Refine
Has Fulltext
- yes (11)
Is part of the Bibliography
- yes (11) (remove)
Year of publication
- 2023 (11) (remove)
Document Type
- Journal article (7)
- Doctoral Thesis (4)
Keywords
- Melanom (2)
- Merkel cell carcinoma (2)
- polyomavirus (2)
- Acne inversa (1)
- Apoptosis (1)
- Biomarker (1)
- Crosstalk (1)
- Endothel (1)
- Endothelium (1)
- Forkhead Transcription Factors (1)
Institute
- Klinik und Poliklinik für Dermatologie, Venerologie und Allergologie (11) (remove)
Forkhead box O transcription factors are a family of proteins involved in cellular processes downstream of the Insulin-PI3K-PKB pathway. In response to extra- or intracellular stresses, for example starvation or oxidative stress, FoxOs are required to direct cell cycle progression and apoptosis. In endothelial cells, they induce apoptosis, and their deregulation is linked to diseases involving the insulin pathway, such as diabetes. FoxOs also exhibit a complex role in tumour transformation: here their main function is to suppress tumorigenesis. In both physiological and cancer contexts, FoxO activation leads to the transcription of some general targets, such as p27kip1 or IGFBP1. The FoxOs can also induce tissue-specific genes, as ANGPT2 and BIM in the endothelium.
In endothelial cells, another pathway with a pivotal function is the MEK5/ERK5 MAPK signalling way. Its activation promotes cell survival and proliferation in stressful conditions, e.g., when blood vessels are exposed to the shear forces exerted by the blood stream. Furthermore, recent data described ERK5 as a kinase directing tumour resistance upon therapy-induced stress.
Comparing their reported roles in various tumours and in the endothelium, FoxO proteins and the MEK5/ERK5 MAPK cascade appear to exert opposite functions. First non-published data confirmed the hypothesis that FoxO factors are subject to a negative modulation by the MEK5/ERK5 pathway. Hence, one goal of this PhD project was to further characterise this crosstalk at molecular level. The major mechanism of FoxO regulation is the balance among several post translational modifications, such as phosphorylation, acetylation, and ubiquitination. Most importantly, the PKB dependent phosphorylation of FoxOs negatively controls their activity, and it is critical for their subcellular localization. Therefore, the regulation of FoxO localization as mechanism of ERK5 dependent suppression was studied, but the results presented in this thesis argue against this hypothesis. However, additional experiments are required to explore the impact of ERK5 activity on FoxO post-translational modifications.
FoxO activity can also be modulated by the interaction with other proteins, which in turn could explain general- and tissue-specific gene expression. Thus, another objective of this work was to investigate FoxO3-interactome in endothelial cells and the impact of MEK5/ERK5 activation on it. As published in (Fusi et al. 2022) and presented here, this analysis unveiled TRRAP as new FoxO bound protein in several cell types. Moreover, the interaction did not rely on the capacity of the FoxOs to bind their consensus DNA sequences at the promoter of target genes. Functional data demonstrated that TRRAP is required for FoxO-dependent gene transcription in endothelial and osteosarcoma cells. In addition, TRRAP expression in the endothelium is important for FoxO induced apoptosis. In summary, the interaction between FoxO factors and TRRAP revealed a new regulatory mechanism of FoxO-dependent gene transcription. It remains to be analysed whether the MEK5/ERK5 cascade may exert its suppressive effect on FoxO activity by interfering with their binding to TRRAP and whether such a mechanism may be relevant for tumorigenesis.
Immune checkpoint blockade therapy is beneficial and even curative for some cancer patients. However, the majority don’t respond to immune therapy. Across different tumor types, pre-existing T cell infiltrates predict response to checkpoint-based immunotherapy. Based on in vitro pharmacological studies, mouse models and analyses of human melanoma patients, we show that the cytokine GDF-15 impairs LFA-1/β2-integrin-mediated adhesion of T cells to activated endothelial cells, which is a pre-requisite of T cell extravasation. In melanoma patients, GDF-15 serum levels strongly correlate with failure of PD-1-based immune checkpoint blockade therapy. Neutralization of GDF-15 improves both T cell trafficking and therapy efficiency in murine tumor models. Thus GDF-15, beside its known role in cancer-related anorexia and cachexia, emerges as a regulator of T cell extravasation into the tumor microenvironment, which provides an even stronger rationale for therapeutic anti-GDF-15 antibody development.
