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  • DKFZ Publication Database  (14)
  • Journal article published  (14)
  • KERATINOCYTES  (14)
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  • DKFZ Publication Database  (14)
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  • 1
    Keywords: EXPRESSION ; IN-VITRO ; DISTINCT ; DIFFERENTIATION ; MESSENGER-RNA ; murine ; KERATINOCYTES ; EPIDERMAL DIFFERENTIATION ; ARACHIDONIC-ACID ; calcium gradient ; ENHANCING FACTOR ; epidermal barrier ; GROUP-II ; GROUP-V ; GROUP-X ; hyperproliferation ; INVITRO CULTIVATION ; LOW-MOLECULAR-WEIGHT ; neonatal mouse ; NEONATAL MOUSE KERATINOCYTES ; PERMEABILITY BARRIER HOMEOSTASIS ; epidermis
    Abstract: The action of secreted phospholipases A(2) in skin is thought to be essential for epidermal barrier homeostasis. The incomplete knowledge of presence and functions of the novel secreted phospholipase A(2) subtypes in skin prompted us to explore their expression in epidermis and primary keratinocytes from murine neonatal skin. We detected secreted phospholipases A(2) -IB, -IIA, -IIC, -IID, -IIE, -IIF, -V, -X, and -XII. To study secreted phospholipase A(2) expression during epidermal differentiation, primary keratinocytes from the basal, suprabasal, and upper differentiated layers of neonatal mouse epidermis were obtained by density gradient centrifugation. mRNA for secreted phospholipases A(2) -IB, -IIE, -IIF, -V, and -XII-1 are mainly expressed in the upper differentiated layers, whereas the most prominent enzymes in the basal and suprabasal layers are secreted phospholipases A(2) -IIA, -IID, and -X. The mRNA for secreted phospholipase A(2) -IIC was found in all fractions. Immunohistochemical analysis in mouse skin sections reflected the mRNA distribution patterns in the different epidermal cell fractions. After in vitro induction of keratinocyte differentiation by increasing the calcium concentration of the medium, secreted phospholipases A(2) -IB, -IIE, -IIF, -V, and -XII-1 were upregulated, whereas secreted phospholipases A(2) -IIA, -IIC, -IID, and -X were mainly expressed in proliferating keratinocytes. The specific secreted phospholipase A(2) expression profile in the skin suggests a distinct function for each enzyme in the epidermis
    Type of Publication: Journal article published
    PubMed ID: 12839576
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  • 2
    Keywords: CELLS ; EXPRESSION ; IN-VITRO ; INHIBITOR ; proliferation ; CELL ; CELL-PROLIFERATION ; Germany ; human ; GENERATION ; SYSTEM ; DISTINCT ; PROTEIN ; PROTEINS ; cell line ; LINES ; ACTIVATION ; RESPONSES ; REDUCTION ; KERATINOCYTES ; SKIN ; CELL-LINES ; ISOFORM ; SUBUNIT ; Western-blot ; MEMBRANE ; CELL-LINE ; LINE ; CYTOCHROME-C ; EPITHELIAL-CELLS ; PROTEIN LEVELS ; western blot ; HaCaT ; MUCOSA ; HOST-DEFENSE ; DEFENSE ; human skin and oral epithelial cells,oxidoreductase,p67phox,spin trapping,superoxide radical ; NAD(P)H OXIDASE ; OXYGEN RADICALS ; P47(PHOX) ; SUPEROXIDE-PRODUCTION
    Abstract: In non-phagocytic cells, superoxide has been implicated in physiological and pathological cellular functions in the skin and mucosa, such as, host defense, mitogenic responses, and malignant conversion. Here, we identify a constitutively expressed heme-flavoprotein NADPH oxidase (Nox) system as a source of superoxide in human skin (HaCaT) and gingival mucosal (GM16) keratinocyte cell lines. Western blot analysis showed that both cell lines expressed the phagocyte oxidase (phox) cytosolic proteins Rac1, p40phox, and p67phox. With respect to the catalytic flavoheme protein subunit, HaCaT membranes, which expressed p22phox, showed an absorbance peak at 558 nm indicative of a b-type cytochrome. At mRNA levels, both GM16 and HaCaT cells expressed gp91phox homologs Nox1, Nox2, and Nox4, however, HaCaT cells expressed very low levels of Nox1 mRNA. At protein levels, Nox1 was readily detected in HaCaT but was nearly undetectable in GM16 cells. Consistently, Nox activity of HaCaT membranes was demonstrated by electron paramagnetic resonance spin-trapping and cytochrome c reduction, and the activity was sensitive to the flavoprotein inhibitor diphenylene iodonium. V-max values were 20-fold lower than those reported for phagocytic oxidase. In conclusion, keratinocytes expressed a Nox distinct from the phox isoform of phagocytes providing molecular evidence for a source of superoxide that may regulate cell proliferation and host defense in skin and oral mucosa
