@phdthesis{Schrama2004,
  author    = {Schrama, David},
  title     = {T-Zell-priming außerhalb sekund{\"a}rer lymphatischer Gewebe},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-15060},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {T-Zellimmunantworten werden normalerweise durch folgenden Weg initiiert: unreife dendritische Zellen nehmen Antigen in der Peripherie auf, wandern in die sekund{\"a}ren lymphatischen Organe, wobei sie auf ihrem Weg sowohl reifen als auch das Antigen prozessieren. In den sekund{\"a}ren lymphatischen Organen angekommen, pr{\"a}sentieren sie als reife dendritische Zellen den T-Zellen die Antigene in Form von Peptiden zusammen mit kostimulierenden Molek{\"u}len. Dadurch rufen sie eine spezifische T-Zellantwort hervor. In der vorliegenden Arbeit wurde untersucht, ob nicht Situationen herbeigef{\"u}hrt werden k{\"o}nnen, die ein T-Zell priming außerhalb der sekund{\"a}ren lymphatischen Organe erlauben. Dazu wurden ein murines Modell, bei dem das Zytokin Lymphotoxin-alpha spezifisch am Tumor angereichert wurde, und ein humanes Modell, bei dem reife, antigenbeladene DC intradermal appliziert wurden, untersucht. Im murinen Modell zeigte sich, dass die gerichtete Anreicherung von Lymphotoxin-alpha am Tumor zu dessen Zerst{\"o}rung f{\"u}hrte, welche durch T-Zellen vermittelt wurde, und mit der Induktion eines terti{\"a}ren lymphatischen Gewebes am Tumor assoziiert war. Dieses terti{\"a}re lymphatische Gewebe war durch die Kompartimentalisierung von T- und B-Zellen und der Pr{\"a}senz von high endothelial venules charakterisiert und besaß zudem mit dendritischen Zellen und na{\"i}ven T-Zellen alle Voraussetzungen f{\"u}r ein in loco priming. Dementsprechend konnte in der Folge der gerichteten Lymphotoxin-alpa Therapie im Tumor ein Anstieg am T-Zellinfiltrat, welches sich oligoklonal zusammensetzte, beobachtet werden. In vitro Experimente verdeutlichte die Tumorspezifit{\"a}t der Therapie-induzierten T-Zellantwort, da die T-Zellen auf ein Tumorantigen mit der Aussch{\"u}ttung von Interferon gamma reagierten und die Tumorzellen lysierten. Im humanen Modell wurden Hautbiopsien von Melanompatienten untersucht, denen im Rahmen einer klinischen Studie autologe, in vitro generierte und antigenbeladene DC intradermal appliziert wurden. Die Patienten erlaubten die Entnahme von Hautbiopsien aus den Injektionsstellen f{\"u}r wissenschaftliche Untersuchungen. Eine Induktion bzw. Verst{\"a}rkung einer spezifischen T-Zellantwort durch die Vakzinierung mit antigenbeladenen dendritischen Zellen konnte bereits in zahlreichen Arbeiten und auch in dem in dieser Arbeit untersuchten Patientenkollektiv gezeigt werden. Bei der Analyse der Injektionsstellen zeigt sich, dass ein großer Teil der injizierten dendritischen Zellen in der Vakzinierungsstelle verharren und dass diese unabh{\"a}ngig von einer Beladung mit Antigen zu einer Induktion von high endothelial venules Charakteristika f{\"u}hrte. Waren die dendritischen Zellen mit Antigen beladen, so f{\"u}hrte dies zu einem st{\"a}rkeren T-Zellinfiltrat in den Injektionsstellen, wobei sowohl na{\"i}ve als auch central memory T-Zellen nachgewiesen wurde. Diese Zellen wurden vermutlich durch die {\"U}berexpression der DC CK1 und SDF1 Chemokinen in den Injektionsstellen, die chemotaktisch auf T-Zellen wirken, angezogen. Das Infiltrat in den Injektionsstellen war oligoklonal und wies tumorspezifische T-Zellen auf. Nachdem diese T-Zellklone im Blut der Patienten vor der Vakzinierung nicht nachweisbar waren, m{\"u}ssen sie zumindest in den Injektionsstellen expandiert sein. Interessanterweise konnte einer dieser Klone in Metastasen nachgewiesen werden, die nach der Vakzinierung dem Patienten entfernt wurden. In beiden Modellen wurde also durch die Manipulation des Mikromilieus, d.h. Lymphotoxin-alpa