Einfluss einer Anthracyclin- und Taxanbehandlung auf die immunologische Tumorabwehr unter Antikörpertherapie

Brustkrebs ist noch immer die häufigste Krebserkrankung bei Frauen. Da bei etwa einem Viertel der Patient*innen, die an Brustkrebs leiden, eine Überexpression von Her2/neu besteht, die mit einem schlechteren klinischen Outcome korreliert, rückte Her2/neu sehr schnell als Target zielgerichteter Therapien in den Fokus. Der erste dieser Anti-Her2-Antikörper, der in die Klinik Einzug hielt, war Trastuzumab. Durch die Her2-Bindung vermittelt Trastuzumab dabei neben direkten, auch indirekte immunvermittelte Effekte, die u. a. von NK-Zellen getragen werden. Denn sie können die Her2+ Zielzellen antikörperabhängig attackieren. Diese antikörperabhängige zelluläre Zytotoxizität (ADCC) wird als wesentlicher Wirkmechanismus der Trastuzumab-Therapie diskutiert. Leitliniengerecht erfolgt die Anti-Her2-Antikörpertherapie bei Patient*innen mit Her2+ Brustkrebs aber i. d. R. in Kombination mit einer (neo-)adjuvanten Chemotherapie. Um deren immunsuppressiven Effekte wissend, wäre auch eine Kompromittierung der NK-Zellen und der NK-Zell-vermittelten ADCC denkbar. Da einige konventionelle Chemotherapeutika aber entgegen der allgemeinen Annahme auch immunogen agieren, stellt sich die Frage, ob und inwieweit die kombinierten Therapien – v. a. im Hinblick auf ADCC – tatsächlich interferieren. Um dem nachzugehen, ahmten wir die (neo-)adjuvante Therapie in einem in-vitro-Kokulturmodell nach, indem wir den Anti-Her2-Antikörper (Trastuzumab) entweder mit einem Anthracyclin (Epirubicin) oder einem Taxan (Paclitaxel) kombinierten. Vorrangig untersucht wurde das in einem Anti-Her2-Antikörper-sensiblen Her2+ Tumormodell (BT-474) mit NK-Zellen der Linie NK3.3, aber auch mit cord-blood derived MNC, die polyklonale NK-Zellen enthalten. In beiden Modellen zeichnete sich – bemessen an der Induktion von Zelltod (Annexin V/FITC-Assay) – ein (mindestens tendenziell) positiver Effekt der additiven Anthracyclin (Epirubicin)- und geringer auch der Taxan (Paclitaxel)-Therapie auf die direkte und indirekte antikörperabhängige zelluläre Zytotoxizität (ADCC) der NK-Zellen ab. Der beobachtete Benefit warf die Folgefrage auf, wie v. a. Epirubicin die antikörperab- und -unabhängige NK-Zell-Zytotoxizität akzentuieren könnten: indirekt, indem sie die Her2+ Tumorzellen „sensibilisieren“ (bereits beschrieben), und/oder direkt, indem sie die NK-Zellen „konditionieren“. Nach Änderungen auf NK-Zell-Ebene fahndend, analysierten wir deren Zytokin- und Proteinprofil in Abhängigkeit der Behandlungen (intra- und extrazelluläre FACS-Analysen, Antibody-Array). Das Protein-Profiling (scioCD antibody array, Sciomics) förderte dabei die differentielle Expression einiger Proteine zu Tage, denen aber – anders als erwartet – eher eine immunregulierende (und weniger eine zytotoxische) Bedeutung zukommt. Über diese könnte die NK-Zelle mit anderen Immunzellen interagieren und nicht nur als „Killer“ agieren – eine Hypothese, die jedoch in dieser in-vitro-Studie nicht weiter verfolgt werden konnte

Expanding the Landscape of Chromatin Modification (CM)-Related Functional Domains and Genes in Human

