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Donald Kufe - One of the best experts on this subject based on the ideXlab platform.
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MUC1 c promotes the suppressive immune microenvironment in non small cell lung cancer
OncoImmunology, 2017Co-Authors: Audrey Bouillez, Hasan Rajabi, Caining Jin, Maroof Alam, Dennis Adeegbe, Ashujit Tagde, Kwokkin Wong, Donald KufeAbstract:The cancer immune microenvironment is of importance for the effectiveness of immunotherapy; however, its dysregulation is poorly understood. The MUC1-C oncoprotein is aberrantly overexpressed in non-small cell lung cancer (NSCLC) and has been linked to the induction of PD-L1. The present work investigated the effects of targeting MUC1-C in an immuno-competent MUC1 transgenic (MUC1.Tg) mouse model. We show that Lewis Lung Carcinoma cells expressing MUC1-C (LLC/MUC1) exhibit upregulation of PD-L1 and suppression of interferon-γ (IFN-γ). In studies of LLC/MUC1 cells growing in vitro and as tumors in MUC1.Tg mice, treatment with the MUC1-C inhibitor, GO-203, was associated with the downregulation of PD-L1 and induction of IFN-γ. The results further demonstrate that targeting MUC1-C results in enhanced effector function of CD8+ tumor-infiltrating lymphocytes (TILs) as evidenced by increased expression of the activation marker CD69, the degranulation marker CD107α, and granzyme B. Notably, targeting MUC1-C was also associated with marked increases in TIL-mediated killing of LLC/MUC1 cells. Analysis of gene expression data sets further showed that overexpression of MUC1 in NSCLCs correlates negatively with CD8, IFNG and GZMB, and that decreases in CD8 and IFNG are associated with poor clinical outcomes. These findings in LLC/MUC1 tumors and in NSCLCs indicate that MUC1-C→PD-L1 signaling promotes the suppression of CD8+ T-cell activation and that MUC1-C is a potential target for reprogramming of the tumor microenvironment.
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MUC1 c oncoprotein induces tcf7l2 transcription factor activation and promotes cyclin d1 expression in human breast cancer cells
Journal of Biological Chemistry, 2012Co-Authors: Hasan Rajabi, Rehan Ahmad, Caining Jin, Michio Kosugi, Maroof Alam, Maya Datt Joshi, Donald KufeAbstract:MUC1 is a heterodimeric glycoprotein that is overexpressed in breast cancers. The present studies demonstrate that the oncogenic MUC1 C-terminal subunit (MUC1-C) associates with the TCF7L2 transcription factor. The MUC1-C cytoplasmic domain (MUC1-CD) binds directly to the TCF7L2 C-terminal region. MUC1-C blocks the interaction between TCF7L2 and the C-terminal-binding protein (CtBP), a suppressor of TCF7L2-mediated transcription. TCF7L2 and MUC1-C form a complex on the cyclin D1 gene promoter and MUC1-C promotes TCF7L2-mediated transcription by the recruitment of β-catenin and p300. Silencing MUC1-C in human breast cancer cells down-regulated activation of the cyclin D1 promoter and decreased cyclin D1 expression. In addition, a MUC1-C inhibitor blocked the interaction with TCF7L2 and suppressed cyclin D1 levels. These findings indicate that the MUC1-C oncoprotein contributes to TCF7L2 activation and thereby promotes cyclin D1 expression in breast cancer cells.
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targeting cysteine mediated dimerization of the MUC1 c oncoprotein in human cancer cells
International Journal of Oncology, 2011Co-Authors: Deepak Raina, Surender Kharbanda, Hasan Rajabi, Rehan Ahmad, Govind Panchamoorthy, Donald KufeAbstract:The MUC1 heterodimeric protein is aberrantly over- expressed in diverse human carcinomas and contributes to the malignant phenotype. The MUC1-C transmembrane subunit contains a CQC motif in the cytoplasmic domain that has been implicated in the formation of dimers and in its oncogenic function. The present study demonstrates that MUC1-C forms dimers in human breast and lung cancer cells. MUC1-C dimer- ization was detectable in the cytoplasm and was independent of MUC1-N, the N-terminal mucin subunit that extends outside the cell. We show that the MUC1-C cytoplasmic domain forms dimers in vitro that are disrupted by reducing agents. Moreover, dimerization of the MUC1-C subunit in cancer cells was blocked by reducing agents and increased by oxidative stress, supporting involvement of the CQC motif in forming disulfide bonds. In support of these observations, mutation of the MUC1-C CQC motif to AQA completely blocked MUC1-C dimerization. Importantly, this study was performed with MUC1-C devoid of fluorescent proteins, such as GFP, CFP and YFP. In this regard, we show that GFP, CFP and YFP themselves form dimers that are readily detectable with cross-linking agents. The present results further demonstrate that a cell-penetrating peptide that targets the MUC1-C CQC cysteines blocks MUC1-C dimerization in cancer cells. These findings provide definitive evidence that: i) the MUC1-C cytoplasmic domain cysteines are necessary and sufficient for MUC1-C dimerization, and ii) these CQC motif cysteines represent an Achilles' heel for targeting MUC1-C function.
