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    German Medical Science GMS Publishing House; Düsseldorf
    In:  G-I-N Conference 2012; 20120822-20120825; Berlin; DOCP062 /20120710/
    Publication Date: 2012-07-11
    Keywords: ddc: 610
    Language: English
    Type: conferenceObject
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    Keywords: CELLS ; EXPRESSION ; carcinoma ; CELL ; Germany ; human ; GENE ; GENE-EXPRESSION ; GENES ; PROTEIN ; PROTEINS ; MOLECULES ; COMPLEX ; COMPLEXES ; KERATINOCYTES ; BOVINE PAPILLOMAVIRUS ; DOWN-REGULATION ; GROWTH-FACTOR RECEPTOR ; papillomavirus ; MOLECULE ; MHC ; TRANSPORT ; IDENTIFICATION ; LESIONS ; gene expression ; DESIGN ; DIFFERENCE ; PLASMA ; MEMBRANE ; STRESS ; SPECTROMETRY ; human papillomavirus ; TYPE-16 ; MASS-SPECTROMETRY ; SURFACE ; CLASS-I ; EPITHELIAL-CELL LINE ; GOLGI-APPARATUS ; HUMAN-PAPILLOMAVIRUS ; MHC class I ; MHC CLASS-I ; CARCINOMAS ; DIFFERENTIAL EXPRESSION ; MEMBRANE PROTEIN ; HaCaT ; MEMBRANE-PROTEIN ; GEL-ELECTROPHORESIS ; MASSES ; E5 PROTEIN ; CERVICAL NEOPLASIA
    Abstract: Membrane proteins differentially expressed in human papillomavirus type 16 (HPV-16) E5-transfected HaCaT cells have been identified. Membrane proteins were isolated and separated by two-dimensional gel electrophoresis. Spots showing quantitative differences between E5-transfected and control cells were extracted and the proteins were identified by nanoelectrospray ionization mass spectrometry. A total of 24 spots was analysed. Among the proteins showing differential expression, a decreased amount of calnexin and increased expression of hsp70, proteins both involved in maturation and transport of MHC class I complexes to the plasma membrane, were noticed. These findings correlate with the decreased surface expression of MHC class I molecules described in E5-expressing cells, HPV-positive cervical lesions and cervical carcinomas. These results stress the value of the proteomic approach, as used here in the experimental design, which allows the correlation of changes in host gene expression with biological functions of viral genes
    Type of Publication: Journal article published
    PubMed ID: 15166425
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    Keywords: RECEPTOR ; APOPTOSIS ; EXPRESSION ; GROWTH ; GROWTH-FACTOR ; Germany ; TYROSINE KINASE ; EXPOSURE ; PROTEIN ; ACTIVATION ; INFECTION ; INDUCTION ; KERATINOCYTES ; DYNAMICS ; MOLECULE ; PLASMA ; MEMBRANE ; STRESS ; human papillomavirus ; TYPE-16 ; EPITHELIAL-CELL LINE ; GOLGI-APPARATUS ; MHC CLASS-I ; PLASMA-MEMBRANE ; RECEPTORS ; HUMAN FORESKIN KERATINOCYTES ; keratinocyte ; phosphatidylcholine ; plasma membrane ; CERVICAL-CANCER WORLDWIDE ; CHOLESTEROL EFFLUX ; CTP-PHOSPHOCHOLINE CYTIDYLYLTRANSFERASE ; CYCLODEXTRIN ; SPHINGOMYELIN
    Abstract: The E5 protein of the human papillomavirus type 16 is a small protein found associated to membranes, mainly in the Golgi apparatus, and expressed in the early stages of viral infection. Its expression modifies the cell response towards growth factors and stress exposures, and also blocks the surface expression of MHC molecules. A global explanation for these multiple effects is hitherto not available. Here we present data showing that the expression of HPV16-E5 increases the amount of free cholesterol readily extractable from the plasma membrane, without altering the total cholesterol content. In addition, HPV16-E5 modifies the composition of the cell membranes, increasing the synthesis rate of phosphatidylcholine and phosphatidylserine, while diminishing that of phosphatidylglycerol. We propose that these changes in the lipid composition of the membrane are the central effect of HPV16-E5 on the cell. The multiple and apparently disconnected effects of HPV16-E5 on tyrosine-kinase receptors, induction of the apoptosis and impairment of MHC trafficking could follow the initial alteration on the membrane composition
    Type of Publication: Journal article published
    PubMed ID: 15503216
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  • 5
    Keywords: CANCER ; Germany ; CLASSIFICATION ; EPIDEMIOLOGY ; HISTORY ; GENE ; GENES ; GENOME ; EPITHELIA ; DNA ; INFECTION ; BIOLOGY ; E7 ; SEQUENCES ; virus ; LESIONS ; CERVICAL-CANCER ; REGION ; TYPE-16 ; EVOLUTION ; E6 ; BENIGN ; L1 ; INFECTIONS ; APPEARANCE ; FRAMEWORK ; LIFE-CYCLE ; E7 PROTEINS ; EPITHELIUM ; L2 ; MULTIPLE ALIGNMENTS ; OPEN READING FRAMES
