIs effects in EGFR-mutant NSCLC. These findings offer insights into the design of novel combination treatment for NSCLC.
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Affiliation(s)
- Yuan Luo
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Shijing Ma
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Department of Geriatrics, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yingming Sun
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Shan Peng
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Zihang Zeng
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Linzhi Han
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Shuying Li
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Wenjie Sun
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Jieyu Xu
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Xiaoli Tian
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Feng Wang
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Qiuji Wu
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yu Xiao
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Junhong Zhang
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yan Gong
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Conghua Xie
- Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital of Wuhan University, Wuhan, China.,Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China
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7
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Abstract
A dynamic mucosal layer shields the epithelial cells lining the body cavities and is made up of high molecular weight, heavily glycosylated, multidomain proteins called mucins. Mucins, broadly grouped into transmembrane and secreted mucins, are the first responders to any mechanical or chemical insult to the epithelia and help maintain tissue homeostasis. However, their intrinsic properties to protect and repair the epithelia are exploited during oncogenic processes, where mucins are metamorphosed to aid the tumor cells in their malignant journey. Diverse domains, like the variable number tandem repeats (VNTR), sea urchin sperm protein enterokinase and agrin (SEA), adhesion-associated domain (AMOP), nidogen-like domain (NIDO), epidermal growth factor-like domain (EGF), and von Willebrand factor type D domain (vWD) on mucins, including MUC1, MUC4, MUC5AC, MUC5B, and MUC16, have been shown to facilitate cell-to-cell and cell-to-matrix interactions, and cell-autonomous signaling to promote tumorigenesis and distant dissemination of tumor cells. Several obstacles have limited the study of mucins, including technical difficulties in working with these huge glycoproteins, the dearth of scientific tools, and lack of animal models; thus, the tissue-dependent and domain-specific roles of mucins during mucosal protection, chronic inflammation, tumorigenesis, and hematological dissemination of malignant cells are still unclear. Future studies should try to integrate information on the rheological, molecular, and biological characteristics of mucins to comprehensively delineate their pathophysiological role and evaluate their suitability as targets in future diagnostic and therapeutic strategies.
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8
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Liberelle M, Jonckheere N, Melnyk P, Van Seuningen I, Lebègue N. EGF-Containing Membrane-Bound Mucins: A Hidden ErbB2 Targeting Pathway? J Med Chem 2020; 63:5074-5088. [PMID: 32027502 DOI: 10.1021/acs.jmedchem.9b02001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Membrane-bound mucins belong to a heterogeneous family of large O-glycoproteins involved in numerous cancers and inflammatory diseases of the epithelium. Some of them are also involved in protein-protein interactions, with receptor tyrosine kinase ErbB2, and fundamental and clinical data showed that these complexes have a detrimental impact on cancer outcome, thus raising interest in therapeutic targeting. This paper aims to demonstrate that MUC3, MUC4, MUC12, MUC13, and MUC17 have a common evolutionary origin and share a common structural organization with EGF-like and SEA domains. Theoretical structure-function relationship analysis of the conserved domains indicated that the studied membrane-bound mucins share common biological properties along with potential specific functions. Finally, the potential druggability of these complexes is discussed, revealing ErbB2-related pathways of cell signaling to be targeted.
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Affiliation(s)
- Maxime Liberelle
- Univ. Lille, Inserm CHU Lille, UMR-S1172-JPArc-Centre de Recherche Jean-Pierre Aubert Neurosciences et Cancer, F-59000 Lille, France.,Univ. Lille, Inserm, CHU Lille, UMR-S 1172-LiNC-Lille Neuroscience & Cognition, F-59000 Lille, France
| | - Nicolas Jonckheere
- Univ. Lille, Inserm CHU Lille, UMR-S1172-JPArc-Centre de Recherche Jean-Pierre Aubert Neurosciences et Cancer, F-59000 Lille, France.,Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-UMR-S 1277-Canther-Cancer Heterogeneity, Plasticity and Resistance to Therapies, F-59000 Lille, France
| | - Patricia Melnyk
- Univ. Lille, Inserm CHU Lille, UMR-S1172-JPArc-Centre de Recherche Jean-Pierre Aubert Neurosciences et Cancer, F-59000 Lille, France.,Univ. Lille, Inserm, CHU Lille, UMR-S 1172-LiNC-Lille Neuroscience & Cognition, F-59000 Lille, France
| | - Isabelle Van Seuningen
- Univ. Lille, Inserm CHU Lille, UMR-S1172-JPArc-Centre de Recherche Jean-Pierre Aubert Neurosciences et Cancer, F-59000 Lille, France.,Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-UMR-S 1277-Canther-Cancer Heterogeneity, Plasticity and Resistance to Therapies, F-59000 Lille, France
| | - Nicolas Lebègue
- Univ. Lille, Inserm CHU Lille, UMR-S1172-JPArc-Centre de Recherche Jean-Pierre Aubert Neurosciences et Cancer, F-59000 Lille, France.,Univ. Lille, Inserm, CHU Lille, UMR-S 1172-LiNC-Lille Neuroscience & Cognition, F-59000 Lille, France
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9
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Geerlings SY, Kostopoulos I, de Vos WM, Belzer C. Akkermansia muciniphila in the Human Gastrointestinal Tract: When, Where, and How? Microorganisms 2018; 6:microorganisms6030075. [PMID: 30041463 PMCID: PMC6163243 DOI: 10.3390/microorganisms6030075] [Citation(s) in RCA: 257] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/03/2018] [Accepted: 07/12/2018] [Indexed: 02/06/2023] Open
Abstract
Akkermansia muciniphila is a mucin-degrading bacterium of the phylum Verrucomicrobia. Its abundance in the human intestinal tract is inversely correlated to several disease states. A. muciniphila resides in the mucus layer of the large intestine, where it is involved in maintaining intestinal integrity. We explore the presence of Akkermansia-like spp. based on its 16S rRNA sequence and metagenomic signatures in the human body so as to understand its colonization pattern in time and space. A. muciniphila signatures were detected in colonic samples as early as a few weeks after birth and likely could be maintained throughout life. The sites where Akkermansia-like sequences (including Verrucomicrobia phylum and/or Akkermansia spp. sequences found in the literature) were detected apart from the colon included human milk, the oral cavity, the pancreas, the biliary system, the small intestine, and the appendix. The function of Akkermansia-like spp. in these sites may differ from that in the mucosal layer of the colon. A. muciniphila present in the appendix or in human milk could play a role in the re-colonization of the colon or breast-fed infants, respectively. In conclusion, even though A. muciniphila is most abundantly present in the colon, the presence of Akkermansia-like spp. along the digestive tract indicates that this bacterium might have more functions than those currently known.
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Affiliation(s)
- Sharon Y Geerlings
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708WE Wageningen, The Netherlands.
| | - Ioannis Kostopoulos
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708WE Wageningen, The Netherlands.
| | - Willem M de Vos
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708WE Wageningen, The Netherlands.
- Immunobiology Research Program, Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, 00014 Helsinki, Finland.
| | - Clara Belzer
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708WE Wageningen, The Netherlands.
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10
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Katamreddy JD, Yalavarthi PR, D SR, Battu S, Peesa JP. Biopharmaceutical insights of particulate emulsified systems - a prospective overview. Lipids Health Dis 2018; 17:112. [PMID: 29747645 PMCID: PMC5946457 DOI: 10.1186/s12944-018-0757-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 04/24/2018] [Indexed: 11/10/2022] Open
Abstract
During the twenty-first century, drug discovery is expanding rapidly and a large number of chemical moieties are recognized. Many of them are poorly soluble and hence related biopharmaceutical constraints are to be addressed systematically. Among novel approaches to resolving biopharmaceutical issues, micro- and nano-emulsified systems serve as the best strategy for delivering both hydrophobic and hydrophilic drugs owing to their greater solubilization and transportation capabilities. Of late, the unique physical and biopharmaceutical properties of these liquid isotropic homogenous systems have gained substantive research importance. In addition nano/micro lipid systems share structural and functional similarity with that of the physiological lipids which offer better tolerance ability in the body. In this context, this article provides information on the historical emergence of particulate emulsified systems, importance and rationale of selection of carriers. It also encompasses the physicochemical principles that are responsible for the elevation of therapeutic outcomes of delivery systems. Detailed and schematic absorption of these drug delivery systems is explained here. Gastro-intestinal biochemistry necessary in the understanding of digestion process, lipolytic products formed, micellar structures, enzymes, transporters, mechanism of cell uptake involved after subsequent oral absorption are also emphasized. In addition, this article also explains disposition and pharmacokinetic properties of emulsified systems with real-time therapeutic research outcomes. The influence of biochemical compositions and biopharmaceutical principles on absorption and disposition patterns of ME/NEs was described in the article for the interest of readers and young researchers.