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mucin 1 c terminal subunit oncoprotein is a target for small molecule inhibitors
Molecular Pharmacology, 2011Co-Authors: Yongchun Zhou, Hasan Rajabi, Donald KufeAbstract:Mucin 1 (MUC1) is a heterodimeric protein that is overexpressed in diverse human carcinomas. The oncogenic function of the MUC1 C-terminal subunit (MUC1-C) subunit is dependent on the formation of dimers through its cytoplasmic domain; however, it is not known whether MUC1-C can be targeted with small-molecule inhibitors. In the present work, an assay using the MUC1-C cytoplasmic domain (MUC1-CD) was established to screen small-molecule libraries for compounds that block its dimerization. Using this approach, the flavone apigenin was identified as an inhibitor of MUC1-CD dimerization in vitro and in cells. By contrast, the structurally related flavone baicalein was ineffective in blocking the formation of MUC1-CD dimers. In concert with these results, apigenin, and not baicalein, blocked the localization of MUC1-C to the nucleus. MUC1-C activates MUC1 gene expression in an autoinductive loop, and apigenin, but not baicalein, treatment was associated with down-regulation of MUC1 mRNA levels and MUC1-C protein. The results also demonstrate that apigenin-induced suppression of MUC1-C expression is associated with apoptotic cell death and loss of clonogenic survival. These findings represent the first demonstration that the MUC1-C cytoplasmic domain is a target for the development of small-molecule inhibitors.
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MUC1 c oncoprotein promotes stat3 activation in an autoinductive regulatory loop
Science Signaling, 2011Co-Authors: Rehan Ahmad, Surender Kharbanda, Hasan Rajabi, Michio Kosugi, Maroof Alam, Maya Datt Joshi, Baldev Vasir, Takeshi Kawano, Donald KufeAbstract:Signal transducer and activator of transcription 3 (STAT3) is activated in human breast cancer and other malignancies. Mucin 1 (MUC1) is a heterodimeric cell surface glycoprotein that is overexpressed in human carcinomas and, like STAT3, promotes cell survival and induces transformation. We found that in breast cancer cells, the MUC1 carboxyl-terminal receptor subunit (MUC1-C) associates with the gp130–Janus-activated kinase 1 (JAK1)–STAT3 complex. The MUC1-C cytoplasmic domain interacted directly with JAK1 and STAT3, and MUC1-C was necessary for JAK1-mediated STAT3 activation. In turn, MUC1-C and activated STAT3 occupied the promoter of MUC1 , and MUC1-C contributed to STAT3-mediated activation of MUC1 transcription. The MUC1-C inhibitor GO-201 blocked the MUC1-C interaction with STAT3, thereby decreasing MUC1-C and STAT3 occupancy on the MUC1 and STAT3 promoters and activation of STAT3 target genes, including MUC1 itself. These findings indicate that MUC1-C promotes STAT3 activation and that MUC1-C and STAT3 function in an autoinductive loop that may play a role in cancer cell survival.
Michael A. Mcguckin - One of the best experts on this subject based on the ideXlab platform.
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The cell surface mucin MUC1 limits the severity of influenza A virus infection.
Mucosal immunology, 2017Co-Authors: Julie L. Mcauley, Michael A. Mcguckin, Leo Corcilius, Hyon Xhi Tan, Richard J. Payne, Lorena E. BrownAbstract:Cell surface mucin (cs-mucin) glycoproteins are constitutively expressed at the surface of respiratory epithelia where pathogens such as influenza A virus (IAV) gain entry into cells. Different members of the cs-mucin family each express a large and heavily glycosylated extracellular domain that towers above other receptors on the epithelial cell surface, a transmembrane domain that enables shedding of the extracellular domain, and a cytoplasmic tail capable of triggering signaling cascades. We hypothesized that IAV can interact with the terminal sialic acids presented on the extracellular domain of cs-mucins, resulting in modulation of infection efficiency. Utilizing human lung epithelial cells, we found that IAV associates with the cs-mucin MUC1 but not MUC13 or MUC16. Overexpression of MUC1 by epithelial cells or the addition of sialylated synthetic MUC1 constructs, reduced IAV infection in vitro. In addition, MUC1-/- mice infected with IAV exhibited enhanced morbidity and mortality, as well as greater inflammatory mediator responses compared to wild type mice. This study implicates the cs-mucin MUC1 as a critical and dynamic component of the innate host response that limits the severity of influenza and provides the foundation for exploration of MUC1 in resolving inflammatory disease.
