Monitoring middleware for distributed applications

With growing maturity Internet services are proving integral to the provision of computer services. To provide consistent end-user experiences these services are increasingly augmented with some notion of 'Quality-of-Service' (QoS), which typically requires the management of computing resources to maintain a predictable level of service performance. It is difficult to guarantee consistent servIce provision In dynamic and open environments such as the Internet. However service monitoring can be used to inform compensatory actions by collecting meaningful service performance data from strategic points in an active service environment. Due to the unpredictable nature of the Internet distributed monitoring mechanisms face challenges with respect to the various communication protocols, application languages, and monitoring requirements associated with a service environment. With the growing popularity of Internet services creation of monitoring solutions on a per- service basis becomes time-consuming and misses opportunities to re-use existing logic. Ideally monitoring solutions would be domain-agnostic, automatically generated and automatically deployed. This thesis progresses these ambitions by providing a generic, distributed monitoring and evaluation framework based on Metric Collector (MeCo) components. These components can transparently gather measurement data across a range of service technologies as used within E-Commerce service environments. MeCo components form part of a framework which can interpret Service Level Agreements (SLAs) to automatically provide tailored service monitoring. The evaluation paradigms of the Meeo Framework are re-appropriated for use in Distributed Virtual Environments (DYEs). Quantifiable QoS requirements are established for Interest Management mechanisms (which limit message production based on object localities within a DYE). These are then incorporated into a DVE Simulator application. This application allows DYE application developers to evaluate Interest Management configurations for their suitability. Extensions to the DVE Simulator are exhibited in the Evolutionary Optimisation Simulator (EOS), which provides automated optimisation capabilities for DVE configurations through utilisation of genetic algorithm techniques.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The E1 copper binding domain of full-length amyloid precursor protein mitigates copper-induced growth inhibition in brain metastatic prostate cancer DU145 cells

Copper plays an important role in the aetiology and growth of tumours and levels of the metal are increased in the serum and tumour tissue of patients affected by a range of cancers including prostate cancer (PCa). The molecular mechanisms that enable cancer cells to proliferate in the presence of elevated copper levels are, therefore, of key importance in our understanding of tumour growth progression. In the current study, we have examined the role played by the amyloid precursor protein (APP) in mitigating copper-induced growth inhibition of the PCa cell line, DU145. A range of APP molecular constructs were stably over-expressed in DU145 cells and their effects on cell proliferation in the presence of copper were monitored. Our results show that endogenous APP expression was induced by sub-toxic copper concentrations in DU145 cells and over-expression of the wild-type protein was able to mitigate copper-induced growth inhibition via a mechanism involving the cytosolic and E1 copper binding domains of the full-length protein. APP likely represents one of a range of copper binding proteins that PCa cells employ in order to ensure efficient proliferation despite elevated concentrations of the metal within the tumour microenvironment. Targeting the expression of such proteins may contribute to therapeutic strategies for the treatment of cancers

Stroma-induced Jagged1 expression drives PC3 prostate cancer cell migration:disparate effects of RIP-generated proteolytic fragments on cell behaviour and Notch signaling

The Notch ligand Jagged1 is subject to regulated intramembrane proteolysis (RIP) which yields a soluble ectodomain (sJag) and a soluble Jagged1 intracellular domain (JICD). The full-length Jagged1 protein enhances prostate cancer (PCa) cell proliferation and is highly expressed in metastatic cells. However, little is known regarding the mechanisms by which Jagged1 or its RIP-generated fragments might promote PCa bone metastasis. In the current study we show that bone marrow stroma (BMS) induces Jagged1 expression in bone metastatic prostate cancer PC3 cells and that this enhanced expression is mechanistically linked to the promotion of cell migration. We also show that RIP-generated Jagged1 fragments exert disparate effects on PC3 cell behaviour and Notch signaling. In conclusion, the expression of both the full-length ligand and its RIP-generated fragments must be considered in tandem when attempting to regulate Jagged1 as a possible PCa therapy

Notch Signalling as a Therapeutic Target in Cancer

Notch signalling is a conserved developmental pathway involved, inter alia, in cell-fate decision, morphogenesis and tissue patterning. Extensive research has linked this pathways with a variety of malignancies, cancer stem cell renewal, induction of epithelial-to-mesenchymal transition and tumor angiogenesis. These data indicate that Notch can act as both a tumor suppressor and an oncoprotein, depending upon cellular context and identify it as a potential therapeutic target in cancer treatment. This review discusses the implications of Notch in a number of hematologic and solid malignancies and some of the currently available inhibitors developed against this pathway as potential cancer therapeutics

Pyruvate dehydrogenase kinase inhibition: Reversing the Warburg effect in cancer therapy

The poor efficacy of many cancer chemotherapeutics, which are often non-selective and highly toxic, is attributable to the remarkable heterogeneity and adaptability of cancer cells. The Warburg effect describes the up regulation of glycolysis as the main source of adenosine 5’-triphosphate in cancer cells, even under normoxic conditions, and is a unique metabolic phenotype of cancer cells. Mitochondrial suppression is also observed which may be implicated in apoptotic suppression and increased funneling of respiratory substrates to anabolic processes, conferring a survival advantage. The mitochondrial pyruvate dehydrogenase complex is subject to meticulous regulation, chiefly by pyruvate dehydrogenase kinase. At the interface between glycolysis and the tricarboxylic acid cycle, the pyruvate dehydrogenase complex functions as a metabolic gatekeeper in determining the fate of glucose, making pyruvate dehydrogenase kinase an attractive candidate in a bid to reverse the Warburg effect in cancer cells. The small pyruvate dehydrogenase kinase inhibitor dichloroacetate has, historically, been used in conditions associated with lactic acidosis but has since gained substantial interest as a potential cancer chemotherapeutic. This review considers the Warburg effect as a unique phenotype of cancer cells in-line with the history of and current approaches to cancer therapies based on pyruvate dehydrogenase kinase inhibition with particular reference to dichloroacetate and its derivatives