    Type of Publication: Journal article published
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  • 3
    Keywords: CELLS ; ACTIVATION ; KERATINOCYTES ; SKIN ; CYCLE ; MIGRATION ; E6 ; E-cadherin ; EPIDERMODYSPLASIA-VERRUCIFORMIS ; LIFE ; DNA LOADS
    Abstract: Human papillomaviruses (HPVs), which are contained in the alpha, beta, gamma, mu, and nu genera, differ in their oncogenic potential and their tropism for cutaneous or mucosal epidermis. Langerhans cells (LC), the only epidermal professional antigen-presenting cells, are readily detected in normal mucosal and cutaneous epithelium. The aim of this study is to determine whether LC loss, which has been reported for HPV16, occurs in other HPV genera and establish its significance in viral pathology. We found that, as for HPV16, LCs were reduced in lesions infected with high-risk mucosal (alpha 7 and alpha 9 species) and low-risk cutaneous (gamma and mu) types. Lesions infected with alpha 10 low-risk genital types had reduced LC but contained epidermal LC patches, coincident with dermis-localized regulatory T cells (T-regs). In contrast to other genera, LCs were common in the epidermis, and T-regs occupied the dermis of the potentially high-risk cutaneous beta-HPV type infected lesions. Therefore, LC loss in the infected lesions occurred irrespective of tropism or oncogenic potential of the HPV type. LC depletion in the HPV-infected epidermis may create an environment that is permissive for viral persistence and in HPV lesions in which LCs are found, the presence of typically immunosuppressive T-regs may compensate for their continued presence
    Type of Publication: Journal article published
    PubMed ID: 19759549
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  • 4
    Keywords: EXPRESSION ; AGENTS ; human ; GENE ; PROTEIN ; DIFFERENTIATION ; TISSUE ; MICE ; MECHANISM ; INDUCTION ; TISSUES ; KERATINOCYTES ; mechanisms ; SKIN ; SEQUENCE ; SEQUENCES ; STAGE ; TRANSGENIC MICE ; IDENTIFICATION ; PROMOTER ; transgenic ; REGION ; FRANCE ; hyperproliferation ; epidermis ; TERMINAL DIFFERENTIATION ; LAYER ; MAMMALIAN-TISSUES ; HASSALLS CORPUSCLES ; FOLLICLE ; HAIR-FOLLICLES ; HUMAN TISSUES ; INNER-ROOT-SHEATH ; AGENT ; PATTERN ; HAIR FOLLICLE ; corneodesmosin ; CORNIFIED EPITHELIA ; GENE PROMOTER ; hyperkeratosis ; KERATINOCYTE DIFFERENTIATION ; promoter regions ; PSORIASIS SUSCEPTIBILITY ; REPORTER GENE ; S GENE ; STRATUM-CORNEUM
    Abstract: Corneodesmosin (CDSN) is a desmosomal protein expressed in the epidermis during the late stages of differentiation and in the inner root sheath of hair follicles. The homophilic adhesive properties of the protein suggest that it reinforces keratinocyte cohesion in the upper layers of the epidermis (stratum granulosum and stratum corneum). In this study, we analyzed the expression of the CDSN gene in 16 human tissues. We confirmed the closely restricted expression pattern of CSDN. Indeed, apart from the skin, the mRNA was significantly detected only in the placenta and the thymus. As a step in elucidating the mechanisms of tissue-specific expression, transgenic mice bearing a 4.2 kb fragment of the human CSDN gene promoter linked to the LacZ gene were generated. The reporter-gene expression was detected in special areas of the inner root sheath of the hair follicles and the hair medulla but not in the epidermis. Induction of epidermis hyperproliferation however either by pharmacological agents or by wounding led to strong expression of the reporter gene in the keratinocytes of the stratum granulosum and the parakeratotic corneocytes of the stratum corneum. The data suggest that the genomic sequences and/or regulating factors responsible for the cell-specific expression of the human CDSN gene in the normal hair follicle as well as in the hyperproliferative epidermis are different from those necessary for expression in the normal epidermis
    Type of Publication: Journal article published
    PubMed ID: 15086560
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  • 5