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the MUC1 mucin protects against helicobacter pylori pathogenesis in mice by regulation of the nlrp3 inflammasome
Gut, 2016Co-Authors: Trevelyan R Menheniott, Alison L. Every, Andrew Stent, Louise M Judd, Yok Teng Chionh, Poshmaal Dhar, Jasper C Komen, Andrew S Giraud, Timothy C Wang, Michael A. McguckinAbstract:Objectives The mucin MUC1, best known for providing an epithelial barrier, is an important protective host factor in both humans and mice during Helicobacter pylori pathogenesis. This study aimed to identify the long-term consequences of MUC1 deficiency on H. pylori pathogenesis and the mechanism by which MUC1 protects against H. pylori gastritis. Design Wildtype and MUC1 −/− mice were infected for up to 9 months, and the gastric pathology, immunological response and epigenetic changes assessed. The effects of MUC1 on the inflammasome, a potent inflammatory pathway, were examined in macrophages and H. pylori -infected mice deficient in both MUC1 and inflammasome components. Results MUC1 −/− mice began to die 6 months after challenge, indicating MUC1 deficiency made H. pylori a lethal infection. Surprisingly, chimaeric mouse infections revealed MUC1 expression by haematopoietic-derived immune cells limits H. pylori -induced gastritis. Gastritis in infected MUC1 −/− mice was associated with elevated interleukin (IL)-1β and epigenetic changes in their gastric mucosa similar to those in transgenic mice overexpressing gastric IL-1β, implicating MUC1 regulation of an inflammasome. In support of this, infected MUC1 −/− Casp1 −/− mice did not develop severe gastritis. Further, MUC1 regulated Nlrp3 expression via an nuclear factor (NF)-κB-dependent pathway and reduced NF-κB pathway activation via inhibition of IRAK4 phosphorylation. The importance of this regulation was proven using MUC1 −/− Nlrp3 −/− mice, which did not develop severe gastritis. Conclusions MUC1 is an important, previously unidentified negative regulator of the NLRP3 inflammasome. H. pylori activation of the NLRP3 inflammasome is normally tightly regulated by MUC1, and loss of this critical regulation results in the development of severe pathology.
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MUC1 and MUC13 differentially regulate epithelial inflammation in response to inflammatory and infectious stimuli
Mucosal Immunology, 2013Co-Authors: Y H Sheng, S Triyana, K Gerloff, T H Florin, P Sutton, R. Wang, Michael A. McguckinAbstract:The MUC1 cell-surface mucin is highly expressed on the gastric mucosal surface, while MUC13 is highly expressed on the intestinal mucosal surface. Polymorphisms in both MUC1 and MUC13 have been linked to inflammatory bowel diseases. MUC1 can act as a decoy molecule on the apical cell surface of epithelial cells and thereby limit bacterial adherence, infection, and inflammation. In this study, we examined whether and how MUC1 and MUC13 modulate infectious and inflammatory signaling. Using gastrointestinal tissue from MUC1 - or MUC13 -deficient mice in ex vivo culture, MUC1 small interfering RNA (siRNA) silencing in MKN7 gastric epithelial cells, and MUC13 siRNA silencing in LS513 intestinal epithelial cells, we showed that loss of MUC1 increased chemokine secretion, whereas loss of MUC13 decreased chemokine secretion in response to tumor necrosis factor-α. Anti-inflammatory activity of MUC1 and pro-inflammatory activity of MUC13 were also seen after exposure to pathogens, NOD1 (nucleotide-binding oligomerisation domain-containing protein-1), and Toll-like receptor ligands. MUC1 and MUC13 both regulate chemokine secretion in gastrointestinal epithelial cells through a nuclear factor-κB-dependent pathway, although MUC13 modulation could also involve other pathways. Our studies demonstrate that MUC1 and MUC13 are important components of gastrointestinal homeostasis and that disruption or inappropriate expression of these mucins could predispose to infectious and inflammatory disease and inflammation-induced cancer.
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MUC1 limits Helicobacter pylori infection both by steric hindrance and by acting as a releasable decoy.
PLOS Pathogens, 2009Co-Authors: Sara K. Lindén, Yong H. Sheng, Alison L. Every, Kim M. Miles, Emma C. Skoog, Timothy H. Florin, Philip Sutton, Michael A. McguckinAbstract:The bacterium Helicobacter pylori can cause peptic ulcer disease, gastric adenocarcinoma and MALT lymphoma. The cell-surface mucin MUC1 is a large glycoprotein which is highly expressed on the mucosal surface and limits the density of H. pylori in a murine infection model. We now demonstrate that by using the BabA and SabA adhesins, H. pylori bind MUC1 isolated from human gastric cells and MUC1 shed into gastric juice. Both H. pylori carrying these adhesins, and beads coated with MUC1 antibodies, induced shedding of MUC1 from MKN7 human gastric epithelial cells, and shed MUC1 was found bound to H. pylori. Shedding of MUC1 from non-infected cells was not mediated by the known MUC1 sheddases ADAM17 and MMP-14. However, knockdown of MMP-14 partially affected MUC1 release early in infection, whereas ADAM17 had no effect. Thus, it is likely that shedding is mediated both by proteases and by disassociation of the non-covalent interaction between the α- and β-subunits. H. pylori bound more readily to MUC1 depleted cells even when the bacteria lacked the BabA and SabA adhesins, showing that MUC1 inhibits attachment even when bacteria cannot bind to the mucin. Bacteria lacking both the BabA and SabA adhesins caused less apoptosis in MKN7 cells than wild-type bacteria, having a greater effect than deletion of the CagA pathogenicity gene. Deficiency of MUC1/MUC1 resulted in increased epithelial cell apoptosis, both in MKN7 cells in vitro, and in H. pylori infected mice. Thus, MUC1 protects the epithelium from non-MUC1 binding bacteria by inhibiting adhesion to the cell surface by steric hindrance, and from MUC1-binding bacteria by acting as a releasable decoy.