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Affiliation(s)
- Jyothshna Devi Katamreddy
- Faculty of Pharmaceutical Sciences, JNTUA, Ananthapuramu, 515002, India. .,Department of Pharmaceutics, Krishna Teja Pharmacy College, Tirupati, 517506, India.
| | | | - Subba Rao D
- Department of Chemical Engineering, JNTUA College of Engineering, Ananthapuramu, 515002, India
| | - Sowjanya Battu
- Department of Pharmaceutics, CMR College of Pharmacy, Hyderabad, 501401, India
| | - Jaya Preethi Peesa
- Department of Pharmaceutical Chemistry, Sree Vidyanikethan College of Pharmacy, Tirupati, 517102, India
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11
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Increased expression of MUC3A is associated with poor prognosis in localized clear-cell renal cell carcinoma. Oncotarget 2018; 7:50017-50026. [PMID: 27374181 PMCID: PMC5226565 DOI: 10.18632/oncotarget.10312] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 06/13/2016] [Indexed: 01/04/2023] Open
Abstract
MUC3A is a membrane-associated mucin that recent evidence reveals the role of MUC3A in pathogenesis and progression of cancers. To evaluate the association between MUC3A expression with overall survival (OS) and recurrence-free survival (RFS) in patients with localized clear-cell renal cell carcinoma (ccRCC), we retrospectively detected MUC3A expression in samples of 384 postoperative localized ccRCC patients by immunohistochemistry. Median follow-up was 73 months (range: 42 – 74 mo). Overall, 41 patients died, 47 experienced recurrence. High MUC3A expression occurred in 45.8% of localized ccRCC cases, which was significantly associated with high pT-stage, high Fuhrman grade, high frequency of necrosis and LVI, and increased risk of recurrence and death (Logrank test P < 0.001 and P < 0.001, respectively). By multivariate analysis, MUC3A expression was confirmed as an adverse independent prognostic factor for OS and RFS. The prognostic accuracy of UISS, SSIGN, Leibovich models was significantly increased when MUC3A expression was integrated. Meanwhile, MUC3A was enrolled into a newly built nomogram with other factors selected by multivariate analysis. Calibration curves revealed optimal consistency between observations and prognosis. In conclusion, high MUC3A expression is an adverse prognostic biomarker for OS and RFS in postoperative localized ccRCC patients.
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12
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Dhanisha SS, Guruvayoorappan C, Drishya S, Abeesh P. Mucins: Structural diversity, biosynthesis, its role in pathogenesis and as possible therapeutic targets. Crit Rev Oncol Hematol 2017; 122:98-122. [PMID: 29458795 DOI: 10.1016/j.critrevonc.2017.12.006] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 10/28/2017] [Accepted: 12/12/2017] [Indexed: 12/25/2022] Open
Abstract
Mucins are the main structural components of mucus that create a selective protective barrier for epithelial surface and also execute wide range of other physiological functions. Mucins can be classified into two types, namely secreted mucins and membrane bounded mucins. Alterations in mucin expression or glycosylation and mislocalization have been seen in various types of pathological conditions such as cancers, inflammatory bowel disease and ocular disease, which highlight the importance of mucin in maintaining homeostasis. Hence mucins can be used as attractive target for therapeutic intervention. In this review, we discuss in detail about the structural diversity of mucins; their biosynthesis; its role in pathogenesis; regulation and as possible therapeutic targets.
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Affiliation(s)
- Suresh Sulekha Dhanisha
- Laboratory of Immunopharmacology and Experimental Therapeutics, Division of Cancer Research, Regional Cancer Centre, Medical College Campus, Thiruvananthapuram 695011, Kerala, India
| | - Chandrasekharan Guruvayoorappan
- Laboratory of Immunopharmacology and Experimental Therapeutics, Division of Cancer Research, Regional Cancer Centre, Medical College Campus, Thiruvananthapuram 695011, Kerala, India.
| | - Sudarsanan Drishya
- Laboratory of Immunopharmacology and Experimental Therapeutics, Division of Cancer Research, Regional Cancer Centre, Medical College Campus, Thiruvananthapuram 695011, Kerala, India
| | - Prathapan Abeesh
- Laboratory of Immunopharmacology and Experimental Therapeutics, Division of Cancer Research, Regional Cancer Centre, Medical College Campus, Thiruvananthapuram 695011, Kerala, India
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Pelaseyed T, Bergström JH, Gustafsson JK, Ermund A, Birchenough GMH, Schütte A, van der Post S, Svensson F, Rodríguez-Piñeiro AM, Nyström EEL, Wising C, Johansson MEV, Hansson GC. The mucus and mucins of the goblet cells and enterocytes provide the first defense line of the gastrointestinal tract and interact with the immune system. Immunol Rev 2015; 260:8-20. [PMID: 24942678 DOI: 10.1111/imr.12182] [Citation(s) in RCA: 781] [Impact Index Per Article: 86.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The gastrointestinal tract is covered by mucus that has different properties in the stomach, small intestine, and colon. The large highly glycosylated gel-forming mucins MUC2 and MUC5AC are the major components of the mucus in the intestine and stomach, respectively. In the small intestine, mucus limits the number of bacteria that can reach the epithelium and the Peyer's patches. In the large intestine, the inner mucus layer separates the commensal bacteria from the host epithelium. The outer colonic mucus layer is the natural habitat for the commensal bacteria. The intestinal goblet cells secrete not only the MUC2 mucin but also a number of typical mucus components: CLCA1, FCGBP, AGR2, ZG16, and TFF3. The goblet cells have recently been shown to have a novel gate-keeping role for the presentation of oral antigens to the immune system. Goblet cells deliver small intestinal luminal material to the lamina propria dendritic cells of the tolerogenic CD103(+) type. In addition to the gel-forming mucins, the transmembrane mucins MUC3, MUC12, and MUC17 form the enterocyte glycocalyx that can reach about a micrometer out from the brush border. The MUC17 mucin can shuttle from a surface to an intracellular vesicle localization, suggesting that enterocytes might control and report epithelial microbial challenge. There is communication not only from the epithelial cells to the immune system but also in the opposite direction. One example of this is IL10 that can affect and improve the properties of the inner colonic mucus layer. The mucus and epithelial cells of the gastrointestinal tract are the primary gate keepers and controllers of bacterial interactions with the host immune system, but our understanding of this relationship is still in its infancy.
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Affiliation(s)
- Thaher Pelaseyed
- Department of Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden
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14
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Abstract
Mucins--large, highly glycosylated proteins--are important for the luminal protection of the gastrointestinal tract. Enterocytes have their apical surface covered by transmembrane mucins and goblet cells produce the secreted gel-forming mucins that form mucus. The small intestine has a single unattached mucus layer, which in cystic fibrosis becomes attached, accounting for the intestinal manifestations of this disease. The stomach and colon have two layers of mucus; the inner layer is attached and the outer layer is less dense and unattached. In the colon, the outer mucus layer is the habitat for commensal bacteria. The inner mucus layer is impervious to bacteria and is renewed every hour by surface goblet cells. The crypt goblet cells have the ability to restitute the mucus layer by secretion, for example after an ischaemic challenge. Proteases of certain parasites and some bacteria can cleave mucins and dissolve the mucus as part of their pathogenicity. The inner mucus layer can, however, also become penetrable to bacteria by several other mechanisms, including aberrations in the immune system. When bacteria reach the epithelial surface, the immune system is activated and inflammation is triggered. This mechanism might occur in some types of ulcerative colitis.
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Lillehoj EP, Kato K, Lu W, Kim KC. Cellular and molecular biology of airway mucins. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 303:139-202. [PMID: 23445810 PMCID: PMC5593132 DOI: 10.1016/b978-0-12-407697-6.00004-0] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Airway mucus constitutes a thin layer of airway surface liquid with component macromolecules that covers the luminal surface of the respiratory tract. The major function of mucus is to protect the lungs through mucociliary clearance of inhaled foreign particles and noxious chemicals. Mucus is comprised of water, ions, mucin glycoproteins, and a variety of other macromolecules, some of which possess anti-microbial, anti-protease, and anti-oxidant activities. Mucins comprise the major protein component of mucus and exist as secreted and cell-associated glycoproteins. Secreted, gel-forming mucins are mainly responsible for the viscoelastic property of mucus, which is crucial for effective mucociliary clearance. Cell-associated mucins shield the epithelial surface from pathogens through their extracellular domains and regulate intracellular signaling through their cytoplasmic regions. However, neither the exact structures of mucin glycoproteins, nor the manner through which their expression is regulated, are completely understood. This chapter reviews what is currently known about the cellular and molecular properties of airway mucins.
