Ex vivo determination of an estradiol analogue-induced changes on platelet morphology and angiogenic biomarkers

Angiogenesis is a closely controlled biological process that takes place during fetal development of blood vessels and wound healing, and includes the development of new blood vessels from preexisting blood vessels. Tumor angiogenesis is a means by which tumors obtain oxygen, nutrition and promote tumor growth. Angiogenesis-regulating proteins are therefore ideal biomarkers in the study of tumor pathophysiology. In our laboratory, a new in silico-designed analogue of 2-methoxyestradiol has been synthesized with angiogenic properties, namely 2-ethyl-3-O-sulfamoyl-estra-1,3,5(10)16-tetraene (ESE-16). The ex vivo influence of ESE-16 on angiogenesis and morphology in platelets of healthy participants was investigated. Scanning electron microscopy revealed no morphological changes in ESE-16-treated platelets. The possible antiangiogenic effect of ESE-16-exposed platelets was determined by means of flow cytometry measurement of angiogenic protein levels, which were significantly increased after platelets were added to tumorigenic breast epithelial cells. This indicates that binding of platelets to cancer cells causes differential release of platelet constituents. Vascular endothelial growth factor levels were decreased in platelets, whereas platelet-derived growth factor and matrix metallopeptidase-9 levels were not significantly affected in platelets. In light of the above-mentioned data, further investigation of ESE-16’s influence on morphology and angiogenic markers in platelets of cancer patients is warranted.Struwig-Germeshuysen Research Trust of South Africa, the National Research Foundation, the Cancer Association of South Africa, and the South African Medical Research Council.http://journals.cambridge.org/action/displayJournal?jid=MAM2016-06-30hb201

In Vitro Evaluation of the Influence of Substrate Mechanics on Matrix-Assisted Human Chondrocyte Transplantation

Matrix-assisted chondrocyte transplantation (MACT) is of great interest for the treatment of patients with cartilage lesions. However, the roles of the matrix properties in modulating cartilage tissue integration during MACT recovery have not been fully understood. The objective of this study was to uncover the effects of substrate mechanics on the integration of implanted chondrocyte-laden hydrogels with native cartilage tissues. To this end, agarose hydrogels with Young’s moduli ranging from 0.49 kPa (0.5%, w/v) to 23.08 kPa (10%) were prepared and incorporated into an in vitro human cartilage explant model. The hydrogel-cartilage composites were cultivated for up to 12 weeks and harvested for evaluation via scanning electron microscopy, histology, and a push-through test. Our results demonstrated that integration strength at the hydrogel-cartilage interface in the 1.0% (0.93 kPa) and 2.5% (3.30 kPa) agarose groups significantly increased over time, whereas hydrogels with higher stiffness (\u3e8.78 kPa) led to poor integration with articular cartilage. Extensive sprouting of extracellular matrix in the interfacial regions was only observed in the 0.5% to 2.5% agarose groups. Collectively, our findings suggest that while neocartilage development and its integration with native cartilage are modulated by substrate elasticity, an optimal Young’s modulus (3.30 kPa) possessed by agarose hydrogels is identified such that superior quality of tissue integration is achieved without compromising tissue properties of implanted constructs

The dynamic roles of TGF-β signalling in EBV-associated cancers

The transforming growth factor-β (TGF-β) signalling pathway plays a critical role in carcinogenesis. It has a biphasic action by initially suppressing tumorigenesis but promoting tumour progression in the later stages of disease. Consequently, the functional outcome of TGF-β signalling is strongly context-dependent and is influenced by various factors including cell, tissue and cancer type. Disruption of this pathway can be caused by various means, including genetic and environmental factors. A number of human viruses have been shown to modulate TGF-β signalling during tumorigenesis. In this review, we describe how this pathway is perturbed in Epstein-Barr virus (EBV)-associated cancers and how EBV interferes with TGF-β signal transduction. The role of TGF-β in regulating the EBV life cycle in tumour cells is also discussed

The Isolation and Characterization of Growth Regulatory Factors Produced by a Herpes Simplex Virus Type 2 Transformed Mouse Tumor Cell Line, H238

Transformation of cells with herpes simplex virus Type 2 (HSV- 2)occurs by an unknown mechanism. No specific gene or gene product has been consistently associated with HSV-2 transformation as is the case for other tumor viruses. This study was performed in an attempt to associate HSV-2-transformation with specific growth factors in order to develop a testable model for HSV-2-transformation. For some tumor viruses, particularly those containing RNA, there has been a central concept (autocrine secretion) linking oncogenes and growth factors. This concept centers on the ability of the cancer cells to produce and respond to their own autologous factors. We report here the isolation and characterization of four growth regulatory factors produced by H238, an HSV-2-transformed mouse tumor cell line. The H238 cells were grown in culture flasks to two-thirds confluency in medium containing 10% fetal bovine serum. The medium was removed, the cells were washed and medium without serum was added to the cells. At intervals of 48 hours, this conditioned medium (H238-CM), which contained growth regulatory factors, produced by the cells, was withdrawn and stored frozen. These factors were separated from the H238-CM by heparin-sepharose affinity chromatography into three peaks of mitogenic activity and a fourth containing inhibitory activity for splenocytes. The three peaks of mitogenic activity have been identified based on physiochemical characteristics: the first supported the anchorage-independent growth of EGF treated NRK-c-49 cells and resembles transforming growth factor-^ (TGF-/3); the second bound to lectin-coated sepharose beads and was sensitive to trypsin, neuroaminidase, and the reducing agent dithiothreitol (DTT) and, resembled a platelet-derived growth factor (PDGF)-like factor; and the third displaced [ 125I]-labeled basic fibroblast growth factor (bFGF) in a dose dependent fashion when tested with a radioimmune assay (RIA). The fourth peak was inhibitory for a variety of splenocyte function assays. It inhibited lectininduced blastogenesis, allogenic mixed lymphocyte reaction (MLR), and It appeared to act on splenocyte Gq/G-^ transition causing growth arrest by inhibiting c-myc proto-oncogene IL-2 production by splenocytes. expression. A model for the interaction of these factors in vivo is presented with an emphasis on testability