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MUC1 limits helicobacter pylori infection both by steric hindrance and by acting as a releasable decoy
PLOS Pathogens, 2009Co-Authors: Sara K. Lindén, Yong H. Sheng, Alison L. Every, Kim M. Miles, Emma C. Skoog, Timothy H. Florin, Philip Sutton, Michael A. McguckinAbstract:The bacterium Helicobacter pylori can cause peptic ulcer disease, gastric adenocarcinoma and MALT lymphoma. The cell-surface mucin MUC1 is a large glycoprotein which is highly expressed on the mucosal surface and limits the density of H. pylori in a murine infection model. We now demonstrate that by using the BabA and SabA adhesins, H. pylori bind MUC1 isolated from human gastric cells and MUC1 shed into gastric juice. Both H. pylori carrying these adhesins, and beads coated with MUC1 antibodies, induced shedding of MUC1 from MKN7 human gastric epithelial cells, and shed MUC1 was found bound to H. pylori. Shedding of MUC1 from non-infected cells was not mediated by the known MUC1 sheddases ADAM17 and MMP-14. However, knockdown of MMP-14 partially affected MUC1 release early in infection, whereas ADAM17 had no effect. Thus, it is likely that shedding is mediated both by proteases and by disassociation of the non-covalent interaction between the alpha- and beta-subunits. H. pylori bound more readily to MUC1 depleted cells even when the bacteria lacked the BabA and SabA adhesins, showing that MUC1 inhibits attachment even when bacteria cannot bind to the mucin. Bacteria lacking both the BabA and SabA adhesins caused less apoptosis in MKN7 cells than wild-type bacteria, having a greater effect than deletion of the CagA pathogenicity gene. Deficiency of MUC1/MUC1 resulted in increased epithelial cell apoptosis, both in MKN7 cells in vitro, and in H. pylori infected mice. Thus, MUC1 protects the epithelium from non-MUC1 binding bacteria by inhibiting adhesion to the cell surface by steric hindrance, and from MUC1-binding bacteria by acting as a releasable decoy.
Dongshu Chen - One of the best experts on this subject based on the ideXlab platform.
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nuclear import of the MUC1 c oncoprotein is mediated by nucleoporin nup62
Journal of Biological Chemistry, 2007Co-Authors: Yumei Leng, Dongshu Chen, Lei Huang, Donald KufeAbstract:Abstract The MUC1 heterodimeric transmembrane protein is aberrantly overexpressed by most human carcinomas. The MUC1 C-terminal subunit (MUC1-C) is devoid of a classical nuclear localization signal and is targeted to the nucleus by an unknown mechanism. The present results demonstrate that MUC1-C associates with importin β and not importin α. The results also show that, like importin β, MUC1-C binds to Nup62 (nucleoporin p62). MUC1-C binds directly to the Nup62 central domain and indirectly to the Nup62 C-terminal α-helical coiled-coil domain. We demonstrate that MUC1-C forms oligomers and that oligomerization is necessary for binding to Nup62. The MUC1-C cytoplasmic domain contains a CQC motif that when mutated to AQA abrogates oligomerization and binding to Nup62. Stable expression of MUC1 with the CQC → AQA mutations was associated with targeting to the cell membrane and cytosol and attenuation of nuclear localization. The results further show that expression of MUC1(CQC-AQA) attenuates MUC1-induced (i) transcriptional coactivation, (ii) anchorage-independent growth, and (iii) tumorigenicity. These findings indicate that the MUC1-C oncoprotein is imported to the nucleus by a pathway involving Nup62.
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MUC1 oncoprotein blocks glycogen synthase kinase 3β mediated phosphorylation and degradation of β catenin
Cancer Research, 2005Co-Authors: Lei Huang, Dongshu Chen, Surender Kharbanda, Donald KufeAbstract:Dysregulation of β-catenin is of importance to the development of diverse human malignancies. The MUC1 oncoprotein is aberrantly overexpressed by most human carcinomas and associates with β-catenin. However, the functional significance of the MUC1-β-catenin interaction is not known. Here, we show that MUC1 increases β-catenin levels in the cytoplasm and nucleus of carcinoma cells. Previous studies have shown that glycogen synthase kinase 3β (GSK3β) phosphorylates β-catenin and thereby targets it for proteosomal degradation. Consistent with the up-regulation of β-catenin levels, our results show that MUC1 blocks GSK3β-mediated phosphorylation and degradation of β-catenin. To further define the interaction between MUC1 and β-catenin, we identified a serine-rich motif (SRM) in the MUC1 cytoplasmic domain that binds directly to β-catenin Armadillo repeats. Mutation of the SRM attenuated binding of MUC1 to β-catenin and MUC1-mediated inhibition of β-catenin degradation. Importantly, disruption of the MUC1-β-catenin interaction with the SRM mutant also attenuated MUC1-induced anchorage-dependent and -independent growth and delayed MUC1-mediated tumorigenicity. These findings indicate that MUC1 promotes transformation, at least in part, by blocking GSK3β-mediated phosphorylation and thereby degradation of β-catenin.
