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Merkel cell carcinoma (MCC) is a primary neuroendocrine carcinoma of the skin. This neoplasia features aggressive behavior, resulting in a 5-year overall survival rate of 40%. In 2008, Feng et al. identified Merkel cell polyomavirus (MCPyV) integration into the host genome as the main event leading to MCC oncogenesis. However, despite identification of this crucial viral oncogenic trigger, the nature of the cell in which MCC oncogenesis occurs is actually unknown. In fact, several hypotheses have been proposed. Despite the large similarity in phenotype features between MCC tumor cells and physiological Merkel cells (MCs), a specialized subpopulation of the epidermis acting as mechanoreceptor of the skin, several points argue against the hypothesis that MCC derives directly from MCs. Alternatively, MCPyV integration could occur in another cell type and induce acquisition of an MC-like phenotype. Accordingly, an epithelial as well as a fibroblastic or B-cell origin of MCC has been proposed mainly based on phenotype similarities shared by MCC and these potential ancestries. The aim of this present review is to provide a comprehensive review of the current knowledge of the histogenesis of MCC.
Background
Conjunctival melanoma is a potentially deadly eye tumour. Despite effective local therapies, tumour recurrence and metastasis remain frequent. The genetics of conjunctival melanomas remain incompletely understood.
Methods
A large cohort of 63 conjunctival melanomas was screened for gene mutations known to be important in other melanoma subtypes by targeted next-generation sequencing. Mutation status was correlated with patient prognosis.
Results
Frequent mutations in genes activating the MAP kinase pathway were identified. NF1 mutations were most frequent (n = 21, 33%). Recurrent activating mutations were also identified in BRAF (n = 16, 25%) and RAS genes (n = 12, 19%; 11 NRAS and 1 KRAS).
Conclusions
Similar to cutaneous melanomas, conjunctival melanomas can be grouped genetically into four groups: BRAF-mutated, RAS-mutated, NF1-mutated and triple wild-type melanomas. This genetic classification may be useful for assessment of therapeutic options for patients with metastatic conjunctival melanoma
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.
Hintergrund: Bei der Entscheidung für eine intravenöse Kortikosteroid-Pulstherapie bei schweren Formen der AA ist die Abwägung von Therapieaufwand, Nebenwirkungen und Risiken einerseits und der Erfolgsaussicht andererseits von zentraler Bedeutung.
Ziel: Ziel dieser retrospektiven Analyse war es daher, die Wirksamkeit und Sicherheit der intravenösen Kortikosteroid-Pulstherapie bei Patient:innen mit ausgeprägter AA klinikintern als qualitätssichernde Maßnahme zu untersuchen, prognostisch bedeutsame Faktoren für den Therapieeffekt zu ermitteln und hierdurch die beste Indikation herauszuarbeiten.
Methode: 126 Patient:innen (13 Kinder und Jugendliche) erhielten Dexamethason 100 mg (122 Patienten) oder Methylprednisolon 20-30 mg/kg/KG (max. 1000 mg, 4 Patienten) an drei aufeinanderfolgenden Tagen für ein bis drei Zyklen.
Ergebnisse: Patienten mit einer AA partialis bzw. diffusa zeigten im Hinblick auf ein vollständiges oder kosmetisch akzeptables Wiederwachstum die besten Ansprechraten (44,3%, n=43). Unter den Ophiasis-Patienten und den Patienten mit AA totalis/universalis sprach nur etwa ein Viertel auf die Therapie an (Ophiasis 23,8%, n=5; AA totalis/universalis: 25%, n=2). Schwerwiegende unerwünschte Nebenwirkungen wurden nicht beobachtet.
Schlussfolgerung: In der vorliegenden Untersuchung ließen sich eine längere Bestandsdauer der Erkrankung und Erkrankungsepisode (über 6 Monate), ein schwerer Ausprägungsgrad (Ophiasis, AA totalis/universalis) und krankheitstypische Nagelveränderungen als wichtige ungünstige prognostische Faktoren nachweisen. Dagegen wirkten sich die untersuchten Kriterien Alter, Geschlecht, atopisches Ekzem und andere Erkrankungen des atopischen Formenkreises, Schilddrüsen- und Autoimmunerkrankungen in der Eigenanamnese sowie AA in der Familienanamnese nicht negativ auf den Behandlungserfolg aus. Patienten mit AA partialis und einer Bestandsdauer der AA von maximal 6 Monaten haben die besten Erfolgsaussichten.
