Wharton’s jelly-derived mesenchymal stromal cells and fibroblast-derived extracellular matrix synergistically activate apoptosis in a p21-dependent mechanism in WHCO1 and MDA MB 231 cancer cells in vitro

The tumour microenvironment plays a crucial role in tumour progression and comprises tumour stroma which is made up of different cell types and the extracellular matrix (ECM).Mesenchymal stromal cells (MSCs) are part of the tumour stroma and may have conflicting effects on tumour growth. In this study we investigated the effect of Wharton’s Jelly-derived MSCs (WJ-MSCs) and a fibroblast-derived ECM (fd-ECM) on esophageal (WHCO1) and breast (MDAMB 231) cancer cells in vitro. BothWJ-MSCs and the fd-ECM, alone or in combination, downregulate PCNA, cyclin D1, Bcl-2, Bcl-xL, and MMPs and upregulate p53 and p21. p21 induction resulted in G2 phase cell cycle arrest and induced apoptosis in vitro. Our data suggest that p21 induction is via p53- dependent and p53-independent mechanisms inWHCO1 andMDA MB 231 cells, respectively. Vascular endothelial growth factor, Akt, and Nodal pathways were downregulated in cancer cells cocultured with WJ-MSCs. We also demonstrate that WJ-MSCs effects on cancer cells appear to be short-lived whilst the fd-ECM effect is long-lived. This study shows the influence of tumour microenvironment on cancer cell behaviour and provides alternative therapeutic targets for potential regulation of tumour cells.The International Centre for Genetic Engineering and Biotechnology (ICGEB), the South African Medical Research Council, the National Research Foundation (NRF) of South Africa, theUniversity of Pretoria, and the University of Cape Town. Karlien Kallmeyer and Michael S. Pepper’s work was funded by the South African Medical Research Council (University Flagship award and Extramural Stem Cell Unit).http://www.hindawi.com/journals/sci/am2016Immunolog

The garlic compound ajoene covalently binds vimentin, disrupts the vimentin network and exerts anti-metastatic activity in cancer cells

Background Garlic has been used for centuries for its flavour and health promoting properties that include protection against cancer. The vinyl disulfide-sulfoxide ajoene is one of the phytochemicals found in crushed cloves, hypothesised to act by S-thiolating reactive cysteines in target proteins. Methods Using our fluorescently labelled ajoene analogue called dansyl-ajoene, ajoene’s protein targets in MDA-MB-231 breast cancer cells were tagged and separated by 2D electrophoresis. A predominant band was identified by MALDI-TOF MS/MS to be vimentin. Target validation experiments were performed using pure recombinant vimentin protein. Computational modelling of vimentin bound to ajoene was performed using Schrödinger and pKa calculations by Epik software. Cytotoxicity of ajoene in MDA-MB-231 and HeLa cells was measured by the MTT assay. The vimentin filament network was visualised in ajoene-treated and non-treated cells by immunofluorescence and vimentin protein expression was determined by immunoblot. The invasion and migration activity was measured by wound healing and transwell assays using wildtype cells and cells in which the vimentin protein had been transiently knocked down by siRNA or overexpressed. Results The dominant protein tagged by dansyl-ajoene was identified to be the 57 kDa protein vimentin. The vimentin target was validated to reveal that ajoene and dansyl-ajoene covalently bind to recombinant vimentin via a disulfide linkage at Cys-328. Computational modelling showed Cys-328 to be exposed at the termini of the vimentin tetramer. Treatment of MDA-MB-231 or HeLa cells with a non-cytotoxic concentration of ajoene caused the vimentin filament network to condense; and to increase vimentin protein expression. Ajoene inhibited the invasion and migration of both cancer cell lines which was found to be dependent on the presence of vimentin. Vimentin overexpression caused cells to become more migratory, an effect that was completely rescued by ajoene. Conclusions The garlic-derived phytochemical ajoene targets and covalently modifies vimentin in cancer cells by S-thiolating Cys-328. This interaction results in the disruption of the vimentin filament network and contributes to the anti-metastatic activity of ajoene in cancer cells