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MUC1 oncoprotein blocks glycogen synthase kinase 3β mediated phosphorylation and degradation of β catenin
Cancer Research, 2005Co-Authors: Lei Huang, Dongshu Chen, Surender Kharbanda, Derek Liu, Li Yin, Donald KufeAbstract:Dysregulation of beta-catenin is of importance to the development of diverse human malignancies. The MUC1 oncoprotein is aberrantly overexpressed by most human carcinomas and associates with beta-catenin. However, the functional significance of the MUC1-beta-catenin interaction is not known. Here, we show that MUC1 increases beta-catenin levels in the cytoplasm and nucleus of carcinoma cells. Previous studies have shown that glycogen synthase kinase 3beta (GSK3beta) phosphorylates beta-catenin and thereby targets it for proteosomal degradation. Consistent with the up-regulation of beta-catenin levels, our results show that MUC1 blocks GSK3beta-mediated phosphorylation and degradation of beta-catenin. To further define the interaction between MUC1 and beta-catenin, we identified a serine-rich motif (SRM) in the MUC1 cytoplasmic domain that binds directly to beta-catenin Armadillo repeats. Mutation of the SRM attenuated binding of MUC1 to beta-catenin and MUC1-mediated inhibition of beta-catenin degradation. Importantly, disruption of the MUC1-beta-catenin interaction with the SRM mutant also attenuated MUC1-induced anchorage-dependent and -independent growth and delayed MUC1-mediated tumorigenicity. These findings indicate that MUC1 promotes transformation, at least in part, by blocking GSK3beta-mediated phosphorylation and thereby degradation of beta-catenin.
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human MUC1 carcinoma associated protein confers resistance to genotoxic anticancer agents
Cancer Cell, 2004Co-Authors: Jian Ren, Dongshu Chen, Surender Kharbanda, Lei Huang, Deepak Raina, Wen Chen, Naoki Agata, Donald KufeAbstract:The MUC1 transforming protein is overexpressed by most human carcinomas. The present studies demonstrate that the MUC1 C-terminal subunit (MUC1 C-ter) localizes to mitochondria in HCT116/MUC1 colon carcinoma cells and that heregulin stimulates mitochondrial targeting of MUC1 C-ter. We also show that MUC1 attenuates cisplatin-induced (1) release of mitochondrial apoptogenic factors, (2) activation of caspase-3, and (3) induction of apoptosis. Moreover, knockdown of MUC1 expression in A549 lung and ZR-75-1 breast carcinoma cells by MUC1siRNA was associated with increased sensitivity to genotoxic drugs in vitro and in vivo. These findings indicate that MUC1 attenuates the apoptotic response to DNA damage and that this oncoprotein confers resistance to genotoxic anticancer agents.
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MUC1 cytoplasmic domain coactivates wnt target gene transcription and confers transformation
Cancer Biology & Therapy, 2003Co-Authors: Lei Huang, Dongshu Chen, Surender Kharbanda, Jian Ren, Donald KufeAbstract:The DF3/MUC1 mucin-like transmembrane oncoprotein is overexpressed by most human carcinomas. The MUC1 cytoplasmic domain (CD) binds directly to the Wnt effector, beta-catenin, and colocalizes with beta-catenin in the nucleus; however, the nuclear function of MUC1 is unknown. The present results demonstrate that MUC1 coactivates transcription of beta-catenin-Tcf-binding sites in the pTOPFLASH reporter. Activation of transcription was abrogated by expression of MUC1 with a Y-46->F mutation in the CD that attenuates binding of MUC1 and beta-catenin. We also show that transcription of the Wnt responsive cyclin D1 promoter is activated by MUC1, but not MUC1(Y46F), and that the cyclin D1 gene is upregulated in MUC1-positive cells. In concert with these results, MUC1-induced anchorage-independent growth and tumorigenicity were also abrogated by mutating MUC1 at the Y-46 site. These findings support a model in which the MUC1 functions as a transforming protein by coactivating transcription of Wnt target genes.
Sara K. Lindén - One of the best experts on this subject based on the ideXlab platform.
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In-Depth Study of Transmembrane Mucins in Association with Intestinal Barrier Dysfunction During the Course of T Cell Transfer and DSS-Induced Colitis.
