Integrins as therapeutic targets: lessons and opportunities.

The integrins are a large family of cell adhesion molecules that are essential for the regulation of cell growth and function. The identification of key roles for integrins in a diverse range of diseases, including cancer, infection, thrombosis and autoimmune disorders, has revealed their substantial potential as therapeutic targets. However, so far, pharmacological inhibitors for only three integrins have received marketing approval. This article discusses the structure and function of integrins, their roles in disease and the chequered history of the approved integrin antagonists. Recent advances in the understanding of integrin function, ligand interaction and signalling pathways suggest novel strategies for inhibiting integrin function that could help harness their full potential as therapeutic targets

A computational analysis of the dynamic roles of talin, Dok1, and PIPKI for integrin activation

Integrin signaling regulates cell migration and plays a pivotal role in developmental processes and cancer metastasis. Integrin signaling has been studied extensively and much data is available on pathway components and interactions. Yet the data is fragmented and an integrated model is missing. We use a rule-based modeling approach to integrate available data and test biological hypotheses regarding the role of talin, Dok1 and PIPKI in integrin activation. The detailed biochemical characterization of integrin signaling provides us with measured values for most of the kinetics parameters. However, measurements are not fully accurate and the cellular concentrations of signaling proteins are largely unknown and expected to vary substantially across different cellular conditions. By sampling model behaviors over the physiologically realistic parameter range we find that the model exhibits only two different qualitative behaviours and these depend mainly on the relative protein concentrations, which offers a powerful point of control to the cell. Our study highlights the necessity to characterize model behavior not for a single parameter optimum, but to identify parameter sets that characterize different signaling modes

Immunostaining with D2–40 improves evaluation of lymphovascular invasion, but may not predict sentinel lymph node status in early breast cancer

<p>Abstract</p> <p>Background</p> <p>Sentinel lymph node (SLN) biopsy is a widely used diagnostic procedure in the management of early breast cancer. When SLN is free of metastasis, complete axillary dissection may be skipped for staging in clinically N0 patients, allowing a more conservative procedure. Histological tumor features that could reliably predict SLN status have not yet been established. Since the degree of tumor lymphangiogenesis and vascularization may theoretically be related to the risk of lymph node metastasis, we sought to evaluate the relationship between lymph vessel invasion (LVI), lymphatic microvascular density (LVD), microvascular density (MVD) and VEGF-A expression, with SLN status and other known adverse clinical risk factors.</p> <p>Methods</p> <p>Protein expression of D2–40, CD34, and VEGF-A was assessed by immunohistochemistry on paraffin-embedded sections of primary breast cancer specimens from 92 patients submitted to SLN investigation. The presence of LVI, the highest number of micro vessels stained for D2–40 and CD34, and the protein expression of VEGF-A were compared to SLN status, clinicopathological features and risk groups.</p> <p>Results</p> <p>LVI was detected in higher ratios by immunostaining with D2–40 (p < 0.0001), what would have changed the risk category from low to intermediate in four cases (4.3%). There was no association between LVI and other angiogenic parameters determined by immunohistochemistry with SLN macrometastases, clinical features or risk categories.</p> <p>Conclusion</p> <p>Assessment of LVI in breast carcinoma may be significantly increased by immunostaining with D2–40, but the clinical relevance of altering the risk category using this parameter may not be advocated according to our results, neither can the use of LVI and LVD as predictors of SLN macrometastasis in early breast cancer.</p

The interaction of Thrombospondins with extracellular matrix proteins

The thrombospondins (TSPs) are a family of five matricellular proteins that appear to function as adapter molecules to guide extracellular matrix synthesis and tissue remodeling in a variety of normal and disease settings. Various TSPs have been shown to bind to fibronectin, laminin, matrilins, collagens and other extracellular matrix (ECM) proteins. The importance of TSP-1 in this context is underscored by the fact that it is rapidly deposited at the sites of tissue damage by platelets. An association of TSPs with collagens has been known for over 25 years. The observation that the disruption of the TSP-2 gene in mice leads to collagen fibril abnormalities provided important in vivo evidence that these interactions are physiologically important. Recent biochemical studies have shown that TSP-5 promotes collagen fibril assembly and structural studies suggest that TSPs may interact with collagens through a highly conserved potential metal ion dependent adhesion site (MIDAS). These interactions are critical for normal tissue homeostasis, tumor progression and the etiology of skeletal dysplasias

