Mesenchymal stem cells as vectors for lung cancer therapy

Despite recent advances in treatment, lung cancer accounts for one third of all cancer-related deaths, underlining the need of development of new therapies. Mesenchymal stem cells (MSCs) possess the ability to specifically home into tumours and their metastases. This property of MSCs could be exploited for the delivery of various anti-tumour agents directly into tumours. However, MSCs are not simple delivery vehicles but cells with active physiological process. This review outlines various agents which can be delivered by MSCs with substantial emphasis on TRAIL (tumour necrosis factor-related apoptosis-inducing ligand)

Synergy of Bosutinib and Chk-1 Inhibitor (PF) in Chemotherapy

Chronic myelogenous leukemia (CML) is a cancer described by uncontrolled proliferation of bone marrow cells that develop into the cells of the blood (Chen, 2014). In this study, the synergy of two drugs, bosutinib and a PF were tested for their efficacy in chemotherapy. Bosutinib is a kinase inhibitor that blocks phosphorylation of key proteins in the cell cycle of CML cells that allow them to proliferate (Boschelli et al., 2010). PF is an inhibitor of the Chk-1 protein that regulates many of the cell cycle checkpoints (Zhang et al., 2009). Two cell lines from CML were used in this experiment, BAF3/T315I and Adult/T315I. Both of these cell lines had the T315I mutation that provides resistance to the common CML chemotherapy drug imatinib (Gleevec). The cultured cells were treated with both bosutinib at 0.3 – 0.4 μM and PF at 1 – 1.2 μM individually as well as simultaneously. Results showed that the combined treatment of bosutinib and PF caused a large increase in cell apoptosis. These results show the possibility of a novel and effective chemotherapy combination for CML.https://scholarscompass.vcu.edu/uresposters/1106/thumbnail.jp

Black Resistance: Interpretive Agency Enacted Against Mutable Violence

Titled Black Resistance: Interpretive Agency Enacted Against Mutable Violence, my research discusses a reformed understanding of racial trauma and autonomy. I elaborate on the common reading of slavery in political thought and defend my argument with modern examples of resistance and theory. This text aims to shine light on assumptive narratives by classifying and redefining mutable violence against black America

Upregulation of Heme Pathway Enzyme ALA Synthase-1 by Glutethimide and 4,6-Dioxoheptanoic Acid and Downregulation by Glucose and Heme: A Dissertation

5-Aminolevulinic acid synthase-1 (ALAS-1) is the first and normally rate-controlling enzyme for hepatic heme biosynthesis. ALAS-1 is highly inducible, especially in liver, in response to changes in nutritional status, and to drugs that induce cytochrome P-450. The critical biochemical abnormality of the acute porphyrias, a group of disorders of heme synthesis, is an uncontrolled up-regulation of ALAS-1. High intakes of glucose or other metabolizable sugars and intravenous heme are the cornerstones of therapy for acute attacks of porphyrias and both repress the over-expression ALAS-1, although their mechanisms of action have not been fully characterized. In this work, the chick hepatoma cell line, LMH, was characterized with respect to its usefulness in studies of heme biosynthesis and compared with chick embryo liver cells (CELCs), a widely used model for studies of heme metabolism. The inducibility of ALAS-1 mRNA and enzyme activity and accumulation of porphyrins by chemicals were used to evaluate heme biosynthesis in LMH cells. Repression of ALAS-1 mRNA and induced activity by exogenous heme (20 μM) was shown to occur in LMH cells as in CELCs. In addition, a synergistic induction of ALAS-1 enzyme activity was observed in LMH cells, as shown previously in CELCs, by treatment with a barbiturate-like chemical, Glutethimide (Glut), in combination with an inhibitor of heme synthesis, 4,6-dioxoheptanoic acid (DHA). This induction of ALAS-1 enzyme activity is analogous to what occurs in patients with acute hepatic porphyrias and LMH cells were used to further characterize effects of Glut, DHA, glucose, and heme on ALAS-1. A glucose effect to decrease Glut and DHA-induced ALAS-1 enzyme activity was obtained in LMH cells and CELCs in the absence of serum or hormones. This glucose effect was further characterized in LMH cells using a construct containing approximately 9.1 kb of chick ALAS-1 5\u27- flanking and 5\u27 -UTR region attached to a luciferase/reporter gene (pGcALAS9.1-Luc). Glut (50 μM) and DHA (250 μM) synergistically induced luciferase activity (5-fold) in LMH cells transiently transfected with pGcALAS9.l-Luc. Addition of glucose (11 or 33 mM), in a dose-dependent manner, decreased the Glut+DHA up-regulation of pGcALAS9.1-Luc activity. Gluconeogenic or glycolytic substrates such as fructose, galactose, glycerol and lactate, but not the non-metabolizable sugar sorbitol, also down-regulated pGcALAS9.1-Luc in LMH cells. The cAMP analog 8-CPT-cAMP, augmented Glut induction of ALAS-1, indicating that the glucose effect may be partly mediated by changes in cAMP levels. The remaining studies focused on delineating the synergistic effect of Glut and DHA, and heme-dependent repression of ALAS-1. The 9.1 kb construct was compared with a construct containing the first 3.5 kb (pGcALAS3.5-Luc). The drug and heme effects were shown to be separate as drug induction was present in -3.4 to +0.082 kb region while the heme responsiveness was present in the -9.1 to -3.4 kb region. Using computer sequence analysis, several consensus activator protein-1 (AP-1) sites were found in the 9.1 kb ALAS-1 sequence but no consensus direct repeat (DR)-4 or DR-5 type recognition sequences for nuclear receptors were identified in the drug-responsive 3.5 kb region. Deletion constructs containing +0.082 to -7.6 kb (pGcALAS7.6-Luc) and +0.082 to -6.2 kb (pGcALAS6.3-Luc) cALAS 5\u27- flanking and 5\u27 - UTR region were generated and tested and pGcALAS6.3-Luc was shown to have heme-dependent repression of basal and Glut and DHA-induced activity. A recently identified 167 bp chick ALAS-1 drug responsive enhancer (DRE) was PCR amplified and inserted upstream of the 9.1 kb (pGcALAS9.1+DRE), a 0.399 kb (+0.082 to -0.317) (pGcALAS0.3+DRE), and pGL3SV40 construct (pGL3SV40+DRE). DRE mediated the up-regulation of pGL3SV40+DRE construct by Glut was ~ 15-30 fold but interestingly only 3.2 and 3.7-fold for pGcALAS9.l +DRE and pGcALAS0.3+DRE constructs, respectively. In summary, in LMH cells drugs up-regulate ALAS-1 through non-DRE element(s) in the first 3.5 kb of ALAS-1 5\u27-flanking and 5\u27-UTR region and heme down-regulates ALAS-1 and determines the extent of the drug response through element(s) in the -6.3 to -3.5 kb region of ALAS-1 5\u27- flanking region