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Affiliation(s)
- Erik P. Lillehoj
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kosuke Kato
- Center for Inflammation, Translational and Clinical Lung Research and Department of Physiology, Temple University School of Medicine, Philadelphia, PA, USA
| | - Wenju Lu
- Guangzhou Institute of Respiratory Diseases, State Key Laboratory of Respiratory Diseases, The First Affiliated Hospital, Guangzhou Medical University, Guangzhou, PR China
| | - Kwang C. Kim
- Center for Inflammation, Translational and Clinical Lung Research and Department of Physiology, Temple University School of Medicine, Philadelphia, PA, USA
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Garcia I, Etxebarria J, Boto-de-Los-Bueis A, Díaz-Valle D, Rivas L, Martínez-Soroa I, Saenz N, López C, Del-Hierro-Zarzuelo A, Méndez R, Soria J, González N, Suárez T, Acera A. Comparative Study of Limbal Stem Cell Deficiency Diagnosis Methods: Detection of MUC5AC mRNA and Goblet Cells in Corneal Epithelium. Ophthalmology 2012; 119:923-9. [DOI: 10.1016/j.ophtha.2011.10.031] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 10/24/2011] [Accepted: 10/24/2011] [Indexed: 11/28/2022] Open
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Barnett AM, Roy NC, McNabb WC, Cookson AL. The interactions between endogenous bacteria, dietary components and the mucus layer of the large bowel. Food Funct 2012; 3:690-9. [DOI: 10.1039/c2fo30017f] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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18
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Yonezawa S, Higashi M, Yamada N, Yokoyama S, Kitamoto S, Kitajima S, Goto M. Mucins in human neoplasms: clinical pathology, gene expression and diagnostic application. Pathol Int 2011; 61:697-716. [PMID: 22126377 DOI: 10.1111/j.1440-1827.2011.02734.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Mucins are high molecular weight glycoproteins that play important roles in carcinogenesis and tumor invasion. Our immunohistochemical studies demonstrated that MUC1 or MUC4 expression is related to the aggressive behavior and poor outcome of human neoplasms. MUC2 is expressed in indolent pancreatobiliary neoplasms, but these tumors sometimes show invasive growth with MUC1 expression in invasive areas. MUC5AC shows de novo high expression in many types of precancerous lesions of pancreatobiliary cancers and is an effective marker for early detection of the neoplasms. The combination of MUC1, MUC2, MUC4 and MUC5AC expression may be useful for early detection and evaluation of the potential for malignancy of pancreatobiliary neoplasms. Regarding the mechanism of mucin expression, we have recently reported that expression of the mucin genes is regulated epigenetically in cancer cell lines, using quantitative MassARRAY analysis, methylation-specific polymerase chain reaction analysis and chromatin immunoprecipitation analysis, with confirmation by the treatment with 5-aza-2'-deoxycytidine and trichostatin A. We have also developed a monoclonal antibody against the MUC1 cytoplasmic tail domain, which has many biological roles. Based on all of the above findings, we suggest that translational research into mucin gene expression mechanisms, including epigenetics, may provide new tools for early and accurate detection of human neoplasms.
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Affiliation(s)
- Suguru Yonezawa
- Department of Human Pathology, Field of Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
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Yamada N, Kitamoto S, Yokoyama S, Hamada T, Goto M, Tsutsumida H, Higashi M, Yonezawa S. Epigenetic regulation of mucin genes in human cancers. Clin Epigenetics 2011; 2:85-96. [PMID: 22704331 PMCID: PMC3365379 DOI: 10.1007/s13148-011-0037-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 04/18/2011] [Indexed: 12/16/2022] Open
Abstract
Mucins are high molecular weight glycoproteins that play important roles in diagnostic and prognostic prediction and in carcinogenesis and tumor invasion. Regulation of expression of mucin genes has been studied extensively, and signaling pathways, transcriptional regulators, and epigenetic modification in promoter regions have been described. Detection of the epigenetic status of cancer-related mucin genes is important for early diagnosis of cancer and for monitoring of tumor behavior and response to targeted therapy. Effects of micro-RNAs on mucin gene expression have also started to emerge. In this review, we discuss the current views on epigenetic mechanisms of regulation of mucin genes (MUC1, MUC2, MUC3A, MUC4, MUC5AC, MUC5B, MUC6, MUC16, and MUC17) and the possible clinical applications of this epigenetic information.
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20
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Kim YS, Ho SB. Intestinal goblet cells and mucins in health and disease: recent insights and progress. Curr Gastroenterol Rep 2011; 12:319-30. [PMID: 20703838 PMCID: PMC2933006 DOI: 10.1007/s11894-010-0131-2] [Citation(s) in RCA: 903] [Impact Index Per Article: 69.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The mucus layer coating the gastrointestinal tract is the front line of innate host defense, largely because of the secretory products of intestinal goblet cells. Goblet cells synthesize secretory mucin glycoproteins (MUC2) and bioactive molecules such as epithelial membrane-bound mucins (MUC1, MUC3, MUC17), trefoil factor peptides (TFF), resistin-like molecule beta (RELMbeta), and Fc-gamma binding protein (Fcgbp). The MUC2 mucin protein forms trimers by disulfide bonding in cysteine-rich amino terminal von Willebrand factor (vWF) domains, coupled with crosslinking provided by TFF and Fcgbp proteins with MUC2 vWF domains, resulting in a highly viscous extracellular layer. Colonization by commensal intestinal microbiota is limited to an outer "loose" mucus layer, and interacts with the diverse oligosaccharides of mucin glycoproteins, whereas an "inner" adherent mucus layer is largely devoid of bacteria. Defective mucus layers resulting from lack of MUC2 mucin, mutated Muc2 mucin vWF domains, or from deletion of core mucin glycosyltransferase enzymes in mice result in increased bacterial adhesion to the surface epithelium, increased intestinal permeability, and enhanced susceptibility to colitis caused by dextran sodium sulfate. Changes in mucin gene expression and mucin glycan structures occur in cancers of the intestine, contributing to diverse biologic properties involved in the development and progression of cancer. Further research is needed on identification and functional significance of various components of mucus layers and the complex interactions among mucus layers, microbiota, epithelial cells, and the underlying innate and adaptive immunity. Further elucidation of the regulatory mechanisms involved in mucin changes in cancer and inflammation may lead to the development of novel therapeutic approaches.
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Affiliation(s)
- Young S Kim
- Genemed Biotechnologies, 458 Carlton Court, South San Francisco, CA 94080, USA.
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Kitamoto S, Yamada N, Yokoyama S, Houjou I, Higashi M, Yonezawa S. Promoter hypomethylation contributes to the expression of MUC3A in cancer cells. Biochem Biophys Res Commun 2010; 397:333-9. [DOI: 10.1016/j.bbrc.2010.05.124] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Accepted: 05/24/2010] [Indexed: 01/04/2023]
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22
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Ho SB, Luu Y, Shekels LL, Batra SK, Kandarian B, Evans DB, Zaworski PG, Wolfe CL, Heinrikson RL. Activity of recombinant cysteine-rich domain proteins derived from the membrane-bound MUC17/Muc3 family mucins. Biochim Biophys Acta Gen Subj 2010; 1800:629-38. [PMID: 20332014 DOI: 10.1016/j.bbagen.2010.03.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2009] [Revised: 03/12/2010] [Accepted: 03/15/2010] [Indexed: 01/06/2023]
Abstract
BACKGROUND The membrane-bound mucins, MUC17 (human) and Muc3 (mouse), are highly expressed on the apical surface of intestinal epithelia and have cytoprotective properties. Their extracellular regions contain two EGF-like Cys-rich domains (CRD1 and CRD2) connected by an intervening linker segment with SEA module (L), and may function to stimulate intestinal cell restitution. The purpose of this study was to determine the effect of size, recombinant host source, and external tags on mucin CRD1-L-CRD2 protein activity. METHODS Four recombinant Muc3-CRD proteins and three MUC17-CRD proteins were generated using Escherichiacoli or baculovirus-insect cell systems and tested in colonic cell cultures for activity related to cell migration and apoptosis. RESULTS N-terminal glutathione-S-transferase (GST) or C-terminal His(8) tags had no effect on either the cell migration or anti-apoptosis activity of Muc3-CRD1-L-CRD2. His-tagged Muc3-CRD1-L-CRD2 proteins with truncated linker regions, or the linker region alone, did not demonstrate biologic activity. The human recombinant MUC17-CRD1-L-CRD2-His(8) was shown to have anti-apoptotic and pro-migratory activity, but did not stimulate cell proliferation. This protein showed similar in vitro biologic activity, whether produced in E. coli or a baculovirus-insect cell system. CONCLUSIONS Recombinant mucin proteins containing a bivalent display of Cys-rich domains accelerate colon cell migration and inhibit apoptosis, require a full-length intervening Linker-SEA segment for optimal biologic activity, and are functional when synthesized in either E. coli and insect cell systems. GENERAL SIGNIFICANCE These results indicate that an Escherichiacoli-derived full-length His(8)-tagged human MUC17 CRD1-L-CRD2 recombinant protein is a biologically active candidate for further development as a therapeutic agent.