    Keywords: APOPTOSIS ; CELLS ; EXPRESSION ; GROWTH ; proliferation ; TUMOR-CELLS ; DIFFERENTIATION ; KERATINOCYTES ; fibroblasts ; CATALYTIC SUBUNIT GENE ; CELL- PROLIFERATION ; differentiation markers ; DIRECT ACTIVATION ; EPIDERMAL DIFFERENTIATION ; IMMORTAL CELLS ; organotypic cocultures ; STEM-CELLS ; telomerase
    Abstract: Formation of a well structured epidermis strictly depends on a tight balance between proliferation and differentiation. Accordingly, telomerase, which is restricted to proliferating cells, is downregulated with differentiation. It is unclear, however, whether this inhibition is essential to or only a consequence of the differentiation process. By studying different variants of the HaCaT skin keratinocytes we now show that constitutive overexpression of human telomerase reverse transcriptase (hTERT) in HaCaT-TERT cells (lacking its own differentiation-sensitive promoter) and constitutive expression of the c-myc gene in HaCaT-myc cells caused increased proliferation in conventional cultures; however, this proliferative advantage was not maintained in tissue-like organotypic cocultures. Despite reduced stratification, HaCaT- myc cells were still able to develop a fully differentiated epithelium. HaCaT-TERT cultures, on the other hand, expressed all markers of early but not of terminal differentiation. The failure to differentiate terminally was observed in hTERT mass cultures and individual clones and correlated with an intense nuclear hTERT staining of the uppermost cells of the HaCaT-TERT epithelia. Thus, our data suggest that constitutive overexpression of hTERT does not interfere with epidermal differentiation per se but blocks the terminal stage of differentiation and therefore indicates that hTERT/telomerase plays an active part in the regulatory pathway of epidermal differentiation
    Type of Publication: Journal article published
    PubMed ID: 12839571
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  • 6
    Keywords: APOPTOSIS ; CELLS ; EXPRESSION ; tumor ; INHIBITION ; transcription ; NF-KAPPA-B ; TUMOR-NECROSIS-FACTOR ; ACTIVATION ; LIGAND ; KERATINOCYTES ; PHOSPHORYLATION ; DEGRADATION ; NF-kappa B ; IL-8 ; DEATH RECEPTORS ; I kappa B ; IL-1Ra
    Abstract: Tumor necrosis factor related apoptosis-inducing ligand (TRAIL) exerts a potent cytotoxic activity especially against many tumor cell types such as transformed keratinocytes. The specific role of the different TRAIL receptors in this process, however, is unknown. In this report we examine the role the TRAIL receptors play in both the apoptotic and nonapoptotic responses of HaCaT keratinocytes to leucine zipper TRAIL (LZ- TRAIL). By employing receptor-specific blocking antibodies we demonstrate that TRAIL receptor 1 plays the primary role in mediating caspase activation and apoptosis in HaCaT cells. Furthermore, we show that this receptor mainly mediates nuclear factor kappaB activation and expression of the pro-inflammatory cytokine interleukin-8 and that nuclear factor kappaB activation is critically required for the induction of pro- inflammatory cytokines in response to LZ-TRAIL. Taken together, our data suggest that beside its potent pro-apoptotic role, LZ- TRAIL leads to pro-inflammatory responses that are mainly mediated by TRAIL receptor 1 in HaCaT keratinocytes
    Type of Publication: Journal article published
    PubMed ID: 12839575
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  • 7
    Keywords: CANCER ; CELLS ; EXPRESSION ; INVASION ; tumor ; TUMOR-CELLS ; CELL ; human ; DISEASE ; cell line ; TISSUE ; INFECTION ; DOMAIN ; INDUCTION ; TISSUES ; KERATINOCYTES ; ASSOCIATION ; culture ; STAGE ; ACQUISITION ; PROGRESSION ; DISRUPTION ; MEMBRANE ; SIGNAL-TRANSDUCTION ; LINE ; ADHESION ; CELL-ADHESION ; TRANSFORMATION ; NEOPLASTIC PROGRESSION ; DEGRADATION ; INTEGRIN ; CARCINOMAS ; beta-catenin ; ORGANIZATION ; ADENOVIRUS ; ARCHITECTURE ; organotypic culture ; adherens junctions,basement membrane,E-cadherin,organotypic culture,tumor cell invasion ; CATENIN ; HUMAN BREAST ; MELANOMA DEVELOPMENT