Background
Severe acute respiratory syndrome coronavirus 2 is a virus affecting different organs and causing a wide variety and severity of symptoms. Headache as well as loss of smell and taste are the most frequently reported neurological manifestations of coronavirus disease 2019 induced by severe acute respiratory syndrome coronavirus 2. Here we report on a patient with chronic migraine and medication overuse headache, who experienced remarkable mitigation of migraine following coronavirus disease 2019.
Case presentation
For many years prior to the severe acute respiratory syndrome coronavirus 2 infection, a 57-year-old Caucasian male suffered from very frequent migraine attacks and for control of headaches he had been taking triptans almost daily. In the 16-month period before the outbreak of coronavirus disease 2019, triptan was taken 98% of the days with only a 21-day prednisolone-supported triptan holiday, which, however, had no longer-lasting consequences on migraine frequency. Upon severe acute respiratory syndrome coronavirus 2 infection, the patient developed only mild symptoms including fever, fatigue, and headache. Directly following recovery from coronavirus disease 2019, the patient surprisingly experienced a period with largely reduced frequency and severity of migraine attacks. Indeed, during 80 days following coronavirus disease 2019, migraine as well as triptan usage were restricted to only 25% of the days, no longer fulfilling criteria of a chronic migraine and medication overuse headache.
Conclusion
Severe acute respiratory syndrome coronavirus 2 infection might be capable of triggering mitigation of migraine.
Merkel cell carcinoma (MCC) is frequently caused by the Merkel cell polyomavirus (MCPyV), and MCPyV-positive tumor cells depend on expression of the virus-encoded T antigens (TA). Here, we identify 4-[(5-methyl-1H-pyrazol-3-yl)amino]-2H-phenyl-1-phthalazinone (PHT) — a reported inhibitor of Aurora kinase A — as a compound inhibiting growth of MCC cells by repressing noncoding control region (NCCR)-controlled TA transcription. Surprisingly, we find that TA repression is not caused by inhibition of Aurora kinase A. However, we demonstrate that β-catenin — a transcription factor repressed by active glycogen synthase kinase 3 (GSK3) — is activated by PHT, suggesting that PHT bears a hitherto unreported inhibitory activity against GSK3, a kinase known to function in promoting TA transcription. Indeed, applying an in vitro kinase assay, we demonstrate that PHT directly targets GSK3. Finally, we demonstrate that PHT exhibits in vivo antitumor activity in an MCC xenograft mouse model, suggesting a potential use in future therapeutic settings for MCC.
The best characterized polyomavirus family member, i.e., simian virus 40 (SV40), can cause different tumors in hamsters and can transform murine and human cells in vitro. Hence, the SV40 contamination of millions of polio vaccine doses administered from 1955–1963 raised fears that this may cause increased tumor incidence in the vaccinated population. This is, however, not the case. Indeed, up to now, the only polyomavirus family member known to be the most important cause of a specific human tumor entity is Merkel cell polyomavirus (MCPyV) in Merkel cell carcinoma (MCC). MCC is a highly deadly form of skin cancer for which the cellular origin is still uncertain, and which appears as two clinically very similar but molecularly highly different variants. While approximately 80% of cases are found to be associated with MCPyV the remaining MCCs carry a high mutational load. Here, we present an overview of the multitude of molecular functions described for the MCPyV encoded oncoproteins and non-coding RNAs, present the available MCC mouse models and discuss the increasing evidence that both, virus-negative and -positive MCC constitute epithelial tumors.
Bullous pemphigoid is the most common autoimmune blistering disease in industrialized countries and particularly affects the elderly. In this patient population, comorbid diseases are frequent and may complicate management and treatment of bullous pemphigoid. A better understanding why distinct diseases are more frequent in bullous pemphigoid patients may lead to new pathophysiological insights and - as a consequence - result in better patient care. The association of bullous pemphigoid with neurological and psychiatric diseases is well known and confirmed by several case-control studies. Association with further diseases such as malignancy and metabolic diseases are still discussed controversially. In recent years new relationships between bullous pemphigoid and autoimmune as well as inflammatory skin diseases have been reported. This review provides a systematic overview on studies addressing comorbidity in bullous pemphigoid patients. Increasing the awareness of both, common and rare comorbid diseases, may enable clinicians to optimize patient support and individualized treatment of bullous pemphigoid.