Anreicherung am Tumor bzw. Injektion von reifen dendritischen Zellen in die Haut, Strukturen wie z.B. high endothelial venules induziert, die ein in loco priming erm{\"o}glichen sollten. Dementsprechend riefen diese Ver{\"a}nderungen ein Tumorantigen-spezifisches Infiltrat hervor. Diese Ergebnisse deuten darauf hin, dass T-Zell priming auch außerhalb sekund{\"a}rer lymphatischer Organe erfolgen kann. Prinzipiell scheint also nur der Kontakt von reifen, antigenbeladenen dendritischen Zellen mit den entsprechenden antigenspezifischen, na{\"i}ven T-Zellen entscheiden zu sein. Die M{\"o}glichkeit des in vitro primings bekr{\"a}ftigt diese These. In vivo erfolgt dieses Aufeinandertreffen normalerweise in den sekund{\"a}ren lymphatischen Organen, doch konnte in der vorliegenden Arbeit gezeigt werden, dass Ver{\"a}nderungen des Mikromilieus diesen Kontakt auch in anderen Geweben erm{\"o}glicht.},
  subject      = {T-Lymphozyt},
  language  = {de}
}
@article{HoubenHesbacherSchmidetal.2011,
  author    = {Houben, Roland and Hesbacher, Sonja and Schmid, Corinna P. and Kauczok, Claudia S. and Flohr, Ulrike and Haferkamp, Sebastian and M{\"u}ller, Cornelia S. L. and Schrama, David and Wischhusen, J{\"o}rg and Becker, J{\"u}rgen C.},
  title     = {High-Level Expression of Wild-Type p53 in Melanoma Cells is Frequently Associated with Inactivity in p53 Reporter Gene Assays},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-69012},
  year      = {2011},
  abstract  = {Background: Inactivation of the p53 pathway that controls cell cycle progression, apoptosis and senescence, has been proposed to occur in virtually all human tumors and p53 is the protein most frequently mutated in human cancer. However, the mutational status of p53 in melanoma is still controversial; to clarify this notion we analysed the largest series of melanoma samples reported to date. Methodology/Principal Findings: Immunohistochemical analysis of more than 180 melanoma specimens demonstrated that high levels of p53 are expressed in the vast majority of cases. Subsequent sequencing of the p53 exons 5-8, however, revealed only in one case the presence of a mutation. Nevertheless, by means of two different p53 reporter constructs we demonstrate transcriptional inactivity of wild type p53 in 6 out of 10 melanoma cell lines; the 4 other p53 wild type melanoma cell lines exhibit p53 reporter gene activity, which can be blocked by shRNA knock down of p53. Conclusions/Significance: In melanomas expressing high levels of wild type p53 this tumor suppressor is frequently inactivated at transcriptional level.},
  subject      = {Krebs <Medizin>},
  language  = {en}
}
@article{BeckerAndersenHofmeisterMuelleretal.2012,
  author    = {Becker, J{\"u}rgen C. and Andersen, Mads H. and Hofmeister-M{\"u}ller, Valeska and Wobser, Marion and Frey, Lidia and Sandig, Christiane and Walter, Steffen and Singh-Jasuja, Harpreet and K{\"a}mpgen, Eckhart and Opitz, Andreas and Zapatka, Marc and Br{\"o}cker, Eva-B. and thor Straten, Per and Schrama, David and Ugurel, Selma},
  title     = {Survivin-specific T-cell reactivity correlates with tumor response and patient survival: a phase-II peptide vaccination trial in metastatic melanoma},
  series = {Cancer Immunology, Immunotherapy},
  volume    = {61},
  journal   = {Cancer Immunology, Immunotherapy},
  number    = {11},
  doi       = {10.1007/s00262-012-1266-9},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126215},
  pages     = {2091-2103},
  year      = {2012},