Transformation of PVP coated silver nanoparticles in a simulated wastewater treatment process and the effect on microbial communities

Extent: 18p.Background: Manufactured silver nanoparticles (AgNPs) are one of the most commonly used nanomaterials in consumer goods and consequently their concentrations in wastewater and hence wastewater treatment plants are predicted to increase. We investigated the fate of AgNPs in sludge that was subjected to aerobic and anaerobic treatment and the impact of AgNPs on microbial processes and communities. The initial identification of AgNPs in sludge was carried out using transmission electron microscopy (TEM) with energy dispersive X-ray (EDX) analysis. The solid phase speciation of silver in sludge and wastewater influent was then examined using X-ray absorption spectroscopy (XAS). The effects of transformed AgNPs (mainly Ag-S phases) on nitrification, wastewater microbial populations and, for the first time, methanogenesis was investigated. Results: Sequencing batch reactor experiments and anaerobic batch tests, both demonstrated that nitrification rate and methane production were not affected by the addition of AgNPs [at 2.5 mg Ag L-1 (4.9 g L-1 total suspended solids, TSS) and 183.6 mg Ag kg -1 (2.9 g kg-1 total solids, TS), respectively]. The low toxicity is most likely due to AgNP sulfidation. XAS analysis showed that sulfur bonded Ag was the dominant Ag species in both aerobic (activated sludge) and anaerobic sludge. In AgNP and AgNO3 spiked aerobic sludge, metallic Ag was detected (~15%). However, after anaerobic digestion, Ag(0) was not detected by XAS analysis. Dominant wastewater microbial populations were not affected by AgNPs as determined by DNA extraction and pyrotag sequencing. However, there was a shift in niche populations in both aerobic and anaerobic sludge, with a shift in AgNP treated sludge compared with controls. This is the first time that the impact of transformed AgNPs (mainly Ag-S phases) on anaerobic digestion has been reported. Conclusions: Silver NPs were transformed to Ag-S phases during activated sludge treatment (prior to anaerobic digestion). Transformed AgNPs, at predicted future Ag wastewater concentrations, did not affect nitrification or methanogenesis. Consequently, AgNPs are very unlikely to affect the efficient functioning of wastewater treatment plants. However, AgNPs may negatively affect sub-dominant wastewater microbial communities.Casey L Doolette, Mike J McLaughlin, Jason K Kirby, Damien J Batstone, Hugh H Harris, Huoqing Ge and Geert Corneli

Myocardial ischemia and reperfusion: The role of oxygen radicals in tissue injury

Thrombolytic therapy has gained widespread acceplance as a means of treating coronary artery thrombosis in patients with acute myocardial infarction. Although experimental data have demonstrated that timely reperfusion limits the extent of infarction caused by regional ischemia, there is growing evidence that reperfusion is associated with an inflammatory response to ischemia that exacerbates the tissue injury. Ischemic myocardium releases archidonate and complement-derived chemotactic factors, e.g., leukotriene B 4 and C 5a , which attract and activate neutrophils. Reperfusion of ischemic myocardium accelerates the influx of neutrophils, which release reactive oxygen products, such as superoxide anion and hydrogen peroxide, resulting in the formation of a hydroxyl radical and hypochlorous acid. The latter two species may damage viable endothelial cells and myocytes via the peroxidation of lipids and oxidation of protein sulfhydryl groups, leading to perturbations of membrane permeability and enzyme function. Neutrophil depletion by antiserum and inhibition of neutrophil function by drugs, e.g., ibuprofen, prostaglandins (prostacyclin and PGE 1 ), or a monoclonal antibody, to the adherence-promoting glycoprotein Mo-1 receptor, have been shown to limit the extent of canine myocardial injury due to coronary artery occlusion/reperfusion. Recent studies have challenged the hypothesis that xanthine-oxidase-derived oxygen radicals are a cause of reperfusion injury. Treatment with allopurinol or oxypurinol may exert beneficial effects on ischemic myocardium that are unrelated to the inhibition of xanthine oxidase. Furthermore, the human heart may lack xanthine oxidase activity. Further basic research is needed, therefore, to clarify the importance of xanthine oxidase in the pathophysiology of reperfusion injury. Current data are highly suggestive of a deleterious role of the neutrophil in organ reperfusion and justify consideration of the clinical investigation of neutrophil inhibitors in patients receiving thrombolytic agents during the evolution of an acute myocardial infarction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44595/1/10557_2004_Article_BF00133206.pd