    Abstract: The role of cell-cell adhesion in the transition from premalignancy to invasive cancer is not well understood. The purpose of this study was to determine how abrogation of E-cadherin-mediated adhesion influenced early neoplastic progression in tissues that mimic human, premalignant disease. To accomplish this, E-cadherin function was abrogated in a human cell line representing an early stage in the transformation process (HaCaT-II-4 cells) that was grown in three-dimensional, organotypic cultures with intact basement membrane. Before modification, this cell line showed a paucity of cell adhesion structures by ultrastructural and immunohistochemical analysis, whereas immunoblot studies demonstrated that expression and association of E-cadherin and catenins were not diminished when compared with normal keratinocytes. To further reduce functional E-cadherin, II-4 cells were infected with a dominant-negative, recombinant adenovirus, expressing E-cadherin lacking an extracellular domain (AdECadEC). AdECadEC infection resulted in loss of endogenous E-cadherin and completely disrupted II-4 cell adhesion, as seen by loss of beta-catenin from II-4 cell junctions in monolayer culture. In three-dimensional cultures, AdECadEC-infected cells demonstrated disruption of tissue architecture, loss of cell-cell adhesion, and the invasion of individual tumor cells into the stroma. The induction of this invasive phenotype was associated with loss of basement membrane integrity, as seen by degradation of type IV collagen and laminin 5. These studies showed that loss of E-cadherin-mediated adhesion enabled acquisition of an invasive phenotype, suggesting that maintenance of intercellular adhesion and tissue organization plays a crucial part in suppressing the incipient stages of squamous cell cancer progression
    Type of Publication: Journal article published
    PubMed ID: 14708624
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  • 8
    Keywords: APOPTOSIS ; CANCER ; CELLS ; GROWTH ; IRRADIATION ; proliferation ; tumor ; TUMOR-CELLS ; MODEL ; CARCINOGENESIS ; KERATINOCYTES ; MOUSE ; EQUIVALENT ; PROGRESSION ; MUTATION ; MUTATIONS ; NEOPLASTIC PROGRESSION ; intraepithelial neoplasia ; organotypic culture ; HA-RAS ; HACAT-RAS ; HUMAN SKIN ; MALIGNANT KERATINOCYTES ; RECONSTRUCTED IN-VITRO ; SUNLIGHT ; UVB irradiation
    Abstract: Ultraviolet B irradiation is thought to enable skin cancer progression as clones of genetically damaged keratinocytes escape apoptosis and expand at the expense of adjacent normal cells. Mechanisms through which potentially malignant cells in human skin undergo clonal expansion, however, are not well understood. The goal of this study was to characterize the role of ultraviolet B irradiation on the intraepithelial expansion of early stage human tumor cells in organotypic skin cultures. To accomplish this, we have studied the effect of ultraviolet B irradiation on organotypic cultures that were fabricated by mixing normal human keratinocytes with beta-galactosidase- marked, intraepithelial tumor cells (HaCaT-ras , clone II-4), which bear mutations in both p53 alleles and harbor an activated H-ras oncogene. We found that when organotypic mixtures were exposed to an ultraviolet B dose of 50 mJ per cm(2) , intraepithelial tumor cells underwent a significant degree of proliferative expansion compared to nonirradiated cultures. To understand this response, organotypic cultures of nor-mal keratinocytes were exposed to ultraviolet B and showed a dose-dependent increase in numbers of sunburn cells and TUNEL-positive cells although their proliferation was suppressed. In contrast, neither the apoptotic nor the proliferative response of II-4 cells was altered by ultraviolet B in organotypic cultures. The differential response of these cell types suggested that II-4 cells were resistant to ultraviolet-B-induced alterations, which allowed these intraepithelial tumor cells to gain a selective growth and survival advantage relative to neighboring normal cells. These findings demonstrate that ultraviolet B exposure can induce the intraepithelial expansion of apoptosis-resistant, p53-mutant, and ras -activated keratinocytes, suggesting that this agent can act to promote the early stages of epithelial carcinogenesis
    Type of Publication: Journal article published
    PubMed ID: 12839581
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  • 9