Die Einführung von zielgerichteter Therapie und Immuntherapie hat die Behandlungsmöglichkeiten des Melanoms revolutioniert. Jedoch profitieren viele Patienten nicht langfristig von diesen Therapien. Derzeit werden klinische Studien durchgeführt, die zielgerichtete Therapie und Immuntherapie miteinander kombinieren.
In dieser Arbeit wurden in vitro Untersuchungen an den drei BRAF-V600E-mutieren Melanomzelllinien UACC 257, Malme 3M und Sk-Mel 5 unter kombinierter MAPK-Inhibitortherapie durchgeführt. Es wurden die aus der klinischen Routine bekannten Kombinationen aus BRAF- und MEK-Inhibitor – Vemurafenib und Cobimetinib, Dabrafenib und Trametinib sowie Encorafenib und Binimetinib – verwendet. Es wurde untersucht, ob obige zielgerichtete Therapeutika einen Effekt auf immunologische Marker im Melanom haben und ob sich eine der Kombinationen in ihrer Wirkung signifikant von den übrigen unterscheidet.
Mittels MTS-Assay und Zellzyklusanalysen konnte eine konzentrationsabhängige Wirkung der Inhibitoren gezeigt und in ihrer Wirkung vergleichbare Inhibitorkonzentrationen eingestellt werden. Unter kombinierter MAPK-Inhibitortherapie zeigte sich ein begrenzter Effekt auf die theoretische Immunogenität des Melanoms. So konnte eine erhöhte MHC-I-Expression (+14 %) und eine verminderte PD-L1-Expression (-24 %) gezeigt werden. Die gewählten Dosen an Inhibitoren induzierten keinen ER-Stress. Ebenso konnte keine Ekto-Calreticulin-Expression auf lebenden Zellen nachgewiesen werden. Zwischen den drei Inhibitorkombinationen zeigten sich keine signifikanten Unterschiede.
Die in dieser Arbeit gezeigten begrenzten immunologischen Effekte unter kombinierter MAPK-Inhibitortherapie legen nahe, dass eine Kombination mit Immuntherapie in Teilen synergistisch wirken könnte. Hier sind die Ergebnisse weiterer Studien abzuwarten, die zielgerichtete und Immuntherapie miteinander kombinieren, um ein tiefgreifenderes Verständnis bzgl. etwaiger Synergien zu generieren. Da zwischen den Inhibitorkombinationen keine signifikanten Unterschiede hinsichtlich ihrer Wirkung auf die Immunogenität des Melanoms gefunden wurden, ist anzunehmen, dass sie sich grundsätzlich alle gleichermaßen für eine Kombination mit einer Immuntherapie eignen. Die gezeigte MHC-I-Erhöhung trat bereits bei geringen Inhibitorkonzentrationen auf. Möglicherweise genügt bei einer Kombination mit Immuntherapie bereits eine niedrige Dosis der zielgerichteten Therapie, um die Immuntherapie zu boostern. Um die Frage nach einer möglichen Kombinationstherapie fortwährend zu analysieren, sollten zusätzliche Aspekte der Immunogenität unter kombinierter MAPK-Inhibitortherapie untersucht und die Inhibitortitration zum Vergleich der zielgerichteten Therapeutika weiter präzisiert werden.
(1) Background: C-X-C Motif Chemokine Receptor 4 (CXCR4) and Fibroblast Activation Protein Alpha (FAP) are promising theranostic targets. However, it is unclear whether CXCR4 and FAP positivity mark distinct microenvironments, especially in solid tumors. (2) Methods: Using Random Forest (RF) analysis, we searched for entity-independent mRNA and microRNA signatures related to CXCR4 and FAP overexpression in our pan-cancer cohort from The Cancer Genome Atlas (TCGA) database — representing n = 9242 specimens from 29 tumor entities. CXCR4- and FAP-positive samples were assessed via StringDB cluster analysis, EnrichR, Metascape, and Gene Set Enrichment Analysis (GSEA). Findings were validated via correlation analyses in n = 1541 tumor samples. TIMER2.0 analyzed the association of CXCR4 / FAP expression and infiltration levels of immune-related cells. (3) Results: We identified entity-independent CXCR4 and FAP gene signatures representative for the majority of solid cancers. While CXCR4 positivity marked an immune-related microenvironment, FAP overexpression highlighted an angiogenesis-associated niche. TIMER2.0 analysis confirmed characteristic infiltration levels of CD8+ cells for CXCR4-positive tumors and endothelial cells for FAP-positive tumors. (4) Conclusions: CXCR4- and FAP-directed PET imaging could provide a non-invasive decision aid for entity-agnostic treatment of microenvironment in solid malignancies. Moreover, this machine learning workflow can easily be transferred towards other theranostic targets.