Abstract P4-09-08: miR-135a is associated with a metastatic phenotype in invasive lobular carcinoma

Abstract Invasive lobular carcinoma (ILC) is the second most common type of breast cancer. Classic type ILC is generally regarded as indolent in nature with its favourable biologic characteristics such as low grade, ER positivity and luminal A subtype. Despite this, patients with ILC can develop significant distant recurrence or metastases. Thus the ability to identify those patients at highest risk of recurrence or metastasis, and identification of novel therapies for ILC are urgently required. To this end, we recently profiled the miRNA expression in primary surgical ILC specimens from patients who went on to have metastatic disease compared to those who remained tumor free long term. As miRNA are stable in formalin fixed paraffin embedded tissues1, we speculated they could be robust biomarkers. RNA was isolated from laser capture microdissected ILC tumor epithelium, and subjected to miRNome analysis using a PCR-based amplification method. Many differentially expressed miRNAs were identified, and we initially focused further validation on those which had been previously linked to metastasis. One of these, miR-135a, was elevated in tumors from ILC patients who developed metastases compared to those that did not. We utilized two representative ILC cell lines which differ in their invasive ability, MDA-MB-134VI (non-invasive) and MDA-MB-330 (invasive), to test whether miR-135a regulated ILC invasion. We found that levels of miR-135a correlated with the invasive potential of ILC cell lines and was elevated in the invasive MDA-MB-330 cells compared to less invasive MDA-MB-134VI cells. We also found that decreasing miR-135a expression using specific hairpin inhibitors in MDA-MB-330 cells resulted in decreased cell invasion. As miR-135a has been shown to regulate invasion via targeting metastasis suppressor 1 (MTSS1) mRNA for degradation2, we examined whether MTSS1 levels were inversely associated with miR-135a levels in ILC cells. As predicted, in MDA-MB-330 cells where miR-135a levels were significantly higher, levels of MTSS1 were the lowest while MTSS1 levels were higher in parallel with decreased levels of miR-135a in the non-invasive MDA-MB-134VI cells. Overexpressing miR-135a using miRNA mimics in normal mammary epithelial cells (HMEC) where miR-135a is normally low, reduced levels of MTSS1 supporting suggestions it is a direct target of miR-135a. We also confirmed reduced mRNA levels of MTSS1 in surgical specimens from ILC patients who developed metastases compared to those that did not. Taken together, our results suggest that high levels of miR-135a, and low levels of MTSS1 may be useful prognostic information to assess risk of metastasis in ILC. References 1. Bovell L, Shanmugam C, Katkoori VR, et al: miRNAs are stable in colorectal cancer archival tissue blocks. Front Biosci (Elite Ed) 4:1937-40, 2012 2. Zhou W, Li X, Liu F, et al: MiR-135a promotes growth and invasion of colorectal cancer via metastasis suppressor 1 in vitro. Acta Biochim Biophys Sin (Shanghai) 44:838-46, 2012. Citation Format: Howe GA, Zhao H, Daneshmand M, Clemons M, Robertson SJ, Arnaout A, Addison CL. miR-135a is associated with a metastatic phenotype in invasive lobular carcinoma. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-09-08.</jats:p