Nicole Schwinn

University Hospital Essen, Essen, North Rhine-Westphalia, Germany

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Publications (5)22.27 Total impact

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    ABSTRACT: NKG2D operates as an activating receptor on natural killer (NK) cells and costimulates the effector function of β CD8+ T cells. Ligands of NKG2D, the MHC class I chain-related (MIC) and UL16 binding protein (ULBP) molecules, are expressed on a variety of human tumors, including melanoma. Recent studies in mice demonstrated that NKG2D mediates tumor immune surveillance, suggesting that antitumor immunity in humans could be enhanced by therapeutic manipulation of NKG2D ligand (NKG2DL) expression. However, signals and mechanisms regulating NKG2DL expression still need to be elucidated. Here, we asked whether the proinflammatory cytokine Interferon- (IFN-) affects NKG2DL expression in melanoma. Cell lines, established from MHC class I-negative and -positive melanoma metastases, predominantly expressed MICA and ULBP2 molecules on their surface. Upon IFN- treatment, expression of MICA, in some cases, also of ULBP2 decreased. Besides melanoma, this observation was made also for glioma cells. Down-regulation of NKG2DL surface expression was dependent on the cytokine dose and the duration of treatment, but was neither due to an intracellular retention of the molecules nor to an increased shedding of ligands from the tumor cell surface. Instead, quantitative RT-PCR revealed a decrease of MICA-specific mRNA levels upon IFN- treatment and siRNA experiments pointed to an involvement of STAT-1 in this process. Importantly, IFN--treated MHC class I-negative melanoma cells were less susceptible to NKG2D-mediated NK cell cytotoxicity. Our study suggests that IFN-, by down-regulating ligand expression, might facilitate escape of MHC class I-negative melanoma cells from NKG2D-mediated killing by NK cells. © 2008 Wiley-Liss, Inc.
    International Journal of Cancer 10/2008; 124(7):1594 - 1604. · 6.20 Impact Factor
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    ABSTRACT: The clonotypic T-cell receptor (TCR) is a potential target antigen for specific immunotherapy of cutaneous T-cell lymphoma (CTCL). We identified T-cell epitopes from the rearranged TCR beta chain of the malignant T-cell population by the "reverse immunology" approach. Peptide-specific T-cell lines were generated against predicted epitopes and tested for the recognition of tumor cells and cells transfected with the full-length DNA coding for TCRV beta chain. Two peptides derived from the clonotypic TCRVbeta of a HLA-A2 positive patient could induce peptide-specific T cells from peripheral blood mononuclear cells of healthy donors and the patient as assessed by IFN-gamma ELISpot assay. Furthermore, the reactive CTLs efficiently recognized autologous Sézary tumor cells, as well as HLA-A2 positive 293 cells transfected with recombinant plasmid expressing the corresponding TCRVbeta29 protein. Similar results were obtained in a HLA-A3+ patient for TCRVbeta7-Jbeta2.7. In conclusion, our experiments show that the TCR beta chain harbors epitopes suitable as targets for specific vaccination which might be a promising approach for the specific immunotherapy of cutaneous T-cell lymphoma patients.
    International Journal of Cancer 12/2006; 119(10):2476-80. · 6.20 Impact Factor
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    ABSTRACT: Total loss of surface presentation of human leukocyte antigen (HLA) class I molecules, protecting tumor cells from the recognition by cytotoxic host CD8+ T cells, is known to be caused by mutations in the beta2-microglobulin (beta2m) gene. We asked whether abnormalities of chromosome 15, harboring the beta2m gene on 15q21, in addition to beta2m gene mutations, are causative for the HLA class I-negative phenotype of melanoma cells. To answer this, we established primary cell lines from the beta2m-negative metastatic melanoma tissues of four different patients and analyzed them for beta2m gene mutations and chromosome 15 aberrations, the latter by loss of heterozygosity analysis, fluorescence in situ hybridization (FISH), and multicolor FISH. Mutations at the beta2m gene level were detected in all cell lines. The loss of heterozygosity analysis of microsatellite markers located on chromosome 15 in three of the four cell lines pointed to an extensive loss of chromosome 15 material. Subsequent molecular cytogenetic analysis revealed the coexistence of apparently normal and rearranged versions of chromosome 15 in three cell lines whereas the fourth cell line solely showed rearranged versions. Two of the four cell lines exhibited a special type of intrachromosomal rearrangement characterized by FISH signals specific for the subtelomeric region of 15q at both ends of the chromosome and one centromeric signal in between. Our data indicate that the complete loss of HLA class I expression in melanoma cells is due to the coincidence of the following mutational events: (a) chromosome 15 instability associated with an extensive loss of genetic material and (b) beta2m gene mutations.
