Purines and 9-deazapurines as Modulators of Multidrug Resistance-associated Protein 1 (MRP1/ABCC1)-mediated Transport

Expression of ABC-transport proteins is a major obstacle in cancer chemotherapy. Especially MRP1, P-gp and BCRP are expressed in different malignancies like lung cancer, colon carcinomas, leukemias, bladder cancer, myeloma, ovarian carcinomas or breast cancer, often simultaneously. These key proteins extrude a variety of structurally diverse antineoplastic agents out of cells, which results in the phenomenon called multidrug resistance (MDR). Many compounds of different origin were found to inhibit different ABC-transporters, e.g. pharmacological drugs, natural compounds, intrinsic substrates and synthetic compounds derived from screening of huge compound libraries. But most of these inhibitors lacked the necessary potency and selectivity, and often led to severe side effects in clinical evaluations. Especially with respect to MRP1, only rare reports have been made for compounds in the submicromolar concentration range. Hence, the development of new compounds is desirable to obtain more potent inhibitors for this transport protein. The aim of the thesis was to develop new, potent, nontoxic and selective inhibitors of MRP1, based on earlier reports of pyrrolo- and indolopyrimidines. The compounds have been evaluated in two different assays, the calcein AM and daunorubicin assay. The substituents of the starting compound 74 were varied to elucidate the preferences with regard to MRP1 inhibition. It was found that the phenethylpiperazine side chain at position 6 was superior in comparison to shortened alkyl linker or abolishing of the piperazine partial structure. Additionally, alkyl, aryl or arylalkyl substituents could be introduced at position 7 leading to potent compounds in submicromolar range. Compound 92 with its cyclopropyl residue was shown to be the best inhibitor of the newly synthesized compounds. It was equally potent in comparison to the standard inhibitor and starting compound 74. But in contrast to the latter, the former had no inhibitory activity against P-gp and BCRP, which makes this compound a very selective inhibitor of MRP1. Compound 92 was able to reduce MDR of H69AR cells by half in submicromolar concentration range, reversed MRP1-mediated MDR completely at 10 µmol ∙ L-1 and possessed no noteworthy toxicity at this concentration. Compound 92 is only six times less effective than the best known inhibitor of MRP1, and in contrast to the latter, it is absolutely selective, which makes it a great aspirant for clinical evaluation in cancer cell lines that overexpress MRP1. Purine analogs of 9-deazapurines showed only inhibitory power in upper double-digit concentration range, but were able to stimulate MRP1-mediated transport. This was found for calcein AM and daunorubicin in two different MRP1 expressing cell lines, H69AR and MDCK II MRP1. Several 9-deazapurines also stimulated MRP1-mediated transport, although long side chains at position 6 also gave compounds with moderate to good inhibitory power. These compounds gave biphasic concentration-effect curves. Most of the compounds were selective inhibitors of MRP1, only compound 104 affected all three transporters in an inhibitory way. It was the first herein reported triple inhibitor, although the inhibitory power toward P-gp and BCRP was rather low. The purine and 9-deazapurine activators were biologically evaluated with respect to their half-maximal activating concentration and activation ratio, which could only be observed with respect to MRP1. Analyzation of the type of activation of compound 101 as representative of the MRP1 activators showed that these compounds are nonessential activators, most likely “mixed-type” according to Segel’s “Enzyme Kinetics”. Although the compounds could reduce the intracellular concentration of the cytotoxic agent daunorubicin in the daunorubicin assay, this activating power could not be transferred to the MDR reversal-efficacy assay. Except for compound 110, none of the compounds enhanced MDR, on the contrary compounds with good inhibitory power rather reversed resistance in MRP1 overexpressing cancer cell lines (e.g. 104). Since pyrrolo- und indolopyrimidines were shown before to inhibit P-gp, but also BCRP, some 9-deazapurines were evaluated regarding their capability to inhibit all three transporters reported in this thesis. Besides some dual inhibitors, compound 125 was found as the best triple inhibitor ever reported until now. It was able to inhibit MRP1 in submicromolar range and P-gp as well as BCRP at low micromolar concentrations. It is a noncompetitive inhibitor of daunorubicin, calcein AM and pheophorbide A transport mediated by MRP1, P-gp and BCRP, respectively. Finally, the compound could reduce MDR in several cancer cell lines. The effectiveness of this MDR reversal was in submicromolar range, comparable to the data obtained for the standard inhibitor 74 and the best compound of this thesis, 92. This makes compound 125 also a great aspirant for clinical evaluation for use in cancers with multiple expression of ABC-transport proteins. Finally, the H69AR lung cancer cell line could be established as test system and compounds 74 and 126 were established as standard inhibitors for the calcein AM and daunorubicin assay, superseding the former standard inhibitors indomethacin, cyclosporine A, MK571 and ONO-1078, which all lacked either the necessary selectivity, potency or reliability. The results of this thesis give new insights in the field of MRP1-mediated MDR and the compound classes of purines and 9-deazapurines. These contain compounds that inhibit MRP1 with great potency and selectivity, which has rarely been reported. But also broad-spectrum inhibitors have been found, which is a good starting point for clinical evaluation in oncology. Finally, the activating property of several representatives might be a good tool for further experiments to elucidate the mechanistic aspects of ABC-transport proteins