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Affiliation(s)
- Samuel B Ho
- Department of Medicine, University of California-San Diego, San Diego, CA, USA.
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23
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Luu Y, Junker W, Rachagani S, Das S, Batra SK, Heinrikson RL, Shekels LL, Ho SB. Human intestinal MUC17 mucin augments intestinal cell restitution and enhances healing of experimental colitis. Int J Biochem Cell Biol 2010; 42:996-1006. [PMID: 20211273 DOI: 10.1016/j.biocel.2010.03.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 02/13/2010] [Accepted: 03/01/2010] [Indexed: 12/19/2022]
Abstract
UNLABELLED The membrane-bound mucins, MUC17 (human) and Muc3 (mouse), are highly expressed on the apical surface of intestinal epithelia and are thought to be cytoprotective. The extracellular regions of these mucins contain EGF-like Cys-rich segments (CRD1 and CRD2) connected by an intervening linker domain (L). The purpose of this study was to determine the functional activity of human MUC17 membrane-bound mucin. METHODS Endogenous MUC17 was inhibited in LS174T colon cells by stable transfection of a small hairpin RNA targeting MUC17 (LSsi cells). The effect of recombinant MUC17-CRD1-L-CRD2 protein on migration, apoptosis, and experimental colitis was determined. RESULTS Reduced MUC17 expression in LSsi cells was associated with visibly reduced cell aggregation, reduced cell-cell adherence, and reduced cell migration, but no change in tumorigenicity. LSsi cells also demonstrated a 3.7-fold increase in apoptosis rates compared with control cells following treatment with etoposide. Exposure of colonic cell lines to exogenous recombinant MUC17-CRD1-L-CRD2 protein significantly increased cell migration and inhibited apoptosis. As a marker of biologic activity, MUC17-CRD1-L-CRD2 proteins stimulate ERK phosphorylation in colonic cell lines; and inhibition of ERK phosphorylation reduced the anti-apoptosis and migratory effect of MUC17-CRD1-L-CRD2. Finally, mice treated with MUC17-CRD1-L-CRD2 protein given per rectum demonstrated accelerated healing in acetic acid and dextran sodium sulfate induced colitis in vivo. These data indicate that both native MUC17 and the exogenous recombinant cysteine-rich domain of MUC17 play a role in diverse cellular mechanisms related to cell restitution, and suggest a potential role for MUC17-CRD1-L-CRD2 recombinant protein in the treatment of mucosal inflammatory diseases.
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Affiliation(s)
- Ying Luu
- Department of Medicine, VA San Diego Healthcare System and University of California San Diego, 3350 La Jolla Village Drive, San Diego, CA 92161, United States
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Derrien M, van Passel MWJ, van de Bovenkamp JHB, Schipper RG, de Vos WM, Dekker J. Mucin-bacterial interactions in the human oral cavity and digestive tract. Gut Microbes 2010; 1:254-268. [PMID: 21327032 PMCID: PMC3023607 DOI: 10.4161/gmic.1.4.12778] [Citation(s) in RCA: 379] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 06/20/2010] [Accepted: 06/23/2010] [Indexed: 02/03/2023] Open
Abstract
Mucins are a family of heavily glycosylated proteins that are the major organic components of the mucus layer, the protective layer covering the epithelial cells in many human and animal organs, including the entire gastro-intestinal tract. Microbes that can associate with mucins benefit from this interaction since they can get available nutrients, experience physico-chemical protection and adhere, resulting in increased residence time. Mucin-degrading microorganisms, which often are found in consortia, have not been extensively characterized as mucins are high molecular weight glycoproteins that are hard to study because of their size, complexity and heterogeneity. The purpose of this review is to discuss how advances in mucus and mucin research, and insight in the microbial ecology promoted our understanding of mucin degradation. Recent insight is presented in mucin structure and organization, the microorganisms known to use mucin as growth substrate, with a specific attention on Akkermansia muciniphila, and the molecular basis of microbial mucin degradation owing to availability of genome sequences.
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Affiliation(s)
- Muriel Derrien
- TI Food and Nutrition; Wageningen University and Research Centre; Wageningen, The Netherlands,Laboratory of Microbiology; Wageningen University and Research Centre; Wageningen, The Netherlands
| | - Mark WJ van Passel
- Laboratory of Microbiology; Wageningen University and Research Centre; Wageningen, The Netherlands
| | - Jeroen HB van de Bovenkamp
- TI Food and Nutrition; Wageningen University and Research Centre; Wageningen, The Netherlands,Laboratory of Food Chemistry; Wageningen University and Research Centre; Wageningen, The Netherlands
| | - Raymond G Schipper
- TI Food and Nutrition; Wageningen University and Research Centre; Wageningen, The Netherlands,Laboratory of Food Chemistry; Wageningen University and Research Centre; Wageningen, The Netherlands
| | - Willem M de Vos
- Laboratory of Microbiology; Wageningen University and Research Centre; Wageningen, The Netherlands,Department of Basic Veterinary Sciences; University of Helsinki; Helsinki, Finland
| | - Jan Dekker
- TI Food and Nutrition; Wageningen University and Research Centre; Wageningen, The Netherlands
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Baldus SE, Engelmann K, Hanisch FG. MUC1 and the MUCs: A Family of Human Mucins with Impact in Cancer Biology. Crit Rev Clin Lab Sci 2008; 41:189-231. [PMID: 15270554 DOI: 10.1080/10408360490452040] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Mucins represent a family of glycoproteins characterized by repeat domains and a dense O-glycosylation. During the last two decades, the gene and peptide structures of various mucins as well as their glycosylation states were partly elucidated. Characteristic tumor-associated alterations of the expression patterns and glycosylation profiles were observed in biochemical, immunochemical, and histological studies and are discussed in the light of efforts to use the most prominent member in this family, MUC1, as a tumor target in anti-tumor strategies. Within this context the present review, focusing on MUC1, describes recent work on the regulation of mucin biosynthesis by cytokines and hormones, the role of mucins in cell adhesion, and their interaction with the immune system. Important aspects of clinical diagnostics based on mucin antigens are discussed, including the application of tumor serum assays and the significance of numerous studies revealing correlations between the expression of peptide cores or mucin-associated carbohydrates and clinicopathological parameters like tumor progression and prognosis.
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Affiliation(s)
- Stephan E Baldus
- Institute of Pathology and Center of Biochemistry, University of Cologne, Cologne, Germany.
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26
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Architecture of the large membrane-bound mucins. Gene 2007; 410:215-22. [PMID: 18242885 DOI: 10.1016/j.gene.2007.12.014] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 12/03/2007] [Accepted: 12/13/2007] [Indexed: 11/23/2022]
Abstract
Epithelial membrane-bound mucins are high molecular mass glycoproteins that may be also secreted or released into the extracellular environment. The genomic and multi-domain organizations of human large epithelial membrane-bound mucins are reviewed here with the purpose to clarify the literature on the subject with the help of mouse sequences. This family of complex molecules contains at least MUC3A, MUC12, MUC17, all organized in a cluster of genes, MUC4 and likely MUC16. In addition, we discuss the splicing events reported for these mucins with an emphasis on the human mucin MUC4.
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27
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The Mucin Expression Profile of Endometrial Carcinoma and Correlation With Clinical-Pathologic Parameters. Appl Immunohistochem Mol Morphol 2007; 15:426-31. [DOI: 10.1097/01.pai.0000213117.73720.89] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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28
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Walsh MD, Young JP, Leggett BA, Williams SH, Jass JR, McGuckin MA. The MUC13 cell surface mucin is highly expressed by human colorectal carcinomas. Hum Pathol 2007; 38:883-92. [PMID: 17360025 DOI: 10.1016/j.humpath.2006.11.020] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Revised: 11/24/2006] [Accepted: 11/29/2006] [Indexed: 01/09/2023]
Abstract
Mucins are complex mucosal glycoproteins that can be highly expressed by adenocarcinomas, having diagnostic, therapeutic, and biological significance. MUC13 encodes a cell surface membrane-anchored mucin expressed in the normal gastrointestinal tract, trachea, and kidney as well as colorectal, esophageal, gastric, pancreatic, and lung cancers. MUC13 protein expression was determined immunohistochemically in 99 sporadic colorectal cancers, assessing proportion of tumor cells stained, stain intensity, and localization. In normal colon, intense apical membrane and variable cytoplasmic MUC13 staining was present in both goblet and columnar cells, with strongest reactivity in the upper crypts and surface epithelium. All cancers showed staining of most tumor cells, being most conspicuous in the apical membranes of gland spaces. Left-sided tumors had a higher overall proportion of MUC13-positive tumor cells than right-sided tumors (P < .05), and high staining intensity was more frequent in adenocarcinomas (81%) than mucinous tumors (50%) (P < .05). Poorly differentiated and late-stage tumors were more likely to have high-intensity cytoplasmic staining (P < or = .025). Basolateral cell membranes were stained in 24% of cases, being more common in poorly differentiated tumors (55%) than well or moderately differentiated tumors (16%) (P < or = .001). Partial or full circumferential MUC13 staining was frequently observed in areas of tumor budding. Although MUC13 immunoreactivity was not predictive of patient outcome, there was a trend toward poorer outcome in patients with tumors showing basolateral MUC13. In summary, MUC13 was expressed abundantly by all colorectal cancers, with the highest expression in more poorly differentiated tumors.