  abstract  = {Background Therapeutic vaccination directed to induce an anti-tumoral T-cell response is a field of extensive investigation in the treatment of melanoma. However, many vaccination trials in melanoma failed to demonstrate a correlation between the vaccine-specific immune response and therapy outcome. This has been mainly attributed to immune escape by antigen loss, rendering us in the need of new vaccination targets. Patients and methods This phase-II trial investigated a peptide vaccination against survivin, an oncogenic inhibitor-of-apoptosis protein crucial for the survival of tumor cells, in HLA-A1/-A2/-B35-positive patients with treatment-refractory stage-IV metastatic melanoma. The study endpoints were survivin-specific T-cell reactivity (SSTR), safety, response, and survival (OS). Results Sixty-one patients (ITT) received vaccination therapy using three different regimens. 55 patients (PP) were evaluable for response and survival, and 41/55 for SSTR. Patients achieving progression arrest (CR + PR + SD) more often showed SSTRs than patients with disease progression (p = 0.0008). Patients presenting SSTRs revealed a prolonged OS (median 19.6 vs. 8.6 months; p = 0.0077); multivariate analysis demonstrated SSTR as an independent predictor of survival (p = 0.013). The induction of SSTRs was associated with gender (female vs. male; p = 0.014) and disease stage (M1a/b vs. M1c; p = 0.010), but not with patient age, HLA type, performance status, or vaccination regimen. Conclusion Survivin-specific T-cell reactivities strongly correlate with tumor response and patient survival, indicating that vaccination with survivin-derived peptides is a promising treatment strategy in melanoma.},
  language  = {en}
}
@article{BeckerAndersenHofmeisterMuelleretal.2012,
  author    = {Becker, J{\"u}rgen C. and Andersen, Mads H. and Hofmeister-M{\"u}ller, Valeska and Wobser, Marion and Frey, Lidia and Sandig, Christiane and Walter, Steffen and Singh-Jasuja, Harpreet and K{\"a}mpgen, Eckhart and Opitz, Andreas and Zapatka, Marc and Br{\"o}cker, Eva-B. and thor Straten, Per and Schrama, David and Ugurel, Selma},
  title     = {Survivin-specific T-cell reactivity correlates with tumor response and patient survival: a phase-II peptide vaccination trial in metastatic melanoma},
  series = {Cancer Immunology, Immunotherapy},
  volume    = {61},
  journal   = {Cancer Immunology, Immunotherapy},
  number    = {11},
  doi       = {10.1007/s00262-012-1266-9},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-124830},
  pages     = {2091-2103},
  year      = {2012},
  abstract  = {Background Therapeutic vaccination directed to induce an anti-tumoral T-cell response is a field of extensive investigation in the treatment of melanoma. However, many vaccination trials in melanoma failed to demonstrate a correlation between the vaccine-specific immune response and therapy outcome. This has been mainly attributed to immune escape by antigen loss, rendering us in the need of new vaccination targets. Patients and methods This phase-II trial investigated a peptide vaccination against survivin, an oncogenic inhibitor-of-apoptosis protein crucial for the survival of tumor cells, in HLA-A1/-A2/-B35-positive patients with treatment-refractory stage-IV metastatic melanoma. The study endpoints were survivin-specific T-cell reactivity (SSTR), safety, response, and survival (OS). Results Sixty-one patients (ITT) received vaccination therapy using three different regimens. 55 patients (PP) were evaluable for response and survival, and 41/55 for SSTR. Patients achieving progression arrest (CR + PR + SD) more often showed SSTRs than patients with disease progression (p = 0.0008). Patients presenting SSTRs revealed a prolonged OS (median 19.6 vs. 8.6 months; p = 0.0077); multivariate analysis demonstrated SSTR as an independent predictor of survival (p = 0.013). The induction of SSTRs was associated with gender (female vs. male; p = 0.014) and disease stage (M1a/b vs. M1c; p = 0.010), but not with patient age, HLA type, performance status, or vaccination regimen. Conclusion Survivin-specific T-cell reactivities strongly correlate with tumor response and patient survival, indicating that vaccination with survivin-derived peptides is a promising treatment strategy in melanoma.},