Simulation of new Display Concepts for Air/Space Traffic Control Systems

A long track record on research on display concepts is available in the domain to assist the Air Traffic Controller in his situation awareness. Most of the concepts were designed to reduce Air Traffic Management (ATM) complexity with respect to traffic density, identification and resolution of conflict situations as well as to enhance the efficiency of the air transport system. The existing concepts mostly do not take into consideration air traffic and space traffic above flight level 500. Further on, higher speed and higher rates of decent of space vehicles are not fully considered. Also the operation of space vehicles at spaceports - which could be also passenger airports - has to be considered. Landing and ground operations can make use of modern remote tower installations (RTO), which will especially facilitate landing on remote sites or sites located away from operation centers and the related customers. For the implementation of future display concepts, a validation process is required. We discuss the assets of the DLR Air Transport Validation Center for life virtual constructive simulations and the methodology of the European Operation Concept Validation Methodology (EOCVM) of Eurocontrol. Results include the validation of 3D-Displays for enhanced situation awareness for new types of airspace users and a successful validation for RTO systems

Forensic Analysis of Smartphones: The Android Data Extractor Lite (ADEL)

Due to the ubiquitous use of smartphones, these devices become an increasingly important source of digital evidence in forensic investigations. Thus, the recovery of digital traces from smartphones often plays an essential role for the examination and clarification of the facts in a case. Although some tools already exist regarding the examination of smartphone data, there is still a strong demand to develop further methods and tools for forensic extraction and analysis of data that is stored on smartphones. In this paper we describe specifications of smartphones running Android. We further introduce a newly developed tool – called ADEL – that is able to forensically extract and analyze data from SQLite databases on Android devices. Finally, a detailed report containing the results of the examination is created by the tool. The whole process is fully automated and takes account of main forensic principles. Keywords: Android, Smartphones, Mobile devices, Forensics

NAS Integration: CST and Air Traffic Insertion The Way Ahead

Differences in handling aircraft vs. spacecraft in ATM Challenges for CST ATM & STM Integration CST Integration in Airspace ERAU and DLR Collaboration EUROCONTROL - Network Manager DLR Remote Tower solutions for Spaceports ATM Integration of Space Vehicles in Europe / Germany SESAR Requirements & SWIM Spacecraft Flight Planning and Executio

Automated operation of chains of barrages – development of controller algorithms with the use of model-based design

River engineeringFlow management and contro

Examining trade-offs between social, psychological, and energy potential of urban form

Urban planners are often challenged with the task of developing design solutions which must meet multiple, and often contradictory, criteria. In this paper, we investigated the trade-offs between social, psychological, and energy potential of the fundamental elements of urban form: the street network and the building massing. Since formal methods to evaluate urban form from the psychological and social point of view are not readily available, we developed a methodological framework to quantify these criteria as the first contribution in this paper. To evaluate the psychological potential, we conducted a three-tiered empirical study starting from real world environments and then abstracting them to virtual environments. In each context, the implicit (physiological) response and explicit (subjective) response of pedestrians were measured. To quantify the social potential, we developed a street network centrality-based measure of social accessibility. For the energy potential, we created an energy model to analyze the impact of pure geometric form on the energy demand of the building stock. The second contribution of this work is a method to identify distinct clusters of urban form and, for each, explore the trade-offs between the select design criteria. We applied this method to two case studies identifying nine types of urban form and their respective potential trade-offs, which are directly applicable for the assessment of strategic decisions regarding urban form during the early planning stages

Ein vereinfachtes numerisches Verfahren für die mechanische Simulation in Virtual-Reality-Systemen

Derzeitige Systeme für virtuelle Realität (VR-Systeme) müssen noch in erheblichem Umfang funktional erweitert werden, wenn man mit ihrer Hilfe z.B. autonome mobile Roboter als Interaktionspartner in der VR-Welt modellieren will. Insbesondere muss zukünftig verlangt werden, dass mechanische Vorgänge in der VR-Simulation weitgehend korrekt nachbildbar sind. Mit diesem Ziel im Hintergrund wird hier ein vereinfachtes numerisches Verfahren vorgestellt, welches die dynamische und kinematische Simulation von gelenkgekoppelten Mehrkörpersystemen erlaubt. Das Verfahren ist konsequent auf der elementaren Mechanik der Massenpunktsysteme aufgebaut, umgeht die komplizierte mechanische Gleichungstheorie für Mehrkörpersysteme und führt zu extrem kurzen und durchsichtigen Simulationsprogrammen, wobei allerdings bei der Körpermodellierung zunächst nur diskrete Massenpunktverteilungen realisierbar sind, was für VR-Systeme völlig ausreichend erscheint

Manned and Unmanned Space Vehicles: Air Traffic Insertion & SESAR Requirements

Space Traffic Management, SESA

Identification of disulfiram as a secretase-modulating compound with beneficial effects on Alzheimer’s disease hallmarks

ADAM10 is a metalloproteinase acting on the amyloid precursor protein (APP) as an alpha-secretase in neurons. Its enzymatic activity results in secretion of a neuroprotective APP cleavage product (sAPPalpha) and prevents formation of the amyloidogenic A-beta peptides, major hallmarks of Alzheimer’s disease (AD). Elevated ADAM10 levels appeared to contribute to attenuation of A-beta-Plaque formation and learning and memory deficits in AD mouse models. Therefore, it has been assumed that ADAM10 might represent a valuable target in AD therapy. Here we screened a FDA-approved drug library and identified disulfiram as a novel ADAM10 gene expression enhancer. Disulfiram increased ADAM10 production as well as sAPP-alpha in SH-SY5Y human neuronal cells and additionally prevented A-beta aggregation in an in vitro assay in a dose-dependent fashion. In addition, acute disulfiram treatment of Alzheimer model mice induced ADAM10 expression in peripheral blood cells, reduced plaque-burden in the dentate gyrus and ameliorated behavioral deficits. Alcohol-dependent patients are subjected to disulfiram-treatment to discourage alcohol-consumption. In such patients, enhancement of ADAM10 by disulfiram-treatment was demonstrated in peripheral blood cells. Our data suggest that disulfiram could be repurposed as an ADAM10 enhancer and AD therapeutic. However, efficacy and safety has to be analyzed in Alzheimer patients in the future