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  • 1
    Publication Date: 2013-12-05
    Description: Background Most colon cancers start with dysregulated Wnt/β-catenin signalling and remain a major therapeutic challenge. Examining whether HAMLET (human α-lactalbumin made lethal to tumour cells) may be used for colon cancer treatment is logical, based on the properties of the complex and its biological context. Objective To investigate if HAMLET can be used for colon cancer treatment and prevention. Apc Min /+ mice, which carry mutations relevant to hereditary and sporadic human colorectal tumours, were used as a model for human disease. Method HAMLET was given perorally in therapeutic and prophylactic regimens. Tumour burden and animal survival of HAMLET-treated and sham-fed mice were compared. Tissue analysis focused on Wnt/β-catenin signalling, proliferation markers and gene expression, using microarrays, immunoblotting, immunohistochemistry and ELISA. Confocal microscopy, reporter assay, immunoprecipitation, immunoblotting, ion flux assays and holographic imaging were used to determine effects on colon cancer cells. Results Peroral HAMLET administration reduced tumour progression and mortality in Apc Min /+ mice. HAMLET accumulated specifically in tumour tissue, reduced β-catenin and related tumour markers. Gene expression analysis detected inhibition of Wnt signalling and a shift to a more differentiated phenotype. In colon cancer cells with APC mutations, HAMLET altered β-catenin integrity and localisation through an ion channel-dependent pathway, defining a new mechanism for controlling β-catenin signalling. Remarkably, supplying HAMLET to the drinking water from the time of weaning also significantly prevented tumour development. Conclusions These data identify HAMLET as a new, peroral agent for colon cancer prevention and treatment, especially needed in people carrying APC mutations, where colon cancer remains a leading cause of death.
    Keywords: Open access, Colon cancer
    Print ISSN: 0017-5749
    Electronic ISSN: 1468-3288
    Topics: Medicine
    Published by BMJ Publishing Group
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  • 2
    Publication Date: 2013-06-15
    Description: Long-chain fatty acids are internalized by receptor-mediated mechanisms or receptor-independent diffusion across cytoplasmic membranes and are utilized as nutrients, building blocks, and signaling intermediates. Here we describe how the association of long-chain fatty acids to a partially unfolded, extracellular protein can alter the presentation to target cells and cellular effects. HAMLET (human α-lactalbumin made lethal to tumor cells) is a tumoricidal complex of partially unfolded α-lactalbumin and oleic acid (OA). As OA lacks independent tumoricidal activity at concentrations equimolar to HAMLET, the contribution of the lipid has been debated. We show by natural abundance 13C NMR that the lipid in HAMLET is deprotonated and by chromatography that oleate rather than oleic acid is the relevant HAMLET constituent. Compared with HAMLET, oleate (175 μm) showed weak effects on ion fluxes and gene expression. Unlike HAMLET, which causes metabolic paralysis, fatty acid metabolites were less strongly altered. The functional overlap increased with higher oleate concentrations (500 μm). Cellular responses to OA were weak or absent, suggesting that deprotonation favors cellular interactions of fatty acids. Fatty acids may thus exert some of their essential effects on host cells when in the deprotonated state and when presented in the context of a partially unfolded protein.
    Print ISSN: 0021-9258
    Electronic ISSN: 1083-351X
    Topics: Biology , Chemistry and Pharmacology
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  • 3
    Publication Date: 2014-09-21
    Description: Polyethyleneimine (PEI) is an organic polycation used extensively as a gene and DNA vaccine delivery reagent. Although the DNA targeting activity of PEI is well documented, its immune activating activity is not. We recently reported that PEI has robust mucosal adjuvanticity when administered intranasally with glycoprotein antigens. Here, we show that PEI has strong immune activating activity after systemic delivery. PEI administered subcutaneously with viral glycoprotein (HIV-1 gp140) enhanced antigen-specific serum IgG production in the context of mixed T h 1/T h 2-type immunity. PEI elicited higher titers of both antigen binding and neutralizing antibodies than alum in mice and rabbits and induced an increased proportion of antibodies reactive with native antigen. In an intraperitoneal model, PEI recruited neutrophils followed by monocytes to the site of administration and enhanced antigen uptake by antigen-presenting cells. The T h bias was modulated by PEI activation of the Nlrp3 inflammasome; however its global adjuvanticity was unchanged in Nlrp3-deficient mice. When coformulated with CpG oligodeoxynucleotides, PEI adjuvant potency was synergistically increased and biased toward a T h 1-type immune profile. Taken together, these data support the use of PEI as a versatile systemic adjuvant platform with particular utility for induction of secondary structure-reactive antibodies against glycoprotein antigens.