Age-Dependent Decline in Mouse Lung Regeneration with Loss of Lung Fibroblast Clonogenicity and Increased Myofibroblastic Differentiation

While aging leads to a reduction in the capacity for regeneration after pneumonectomy (PNX) in most mammals, this biological phenomenon has not been characterized over the lifetime of mice. We measured the age-specific (3, 9, 24 month) effects of PNX on physiology, morphometry, cell proliferation and apoptosis, global gene expression, and lung fibroblast phenotype and clonogenicity in female C57BL6 mice. The data show that only 3 month old mice were fully capable of restoring lung volumes by day 7 and total alveolar surface area by 21 days. By 9 months, the rate of regeneration was slower (with incomplete regeneration by 21 days), and by 24 months there was no regrowth 21 days post-PNX. The early decline in regeneration rate was not associated with changes in alveolar epithelial cell type II (AECII) proliferation or apoptosis rate. However, significant apoptosis and lack of cell proliferation was evident after PNX in both total cells and AECII cells in 24 mo mice. Analysis of gene expression at several time points (1, 3 and 7 days) post-PNX in 9 versus 3 month mice was consistent with a myofibroblast signature (increased Tnc, Lox1, Col3A1, Eln and Tnfrsf12a) and more alpha smooth muscle actin (αSMA) positive myofibroblasts were present after PNX in 9 month than 3 month mice. Isolated lung fibroblasts showed a significant age-dependent loss of clonogenicity. Moreover, lung fibroblasts isolated from 9 and 17 month mice exhibited higher αSMA, Col3A1, Fn1 and S100A expression, and lower expression of the survival gene Mdk consistent with terminal differentiation. These data show that concomitant loss of clonogenicity and progressive myofibroblastic differentiation contributes to the age-dependent decline in the rate of lung regeneration

Copper modulates zinc metalloproteinase-dependent ectodomain shedding of key signaling and adhesion proteins and promotes the invasion of prostate cancer epithelial cells

A disintegrin and metalloproteinases (ADAMs) and matrix metalloproteinases (MMPs) are zinc metalloproteinases (ZMPs) that catalyse the 'ectodomain shedding' of a range of cell surface proteins including signalling and adhesion molecules. These 'sheddases' are associated with the invasion and metastasis of a range of cancers. Increased serum and tumour tissue levels of copper are also observed in several cancers although little is known about how the metal might promote disease progression at the molecular level. In the current study, we investigated whether copper might regulate the ectodomain shedding of two key cell surface proteins implicated in the invasion and metastasis of prostate cancer, the Notch ligand Jagged1 and the adhesion molecule E-cadherin, and whether the metal was able to influence the invasion of the prostate cancer epithelial cell line PC3. Physiological copper concentrations stimulated the ZMP-mediated proteolysis of Jagged1 and E-cadherin in cell culture models whilst other divalent metals had no effect. Copper-mediated Jagged1 proteolysis was also observed following the pre-treatment of cells with cycloheximide and in a cell-free membrane system, indicating a post-translational mechanism of sheddase activation. Finally, the concentrations of copper that stimulated ZMP-mediated protein shedding also enhanced PC3 invasion; an effect which could be negated using a sheddase inhibitor or copper chelators. Collectively, these data implicate copper as an important factor in promoting prostate cancer cell invasion and indicate that the selective post-translational activation of ZMP-mediated protein shedding might play a role in this process.

Purification of the neurodegenerative disease associated protein TDP-43 and development of TDP-43 aggregation inhibitors.

Transactive response DNA-binding protein-43 (TDP-43) is a protein that has been implicated in multiple neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). In these diseases, TDP-43 is found aggregated in the cytoplasm of neurones in the brain and spinal cord and it is hypothesised that this aggregation leads to neuronal degeneration. Despite identification of TDP-43 as a constituent of pathological aggregates in 2006, progress in biochemical characterisation of TDP-43 and its aggregation has been limited by an inability to purify sufficient soluble protein to allow characterisation. In this study, a novel method for the purification of TDP-43 has been developed. The resulting purified protein exists in multiple oligomeric states depending on buffer conditions, displays evidence of secondary structural content by circular dichroism spectroscopy and in preliminary studies demonstrates DNA binding activity. A TDP-43 C-terminal fragment was also purified and a fluorescence-based assay developed to monitor its aggregation, with transmission electron microscopy (TEM) used to image the aggregates produced. In this assay, small molecules were tested as aggregation inhibitors. Following minimal success re-purposing generic aggregation inhibitor molecules, a series of targeted peptide-based inhibitors were designed. The third-generation peptide inhibitors, designed with the aid of the artificial intelligence system AlphaFold, reduced the aggregation of the C-terminal fragment, with TEM identifying changes to the morphology of the aggregates produced. Finally, a “druggable” Saccharomyces cerevisiae yeast cell model of TDP-43 proteinopathy was developed, in which molecules with potential as TDP-43 aggregation inhibitors can be tested further