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.
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
Healthcare workers and medical students faced new challenges during the COVID-19 pandemic. Processes within many hospitals were completely disrupted. In addition, the face to face teaching of medical students was drastically reduced. Those at risk of developing mental health problems appear to be younger health care workers and women.
Objective
To investigate potential COVID-19 pandemic-related gender differences in psychological distress among medical students and physicians in their first years of practice.
Design and setting
An anonymous survey was carried out online between December 1, 2021, and March 31, 2022, at the Mannheim Medical Faculty and the Würzburg Medical Faculty, Germany, after obtaining informed consent. Primary outcome measures were changes in anxiety and depression symptoms using the Hospital Anxiety and Depression Scale (HADS), and changes in participants' current quality of life using the WHO Quality of Life BREF.
Results
The results show wave-like courses for perceived anxiety and burden overlapping with the course of the COVID-19 incidence. In comparison to men, women showed a significant higher increase in HADS (p = 0.005) and a reduced life quality (p = 0.007) after COVID-19. Both sexes showed different frequencies of the factors influencing quality of life, with the presence of a previous mental illness and mean anxiety having a significant higher negative impact in women.
Conclusion
Future and young female physicians reported a disproportionate higher burden during COVID-19 compared to their male colleges. These observations suggest an increased need for support and prevention efforts especially in this vulnerable population.
ICIs sind inzwischen integrales Therapiemittel vieler Tumoren, selbst in nicht metastasierten Stadien. Das Management von dabei eventuell entstehenden Nebenwirkungen bleibt wichtiger Bestandteil der Therapie vor allem im fortgeschrittenen Alter. Retrospektive Untersuchungen wie unsere tragen dazu bei, das in vielen klinischen Studien unterrepräsentierte Patientenkollektiv älterer Patienten in den klinischen Alltag sowie in Therapieentscheidungen und -planungen zu integrieren.
Der primäre Studienendpunkt unserer Arbeit unterstützt wichtige Erkenntnisse anderer Studien, dass irAEs insgesamt unter älteren Patienten nicht häufiger auftreten. Zwischen allen drei Altersklassen von ~55, ~70 und ~80 Jahren zeigten sich keine signifikanten Unterschiede im Auftreten von irAEs aller Grade, wobei irAEs Grad III/IV etwas häufiger bei ~80-Jährigen auftraten. In unserem Fall stellten wir fest, dass auftretende irAEs im Alter häufiger behandelt wurden, und dass die Immuntherapie häufiger pausiert oder abgebrochen wurde. Zudem war der Anteil an Therapieabbrüchen unter den älteren Patienten wegen bestimmter Ereignisse wie TRAEs und dem Einsatz von Glukokortikoiden höher als bei jüngeren Patienten.
Die Ergebnisse unserer Studie deuten außerdem darauf hin, dass selbst unter Polypharmazie und Multimorbidität irAEs nicht häufiger bei Älteren auftraten. Ebenso können wir die interessante Beobachtung verzeichnen, dass Patienten mit >5 Medikamenten und gleichzeitig >5 Erkrankungen signifikant mehr irAEs Grad III/IV aufwiesen oder mehr Patienten Glukokortikoide verabreicht bekommen haben. Auch der Anteil an Interventionsbedarf oder Therapieabbruch war hier in allen Altersklassen höher. Es stellt sich die Frage, inwiefern hohes Alter, Komorbidität und Polypharmazie Risikofaktoren für Interventionsbedarf oder Therapieabbruch in der Immuntherapie sind, und ob ihnen eher besondere Gewichtung als Risikofaktor zukommt als dem Alter selbst.
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.