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Affiliation(s)
- Michael D Walsh
- Molecular Cancer Epidemiology Laboratory, Bancroft Centre, Queensland Institute of Medical Research, Herston, QLD, Australia
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29
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Abstract
This review focuses on the role and regulation of mucin glycoproteins (mucins) in airway health and disease. Mucins are highly glycosylated macromolecules (> or =50% carbohydrate, wt/wt). MUC protein backbones are characterized by numerous tandem repeats that contain proline and are high in serine and/or threonine residues, the sites of O-glycosylation. Secretory and membrane-tethered mucins contribute to mucociliary defense, an innate immune defense system that protects the airways against pathogens and environmental toxins. Inflammatory/immune response mediators and the overproduction of mucus characterize chronic airway diseases: asthma, chronic obstructive pulmonary diseases (COPD), or cystic fibrosis (CF). Specific inflammatory/immune response mediators can activate mucin gene regulation and airway remodeling, including goblet cell hyperplasia (GCH). These processes sustain airway mucin overproduction and contribute to airway obstruction by mucus and therefore to the high morbidity and mortality associated with these diseases. Importantly, mucin overproduction and GCH, although linked, are not synonymous and may follow from different signaling and gene regulatory pathways. In section i, structure, expression, and localization of the 18 human MUC genes and MUC gene products having tandem repeat domains and the specificity and application of MUC-specific antibodies that identify mucin gene products in airway tissues, cells, and secretions are overviewed. Mucin overproduction in chronic airway diseases and secretory cell metaplasia in animal model systems are reviewed in section ii and addressed in disease-specific subsections on asthma, COPD, and CF. Information on regulation of mucin genes by inflammatory/immune response mediators is summarized in section iii. In section iv, deficiencies in understanding the functional roles of mucins at the molecular level are identified as areas for further investigations that will impact on airway health and disease. The underlying premise is that understanding the pathways and processes that lead to mucus overproduction in specific airway diseases will allow circumvention or amelioration of these processes.
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Affiliation(s)
- Mary Callaghan Rose
- Research Center for Genetic Medicine, Room 5700, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC 20010, USA.
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Andrianifahanana M, Moniaux N, Batra SK. Regulation of mucin expression: mechanistic aspects and implications for cancer and inflammatory diseases. Biochim Biophys Acta Rev Cancer 2006; 1765:189-222. [PMID: 16487661 DOI: 10.1016/j.bbcan.2006.01.002] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Revised: 12/30/2005] [Accepted: 01/03/2006] [Indexed: 12/31/2022]
Abstract
Mucins are large multifunctional glycoproteins whose primary functions are to protect and lubricate the surfaces of epithelial tissues lining ducts and lumens within the human body. Several lines of evidence also support the involvement of mucins in more complex biological processes such as epithelial cell renewal and differentiation, cell signaling, and cell adhesion. Recent studies have uncovered the role of select mucins in the pathogenesis of cancer, underscoring the importance of a detailed knowledge about mucin biology. Under normal physiological conditions, the production of mucins is optimally maintained by a host of elaborate and coordinated regulatory mechanisms, thereby affording a well-defined pattern of tissue-, time-, and developmental state-specific distribution. However, mucin homeostasis may be disrupted by the action of environmental and/or intrinsic factors that affect cellular integrity. This results in an altered cell behavior that often culminates into a variety of pathological conditions. Deregulated mucin production has indeed been associated with numerous types of cancers and inflammatory disorders. It is, therefore, crucial to comprehend the underlying basis of molecular mechanisms controlling mucin production in order to design and implement adequate therapeutic strategies for combating these diseases. Herein, we discuss some physiologically relevant regulatory aspects of mucin production, with a particular emphasis on aberrations that pertain to pathological situations. Our views of the achievements, the conceptual and technical limitations, as well as the future challenges associated with studies of mucin regulation are exposed.
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Affiliation(s)
- Mahefatiana Andrianifahanana
- Department of Biochemistry and Molecular Biology, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, 68198-5870, USA
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Choudhury A, Moniaux N, Ulrich AB, Schmied BM, Standop J, Pour PM, Gendler SJ, Hollingsworth MA, Aubert JP, Batra SK. MUC4 mucin expression in human pancreatic tumours is affected by organ environment: the possible role of TGFbeta2. Br J Cancer 2004; 90:657-64. [PMID: 14760381 PMCID: PMC2409611 DOI: 10.1038/sj.bjc.6601604] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
MUC4 is highly expressed in human pancreatic tumours and pancreatic tumour cell lines, but is minimally or not expressed in normal pancreas or chronic pancreatitis. Here, we investigated the aberrant regulation of MUC4 expression in vivo using clonal human pancreatic tumour cells (CD18/HPAF) grown either orthotopically in the pancreas (OT) or ectopically in subcutaneous tissue (SC) in the nude mice. Histological examination of the OT and SC tumours showed moderately differentiated and anaplastic morphology, respectively. The OT tumour cells showed metastases to distant lymph nodes and faster tumour growth (P<0.01) compared to the SC tumours. The MUC4 transcripts in OT tumours were very high compared to the undetectable levels in SC tumours. The SC tumour cells regained their ability to express MUC4 transcripts after in vitro culture. Immunohistochemical analysis using MUC4-specific polyclonal antiserum confirmed the results obtained by Northern blot analysis. Interestingly, the OT tumours showed expression of TGFβ2 compared to no expression in SC, suggesting a possible link between MUC4 and TGFβ2. The MUC4 expression, morphology, and metastasis of human pancreatic tumour cells are regulated by a local host microenvironment. TGFβ2 may serve as an interim regulator of this function.
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Affiliation(s)
- A Choudhury
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - N Moniaux
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - A B Ulrich
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - B M Schmied
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - J Standop
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - P M Pour
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | | | - M A Hollingsworth
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - J-P Aubert
- Unite 560 INSERM, Place de verdun, Lille Cedex 59045, France
| | - S K Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
- Department of Biochemistry and Molecular Biology, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 984525 Nebraska Medical Center, Omaha, NE 68198-4525, USA. E-mail:
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Affiliation(s)
- Michael A Hollingsworth
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 986805 Nebraska Medical Center, Omaha, Nebraska 68198-6805, USA.
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Gum JR, Hicks JW, Crawley SC, Dahl CM, Yang SC, Roberton AM, Kim YS. Initiation of transcription of the MUC3A human intestinal mucin from a TATA-less promoter and comparison with the MUC3B amino terminus. J Biol Chem 2003; 278:49600-9. [PMID: 12958310 DOI: 10.1074/jbc.m305769200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human intestinal mucin genes MUC3A and MUC3B are members of a membrane mucin gene family residing at chromosome 7q22. In this paper, we utilized genomic and cDNA cloning to elucidate the sequence of the 5'-region of the MUC3A gene including the gene promoter and the amino terminus coding sequence. Following its 21-residue signal peptide, the amino terminus of the mucin consists of a 233-residue Thr-, Ser-, and Pro-rich nonrepetitive sequence that is contiguous with its hypervariable domain of 375-residue repeats. RNase protection analysis and 5'-GeneRacer PCR indicated that MUC3A gene transcripts initiate from multiple start sites along a region spanning approximately 180 bases. The 5'-flanking region of the gene had promoter activity when fused to a luciferase reporter gene in all of the tested cell lines. This region contained binding sites for several transcription factors, including those implicated in the regulation of intestinal genes, but lacked a cognate TATA box. These features of the gene promoter may enable the gene to be expressed at variable levels in several cell types with different repertoires of transcription factors. We also utilized 5'-GeneRacer PCR to determine the sequence of the 5'-terminus of the MUC3B message. The amino termini of the MUC3A and MUC3B mucins are 91% conserved at the amino acid level. Thus, MUC3A and MUC3B have highly conserved amino and carboxyl termini, suggesting a recent duplication of the entire ancestral gene. It remains to be determined whether other members of the 7q22 membrane mucin gene family have amino-terminal domains similar to MUC3A and MUC3B.
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Affiliation(s)
- James R Gum
- Department of Veterans Affairs Medical Center, San Francisco, California 94121, USA.