Trotz der ursprünglichen Bezeichnung der Acne inversa als "hidrosadénite phlegmoneuse", die eine inflammatorische Fehlfunktion der apokrinen Schweißdrüsen impliziert, geriet die Rolle der Schweißdrüsen hinsichtlich der Pathogenese der AI in Vergessenheit. Ziel dieser Studie war die Evaluierung der Rolle der Schweißdrüsen im Hinblick auf die für die AI charakteristischen proinflammatorischen Mediatoren. Zu diesem Zweck wurden gravimetrische Schweißmessungen, Multiplex-Zytokin-Assays von Schweißproben, sowie immunfluoreszenzoptische Zytokin-/Chemokin-Untersuchungen von läsionaler AI-Haut durchgeführt. Die gravimetrische Untersuchung von 17 AI-Patienten zeigte, dass AI nicht mit Hyperhidrose assoziiert ist. Allerdings scheinen sich AI-Patienten durch ihr Schwitzen im Vergleich zu einer gesunden Kontrollgruppe subjektiv stärker beeinträchtigt zu fühlen. Unsere Daten zeigen eine komplexe proinflammatorische Signatur im AI-Schweiß, die durch eine signifikant erhöhte Konzentration von Monozyten-Chemoattraktant-Protein-1 (MCP-1), Interleukin-8 (CXCL8) und Interferon-γ gekennzeichnet ist. Passend dazu konnten wir eine erhöhte Expression dieser Mediatoren in apokrinen Schweißdrüsen läsionaler AI-Haut nachweisen. Diese Ergebnisse werfen ein neues Licht auf die proinflammatorische Kapazität apokriner Schweißdrüsen bei AI, was zu einem Überdenken der Rolle der Schweißdrüsen im Hinblick auf die Pathogenese der AI führen kann.
Despite accounting for only a small proportion of all skin cancers, malignant melanoma
displays a serious health risk with increasing incidence and high mortality rate. Fortunately,
advances in the treatment of malignant melanoma now prolong survival and enhance response
and treatment efficacy. Established biomarkers help evaluate disease progression and
facilitate choosing appropriate and individual treatment options. However, the need for easily
accessible and reliable biomarkers is rising to predict patient-specific clinical outcome.
Eosinophil infiltration into the tumor and high peripheral eosinophil counts prior and during
treatment have been associated with better response in patients for various cancer entities,
including melanoma. An analysis of a heterogeneous study cohort reported high serum ECP
levels in non-responders. Hence, eosinophil frequency and serum ECP as a soluble
eosinophil-secreted mediator were suggested as prognostic biomarkers in melanoma. We
examined whether melanoma patients treated with first-line targeted therapy could also benefit
from the effects of eosinophils. In total, 243 blood and serum samples from patients with
advanced melanoma were prospectively and retrospectively collected before and after drug
initiation. To link eosinophil function to improved clinical outcome, soluble serum markers and
peripheral blood counts were used for correlative studies using a homogeneous study cohort.
In addition, functional and phenotypical characterizations provided insights into the expression
profile and activity of freshly isolated eosinophils, including comparisons between patients and
healthy donors.
Our data showed a significant correlation between high pre-treatment blood eosinophil counts
and improved response to targeted therapy and by trend to combinatorial immunotherapy in
patients with metastatic melanoma. In accordance with previous studies our results links
eosinophil blood counts to better response in melanoma patients. High pre-treatment ECP
serum concentration correlated with response to immunotherapy but not to targeted therapy.
Eosinophils from healthy donors and patients showed functional and phenotypical similarities.
Functional assays revealed a strong cytotoxic potential of blood eosinophils towards
melanoma cells in vitro, inducing apoptosis and necrosis. In addition, in vitro cytotoxicity was
an active process of peripheral eosinophils and melanoma cells with bidirectional features and
required close cell-cell interaction. The extent of cytotoxicity was dose-dependent and showed
susceptibility to changes in physical factors like adherence. Importantly, we provide evidence
of an additive tumoricidal function of eosinophils and combinatorial targeted therapy in vitro. In
summary, we give valuable insights into the complex and treatment-dependent role of
eosinophils in melanoma. As a result, our data support the suggestion of eosinophils and their
secreted mediators as potential prognostic biomarkers. It will take additional studies to
examine the molecular mechanisms that underlie our findings.