Journal of Crohn's & colitis, 2020Co-Authors: Tom Breugelmans, Sara K. Lindén, Hanne Van Spaendonk, Joris G. De Man, Heiko U. De Schepper, Aranzazu Jauregui-amezaga, Elisabeth Macken, Isabel Pintelon, Jean-pierre Timmermans, Benedicte Y. De WinterAbstract:BACKGROUND AND AIMS There is evidence for a disturbed intestinal barrier function in inflammatory bowel diseases [IBD] but the underlying mechanisms are unclear. Because mucins represent the major components of the mucus barrier and disturbed mucin expression is reported in the colon of IBD patients, we studied the association between mucin expression, inflammation and intestinal permeability in experimental colitis. METHODS We quantified 4-kDa FITC-dextran intestinal permeability and the expression of cytokines, mucins, junctional and polarity proteins at dedicated time points in the adoptive T cell transfer and dextran sodium sulfate [DSS]-induced colitis models. Mucin expression was also validated in biopsies from IBD patients. RESULTS In both animal models, the course of colitis was associated with increased interleukin-1β [IL-1β] and tumour necrosis factor-α [TNF-α] expression and increased MUC1 and MUC13 expression. In the T cell transfer model, a gradually increasing MUC1 expression coincided with gradually increasing 4-kDa FITC-dextran intestinal permeability and correlated with enhanced IL-1β expression. In the DSS model, MUC13 expression coincided with rapidly increased 4-kDa FITC-dextran intestinal permeability and correlated with TNF-α and MUC1 overexpression. Moreover, a significant association was observed between MUC1, Cldn1, Ocln, Par3 and aPKCζ expression in the T cell transfer model and between MUC13, Cldn1, Jam2, Tjp2, aPkcζ, Crb3 and Scrib expression in the DSS model. Additionally, MUC1 and MUC13 expression was upregulated in inflamed mucosa of IBD patients. CONCLUSIONS Aberrantly expressed MUC1 and MUC13 might be involved in intestinal barrier dysfunction upon inflammation by affecting junctional and cell polarity proteins, indicating their potential as therapeutic targets in IBD.
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MUC1 limits Helicobacter pylori infection both by steric hindrance and by acting as a releasable decoy.
PLOS Pathogens, 2009Co-Authors: Sara K. Lindén, Yong H. Sheng, Alison L. Every, Kim M. Miles, Emma C. Skoog, Timothy H. Florin, Philip Sutton, Michael A. McguckinAbstract:The bacterium Helicobacter pylori can cause peptic ulcer disease, gastric adenocarcinoma and MALT lymphoma. The cell-surface mucin MUC1 is a large glycoprotein which is highly expressed on the mucosal surface and limits the density of H. pylori in a murine infection model. We now demonstrate that by using the BabA and SabA adhesins, H. pylori bind MUC1 isolated from human gastric cells and MUC1 shed into gastric juice. Both H. pylori carrying these adhesins, and beads coated with MUC1 antibodies, induced shedding of MUC1 from MKN7 human gastric epithelial cells, and shed MUC1 was found bound to H. pylori. Shedding of MUC1 from non-infected cells was not mediated by the known MUC1 sheddases ADAM17 and MMP-14. However, knockdown of MMP-14 partially affected MUC1 release early in infection, whereas ADAM17 had no effect. Thus, it is likely that shedding is mediated both by proteases and by disassociation of the non-covalent interaction between the α- and β-subunits. H. pylori bound more readily to MUC1 depleted cells even when the bacteria lacked the BabA and SabA adhesins, showing that MUC1 inhibits attachment even when bacteria cannot bind to the mucin. Bacteria lacking both the BabA and SabA adhesins caused less apoptosis in MKN7 cells than wild-type bacteria, having a greater effect than deletion of the CagA pathogenicity gene. Deficiency of MUC1/MUC1 resulted in increased epithelial cell apoptosis, both in MKN7 cells in vitro, and in H. pylori infected mice. Thus, MUC1 protects the epithelium from non-MUC1 binding bacteria by inhibiting adhesion to the cell surface by steric hindrance, and from MUC1-binding bacteria by acting as a releasable decoy.
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MUC1 limits helicobacter pylori infection both by steric hindrance and by acting as a releasable decoy
PLOS Pathogens, 2009Co-Authors: Sara K. Lindén, Yong H. Sheng, Alison L. Every, Kim M. Miles, Emma C. Skoog, Timothy H. Florin, Philip Sutton, Michael A. McguckinAbstract:The bacterium Helicobacter pylori can cause peptic ulcer disease, gastric adenocarcinoma and MALT lymphoma. The cell-surface mucin MUC1 is a large glycoprotein which is highly expressed on the mucosal surface and limits the density of H. pylori in a murine infection model. We now demonstrate that by using the BabA and SabA adhesins, H. pylori bind MUC1 isolated from human gastric cells and MUC1 shed into gastric juice. Both H. pylori carrying these adhesins, and beads coated with MUC1 antibodies, induced shedding of MUC1 from MKN7 human gastric epithelial cells, and shed MUC1 was found bound to H. pylori. Shedding of MUC1 from non-infected cells was not mediated by the known MUC1 sheddases ADAM17 and MMP-14. However, knockdown of MMP-14 partially affected MUC1 release early in infection, whereas ADAM17 had no effect. Thus, it is likely that shedding is mediated both by proteases and by disassociation of the non-covalent interaction between the alpha- and beta-subunits. H. pylori bound more readily to MUC1 depleted cells even when the bacteria lacked the BabA and SabA adhesins, showing that MUC1 inhibits attachment even when bacteria cannot bind to the mucin. Bacteria lacking both the BabA and SabA adhesins caused less apoptosis in MKN7 cells than wild-type bacteria, having a greater effect than deletion of the CagA pathogenicity gene. Deficiency of MUC1/MUC1 resulted in increased epithelial cell apoptosis, both in MKN7 cells in vitro, and in H. pylori infected mice. Thus, MUC1 protects the epithelium from non-MUC1 binding bacteria by inhibiting adhesion to the cell surface by steric hindrance, and from MUC1-binding bacteria by acting as a releasable decoy.