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Leroy X, Gouyer V, Ballereau C, Zerimech F, Huet G, Copin MC, Aubert JP, Porchet N. Quantitative RT-PCR assay for MUC3 and VEGF mRNA in renal clear cell carcinoma: relationship with nuclear grade and prognosis. Urology 2003; 62:771-5. [PMID: 14550470 DOI: 10.1016/s0090-4295(03)00560-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
OBJECTIVES To investigate, by real-time quantitative reverse transcriptase-polymerase chain reaction, the expression of MUC3 and vascular endothelial growth factor (VEGF) to correlate them with histologic parameters and with prognosis. Human mucins are large O-glycoproteins expressed in epithelial tissues. Deregulation of mucin genes has been demonstrated in several epithelial neoplasms. In the kidney, MUC3 is expressed in normal convoluted tubules and in renal clear cell carcinoma. METHODS Twenty-six renal clear cell carcinoma specimens were studied. For all tumors, samples of normal and tumor kidney were frozen. After RNA extraction, using ultracentrifugation through a cesium chloride cushion, VEGF and MUC3 mRNA were analyzed by real-time quantitative reverse transcriptase-polymerase chain reaction. The pathologic parameters included Fuhrman nuclear grade and TNM stage. All follow-up data were available. RESULTS The median level of MUC3 and VEGF expression was greater in tumor areas compared with normal areas (P < 0.002 and P < 0.001, respectively). The MUC3 tumor/normal tissue expression ratio was greater in nuclear grade 3 tumor than in low grades (grade 1-2; P < 0.005). No statistically significant relationship was found with the prognosis for MUC3 and VEGF in our study. CONCLUSIONS The results of this study demonstrate that MUC3 and VEGF are overexpressed in renal clear cell carcinoma, and the MUC3 expression ratio is greater in nuclear grade 3 than in grades 1 and 2 (low grades) tumor. These findings suggest the implication of MUC3 in renal carcinogenesis.
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Helander A, Silvey KJ, Mantis NJ, Hutchings AB, Chandran K, Lucas WT, Nibert ML, Neutra MR. The viral sigma1 protein and glycoconjugates containing alpha2-3-linked sialic acid are involved in type 1 reovirus adherence to M cell apical surfaces. J Virol 2003; 77:7964-77. [PMID: 12829836 PMCID: PMC161912 DOI: 10.1128/jvi.77.14.7964-7977.2003] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2003] [Accepted: 04/30/2003] [Indexed: 12/20/2022] Open
Abstract
Type 1 reoviruses invade the intestinal mucosa of mice by adhering selectively to M cells in the follicle-associated epithelium and then exploiting M cell transport activity. The purpose of this study was to identify the apical cell membrane component and viral protein that mediate the M cell adherence of these viruses. Virions and infectious subviral particles of reovirus type 1 Lang (T1L) adhered to rabbit M cells in Peyer's patch mucosal explants and to tissue sections in an overlay assay. Viral adherence was abolished by pretreatment of sections with periodate and in the presence of excess sialic acid or lectins MAL-I and MAL-II (which recognize complex oligosaccharides containing sialic acid linked alpha2-3 to galactose). The binding of T1L particles to polarized human intestinal (Caco-2(BBe)) cell monolayers was correlated with the presence of MAL-I and MAL-II binding sites, blocked by excess MAL-I and -II, and abolished by neuraminidase treatment. Other type 1 reovirus isolates exhibited MAL-II-sensitive binding to rabbit M cells and polarized Caco-2(BBe) cells, but type 2 or type 3 isolates including type 3 Dearing (T3D) did not. In assays using T1L-T3D reassortants and recoated viral cores containing T1L, T3D, or no sigma1 protein, MAL-II-sensitive binding to rabbit M cells and polarized Caco-2(BBe) cells was consistently associated with the T1L sigma1. MAL-II-recognized oligosaccharide epitopes are not restricted to M cells in vivo, but MAL-II immobilized on virus-sized microparticles bound only to the follicle-associated epithelium and M cells. The results suggest that selective binding of type 1 reoviruses to M cells in vivo involves interaction of the type 1 sigma1 protein with glycoconjugates containing alpha2-3-linked sialic acid that are accessible to viral particles only on M cell apical surfaces.
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Affiliation(s)
- Anna Helander
- GI Cell Biology Laboratory, Enders 1220, Children's Hospital and Department of Pediatrics, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
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Wang RQ, Fang DC. Alterations of MUC1 and MUC3 expression in gastric carcinoma: relevance to patient clinicopathological features. J Clin Pathol 2003; 56:378-84. [PMID: 12719460 PMCID: PMC1769961 DOI: 10.1136/jcp.56.5.378] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AIMS Several studies have reported conflicting and inconclusive results concerning the clinical relevance of mucin expression in gastric carcinoma. This study investigated the correlations between aberrant expression of mucins in gastric carcinoma and patient clinicopathological features. METHODS The expression of MUC1, MUC2, MUC3, MUC5AC, and MUC6 was investigated immunohistochemically in gastric carcinoma (n = 46) in relation to patient clinicopathological features. RESULTS All normal gastric mucosa samples expressed MUC1, MUC5AC, and MUC6. MUC1, MUC2, MUC3, MUC5AC, and MUC6 were expressed in 29, 31, 30, 18, and 21 of the 46 cases of gastric carcinoma, respectively. The number of cases expressing MUC1 was significantly higher (p < 0.01) in patients with a small tumour size (>/= 5 cm) and in patients in clinical stages I-II, compared with clinical stages III-IV (p < 0.05). Expression was significantly lower (p < 0.05) in patients exhibiting metastasis. The number of cases expressing MUC3 was significantly higher in patients in clinical stages III-IV (p < 0.05), and in those with serosal invasion (p < 0.05) or metastasis (p<0.01). No significant relations were found between MUC2, MUC5AC, MUC6, and clinical stage, metastasis, or tumour size. CONCLUSIONS Membrane bound mucins MUC1 and MUC3 appear to be associated with the development of gastric carcinoma. Patients who maintained high immunoreactivity for anti-MUC1 antibody had a better prognosis, whereas those with an increase in anti-MUC3 immunoreactivity had a poorer prognosis, as judged by tumour size, serosal invasion, and metastasis. However, no correlation was found between MUC2, MUC5AC, or MUC6 and clinical prognosis.
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Affiliation(s)
- R-Q Wang
- Department of Gastroenterology, Southwestern Hospital, Third Military Medical University, Chongqing 400038, PR China.
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Park HU, Kim JW, Kim GE, Bae HI, Crawley SC, Yang SC, Gum JR, Batra SK, Rousseau K, Swallow DM, Sleisenger MH, Kim YS. Aberrant expression of MUC3 and MUC4 membrane-associated mucins and sialyl Le(x) antigen in pancreatic intraepithelial neoplasia. Pancreas 2003; 26:e48-54. [PMID: 12657964 DOI: 10.1097/00006676-200304000-00022] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Ductal adenocarcinoma of the pancreas has recently been suggested to arise from histologically identifiable ductal lesions known as pancreatic intraepithelial neoplasia (PanINs). Altered levels and patterns of mucin gene expression have been reported to occur in epithelial cancers. AIM To examine the pattern of expression of membrane-associated mucins, MUC3 and MUC4, and a mucin-associated carbohydrate tumor antigen, sialyl Le(x), in these precursor lesions and ductal adenocarcinoma of the pancreas. METHODOLOGY A total of 144 PanIN lesions and 85 cases of ductal adenocarcinoma of the pancreas were examined by using immunohistochemistry and in situ hybridization methods. RESULTS MUC3 showed a progressive increase in expression in PanINs of increasing dysplasia and was also highly expressed in ductal adenocarcinoma. In contrast, neoexpression of MUC4 and sialyl Le(x) antigen was observed, mainly in PanIN-3 and ductal adenocarcinoma. In addition, a decrease in the expression of MUC3 and MUC4 was correlated with the degree of de-differentiation of the tumor. CONCLUSION Aberrant expression of membrane mucins MUC3 and MUC4 and of a mucin-associated carbohydrate tumor antigen Sialyl Le(x) in PanINs and adenocarcinoma further supports the progression model for pancreatic adenocarcinoma.
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Affiliation(s)
- Hee-Ug Park
- Gastrointestinal Research Laboratory, Veterans Affairs Medical Center, San Francisco, California 94121, USA
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Einerhand AWC, Renes IB, Makkink MK, van der Sluis M, Büller HA, Dekker J. Role of mucins in inflammatory bowel disease: important lessons from experimental models. Eur J Gastroenterol Hepatol 2002; 14:757-65. [PMID: 12169985 DOI: 10.1097/00042737-200207000-00008] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Inflammatory bowel disease (IBD) is characterized by a chronically inflamed mucosa of the gastrointestinal tract, caused by an underlying immune imbalance and triggered by luminal substances, including bacteria. Mucus forms a gel layer covering the gastrointestinal tract, acting as a semi-permeable barrier between the lumen and the epithelium. Mucins, the building blocks of the mucus gel, determine the thickness and properties of mucus. In IBD in humans, alterations in both membrane-bound and secretory mucins have been described involving genetic mutations in mucin genes, changes in mucin mRNA and protein levels, degree of glycosylation, sulphation, and degradation of mucins. As mucins are strategically positioned between the vulnerable mucosa and the bacterial contents of the bowel, changes in mucin structure and/or quantity probably influence their protective functions and therefore constitute possible aetiological factors in the pathogenesis of IBD. This hypothesis, however, is difficult to prove in humans. Animal models for IBD permit detailed analysis of those aspects of mucins necessary for protection against disease. These models revealed pertinent data as for how changes in mucins, in particular in MUC2, imposed by immunological or microbial factors, may contribute to the development and/or perpetuation of chronic IBD, and shed some light on possible strategies to counteract disease.