Severe and prolonged liver damage in pityriasis rubra pilaris treated with acitretin: a case report
(2022)
Acitretin is a systemic retinoid that is used in dermatology for treatment of various inflammatory and especially hyperkeratotic diseases. Elevation of liver enzymes may occur occasionally but normally resolves spontaneously, at the latest after termination of acitretin. However, it can very rarely develop into a life-threatening adverse event including drug-induced liver injury (DILI). A 45-year-old man with classical pityriasis rubra pilaris, a frequently severe, inflammatory skin disease, was started on acitretin. After a seemingly harmless elevation of transaminases, a few weeks after initiation of acitretin, the patient experienced a dramatic course of liver injury with hepatic jaundice though acitretin was stopped immediately. Eventually, laboratory values recovered upon high-dose oral prednisolone therapy. Prescribing physicians should keep in mind that acitretin might induce severe liver injury. Even after termination of acitretin laboratory values should be monitored for a while in order to recognize symptomless but harmful drug-induced liver injury in time.
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.
(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.
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.
Blue nevus is a benign melanocytic lesion, typically asymptomatic and of unknown etiology. Several histologic and clinical variants have been distinguished, the most frequent being common blue nevus, cellular blue nevus, and combined blue nevus. Although melanocytic nevi with a satellite lesion are usually suggestive of locally advanced malignant melanoma, very few cases of blue nevi with satellite lesions have been reported. The diagnosis of common or cellular blue nevi is generally straightforward; however, the presence of structures such as irregular edges or satellitosis are highly suggestive for malignancy, and differential diagnoses such as locally advanced malignant melanoma and malignant blue nevus should be considered. Recurrent blue nevi can display atypical features not seen in the primary lesion, such as pleomorphism and mitotic activity. They usually tend to follow a benign course; however, in some cases, recurrence may indicate malignant transformation. We here report the unique case of a 64-year-old woman with a recurrent cellular blue nevus accompanied by satellite lesions. Such a biological behavior resulting in a clinical presentation as a melanoma-like lesion is a rarity in blue nevus and has not been described before.
Cutaneous squamous cell carcinoma (cSCC) is a common malignancy of the skin and has an overall favorable outcome, except for patients with an advanced stage of the disease. The efficacy of checkpoint inhibitors (CPI) for advanced cSCC has been demonstrated in recent clinical studies, but data from real-world cohorts and trial-ineligible cSCC patients are limited. We retrospectively investigated patients with advanced cSCC who have been treated with CPI in a first-line setting at eight German skin cancer centers registered within the multicenter registry ADOReg. Clinical outcome parameters including response, progression-free (PFS) and overall survival (OS), time-to-next-treatment (TTNT), and toxicity were analyzed and have been stratified by the individual immune status. Among 39 evaluable patients, the tumor response rate (rwTRR) was 48.6%, the median PFS was 29.0 months, and the median OS was not reached. In addition, 9 patients showed an impaired immune status due to immunosuppressive medication or hematological diseases. Our data demonstrated that CPI also evoked tumor responses among immunocompromised patients (rwTRR: 48.1 vs. 50.0%), although these responses less often resulted in durable remissions. In line with this, the median PFS (11 vs. 40 months, p = 0.059), TTNT (12 months vs. NR, p = 0.016), and OS (29 months vs. NR, p < 0.001) were significantly shorter for this patient cohort. CPI therapy was well tolerated in both subcohorts with 15% discontinuing therapy due to toxicity. Our real-world data show that first-line CPI therapy produced strong and durable responses among patients with advanced cSCC. Immunocompromised patients were less likely to achieve long-term benefit from anti-PD1 treatment, despite similar tumor response rates.