    Abstract: Papillomaviruses (PVs) infect stratified squamous epithelia in vertebrates. Some PVs are associated with different types of cancer and with certain benign lesions. It has been assumed that PVs coevolved with their hosts. However, recently it has been shown that different regions of the genome have different evolutionary histories. The PV genome has a modular nature and appeared after the addition of pre-existent blocks. This order of appearance in the PV genome is evident today in the different evolutionary rates of the different genes, with new genes - E5, E6 and E7 - diverging faster than old genes - E1, E2, L2 and L1. Here, we propose an evolutionary framework aiming to integrate genome evolution, PV biology and epidemiology of PV infections
    Type of Publication: Journal article published
    PubMed ID: 16181783
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  • 6
    Keywords: CELLS ; EXPRESSION ; proliferation ; tumor ; carcinoma ; KINASE ; DISEASE ; PROTEIN ; DIFFERENTIATION ; TUMORS ; CONTRAST ; ACTIVATED PROTEIN-KINASE ; PHOSPHORYLATION ; BREAST ; IN-SITU ; LESIONS ; immunohistochemistry ; MALIGNANCIES ; PATTERNS ; EPITHELIAL-CELLS ; CARCINOMAS ; INTERCELLULAR COMMUNICATION ; MALIGNANCY ; MOLECULAR-BASIS ; BASAL LAMINA ; breast carcinoma ; connexin43 ; GAP JUNCTIONAL COMMUNICATION ; gap junctions
    Abstract: We applied an antiserum (SA226P) specifically recognizing the phosphorylated form of connexin43 (P-Cx43) to human breast samples including normal breast samples, with fibrocystic disease (FCD), fibroadenomas (FA), in situ and infiltrating carcinomas of all major types, and miscellaneous extramarnmary tumors. The findings were compared with those obtained with commercial antisera recognizing all Cx43 forms (pan-Cx43). A subset of samples was stained for Her2-neu and p44/42 to mitogen-activated protein kinase. Paraffin step sections were used. Immunoblots were performed on frozen samples of a representative subset of cases. In the normal breast, FCD, and FA, SA226P stained strongly and extensively most myoepithelial cells (MECs); luminal cells remained unstained. In proliferative FCD and some cellular FA, SA226P stained MEC and the capillary endothelium (CE). In ductal and lobular in situ carcinomas, SA226P reacted strongly and diffusely with the remaining MEC, the CE, and the transformed luminal cells. SA226P stained all infiltrating carcinomas except the tubular variant. In all breast carcinomas, the CE within and adjacent to tumors and some myofibroblasts stained with SA226P. By contrast, pan-Cx43 stained weakly and sporadically the MEC and rare samples of invasive carcinomas. Notably, Mab p44/42 reacted in parallel with the samples stained with SA226P, whereas reactions with Her2 were negative. Immunoblot findings paralleled those obtained immunohistochemically. We conclude that P-Cx43, restricted to MEC in the normal breast, is up-regulated in the same cells in hyperplasias and dysplasias and FA and is strongly up-regulated in invasive carcinomas. Notably, in some proliferative FCD and in most in situ and infiltrating carcinomas, P-Cx43 is strongly expressed in CE within and adjacent to the lesions but not away from them. These findings were paralleled by the strong nuclear reactions noted with Mab p44/42. These phenomena, although not exclusive to malignancy, are particularly conspicuous in breast carcinomas and seemingly reflect active proliferation associated with abnormal gap junctional intercellular communication. (c) 2005 Elsevier Inc. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 15948121
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  • 7
    Keywords: CANCER ; CELLS ; EXPRESSION ; carcinoma ; Germany ; SITE ; GENES ; PROTEIN ; PROTEINS ; TISSUE ; CARCINOGENESIS ; PHOSPHORYLATION ; antibodies ; MOUSE ; LESIONS ; PROGRESSION ; immunohistochemistry ; CERVIX ; CELL-LINE ; REGION ; REGIONS ; CARCINOMAS ; INTERCELLULAR COMMUNICATION ; STRATIFIED EPITHELIUM ; JUNCTION ; premalignant ; gap junction ; cell communication