    Keywords: CELLS ; EXPRESSION ; GROWTH ; IN-VITRO ; proliferation ; Germany ; VITRO ; SYSTEM ; transcription ; DIFFERENTIATION ; TISSUE ; MICE ; ACTIVATION ; COMPLEX ; COMPLEXES ; FAMILY ; TRANSCRIPTION FACTOR ; KERATINOCYTES ; SKIN ; C-JUN ; fibroblasts ; treatment ; SIGNAL ; TRANSGENIC MICE ; STRESS ; REPAIR ; EPITHELIAL-CELLS ; KINETICS ; REGULATOR ; COLONY-STIMULATING FACTOR ; INTERCELLULAR COMMUNICATION ; TISSUE-SPECIFIC EXPRESSION ; inflammation ; CYTOKINE ; FAMILIES ; MICE LACKING ; KERATINOCYTE DIFFERENTIATION ; IMMUNE-SYSTEM ; LEVEL ; REGULATED GENE ; macrophage ; inflammatory cells ; COLLAGEN GEL ; GROWTH-STIMULATORY ACTIVITY ; TRANSCRIPTION FACTOR AP-1
    Abstract: The cutaneous response to injury and stress comprises a temporary change in the balance between epidermal proliferation and differentiation as well as an activation of the immune system. Soluble factors play an important role in the regulation of these complex processes by coordinating the intercellular communication between keratinocytes, fibroblasts, and inflammatory cells. In this study, we demonstrate that JunB, a member of the activator protein-1 transcription factor family, is an important regulator of cytokine expression and thus critically involved in the cutaneous response to injury and stress. Mice lacking JunB in the skin develop normally, indicating that JunB is neither required for cutaneous organogenesis, nor homeostasis. However, upon wounding and treatment with the phorbol ester 12-O-decanoyl-phorbol-13-acetate, JunB-deficiency in the skin likewise resulted in pronounced epidermal hyperproliferation, disturbed differentiation, and prolonged inflammation. Furthermore, delayed tissue remodelling was observed during wound healing. These phenotypic skin abnormalities were associated with JunB-dependent alterations in expression levels and kinetics of important mediators of wound repair, such as granulocyte macrophage colony-stimulating factor, growth-regulated protein-1, macrophage inflammatory protein-2, and lipocalin-2 in both the dermal and epidermal compartment of the skin, and a reduced ability of wound contraction of mutant dermal fibroblasts in vitro
    Type of Publication: Journal article published
    PubMed ID: 16439969
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  • 10
    Keywords: CANCER ; CELLS ; EXPRESSION ; INVASION ; tumor ; TUMOR-CELLS ; carcinoma ; CELL ; human ; MODEL ; DISEASE ; NEW-YORK ; TISSUE ; ACTIVATION ; INDUCTION ; TISSUES ; KERATINOCYTES ; SKIN ; SUPPRESSION ; culture ; STAGE ; PROGRESSION ; MEMBRANE ; RAS ONCOGENE ; skin cancer ; CELL-LINE ; EXTRACELLULAR-MATRIX ; CARCINOMA-CELLS ; BETA ; ADHESION ; CELL-ADHESION ; MIGRATION ; squamous cell carcinoma ; BEHAVIOR ; ORGANIZATION ; CELL-MIGRATION ; SKIN-CANCER ; E-cadherin ; CELL CARCINOMA ; FEATURES ; BETA-ACTIN ; cell adhesion ; cell migration ; 3D ; USA ; LOSSES ; MOTILITY ; SQUAMOUS-CELL ; ACTIN ; CELL MOTILITY
    Abstract: The link between loss of cell-cell adhesion, the activation of cell migration, and the behavior of intraepithelial (IE) tumor cells during the early stages of skin cancer progression is not well understood. The current study characterized the migratory behavior of a squamous cell carcinoma cell line (HaCaT-II-4) upon E-cadherin suppression in both 2D, monolayer cultures and within human skin equivalents that mimic premalignant disease. The migratory behavior of tumor cells was first analyzed in 3D tissue context by developing a model that mimics transepithelial tumor cell migration. We show that loss of cell adhesion enabled migration of single, IE tumor cells between normal keratinocytes as a prerequisite for stromal invasion. To further understand this migratory behavior, E-cadherin-deficient cells were analyzed in 2D, monolayer cultures and displayed altered cytoarchitecture and enhanced membrane protrusive activity that was associated with circumferential actin organization and induction of the nonmuscle, beta actin isoform. These features were associated with increased motility and random, individual cell migration in response to scrape-wounding. Thus, loss of E-cadherin-mediated adhesion led to the acquisition of phenotypic properties that augmented cell motility and directed the transition from the precancer to cancer in skin-like tissues
    Type of Publication: Journal article published
    PubMed ID: 18528437
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