Chromatin modification (CM) plays a key role in regulating transcription, DNA replication, repair and recombination. However, our knowledge of these processes in humans remains very limited. Here we use computational approaches to study proteins and functional domains involved in CM in humans. We analyze the abundance and the pair-wise domain-domain co-occurrences of 25 well-documented CM domains in 5 model organisms: yeast, worm, fly, mouse and human. Results show that domains involved in histone methylation, DNA methylation, and histone variants are remarkably expanded in metazoan, reflecting the increased demand for cell type-specific gene regulation. We find that CM domains tend to co-occur with a limited number of partner domains and are hence not promiscuous. This property is exploited to identify 47 potentially novel CM domains, including 24 DNA-binding domains, whose role in CM has received little attention so far. Lastly, we use a consensus Machine Learning approach to predict 379 novel CM genes (coding for 329 proteins) in humans based on domain compositions. Several of these predictions are supported by very recent experimental studies and others are slated for experimental verification. Identification of novel CM genes and domains in humans will aid our understanding of fundamental epigenetic processes that are important for stem cell differentiation and cancer biology. Information on all the candidate CM domains and genes reported here is publicly available

Cyclic AMP metabolism and adenylate cyclase concentration in patients with advanced hepatic cirrhosis

Glucagon was tested for its effect on plasma adenosine 3′,5′-cyclic monophosphate (cyclic AMP), insulin, and glucose in healthy subjects and in patients with advanced cirrhosis of the liver. In the normal subjects, intravenous infusion of glucagon caused a significant increase in plasma cyclic AMP, glucose, and insulin. In advanced cirrhotics, plasma cyclic AMP, glucose, and insulin did not increase. Adenylate cyclase concentration was measured in liver tissue from end stage cirrhotic patients and from brain-dead organ donors whose cardiovascular function was maintained in a stable state. Basal and total adenylate cyclase concentration were not different in the two groups. Adenylate cyclase from the livers of advanced cirrhotics was, however, significantly less responsive to glucagon stimulation than was that from donor livers. Hepatocytes in advanced cirrhosis have abnormal metabolic behavior characterized by abnormal adenylate cyclase-cyclic AMP response to hormonal stimulation. © 1978

Spatiotemporal integration of molecular and anatomical data in virtual reality using semantic mapping

We have developed a computational framework for spatiotemporal integration of molecular and anatomical datasets in a virtual reality environment. Using two case studies involving gene expression data and pharmacokinetic data, respectively, we demonstrate how existing knowledge bases for molecular data can be semantically mapped onto a standardized anatomical context of human body. Our data mapping methodology uses ontological representations of heterogeneous biomedical datasets and an ontology reasoner to create complex semantic descriptions of biomedical processes. This framework provides a means to systematically combine an increasing amount of biomedical imaging and numerical data into spatiotemporally coherent graphical representations. Our work enables medical researchers with different expertise to simulate complex phenomena visually and to develop insights through the use of shared data, thus paving the way for pathological inference, developmental pattern discovery and biomedical hypothesis testing

Insulin Resistance and Altered Systemic Glucose Metabolism in Mice Lacking Nur77

OBJECTIVE: Nur77 is an orphan nuclear receptor with pleotropic functions. Previous studies have identified Nur77 as a transcriptional regulator of glucose utilization genes in skeletal muscle and gluconeogenesis in liver. However, the net functional impact of these pathways is unknown. To examine the consequence of Nur77 signaling for glucose metabolism in vivo, we challenged Nur77 null mice with high-fat feeding. RESEARCH DESIGN AND METHODS: Wild-type and Nur77 null mice were fed a high-fat diet (60% calories from fat) for 3 months. We determined glucose tolerance, tissue-specific insulin sensitivity, oxygen consumption, muscle and liver lipid content, muscle insulin signaling, and expression of glucose and lipid metabolism genes. RESULTS: Mice with genetic deletion of Nur77 exhibited increased susceptibility to diet-induced obesity and insulin resistance. Hyperinsulinemic-euglycemic clamp studies revealed greater high-fat diet–induced insulin resistance in both skeletal muscle and liver of Nur77 null mice compared with controls. Loss of Nur77 expression in skeletal muscle impaired insulin signaling and markedly reduced GLUT4 protein expression. Muscles lacking Nur77 also exhibited increased triglyceride content and accumulation of multiple even-chained acylcarnitine species. In the liver, Nur77 deletion led to hepatic steatosis and enhanced expression of lipogenic genes, likely reflecting the lipogenic effect of hyperinsulinemia. CONCLUSIONS: Collectively, these data demonstrate that loss of Nur77 influences systemic glucose metabolism and highlight the physiological contribution of muscle Nur77 to this regulatory pathway.National Institutes of Health (HD-00850, DK-081683-01, DK-30425, HL030568); American Diabetes Associatio