    Abstract: Connexins are proteins that form the connexons, gap junction structures, which allow cells to communicate. Phosphorylation of connexins has been found to impair this communication. Using an antibody specifically recognizing the S279/S282-phosphorylated form of connexin43 (Cx43) for immunohistochemistry, we have analysed Cx43 phosphorylation in normal epithelium, CIN III lesions, and carcinomas of the cervix. We found that in normal epithelium the basal layer was devoid of staining and most of the protein was localized in stratum spinosum and stratum granulosum. In pre-malignant CIN-III lesions Cx43 was strongly phosphorylated, but the basal layer was still negative. In squamous carcinomas, the cells were intensely stained. In these tumours, sites of strong staining were adjacent to less stained regions, suggesting that the tumours are intrinsically heterogeneous. Immunoblotting of proteins extracted from carcinomas with the specific antibody showed the classical pattern of multiple reacting bands, with the appearance of low migrating forms of the protein. Our results suggest that increased S279/S282 phosphorylation of Cx43 is the result of altered tissue structure rather than of cell malignization. (c) 2005 Elsevier Ireland Ltd. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 15958277
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  • 8
    Keywords: human ; IN-VIVO ; MODEL ; MODELS ; DENSITY ; NEW-YORK ; DISTINCT ; GENOME ; microarray ; PROTEIN ; PROTEINS ; SACCHAROMYCES-CEREVISIAE ; RESOLUTION ; COMPLEX ; COMPLEXES ; DNA ; DOMAIN ; chromosome ; ALPHA ; CHROMATIN ; MICROARRAY DATA ; ASSAY ; microarrays ; genetics ; COMPONENT ; PCR ; REGION ; POLYMERASE-CHAIN-REACTION ; CHAIN-REACTION ; ORGANIZATION ; CHROMATIN STRUCTURE ; heredity ; DOMAINS ; LOCATION ; CHAIN ; VARIANT ; polymerase chain reaction ; LEVEL ; analysis ; ASSAYS ; USA ; genomic ; microbiology ; ALPHA-SATELLITE DNA ; FUNCTIONAL HUMAN CENTROMERE ; INNER KINETOCHORE PLATE ; NULL MICE ; RICE CENTROMERE
    Abstract: Background: Mammalian centromere formation is dependent on chromatin that contains centromere protein ( CENP)-A, which is the centromere-specific histone H3 variant. Human neocentromeres have acquired CENP-A chromatin epigenetically in ectopic chromosomal locations on low-copy complex DNA. Neocentromeres permit detailed investigation of centromeric chromatin organization that is not possible in the highly repetitive alpha satellite DNA present at endogenous centromeres. Results: We have examined the distribution of CENP-A, as well as two additional centromeric chromatin-associated proteins ( CENP-C and CENP-H), across neocentromeric DNA using chromatin immunoprecipitation ( ChIP) on CHIP assays on custom genomic microarrays at three different resolutions. Analysis of two neocentromeres using a contiguous bacterial artificial chromosome ( BAC) microarray spanning bands 13q31.3 to 13q33.1 shows that both CENP-C and CENP-H co-localize to the CENP-A chromatin domain. Using a higher resolution polymerase chain reaction ( PCR)-amplicon microarray spanning the neocentromere, we find that the CENP-A chromatin is discontinuous, consisting of a major domain of about 87.8 kilobases ( kb) and a minor domain of about 13.2 kb, separated by an approximately 158 kb region devoid of CENPs. Both CENP-A domains exhibit co-localization of CENP-C and CENP-H, defining a distinct inner kinetochore chromatin structure that is consistent with higher order chromatin looping models at centromeres. The PCR microarray data suggested varying density of CENP-A nucleosomes across the major domain, which was confirmed using a higher resolution oligo-based microarray. Conclusion: Centromeric chromatin consists of several CENP-A subdomains with highly discontinuous CENP-A chromatin at both the level of individual nucleosomes and at higher order chromatin levels, raising questions regarding the overall structure of centromeric chromatin
    Type of Publication: Journal article published
    PubMed ID: 17651496
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  • 9
    Keywords: RECEPTOR ; APOPTOSIS ; CELLS ; EXPRESSION ; CELL ; Germany ; human ; DEATH ; CLONING ; GENE-EXPRESSION ; PROTEIN ; SAMPLE ; SAMPLES ; DIFFERENTIATION ; LIGAND ; MECHANISM ; CONTRAST ; mechanisms ; IN-SITU ; NEOPLASIA ; CELL-DEATH ; DECREASE ; RECEPTORS ; SMALL-INTESTINE ; TRAIL ; protein expression ; LACKING ; molecular ; RECOMBINANT ; MOLECULAR-MECHANISM ; VARIANT ; INCREASE ; CELL-SURFACE EXPRESSION ; PH ; regulation ; development ; MOLECULAR-MECHANISMS ; methods ; cell death ; CELIAC-DISEASE ; death receptor ; USA ; LIGAND TRAIL ; HOMEOSTASIS ; INCREASES ; apoptotic ; MUCOSAL ; ACYL-COA-SYNTHETASE-5 ; HUMAN SMALL-INTESTINE ; IMPAIRED EXPRESSION