  language  = {en}
}
@article{AlbSieAdametal.2012,
  author    = {Alb, Miriam and Sie, Christopher and Adam, Christian and Chen, Suzie and Becker, J{\"u}rgen C. and Schrama, David},
  title     = {Cellular and cytokine-dependent immunosuppressive mechanisms of grm1-transgenic murine melanoma},
  series = {Cancer Immunology, Immunotherapy},
  volume    = {61},
  journal   = {Cancer Immunology, Immunotherapy},
  number    = {12},
  doi       = {10.1007/s00262-012-1290-9},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125096},
  pages     = {2239-2249},
  year      = {2012},
  abstract  = {Grm1-transgenic mice spontaneously develop cutaneous melanoma. This model allowed us to scrutinize the generic immune responses over the course of melanoma development. To this end, lymphocytes obtained from spleens, unrelated lymph nodes and tumor-draining lymph nodes of mice with no evidence of disease, and low or high tumor burden were analyzed ex vivo and in vitro. Thereby, we could demonstrate an increase in the number of activated CD4\(^+\) and CD8+ lymphocytes in the respective organs with increasing tumor burden. However, mainly CD4\(^+\) T cells, which could constitute both T helper as well as immunosuppressive regulatory T cells, but not CD8\(^+\) T cells, expressed activation markers upon in vitro stimulation when obtained from tumor-bearing mice. Interestingly, these cells from tumor-burdened animals were also functionally hampered in their proliferative response even when subjected to strong in vitro stimulation. Further analyses revealed that the increased frequency of regulatory T cells in tumor-bearing mice is an early event present in all lymphoid organs. Additionally, expression of the immunosuppressive cytokines TGF-β1 and IL-10 became more evident with increased tumor burden. Notably, TGF-β1 is strongly expressed in both the tumor and the tumor-draining lymph node, whereas IL-10 expression is more pronounced in the lymph node, suggesting a more complex regulation of IL-10. Thus, similar to the situation in melanoma patients, both cytokines as well as cellular immune escape mechanisms seem to contribute to the observed immunosuppressed state of tumor-bearing grm1-transgenic mice, suggesting that this model is suitable for preclinical testing of immunomodulatory therapeutics.},
  language  = {en}
}
@article{HafnerHoubenBaeurleetal.2012,
  author    = {Hafner, Christian and Houben, Roland and Baeurle, Anne and Ritter, Cathrin and Schrama, David and Landthaler, Michael and Becker, J{\"u}rgen C.},
  title     = {Activation of the PI3K/AKT Pathway in Merkel Cell Carcinoma},
  series = {PLoS One},
  volume    = {7},
  journal   = {PLoS One},
  number    = {2},
  doi       = {10.1371/journal.pone.0031255},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131398},
  pages     = {e31255},
  year      = {2012},
  abstract  = {Merkel cell carcinoma (MCC) is a highly aggressive skin cancer with an increasing incidence. The understanding of the molecular carcinogenesis of MCC is limited. Here, we scrutinized the PI3K/AKT pathway, one of the major pathways activated in human cancer, in MCC. Immunohistochemical analysis of 41 tumor tissues and 9 MCC cell lines revealed high levels of AKT phosphorylation at threonine 308 in 88\% of samples. Notably, the AKT phosphorylation was not correlated with the presence or absence of the Merkel cell polyoma virus (MCV). Accordingly, knock-down of the large and small T antigen by shRNA in MCV positive MCC cells did not affect phosphorylation of AKT. We also analyzed 46 MCC samples for activating PIK3CA and AKT1 mutations. Oncogenic PIK3CA mutations were found in 2/46 (4\%) MCCs whereas mutations in exon 4 of AKT1 were absent. MCC cell lines demonstrated a high sensitivity towards the PI3K inhibitor LY-294002. This finding together with our observation that the PI3K/AKT pathway is activated in the majority of human MCCs identifies PI3K/AKT as a potential new therapeutic target for MCC patients.},