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Affiliation(s)
- Alexandra W C Einerhand
- Laboratory of Paediatrics, Section Paediatric Gastroenterology and Nutrition, Room Ee 1571a, Erasmus Medical Centre and Sophia Children's Hospital, Dr Molewaterplein 50, 3015 GE Rotterdam, The Netherlands.
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Leroy X, Copin MC, Devisme L, Buisine MP, Aubert JP, Gosselin B, Porchet N. Expression of human mucin genes in normal kidney and renal cell carcinoma. Histopathology 2002; 40:450-7. [PMID: 12010365 DOI: 10.1046/j.1365-2559.2002.01408.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS Human mucins are large O-glycoproteins expressed by epithelial cells. Mucins are thought to be implicated in cell protection, cell adhesion and signalling. The aim of this study was to investigate the expression of the human mucin genes (MUC1-4, 5AC, 5B, 6-7) in normal kidney and renal cell carcinoma. METHODS AND RESULTS We analysed by in-situ hybridization, immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) the expression of these genes in normal adult kidney (n=14) and renal cell carcinomas (n=29). MUC1, MUC3 and MUC6 were expressed both in normal kidney and in renal carcinomas. In normal kidney, MUC1 was expressed in the distal convoluted tubules and in collecting ducts, whereas MUC3 was restricted to the proximal tubules. MUC4 was strongly expressed in epithelial urothelial cells of pyelocalyceal cavities. MUC6 was only detected by RT-PCR. In renal carcinoma, we showed a heterogeneous expression of MUC1 and MUC3 with an over-expression of MUC3 in renal clear cell carcinoma. The level of MUC3 expression by in-situ hybridization was associated with the nuclear grade in clear cell carcinoma. CONCLUSIONS This study is the first large series investigating human mucin gene expression in the kidney. MUC1, MUC3 and MUC6 are expressed in normal and tumour kidney. The over-expression of MUC3 in renal cell carcinomas favours its implication in renal tumorigenesis.
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Affiliation(s)
- X Leroy
- Department of Pathology, University Hospital and Unity INSERM U 377, Lille, France.
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Abstract
Mucins are glycoproteins that are common on the surfaces of many epithelial cells; they are deemed to mediate many interactions between these cells and their milieu. Several of these mucins form the mucus layer that is found in many hollow organs. The biophysical properties of mucins are related to their extensive O-linked glycosylation rather than directly to their polypeptide sequences. Despite the frequent absence of sequence homology, many human genes encoding mucins have been named MUC followed by a number, unjustly suggesting the existence of one large gene family. In this article, it is suggested that the mucin genes be renamed according to their sequence homologies.
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Affiliation(s)
- Jan Dekker
- Laboratory of Paediatrics, Erasmus University and Sophia Children's Hospital, Dr Molewaterplein 50, 3015GE, Rotterdam, The Netherlands.
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Gum JR, Crawley SC, Hicks JW, Szymkowski DE, Kim YS. MUC17, a novel membrane-tethered mucin. Biochem Biophys Res Commun 2002; 291:466-75. [PMID: 11855812 DOI: 10.1006/bbrc.2002.6475] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Membrane mucins have several functions in epithelial cells including cytoprotection, extravasation during metastases, maintenance of luminal structure, and signal transduction. In this paper we describe a large membrane mucin expressed in the normal intestine. This novel mucin, designated MUC17, contains an extended, repetitive extracellular glycosylation domain and a carboxyl terminus with two EGF-like domains, a SEA module domain, a transmembrane domain, and a cytoplasmic domain with potential serine and tyrosine phosphorylation sites. RNA blot analysis and in situ hybridization indicates that MUC17 is expressed in select pancreatic and colon cancer cell lines and in intestinal absorptive cells. Radiation hybrid mapping localized MUC17 to chromosome 7q22 where it resides in close proximity with three other membrane mucin genes, MUC3A, MUC3B, and MUC12. Thus, these membrane mucins reside together in a gene cluster, but are expressed in different tissues and are likely to have different functions as well.
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Affiliation(s)
- James R Gum
- Gastrointestinal Research Laboratory (151M2), Department of Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, California 94121, USA.
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Yu CJ, Shew JY, Liaw YS, Kuo SH, Luh KT, Yang PC. Application of mucin quantitative competitive reverse transcription polymerase chain reaction in assisting the diagnosis of malignant pleural effusion. Am J Respir Crit Care Med 2001; 164:1312-8. [PMID: 11673227 DOI: 10.1164/ajrccm.164.7.2102067] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Aberrant expression of mucin genes occurs frequently in advanced cancer. Using quantitative competitive reverse transcriptase/polymerase chain reaction (QC RT-PCR), the expression of three mucin genes--MUC1 (widely expressed in epithelial cells), MUC2 (mainly expressed in intestinal epithelial cells), and MUC5AC (mainly from airway and gastric epithelial cells)--was evaluated in 112 patients with pleural effusions (including 54 cytologically positive malignant pleural effusions, 35 benign exudative pleural fluids, and 23 cytologically negative pleural effusions from cancer patients). The expression ratios of MUC1 and MUC5AC, but not MUC2 gene, were significantly higher in malignant than benign pleural fluids (p < 0.000). The cutoff value, sensitivity, and specificity of MUC1 expression ratio were: 0.126, 64.6%, and 95.7%; and were 0.028, 72.3%, and 95.7%, respectively, for MUC5AC. In combined evaluation with both MUC1 and MUC5AC, the sensitivity was 86.1% and specificity was 91.5%. The positive and negative predictive values were 93.3%, and 82.7%, respectively. We considered mucin QC RT-PCR to be a useful tool in assisting the diagnosis of malignant pleural effusion.
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Affiliation(s)
- C J Yu
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
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Khatri IA, Ho C, Specian RD, Forstner JF. Characteristics of rodent intestinal mucin Muc3 and alterations in a mouse model of human cystic fibrosis. Am J Physiol Gastrointest Liver Physiol 2001; 280:G1321-30. [PMID: 11352827 DOI: 10.1152/ajpgi.2001.280.6.g1321] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Human mucin MUC3 and rodent Muc3 are widely assumed to represent secretory mucins expressed in columnar and goblet cells of the intestine. Using a 3'-oligonucleotide probe and in situ hybridization, we observed expression of rat Muc3 mostly in columnar cells. Two antibodies specific for COOH-terminal epitopes of Muc3 localized to apical membranes and cytoplasm of columnar cells. An antibody to the tandem repeat (TR) sequence (TTTPDV)3, however, localized to both columnar and goblet cells. On CsCl gradients, Muc3 appeared in both light- and heavy-density fractions. The lighter species was immunoreactive with all three antibodies, whereas the heavier species reacted only with anti-TR antibody. Thus Muc3 is expressed in two forms, a full-length membrane-associated form found in columnar cells (light density) and a carboxyl-truncated soluble form present in goblet cells (heavy density). In a mouse model of human cystic fibrosis, both soluble Muc3 and goblet cell Muc2 were increased in amount and hypersecreted. Thus Muc2 and Muc3 contribute to the excess intestinal luminal mucus of cystic fibrosis mice.