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Mucin dynamics in intestinal bacterial infection.
PloS one, 2008Co-Authors: Sara K. Lindén, Timothy H. Florin, Michael A. McguckinAbstract:Background Bacterial gastroenteritis causes morbidity and mortality in humans worldwide. Murine Citrobacter rodentium infection is a model for gastroenteritis caused by the human pathogens enteropathogenic Escherichia coli and enterohaemorrhagic E. coli. Mucin glycoproteins are the main component of the first barrier that bacteria encounter in the intestinal tract. Methodology/Principal Findings Using Immunohistochemistry, we investigated intestinal expression of mucins (Alcian blue/PAS, MUC1, Muc2, Muc4, Muc5AC, MUC13 and Muc3/17) in healthy and C. rodentium infected mice. The majority of the C. rodentium infected mice developed systemic infection and colitis in the mid and distal colon by day 12. C. rodentium bound to the major secreted mucin, Muc2, in vitro, and high numbers of bacteria were found in secreted MUC2 in infected animals in vivo, indicating that mucins may limit bacterial access to the epithelial surface. In the small intestine, caecum and proximal colon, the mucin expression was similar in infected and non-infected animals. In the distal colonic epithelium, all secreted and cell surface mucins decreased with the exception of the MUC1 cell surface mucin which increased after infection (p
Surender Kharbanda - One of the best experts on this subject based on the ideXlab platform.
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targeting cysteine mediated dimerization of the MUC1 c oncoprotein in human cancer cells
International Journal of Oncology, 2011Co-Authors: Deepak Raina, Surender Kharbanda, Hasan Rajabi, Rehan Ahmad, Govind Panchamoorthy, Donald KufeAbstract:The MUC1 heterodimeric protein is aberrantly over- expressed in diverse human carcinomas and contributes to the malignant phenotype. The MUC1-C transmembrane subunit contains a CQC motif in the cytoplasmic domain that has been implicated in the formation of dimers and in its oncogenic function. The present study demonstrates that MUC1-C forms dimers in human breast and lung cancer cells. MUC1-C dimer- ization was detectable in the cytoplasm and was independent of MUC1-N, the N-terminal mucin subunit that extends outside the cell. We show that the MUC1-C cytoplasmic domain forms dimers in vitro that are disrupted by reducing agents. Moreover, dimerization of the MUC1-C subunit in cancer cells was blocked by reducing agents and increased by oxidative stress, supporting involvement of the CQC motif in forming disulfide bonds. In support of these observations, mutation of the MUC1-C CQC motif to AQA completely blocked MUC1-C dimerization. Importantly, this study was performed with MUC1-C devoid of fluorescent proteins, such as GFP, CFP and YFP. In this regard, we show that GFP, CFP and YFP themselves form dimers that are readily detectable with cross-linking agents. The present results further demonstrate that a cell-penetrating peptide that targets the MUC1-C CQC cysteines blocks MUC1-C dimerization in cancer cells. These findings provide definitive evidence that: i) the MUC1-C cytoplasmic domain cysteines are necessary and sufficient for MUC1-C dimerization, and ii) these CQC motif cysteines represent an Achilles' heel for targeting MUC1-C function.
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MUC1 c oncoprotein promotes stat3 activation in an autoinductive regulatory loop
Science Signaling, 2011Co-Authors: Rehan Ahmad, Surender Kharbanda, Hasan Rajabi, Michio Kosugi, Maroof Alam, Maya Datt Joshi, Baldev Vasir, Takeshi Kawano, Donald KufeAbstract:Signal transducer and activator of transcription 3 (STAT3) is activated in human breast cancer and other malignancies. Mucin 1 (MUC1) is a heterodimeric cell surface glycoprotein that is overexpressed in human carcinomas and, like STAT3, promotes cell survival and induces transformation. We found that in breast cancer cells, the MUC1 carboxyl-terminal receptor subunit (MUC1-C) associates with the gp130–Janus-activated kinase 1 (JAK1)–STAT3 complex. The MUC1-C cytoplasmic domain interacted directly with JAK1 and STAT3, and MUC1-C was necessary for JAK1-mediated STAT3 activation. In turn, MUC1-C and activated STAT3 occupied the promoter of MUC1 , and MUC1-C contributed to STAT3-mediated activation of MUC1 transcription. The MUC1-C inhibitor GO-201 blocked the MUC1-C interaction with STAT3, thereby decreasing MUC1-C and STAT3 occupancy on the MUC1 and STAT3 promoters and activation of STAT3 target genes, including MUC1 itself. These findings indicate that MUC1-C promotes STAT3 activation and that MUC1-C and STAT3 function in an autoinductive loop that may play a role in cancer cell survival.