  language  = {en}
}
@article{SchramaUgurelSuckeretal.2014,
  author    = {Schrama, David and Ugurel, Selma and Sucker, Antje and Ritter, Cathrin and Zapatka, Marc and Schadendorf, Dirk and Becker, J{\"u}rgen Christian},
  title     = {STAT3 Single Nucleotide Polymorphism rs4796793 SNP Does Not Correlate with Response to Adjuvant IFNα Therapy in Stage III Melanoma Patients},
  series = {Frontiers in Medicine},
  volume    = {1},
  journal   = {Frontiers in Medicine},
  number    = {47},
  issn      = {2296-858X},
  doi       = {10.3389/fmed.2014.00047},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120602},
  year      = {2014},
  abstract  = {Interferon alpha (IFNα) is approved for adjuvant treatment of stage III melanoma in Europe and the US. Its clinical efficacy, however, is restricted to a subpopulation of patients while side effects occur in most of treated patients. Thus, the identification of predictive biomarkers would be highly beneficial to improve the benefit to risk ratio. In this regard, STAT3 is important for signaling of the IFNα receptor. Moreover, the STAT3 single-nucleotide polymorphism (SNP) rs4796793 has recently been reported to be associated with IFNα sensitivity in metastatic renal cell carcinoma. To translate this notion to melanoma, we scrutinized the impact of rs4796793 functionally and clinically in this cancer. Interestingly, melanoma cells carrying the minor allele of rs4796793 were the most sensitive to IFNα in vitro. However, we did not detect a correlation between SNP genotype and STAT3 mRNA expression for either melanoma cells or for peripheral blood lymphocytes. Next, we analyzed the impact of rs4796793 on the clinical outcome of 259 stage III melanoma patients of which one-third had received adjuvant IFNα treatment. These analyses did not reveal a significant association between the STAT3 rs4796793 SNP and patients' progression free or overall survival when IFNα treated and untreated patients were compared. In conclusion, STAT3 rs4796793 SNP is no predictive marker for the efficacy of adjuvant IFNα treatment in melanoma patients.},
  language  = {en}
}
@article{AdamBaeurleBrodskyetal.2014,
  author    = {Adam, Christian and Baeurle, Anne and Brodsky, Jeffrey L. and Schrama, David and Wipf, Peter and Becker, J{\"u}rgen Christian and Houben, Roland},
  title     = {The HSP70 Modulator MAL3-101 Inhibits Merkel Cell Carcinoma},
  doi       = {10.1371/journal.pone.0092041},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-112795},
  year      = {2014},
  abstract  = {Merkel Cell Carcinoma (MCC) is a rare and highly aggressive neuroendocrine skin cancer for which no effective treatment is available. MCC represents a human cancer with the best experimental evidence for a causal role of a polyoma virus. Large T antigens (LTA) encoded by polyoma viruses are oncoproteins, which are thought to require support of cellular heat shock protein 70 (HSP70) to exert their transforming activity. Here we evaluated the capability of MAL3-101, a synthetic HSP70 inhibitor, to limit proliferation and survival of various MCC cell lines. Remarkably, MAL3-101 treatment resulted in considerable apoptosis in 5 out of 7 MCC cell lines. While this effect was not associated with the viral status of the MCC cells, quantitative mRNA expression analysis of the known HSP70 isoforms revealed a significant correlation between MAL3-101 sensitivity and HSC70 expression, the most prominent isoform in all cell lines. Moreover, MAL3-101 also exhibited in vivo antitumor activity in an MCC xenograft model suggesting that this substance or related compounds are potential therapeutics for the treatment of MCC in the future.},