Background: Primary cutaneous follicular B-cell lymphoma (PCFBCL) represents an indolent subtype of Non-Hodgkin’s lymphomas, being clinically characterized by slowly growing tumors of the skin and common cutaneous relapses, while only exhibiting a low propensity for systemic dissemination or fatal outcome. Up to now, only few studies have investigated underlying molecular alterations of PCFBCL with respect to somatic mutations. Objectives: Our aim was to gain deeper insight into the pathogenesis of PCFBCL and to delineate discriminatory molecular features of this lymphoma subtype. Methods: We performed hybridization-based panel sequencing of 40 lymphoma-associated genes of 10 cases of well-characterized PCFBCL. In addition, we included two further ambiguous cases of atypical B-cell-rich lymphoid infiltrate/B-cell lymphoma of the skin for which definite subtype attribution had not been possible by routine investigations. Results: In 10 out of 12 analyzed cases, we identified genetic alterations within 15 of the selected 40 target genes. The most frequently detected alterations in PCFBCL affected the TNFRSF14, CREBBP, STAT6 and TP53 genes. Our analysis unrevealed novel mutations of the BCL2 gene in PCFBCL. All patients exhibited an indolent clinical course. Both the included arbitrary cases of atypical B-cell-rich cutaneous infiltrates showed somatic mutations within the FAS gene. As these mutations have previously been designated as subtype-specific recurrent alterations in primary cutaneous marginal zone lymphoma (PCMZL), we finally favored the diagnosis of PCMZL in these two cases based on these molecular findings. Conclusions: To conclude, our molecular data support that PCFBCL shows distinct somatic mutations which may aid to differentiate PCFBCL from pseudo-lymphoma as well as from other indolent and aggressive cutaneous B-cell lymphomas. While the detected genetic alterations of PCFBCL did not turn out to harbor any prognostic value in our cohort, our molecular data may add adjunctive discriminatory features for diagnostic purposes on a molecular level.
Defects in DNA repair pathways have been associated with an improved response to immune checkpoint inhibition (ICI). In particular, patients with the nucleotide excision repair (NER) defect disease Xeroderma pigmentosum (XP) responded impressively well to ICI treatment. Recently, in melanoma patients, pretherapeutic XP gene expression was predictive for anti-programmed cell death-1 (PD-1) ICI response. The underlying mechanisms of this finding are still to be revealed. Therefore, we used CRISPR/Cas9 to disrupt XPA in A375 melanoma cells. The resulting subclonal cell lines were investigated by Sanger sequencing. Based on their genetic sequence, candidates from XPA exon 1 and 2 were selected and further analyzed by immunoblotting, immunofluorescence, HCR and MTT assays. In XPA exon 1, we established a homozygous (c.19delG; p.A7Lfs*8) and a compound heterozygous (c.19delG/c.19_20insG; p.A7Lfs*8/p.A7Gfs*55) cell line. In XPA exon 2, we generated a compound heterozygous mutated cell line (c.206_208delTTG/c.208_209delGA; p.I69_D70delinsN/p.D70Hfs*31). The better performance of the homozygous than the heterozygous mutated exon 1 cells in DNA damage repair (HCR) and post-UV-C cell survival (MTT), was associated with the expression of a novel XPA protein variant. The results of our study serve as the fundamental basis for the investigation of the immunological consequences of XPA disruption in melanoma.
Since 2021, adalimumab biosimilar ABP 501 can be used alternatively to adalimumab originator (ADAO) in the treatment of hidradenitis suppurativa (HS). Effectiveness and safety data remain scarce. We investigated the impact of switching from ADAO to ABP 501 on disease severity and the occurrence of adverse events (AEs) in patients with HS. We analyzed clinical data on patients enrolled in the German HSBest registry. Evaluation outcomes were assessed at three time points (baseline of originator (t0), prior to switching to biosimilar (t1) and 12 to 14 weeks after switching (t2)) and included patient-reported AEs and disease severity using the International Hidradenitis Suppurativa Severity Score System (IHS4) score. In total, 94 patients were switched from ADAO to ABP 501. Overall, 33.3% (n = 31/94) of the patients developed AEs and/or loss of response (LoR) within 12 to 14 weeks after switching. Of these, 61.3% (n = 19/31) experienced LoR but no AEs, 22.6% (n = 7/31) LoR combined with AEs and 16.1% (n = 5/31) AEs only. Our study showed that switching HS patients from ADAO to ABP 501 does significantly affect treatment effectiveness. Switching patients who are on remission maintenance therapy should be viewed critically.
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.