Addiction in the Light of African Values: Undermining Vitality and Community

In this article I address the question of what makes addiction morally problematic, and seek to answer it by drawing on values salient in the sub-Saharan African philosophical tradition. Specifically, I appeal to life-force and communal relationship, each of which African philosophers have at times advanced as a foundational value, and spell out how addiction, or at least salient instances of it, could be viewed as unethical for flouting them. I do not seek to defend either vitality or community as the best explanation of when and why addiction is immoral, instead arguing that each of these characteristically African values grounds an independent and plausible account of that. I conclude that both vitalism and communalism merit consideration as rivals to accounts that Western ethicists would typically make, according to which addiction is immoral insofar as it degrades rationality or autonomy, as per Kantianism, or causes pain or dissatisfaction, à la utilitarianism

Vascular Metabolism as Driver of Atherosclerosis: Linking Endothelial Metabolism to Inflammation

The endothelium is a crucial regulator of vascular homeostasis by controlling barrier integrity as well acting as an important signal transducer, thereby illustrating that endothelial cells are not inert cells. In the context of atherosclerosis, this barrier function is impaired and endothelial cells become activated, resulting in the upregulation of adhesion molecules, secretion of cytokines and chemokines and internalization of integrins. Finally, this leads to increased vessel permeability, thereby facilitating leukocyte extravasation as well as fostering a pro-inflammatory environment. Additionally, activated endothelial cells can form migrating tip cells and proliferative stalk cells, resulting in the formation of new blood vessels. Emerging evidence has accumulated indicating that cellular metabolism is crucial in fueling these pro-atherosclerotic processes, including neovascularization and inflammation, thereby contributing to plaque progression and altering plaque stability. Therefore, further research is necessary to unravel the complex mechanisms underlying endothelial cell metabolic changes, and exploit this knowledge for finding and developing potential future therapeutic strategies. In this review we discuss the metabolic alterations endothelial cells undergo in the context of inflammation and atherosclerosis and how this relates to changes in endothelial functioning. Finally, we will describe several metabolic targets that are currently being used for therapeutic interventions

Lipoprotein(a): An underestimated inflammatory mastermind

Lipoprotein(a) [Lp(a)] has been established as an independent and causal risk factor for cardiovascular disease. Individuals with elevated levels of Lp(a) (>125 nmol/L; >50 mg/dl) display increased arterial wall inflammation characterized by activation of the endothelium by Lp(a)-carried oxidized phospholipids and recruitment of circulating monocytes. This results in increased secretion of chemoattractants and cytokines, upregulation of adhesion molecules and increased migration of leukocytes through the vessel wall. In addition, Lp(a) is also pivotal in the initiation phase of aortic valve stenosis. The oxidized phospholipids associated, in part, with the apolipoprotein(a) [apo(a)] moiety of Lp(a) stimulate the aortic valve residential cell, the valve interstitial cells (VICs), to either induce osteoblastic differentiation or apoptosis, thereby initiating the process of aortic valve calcification. Lastly, Lp(a) has been linked to systemic inflammation, including the acute phase response. Specifically, the cytokine interleukin 6 (IL-6) has a unique relationship with Lp(a), since the LPA gene contains IL-6 response elements. In this review, we will discuss the pathways and cell types affected by Lp(a) in the context of atherosclerosis, aortic valve stenosis and the acute phase response, highlighting the role of Lp(a) as an inflammatory mastermind

Lipoprotein(a): An underestimated inflammatory mastermind

Lipoprotein(a) [Lp(a)] has been established as an independent and causal risk factor for cardiovascular disease. Individuals with elevated levels of Lp(a) (>125 nmol/L; >50 mg/dl) display increased arterial wall inflammation characterized by activation of the endothelium by Lp(a)-carried oxidized phospholipids and recruitment of circulating monocytes. This results in increased secretion of chemoattractants and cytokines, upregulation of adhesion molecules and increased migration of leukocytes through the vessel wall. In addition, Lp(a) is also pivotal in the initiation phase of aortic valve stenosis. The oxidized phospholipids associated, in part, with the apolipoprotein(a) [apo(a)] moiety of Lp(a) stimulate the aortic valve residential cell, the valve interstitial cells (VICs), to either induce osteoblastic differentiation or apoptosis, thereby initiating the process of aortic valve calcification. Lastly, Lp(a) has been linked to systemic inflammation, including the acute phase response. Specifically, the cytokine interleukin 6 (IL-6) has a unique relationship with Lp(a), since the LPA gene contains IL-6 response elements. In this review, we will discuss the pathways and cell types affected by Lp(a) in the context of atherosclerosis, aortic valve stenosis and the acute phase response, highlighting the role of Lp(a) as an inflammatory mastermind