  language  = {en}
}
@article{HesbacherPfitzerWiedorferetal.2016,
  author    = {Hesbacher, Sonja and Pfitzer, Lisa and Wiedorfer, Katharina and Angermeyer, Sabrina and Borst, Andreas and Haferkamp, Sebastian and Scholz, Claus-J{\"u}rgen and Wobser, Marion and Schrama, David and Houben, Roland},
  title     = {RB1 is the crucial target of the Merkel cell polyomavirus Large T antigen in Merkel cell carcinoma cells},
  series = {Oncotarget},
  volume    = {7},
  journal   = {Oncotarget},
  number    = {22},
  doi       = {10.18632/oncotarget.8793},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177858},
  pages     = {32956-32968},
  year      = {2016},
  abstract  = {The pocket protein (PP) family consists of the three members RB1, p107 and p130 all possessing tumor suppressive properties. Indeed, the PPs jointly control the G1/S transition mainly by inhibiting E2F transcription factors. Notably, several viral oncoproteins are capable of binding and inhibiting PPs. Merkel cell polyomavirus (MCPyV) is considered as etiological factor for Merkel cell carcinoma (MCC) with expression of the viral Large T antigen (LT) harboring an intact PP binding domain being required for proliferation of most MCC cells. Therefore, we analyzed the interaction of MCPyV-LT with the PPs. Co-IP experiments indicate that MCPyV-LT binds potently only to RB1. Moreover, MCPyV-LT knockdown-induced growth arrest in MCC cells can be rescued by knockdown of RB1, but not by p107 or p130 knockdown. Accordingly, cell cycle arrest and E2F target gene repression mediated by the single PPs can only in the case of RB1 be significantly reverted by MCPyV-LT expression. Moreover, data from an MCC patient indicate that loss of RB1 rendered the MCPyV-positive MCC cells LT independent. Thus, our results suggest that RB1 is the dominant tumor suppressor PP in MCC, and that inactivation of RB1 by MCPyV-LT is largely sufficient for its growth supporting function in established MCPyV-positive MCC cells.},
  language  = {en}
}
@article{RitterFanPaulsonetal.2016,
  author    = {Ritter, Cathrin and Fan, Kaiji and Paulson, Kelly G. and Nghiem, Paul and Schrama, David and Becker, J{\"u}rgen C.},
  title     = {Reversal of epigenetic silencing of MHC class I chain-related protein A and B improves immune recognition of Merkel cell carcinoma},
  series = {Scientific Reports},
  journal   = {Scientific Reports},
  number    = {21678},
  edition   = {6},
  doi       = {10.1038/srep21678},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167992},
  year      = {2016},
  abstract  = {Merkel cell carcinoma (MCC) is a virally associated cancer characterized by its aggressive behavior and strong immunogenicity. Both viral infection and malignant transformation induce expression of MHC class I chain-related protein (MIC) A and B, which signal stress to cells of the immune system via Natural Killer group 2D (NKG2D) resulting in elimination of target cells. However, despite transformation and the continued presence of virally-encoded proteins, MICs are only expressed in a minority of MCC tumors in situ and are completely absent on MCC cell lines in vitro. This lack of MIC expression was due to epigenetic silencing via MIC promoter hypo-acetylation; indeed, MIC expression was re-induced by pharmacological inhibition of histone deacetylases (HDACs) both in vitro and in vivo. This re-induction of MICs rendered MCC cells more sensitive to immune-mediated lysis. Thus, epigenetic silencing of MICs is an important immune escape mechanism of MCCs.},
  language  = {en}
}