    Clinical Cancer Research 07/2006; 12(11 Pt 1):3297-305. · 7.84 Impact Factor
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    ABSTRACT: Carboxypeptidase, vitellogenic-like (CPVL) is a serine carboxypeptidase of unknown function that was first characterized in human macrophages. Initial studies suggested that CPVL is largely restricted to the monocytic lineage, although it may also be expressed by cells outside the immune system. Here, we use a new monoclonal antibody to characterize the properties and localization of CPVL in human macrophages to elucidate a possible function for the protease. CPVL is up-regulated during the maturation of monocytes (MO) to macrophages, although the protein can be seen in both. In primary macrophages, CPVL is glycosylated with high mannose residues and colocalizes with markers for endoplasmic reticulum, while in MO it is more disperse and less clearly associated with endoplasmic reticulum. CPVL is highly expressed in lamellipodia and membrane ruffles, which also concentrate markers of the secretory pathway (MIP-1alpha and tumour necrosis factor-alpha) and major histocompatibility complex (MHC) class I and II molecules. CPVL can be seen on early latex bead and Candida albicans phagosomes, but it is not retained in the maturing phagosome, unlike MHC class I/II. CPVL has a mixed cytosolic and membrane-associated localization but is not detectable on the outer plasma membrane. We propose that CPVL may be involved in antigen processing, the secretory pathway and/or in actin remodelling and lamellipodium formation.
    International Journal of Experimental Pathology 03/2006; 87(1):29-39. · 2.04 Impact Factor
  • Nicole Schwinn
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    ABSTRACT: Das maligne Melanom stellt eine der aggressivsten Tumorarten dar und ist durch eine stetig ansteigende Inzidenz weltweit charakterisiert. Die Tumormetastasen zeichnen sich häufig durch eine reduzierte und in selteneren Fällen durch den vollständigen Verlust der HLA Klasse I Expression aus, wodurch sich das Melanom der adaptiven Immunantwort durch T-Lymphozyten entziehen kann. Der HLA Klasse I Komplex inhibiert über die Interaktion mit spezifischen Rezeptoren die zytotoxische Aktivität Natürlicher Killerzellen (NK-Zellen). Folglich ist der Verlust der HLA Klasse I Expression (‘missing self’) mit einer Aktivierung von NK-Zellen verbunden, sofern diese stimulierende Signale über weitere Rezeptoren erhalten. Die Aktivierung der NK-Zellen beruht demnach auf der Balance aktivierender und inhibierender Signale. Einer der bedeutendsten aktivierenden Rezeptoren auf NK-Zellen ist NKG2D, der nach Interaktion mit seinen Liganden eine effiziente Stimulierung von NK-Zellen induzieren kann. Die NKG2D Liganden MICA, MICB, ULBP1, ULBP2 und ULBP3 werden häufig auf transformierten Zellen als Stressmarker exprimiert, ihre Regulation ist allerdings nur unzureichend analysiert. In dieser Arbeit wurde die NKG2D-vermittelte Erkennung HLA-Klasse I-defizienter Melanomzellen durch NK-Zellen untersucht, wobei der Fokus auf der Expression und Regulation der NKG2D Liganden in den Tumorzellen lag. Zunächst wurde ein detailliertes RNA und Proteinexpressionsprofil der NKG2D Liganden erstellt. Dabei waren MICA und ULBP2 Transkripte in allen, MICB und ULBP3 Transkripte in den meisten analysierten Linien detektierbar. Auf der Oberfläche exprimierten die Melanomlinien fast ausschließlich die Liganden MICA und ULBP2. Folglich wird die Expression der NKG2D Liganden nicht ausschließlich transkriptionell reguliert. Um den Einfluss von Zytokinen auf die Regulation der NKG2D Liganden zu bestimmen, wurden die Melanomzellen mit den wichtigen immunmodulatorischen Zytokinen Interferon-alpha, Tumor Nekrose Faktor-alpha und Interferon-gamma (IFN-g) behandelt. Nach viertägiger Inkubation beeinflusste lediglich IFN-g die Expression der NKG2D Liganden in den analysierten Melanomzellen deutlich. Die Oberflächenexpression von MICA und teilweise auch von ULBP2 wurde signifikant reduziert. Dies resultierte in einer eingeschränkten NKG2D-vermittelten Lyse der Melanomzellen durch die Natürliche Killerzelllinie NKL. Die IFN-g-vermittelte Reduktion der MICA/ULBP2 Oberflächenexpression korrelierte nicht mit einer entsprechenden Verringerung der spezifischen RNA Menge. Zudem schien die IFN-g-abhängige