Neutron Irradiation Effects in 5xxx and 6xxx Series Aluminum Alloys: A Literature Review

A literature review on highly irradiated 5xxx and 6xxx series Al alloys is conducted to understand the expected changes in mechanical properties of high flux reactor (HFR) vessel material in relation with microstructural aspects beyond the current surveillance data to support the HFR Surveillance Program (SURP). It was found that the irradiation swelling in 5xxx series alloys is not a crucial degradation mechanism. Dislocation damage is expected to reach a saturation limit in both 5xxx and 6xxx series alloys at relatively low fast-fluence values (<2 × 1026 n/m2). The damage caused by precipitation of transmutation Si is found to be the dominant mechanism affecting the fracture toughness properties of irradiated 5xxx and 6xxx series Al alloys at high thermal fluence values. Tensile and fracture toughness data collected from the literature up to very high thermal fluences are analyzed in comparison with the available HFR surveillance data to predict the behavior of the HFR vessel material beyond current surveillance data. The observed changes in mechanical properties are classified into four different regimes. The contribution of various irradiation damage mechanisms, namely the displacement damage and transmutation damage, to the evolution of microstructure and mechanical properties is discussed in all four regimes for 5xxx and 6xxx series alloys

Synergistic treatment of lung cancer with genetically modified cell therapy and chemotherapy

Lung cancer and malignant pleural mesothelioma (MPM) carry a high mortality. Conventional therapies are ineffective in their treatment and there is a need to develop novel therapies. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a pro-apoptotic agent that triggers the extrinsic death pathway selectively in cancer cells. Mesenchymal stem cells (MSCs) are a type of bone marrow-derived stem cell that have been widely shown to home to and to infiltrate areas of the tumour microenvironment. This homing capacity can be exploited to deliver pro-apoptotic agents, including TRAIL, straight into the tumour micro-environment. Earlier studies show cancers can be treated with TRAIL-expressing MSCs (MSC-flT cells). However, some cell lines are resistant to MSC-flT cells. This study aimed to increase the efficiency of tumour cell killing using MSCs that are engineered to express TRAIL. This study investigates if cancer cell-killing by MSC-flT cells could be enhanced for the treatment of TRAIL-resistant cancers. The aims of this study were to increase the tumour cell-killing efficiency of MSCs engineered to express TRAIL by identifying whether the full-length or soluble form of TRAIL expressed by MSCs is superior in tumour cell killing, whether cancer cell-killing by MSC-flT cells can be increased by combining them with novel chemotherapeutic agents and to identify a biomarker to predict sensitivity to TRAIL. Cancer cell-killing by MSCs expressing full-length TRAIL was superior to that of MSCs expressing the shortened soluble form of TRAIL. MSC-flT cells showed a synergistic cancer killing affect when combined with novel chemotherapeutic agents. In collaboration with McDermott’s laboratory in the Wellcome Trust Sanger Institute, it was found that BAP1-mutated MPM cells are sensitive to TRAIL. This was validated by knock-in and knockdown experiments. It was shown that BAP1-mutated tumours are sensitive to TRAIL in vivo. Further work was done to delineate the mechanism of BAP1-induced TRAIL resistance. The deubiquitinating function of BAP1 and its nuclear localization were shown to be required for TRAIL resistance. This indicates that loss of function of BAP1 is a biomarker for TRAIL sensitivity