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MUC1 c oncoprotein functions as a direct activator of the nuclear factor κb p65 transcription factor
Cancer Research, 2009Co-Authors: Rehan Ahmad, Surender Kharbanda, Maya Datt Joshi, Takeshi Kawano, Jian Ren, Deepak Raina, Donald KufeAbstract:Nuclear factor-κB (NF-κB) is constitutively activated in diverse human malignancies. The mucin 1 (MUC1) oncoprotein is overexpressed in human carcinomas and, like NF-κB, blocks cell death and induces transformation. The present studies show that MUC1 constitutively associates with NF-κB p65 in carcinoma cells. The MUC1 COOH-terminal subunit (MUC1-C) cytoplasmic domain binds directly to NF-κB p65 and, importantly, blocks the interaction between NF-κB p65 and its inhibitor IκBα. We show that NF-κB p65 and MUC1-C constitutively occupy the promoter of the Bcl-xL gene in carcinoma cells and that MUC1-C contributes to NF-κB–mediated transcriptional activation. Studies in nonmalignant epithelial cells show that MUC1-C interacts with NF-κB in the response to tumor necrosis factor-α stimulation. Moreover, tumor necrosis factor-α induces the recruitment of NF-κB p65-MUC1-C complexes to NF-κB target genes, including the promoter of the MUC1 gene itself. We also show that an inhibitor of MUC1-C oligomerization blocks the interaction with NF-κB p65 in vitro and in cells. The MUC1-C inhibitor decreases MUC1-C and NF-κB p65 promoter occupancy and expression of NF-κB target genes. These findings indicate that MUC1-C is a direct activator of NF-κB p65 and that an inhibitor of MUC1 function is effective in blocking activation of the NF-κB pathway. [Cancer Res 2009;69(17):7013–21]
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Distinct evolution of the human carcinoma-associated transmembrane mucins, MUC1, MUC4 and MUC16
Gene, 2006Co-Authors: Sekhar Duraisamy, Surender Kharbanda, Selvi Ramasamy, Donald KufeAbstract:The MUC family of mucins consists of secreted and membrane-bound forms. Overexpression of the membrane-bound family members, MUC1 (CA15-3), MUC4 and MUC16 (CA125), is found in diverse human carcinomas. However, despite being classified in the same family, little is known about the genetic origins of the carcinoma-associated mucins. The present results show that MUC1 homologs are restricted to mammalian species. MUC1 has no sequence similarity with the other membrane-bound mucins, except for the presence of a sea urchin sperm protein-enterokinase-agrin (SEA) domain. The results indicate that the MUC1 SEA domain originated from heparin sulfate proteoglycan of basement membrane (HSPG2; perlecan), an inducer of tumor cell growth. MUC4 has no SEA domain, but does have (i) a NIDO domain that evolved from an ancestor common to nidogen, and (ii) AMOP and VWD domains that originated from an ancestor common to the Sushi-domain containing protein. MUC16 contains multiple SEA domains that are found in a chicken gene and were subsequently repeated through duplication events. The SEA domains in MUC16 appear to have evolved from agrin before the divergence of birds and mammals. These findings indicate that MUC1, MUC4 and MUC16 evolved from distinct ancestors and that the membrane-bound mucins consist of different subgroups based on their genetic backgrounds.
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MUC1 oncoprotein blocks glycogen synthase kinase 3β mediated phosphorylation and degradation of β catenin
Cancer Research, 2005Co-Authors: Lei Huang, Dongshu Chen, Surender Kharbanda, Donald KufeAbstract:Dysregulation of β-catenin is of importance to the development of diverse human malignancies. The MUC1 oncoprotein is aberrantly overexpressed by most human carcinomas and associates with β-catenin. However, the functional significance of the MUC1-β-catenin interaction is not known. Here, we show that MUC1 increases β-catenin levels in the cytoplasm and nucleus of carcinoma cells. Previous studies have shown that glycogen synthase kinase 3β (GSK3β) phosphorylates β-catenin and thereby targets it for proteosomal degradation. Consistent with the up-regulation of β-catenin levels, our results show that MUC1 blocks GSK3β-mediated phosphorylation and degradation of β-catenin. To further define the interaction between MUC1 and β-catenin, we identified a serine-rich motif (SRM) in the MUC1 cytoplasmic domain that binds directly to β-catenin Armadillo repeats. Mutation of the SRM attenuated binding of MUC1 to β-catenin and MUC1-mediated inhibition of β-catenin degradation. Importantly, disruption of the MUC1-β-catenin interaction with the SRM mutant also attenuated MUC1-induced anchorage-dependent and -independent growth and delayed MUC1-mediated tumorigenicity. These findings indicate that MUC1 promotes transformation, at least in part, by blocking GSK3β-mediated phosphorylation and thereby degradation of β-catenin.