Regulation der MICA Oberflächenexpression nicht ausschließlich von STAT1, dem klassischen Vermittler IFN-g-induzierter Signale, abhängig zu sein. Es wird daher ein komplexer Kontrollmechanismus vermutet, der die Expression der NKG2D Liganden post-transkriptionell beeinflusst. Da auf Glioblastomzellen, im Gegensatz zu verschiedenen Karzinomzelllinien, ebenfalls eine IFN-g-induzierte verringerte Oberflächenexpression der Liganden detektierbar war, könnte der IFN-g Effekt zumindest für Zellen neuroektodermalen Ursprungs konserviert sein. Basierend auf den Daten dieser Arbeit ist anzunehmen, dass sich HLA Klasse I-negative Melanomzellen nicht nur einer T-Zellantwort, sondern möglicherweise auch einer NK-Zellantwort durch Reduktion der Oberflächenexpression der NKG2D Liganden in einer IFN-g reichen Tumorumgebung entziehen können. Die Ergebnisse dieser Arbeit tragen zu einem besseren Verständnis der Interaktion von Melanom- und NK-Zellen bei und sollten bei der Optimierung bestehender und der Entwicklung neuer Therapien für Melanompatienten berücksichtigt werden. Malignant melanoma is one of the most aggressive tumors with a continuously growing incidence. In the metastatic disease stage tumor cells are characterized by a frequent downregulation and in some cases by an irreversible total loss of HLA class I expression. Consequently these melanoma cells can escape a T lymphocyte-mediated adaptive immune response. HLA class I molecules inhibit the activation of Natural Killer cells (NK cells) by interacting with specific receptors. Therefore loss of HLA class I expression (‘missing self’) is associated with an activation of NK cells if stimulating signals are provided by the tumor cells to NK receptors. Thus activation of NK cells is based on the balance of inhibitory and activating signals. NKG2D is one of the most crucial activating receptors expressed on NK cells. After interaction with its ligands MICA, MICB, ULBP1, ULBP2 and ULBP3 this receptor can induce an effective stimulation of NK cells. The NKG2D ligands are stress induced antigens on transformed cells, however their regulation has been analyzed only insufficiently. This work explores the NKG2D-mediated recognition of HLA class I-deficient melanoma cells by NK cells focusing on the expression and regulation of NKG2D ligands in tumor cells. Initially a detailed profile of RNA and protein expression was compiled. MICA and ULBP2 transcripts were detected in all, MICB and ULBP3 transcripts were expressed by most melanoma cell lines analyzed. On the surface only MICA and ULBP2 were detected unequivocally, thus surface expression did not mirror RNA content. Consequently NKG2D ligand expression is not only regulated transcriptionally. To determine the influence of cytokines on the regulation of NKG2D ligands, melanoma cells were treated with the important immunomodulating cytokines Intereron-alpha, Tumor Necrosis factor-alpha and Interferon-gamma (IFN-g), respectively. After cytokine treatment of melanoma cells for four days IFN-g was the only cytokine capable of affecting NKG2D ligand expression. In doing so, surface expression of MICA and in part also of ULBP2 was reduced significantly. This resulted in impaired NKG2D-mediated lysis of melanoma cells by the NK cell line NKL. There was no correlation between MICA/ULBP2 surface expression and corresponding RNA concentration. Moreover IFN-g-induced downregulation of surface-MICA was not solely dependent on STAT1, the characteristic mediator of IFN-g induced signaling. Hence a complex controlling mechanism is assumed which influences posttranscriptionally the expression of NKG2D ligands. In contrast to diverse carcinoma cell lines, glioblastoma cells also downregulate surface expression of NKG2D ligands in the presence of IFN-g. Therefore the observed IFN-g effect may be conserved at least for cells of neuroectodermal origin. Based on the data of this work one can assume that HLA class I-negative melanoma cells can not only evade T cell-dependent immune responses but might also elude NK immune activity by reducing surface expression of NKG2D ligands in an IFN-g rich environment. The results of this work contribute to an improved understanding of the melanoma and NK cell interaction and should be considered when amending established and designing new therapies for melanoma patients.