    Print ISSN: 0953-8178
    Electronic ISSN: 1460-2377
    Topics: Medicine
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of immunology 37 (1993), S. 0 
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Trauma and infection activated a murine mucosal IL-6 response in different ways: the IL-6 response to bacteria was sensitive to Cyclosporin A (CsA); the IL-6 response to trauma was not. The aim of the present study was to identify possible activators of the CsA-insensitive IL-6 secretion at the epithelial cell level. Two human epithelial cell lines from the kidney (A498) and bladder (J82) were exposed to Escherichia coli Hu734, interleukin-lα (IL-lα) and tumour necrosis factor a (TNF-α). The E. coli strain had been used for the in vivo experiments which led to this study, and IL-lα and TNF-α were likely to be released during infections and trauma. The secretion of IL-6 into the supernatants was compared between cells stimulated in the presence or absence of CsA. E. coli Hu734, IL-lα and TNF-α stimulated an IL-6 response in the two epithelial cell lines. The IL-lα-induced IL-6 response was rapid, and the secreted IL-6 levels were significantly higher than those induced by E. coli Hu734 or TNF-α. The IL-6 response to IL- lα was insensitive to CsA. By contrast, the IL-6 response to E. coli Hu734 and TNF-α was inhibited by CsA. These results demonstrated that the inhibitory effect of CsA depends on the stimulus triggering the IL-6 response. IL-lα may play a role in the induction of trauma-associated CsA-insensitive IL-6 secretion.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Cells in the mucosal barrier are equipped to sense and respond to microbes in the lumen and translate this molecular information into signals that can reach local or distant sites. The interaction of P-fimbriated Escherichia coli with human uroepithelial cells is a model to study the molecular mechanism of epithelial cell activation by mucosal pathogens. Here, we examine the role of lipopolysaccharide (LPS) as a co-stimulatory molecule in epithelial cell activation by P-fimbriated E. coli. P-fimbriated clinical isolates or recombinant strains were shown to trigger a fimbriae-dependent epithelial cell cytokine response. Mutational inactivation of the msbB sequences that control lipid A myristoylation drastically impaired monocyte stimulation but not epithelial responses to P-fimbriated bacteria. Polymyxin B or bactericidal/permeability increasing factor (BPI) neutralized the effects of lipid A in the monocyte assay, but did not reduce epithelial responses. Finally, isolated LPS of the smooth, rough and deep rough chemotypes were poor epithelial cell activators. The cells were shown to lack surface CD14 or CD14 mRNA as well as the CD14 co-receptor function and were also very poor LPS responders in the presence of human serum. These results demonstrate that epithelial cell responses to P-fimbriated E. coli are CD14 and LPS independent, and suggest that attaching pathogens can overcome the LPS unresponsiveness of epithelial cells by fimbriae-dependent activation mechanisms.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: This study examined the role of P and type 1 fimbriae for neutrophil migration across Escherichia coli-infected uroepithelial cell layers in vitro and for neutrophil recruitment to the urinary tract in vivo. Recombinant E. coli K-12 strains differing in P or type 1 fimbrial expression were used to infect confluent epithelial layers on the underside of transwell inserts. Neutrophils were added to the upper well, and their passage across the epithelial cell layers was quantified. Infection with the P- and type 1-fimbriated recombinant E. coli strains stimulated neutrophil migration to the same extent as a fully virulent clinical E. coli isolate, but the isogenic non-fimbriated vector control strains had no stimulatory effect. The enhancement of neutrophil migration was adhesion dependent; it was inhibited by soluble receptor analogues blocking the binding of P fimbriae to the globoseries of glycosphingolipids or of type 1 fimbriae to mannosylated glycoprotein receptors. P- and type 1-fimbriated E. coli triggered higher interleukin (IL) 8 secretion and expression of functional IL-8 receptors than non-fimbriated controls, and the increase in neutrophil migration across infected cell layers was inhibited by anti-IL-8 antibodies. In a mouse infection model, P- or type 1-fimbriated E. coli stimulated higher chemokine (MIP-2) and neutrophil responses than the non-fimbriated vector controls. The results demonstrated that transformation with the pap or fim DNA sequences is sufficient to convert an E. coli K-12 strain to a host response inducer, and that fimbriation enhances neutrophil recruitment in vitro and in vivo. Epithelial chemokine production provides a molecular link between the fimbriated bacteria that adhere to epithelial cells and tissue inflammation.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 730 (1994), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0003-9861
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of immunology 39 (1994), S. 0 
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: It has been shown previously that secretory IgA interacts with the mannose-specific lectin of Escherichia coli. The purpose of the study described here was to evaluate whether the N-linked oligosaccharide chains of the human IgA isotypes IgA1 and IgA2 differ in lectin receptor activity. A range of plant lectins specific for N-linked oligosaccharide chains were tested for their ability to precipitate IgA1 and IgA2 myeloma proteins, secretory IgA and free secretory component. IgA2 myeloma proteins reacted more strongly than IgA1 with the mannose-specific lectin ConA, whereas IgA1 myeloma proteins reacted more strongly than IgA2 with two galactose-specific lectins, Ricinus communis agglutinin I and Abrus precatorius agglutinin. This suggests that IgA2 possesses a larger proportion of short truncated complex type oligosaccharide chains and/or oligomannose type chains than IgA1. Further. IgA2 reacted more strongly than IgA1 myeloma proteins with Lens culinaris (lentil) lectin, and Pisum sativum (pea) lectin, suggesting that IgA2 exposes more of short, complex type chains fucosylated on the core than IgA1. The differences demonstrated in receptor activity between IgA1 and IgA2 may be important in their interaction with the microbial flora, as well with endogenous lectins, such as phagocyte receptors.
    Type of Medium: Electronic Resource
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