    Abstract: Background & Aims: The constant renewal of enterocytes along the crypt-villus axis (CVA) of human small intestine is due to cell-inherent changes resulting in the apoptotic cell death of senescent enterocytes. The aim of the present study was to examine underlying molecular mechanisms of the cell death at the villus tip. Methods: Characterization of human acyl-coenzyme A (CoA) synthetase 5 (ACSL5) was performed by cloning, recombinant protein expression, biochemical approaches, and several functional and in situ analyses. Results: Our data show that different amounts of acyl-CoA synthetase 5-full length (ACSL5-fl) and a so far unknown splice variant lacking exon 20 (ACSL5-Delta 20) are found in human enterocytes. In contrast with the splice variant ACSL5-Delta 20, recombinant and purified ACSL5-fl protein is active at a highly alkaline pH. Over expression of ACSL5-fl protein is associated with a decrease of the anti-apoptotic FLIP protein in a ceramide-dependent manner and an increased cell-surface expression of the death receptor TRAIL-RI. Expression analyses revealed that the ACSL5-fl/ACSL5-Delta 20 ratio increases along the CVA, thereby sensitizing ACSL5-fl-dominated cells at the villus tip to the death ligand TRAIL, which is corroborated by functional studies with human small intestinal mucosal samples and an immortalized human small intestinal cell fine. Conclusions: Our results suggest an ACSL5-dependent regulatory mechanism that contributes to the cellular renewal along the CVA in human small intestine. Deregulation of the ACSL5-fl/ACSL5-Delta 20 homeostasis in the maturation and shedding of cells along the CVA might also be of relevance for the development of intestinal neoplasia
    Type of Publication: Journal article published
    PubMed ID: 17681178
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  • 10
    Keywords: CELLS ; EXPRESSION ; GROWTH ; GROWTH-FACTOR ; Germany ; KINASE ; GENE ; GENES ; transcription ; DIFFERENTIATION ; MOLECULES ; ACTIVATION ; MECHANISM ; TRANSCRIPTION FACTOR ; cell cycle ; CELL-CYCLE ; CYCLE ; DOWN-REGULATION ; fibroblasts ; SUBUNIT ; c-Fos ; STRESS ; MODULATION ; INTEGRIN ; MATRIX METALLOPROTEINASES ; ERK ; HOMEOSTASIS ; matrix metalloproteinase ; FOCAL ADHESIONS ; CELL BIOLOGY ; FAK ; ORTHODONTIC TOOTH MOVEMENT ; OSTEOBLASTS
    Abstract: Background: Mechano-transduction in periodontal ligament (PDL) cells is crucial for physiological and orthodontic tooth movement-associated periodontal remodelling. On the mechanistic level, molecules involved in this mechano-transduction process in PDL cells are not yet completely elucidated. Results: In the present study we show by western blot (WB) analysis and/or indirect immunofluorescence (IIF) that mechanical strain modulates the amount of the matrix metalloproteinase MMP-13, and induces non-coherent modulation in the amount and activity of signal transducing molecules, such as FAK, MAP-kinases p42/44, and p38 stress kinase, suggesting their mechanistic role in mechano-transduction. Increase in the amount of FAK occurs concomitant with increased levels of the focal contact integrin subunits beta 3 and beta 1, as indicated by WB or optionally by IIF. By employing specific inhibitors, we further identified p42/44 and p38 in their activated, i.e. phosphorylated state responsible for the expression of MMP-13. This finding may point to the obedience in the expression of this MMP as extracellular matrix (ECM) remodelling executioner from the activation state of mechano-transducing molecules. mRNA analysis by pathway-specific RT-profiler arrays revealed up- and/or down-regulation of genes assigning to MAP-kinase signalling and cell cycle, ECM and integrins and growth factors. Up-regulated genes include for example focal contact integrin subunit alpha 3, MMP-12, MAP-kinases and associated kinases, and the transcription factor c-fos, the latter as constituent of the AP1-complex addressing the MMP-13 promotor. Among others, genes down-regulated are those of COL-1 and COL-14, suggesting that strain-dependent mechano-transduction may transiently perturbate ECM homeostasis. Conclusions: Strain-dependent mechano-/signal-transduction in PDL cells involves abundance and activity of FAK, MAP-kinases p42/44, and p38 stress kinase in conjunction with the amount of MMP-13, and integrin subunits beta 1 and beta 3. Identifying the activated state of p42/44 and p38 as critical for MMP-13 expression may indicate the mechanistic contribution of mechano-transducing molecules on executioners of ECM homeostasis
    Type of Publication: Journal article published
    PubMed ID: 20109185
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