An in-situ experimental-numerical approach for interface delamination characterization

Interfacial delamination is a key reliability challenge in composites and microelectronic systems due to (high density) integration of dissimilar materials. Delamination occurs due to significant stresses generated at the interfaces, for instance, caused by thermal cycling due to the mismatch in thermal expansion coefficient and Poisson’s ratio of the adherent layers. Predictive finite element models are generally used to minimize delamination failures during the design and optimization of these materials and systems. Successful prediction, however, requires a relevant interface model that can capture the observed (irreversible) crack initiation and propagation behavior in experiments. To this end, dedicated delamination experiments with in-situ microscopic visualization are needed to identify the relevant delamination mechanism(s) and to accurately measure the interface properties, such as the interface toughness, as a function of mode mixity (i.e. loading angle). Hence, the goal of this research is to develop experimental-numerical tools required for accurate characterization and prediction of interface delamination. As a first step to reach this goal, a novel Miniature Mixed Mode Bending (MMMB) delamination setup, which enables in-situ characterization of interface delamination in miniature multi-layer structures, was designed and realized. This setup employs an inventive loading configuration to sensitively measure global load-displacement delamination curves for the full range of mode mixities from which the interface toughness or Critical Energy Release Rate (CERR) can be determined, while it was designed with sufficiently small dimensions to fit in the chamber of a scanning electron microscope or under an optical microscope for detailed real-time fracture analysis during delamination. The performance of the setup was assessed using dedicated test samples, supported by finite element analyses. The measurement concept was successfully validated on homogeneous bilayer sampleswith a glue interface system. The validation experiments also revealed roomfor improvement of themeasurement accuracy, robustness, and applicability. Therefore, further optimization in the design was performed and an improved version of the MMMB setup was developed. This setup can access a considerably larger range of interface systems, shows significantly higher accuracy and reproducibility in load-displacement measurements, and is more robust. The potential of the new in-situ experimental technique for interface parameter identification was also illustrated. For instance, high resolution in-situ SEM imaging during delamination allows for measurement of the strain maps and crack opening displacement (COD) fields using digital image correlation in addition to the identification of the delamination failure mechanism. In-situ SEM observation of delamination in different interface structures reveals failure mechanisms ranging from interface damage to interface plasticity. Hence, an irreversible model description of the interface behavior that can capture the observed unloading-reloading responses is needed for accurate prediction of, for instance, crack branching and crack propagation at multiple interfaces using predictive finite element models. Therefore, a combined damage and plasticity formulation was presented that is suitable for modeling of the unloading response of an interface ranging from full damage to full plasticity, while it introduces a minimum number of model parameters that can be experimentally determined. The unloading model can be used with the existing mixed-mode cohesive zone laws that describe the interface loading behavior. The relevance and applicability of the unloading model was demonstrated, in combination with the existing improved Xu-Needlemanmixed mode cohesive law, by modeling the observed combined damage-plasticity unloading response of the above-mentioned glue interface system. In addition, a procedure to identify the model parameters has been presented. Permanent deformation of the sample structure often occurs during delamination tests, particularly, if the layers forming the interface are ductile and the interface is strong. Therefore, accurate determination of the interface fracture toughness requires identification and separation of the contribution of structural plasticity to the total energy dissipation, taking into account the presence of plasticity mechanisms within the fracture process zone at the interface that contribute to the interface fracture toughness. To this end, a semi-analytical approach accounting for the structural plasticity in the sample layers was developed, in order to obtain an accurate value of the interface fracture toughness in a mode I experiment. The approach was numerically verified by employing a finite element model with cohesive zone elements (at the interface). The proposed approach was experimentally assessed by characterizing the interface fracture toughness of industrially relevant copper lead framemolding compound epoxy (CuLF-MCE) structures with different layer thicknesses. In summary, the combined application of in-situ MMMB experiments, the analytical procedure to determine the CERR, and the cohesive zone model with the parameter identification procedure allows for accurate characterization of the delamination mechanism(s) and prediction of the interface mechanics. As a demonstration, industrially relevant coated CuLF-MCE and uncoated CuLF-white molding compound (WMC) interface systems have been characterized in detail using the developed experimental tools

Molecular-dynamics simulations of stacking-fault-induced dislocation annihilation in pre-strained ultrathin single-crystalline copper films

We report results of large-scale molecular-dynamics (MD) simulations of dynamic deformation under biaxial tensile strain of pre-strained single-crystalline nanometer-scale-thick face-centered cubic (fcc) copper films. Our results show that stacking faults, which are abundantly present in fcc metals, may play a significant role in the dissociation, cross-slip, and eventual annihilation of dislocations in small-volume structures of fcc metals. The underlying mechanisms are mediated by interactions within and between extended dislocations that lead to annihilation of Shockley partial dislocations or formation of perfect dislocations. Our findings demonstrate dislocation starvation in small-volume structures with ultra-thin film geometry, governed by a mechanism other than dislocation escape to free surfaces, and underline the significant role of geometry in determining the mechanical response of metallic small-volume structures.Comment: 28 pages, 3 figure