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Affiliation(s)
- I A Khatri
- Division of Biochemistry and Structural Biology, Research Institute, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada M5G 1X8
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Gouyer V, Wiede A, Buisine MP, Dekeyser S, Moreau O, Lesuffleur T, Hoffmann W, Huet G. Specific secretion of gel-forming mucins and TFF peptides in HT-29 cells of mucin-secreting phenotype. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1539:71-84. [PMID: 11389969 DOI: 10.1016/s0167-4889(01)00092-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Trefoil factor family (TFF) peptides are typical secretory products of mucin-producing cells, e.g. of the gastrointestinal tract. Here, the expression and secretion of mucins and TFF peptides was studied in the HT-29 cell line throughout cellular growth and differentiation in relation to a mucin-secreting (HT-29 MTX) or an enterocyte-like (HT-29 G(-)) phenotype. mRNAs of several MUC and TFF genes were expressed in both cell subpopulations. However, for most MUC and TFF genes, the expression appeared strongly induced with the differentiation into the mucin-secreting phenotype. On the other hand, TFF2 was specifically expressed in the mucin-secreting HT-29 MTX cells. The differentiation of HT-29 MTX cells into the mucin-secreting phenotype was characterised by secretion of the gel-forming mucins MUC2, MUC5AC, and MUC5B, however, according to a different pattern in the course of differentiation. A significant amount of TFF1 and TFF3 was secreted after differentiation, also according to a different pattern, whereas TFF2 was only faintly detected. Secretagogues, known to induce the secretion of mucus, increased the secretion of all three TFF peptides. In contrast, neither a secretory mucin nor a TFF peptide was found in the culture medium of HT-29 G(-) cells. Overlay assays indicated that HT-29 MTX mucins bound to secretory peptides of HT-29 MTX cells with relative molecular mass similar to TFF peptides. TFF1 and TFF3 were specifically localised in the mucus layer of HT-29 MTX cells by confocal microscopy. Finally, the secretion of TFF peptides and mucins appears as a co-ordinated process which only occurs after differentiation into goblet cell-like phenotype.
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Affiliation(s)
- V Gouyer
- Unité INSERM 377, Lille Cedex, France
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Williams SJ, Wreschner DH, Tran M, Eyre HJ, Sutherland GR, McGuckin MA. Muc13, a novel human cell surface mucin expressed by epithelial and hemopoietic cells. J Biol Chem 2001; 276:18327-36. [PMID: 11278439 DOI: 10.1074/jbc.m008850200] [Citation(s) in RCA: 227] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Transmembrane mucins are glycoproteins involved in barrier function in epithelial tissues. To identify novel transmembrane mucin genes, we performed a tblastn search of the GenBanktrade mark EST data bases with a serine/threonine-rich search string, and a rodent gene expressed in bone marrow was identified. We determined the cDNA sequence of the human orthologue of this gene, MUC13, which localizes to chromosome band 3q13.3 and generates 3.2-kilobase pair transcripts encoding a 512-amino acid protein comprised of an N-terminal mucin repeat domain, three epidermal growth factor-like sequences, a SEA module, a transmembrane domain, and a cytoplasmic tail (GenBanktrade mark accession no. ). MUC13 mRNA is expressed most highly in the large intestine and trachea, and at moderate levels in the kidney, small intestine, appendix, and stomach. In situ hybridization in murine tissues revealed expression in intestinal epithelial and lymphoid cells. Immunohistochemistry demonstrated the human MUC13 protein on the apical membrane of both columnar and goblet cells in the gastrointestinal tract, as well as within goblet cell thecae, indicative of secretion in addition to presence on the cell surface. MUC13 is cleaved, and the beta-subunit containing the cytoplasmic tail undergoes homodimerization. Including MUC13, there are at least five cell surface mucins expressed in the gastrointestinal tract.
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Affiliation(s)
- S J Williams
- Mater Medical Research Institute, Level 3, Aubigny Place, Mater Misericordiae Hospitals, Raymond Terrace, South Brisbane, Queensland 4101, Australia
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Metzler DE, Metzler CM, Sauke DJ. Some Pathways of Carbohydrate Metabolism. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50023-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Loukas A, Hintz M, Linder D, Mullin NP, Parkinson J, Tetteh KK, Maizels RM. A family of secreted mucins from the parasitic nematode Toxocara canis bears diverse mucin domains but shares similar flanking six-cysteine repeat motifs. J Biol Chem 2000; 275:39600-7. [PMID: 10950959 DOI: 10.1074/jbc.m005632200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Infective larvae of the parasitic nematode Toxocara canis secrete a family of mucin-like glycoproteins, which are implicated in parasite immune evasion. Analysis of T. canis expressed sequence tags identified a family of four mRNAs encoding distinct apomucins (Tc-muc-1-4), one of which had been previously identified in the TES-120 family of glycoproteins secreted by this parasite. The protein products of all four cDNAs contain signal peptides, a repetitive serine/threonine-rich tract, and varying numbers of 36-amino acid six-cysteine (SXC) domains. SXC domains are found in many nematode proteins and show similarity to cnidarian (sea anemone) toxins. Antibodies to the SXC domains of Tc-MUC-1 and Tc-MUC-3 recognize differently migrating members of TES-120. TES-120 proteins separated by chromatographic methods showed distinct amino acid composition, mass, and sequence information by both Edman degradation and matrix-assisted laser desorption ionization/time of flight mass spectrometry on peptide fragments. Tc-MUC-1, -2, and -3 were shown to be secreted mucins with real masses of 39.7, 47.8, and 45.0 kDa in contrast to their predicted peptide masses of 15.7, 16.2, and 26.0 kDa, respectively. The presence of SXC domains in all mucin products supports the suggestion that the SXC motif is required for mucin assembly or export. Homology modeling indicates that the six-cysteine domains of the T. canis mucins adopt a similar fold to the sea anemone potassium channel-blocking toxin BgK, forming three disulfide bonds within each subunit.
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MESH Headings
- Amino Acid Sequence
- Animals
- Blotting, Western
- Chromatography
- Chromatography, High Pressure Liquid
- Cysteine/chemistry
- DNA, Complementary/metabolism
- Electrophoresis, Polyacrylamide Gel
- Expressed Sequence Tags
- Female
- Gastric Mucins/chemistry
- Gastric Mucins/genetics
- Gene Library
- Models, Biological
- Models, Molecular
- Molecular Sequence Data
- Mucins/chemistry
- Mucins/genetics
- Multigene Family
- Protein Sorting Signals
- Protein Structure, Tertiary
- RNA, Messenger/metabolism
- Recombinant Proteins/metabolism
- Sequence Homology, Amino Acid
- Serine/chemistry
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Threonine/chemistry
- Toxocara canis/chemistry
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Affiliation(s)
- A Loukas
- Institute of Cell, Animal and Population Biology and Department of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, United Kingdom
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Pratt WS, Crawley S, Hicks J, Ho J, Nash M, Kim YS, Gum JR, Swallow DM. Multiple transcripts of MUC3: evidence for two genes, MUC3A and MUC3B. Biochem Biophys Res Commun 2000; 275:916-23. [PMID: 10973822 DOI: 10.1006/bbrc.2000.3406] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The MUC3 gene encodes a transmembrane mucin-type glycoprotein. A number of consistent single nucleotide changes were observed in different MUC3 cDNAs from a single individual, suggesting the presence of at least three different transcripts per individual. This transcript heterogeneity is due both to the existence of a second copy of the MUC3 gene and to allelic changes. Sequencing of the second MUC3 shows that it has the same C-terminal domain and intron/exon structure as the previously described MUC3. The tandem repeat domain has the same amino acid consensus sequence but shows more substitutions. The unique exonic sequences range from 94 to 100% identity at the nucleotide level and correspondingly few amino acid changes have been identified. The introns show around 95% identity. We propose to name this second gene MUC3B, MUC3A being reserved for the first MUC3 gene. MUC3B, like MUC3A, is expressed in intestine and Caco-2 cells.
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Affiliation(s)
- W S Pratt
- MRC Human Biochemical Genetics Unit, University College London, 4 Stephenson Way, London, NW1 2HE, United Kingdom
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Baldus SE, Hanisch FG. Biochemistry and pathological importance of mucin-associated antigens in gastrointestinal neoplasia. Adv Cancer Res 2000; 79:201-48. [PMID: 10818682 DOI: 10.1016/s0065-230x(00)79007-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- S E Baldus
- Institute of Pathology, Medical Faculty, University of Cologne, Germany
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Abstract
There is a layer of mucus lining the gastrointestinal tract, which acts as both a lubricant and as a physical barrier between luminal contents and the mucosal surface. The mucins that make up this layer consist of a protein backbone with oligosaccharides attached to specific areas of the protein core. These areas are called the variable number tandem repeat regions. The degree of glycosylation of the mucins is central to their role in the mucus barrier. The oligosaccharides are variable and complex. It has been demonstrated that the degree of sulphation and sialylation and the length of the oligosaccharide chains all vary in inflammatory bowel disease. These changes can alter the function of the mucins. Mucins are broadly divided into two groups, those that are secreted and those that are membrane bound. The major mucins present in the colorectum are MUC1, MUC2, MUC3, and MUC4. Trefoils are a group of small peptides that have an important role in the mucus layer. Three trefoils have been demonstrated so far. They seem to play a part in mucosal protection and in mucosal repair. They may help to stabilise the mucus layer by cross linking with mucins to aid formation of stable gels. Trefoils can be expressed in the ulcer associated cell lineage, a glandular structure that can occur in the inflamed mucosa. There seem to be differences in the expression of trefoils in the colon and the small bowel, which may imply different method of mucosal repair.
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Affiliation(s)
- T Shirazi
- University of Bristol, Bristol Royal Infirmary: University Department of Medicine, UK.
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