Wilms' tumors (WT), which accountfor 6% of all childhood cancers, arise from dysregulated differentiation of nephrogenic progenitor cells from embryonic kidneys. Though there is an improvement in the prognosis of WT, still 10% of patients with WT die due to recurrence. Thus more effective treatment approaches are necessary. We previously characterized the inflammatory microenvironment in human WT and observed the robust expression of COX-2. The aim of this study was to extend our studies to analyze the role of COX-2 pathway components in WT progression using a mouse model of WT. Herein, COX-2 pathway components such as COX-2, HIF1-α, p-ERK1/2, and p-STAT3 were upregulated in mouse and human tumor tissues. In our RPPA analysis, COX-2 was up-regulated in M15 cells after Wt1 gene was knocked down. Flow cytometry analysis showed the increased infiltration of immune suppressive inflammatory cells such as pDC's and Treg cells in tumors. The chemotactic chemokines responsible for the infiltration of these cells were also induced in CCR5 and CXCR4 dependent manner respectively. The immunosuppressive cytokines IL-10, TGF-β, and TNF-α were also up-regulated. Furthermore, more pronounced Th2 and Treg induced cytokine response was observed than Th1 response in tumors. Basing on all these evidences it is speculated that COX-2 pathway may be a beneficial target for the treatment of WT. It may be most effective as an adjuvant therapy together with other inhibitors. Thus, our current study provides a good rationale for initiating animal studies to confirm the efficacy of COX-2 inhibitors in decreasing tumor cell growth in vivo.

The role of inflammation in cancer has been reported in various adult malignant neoplasms. By contrast, its role in pediatric tumors has not been as well studied. In this study, we have identified and characterized the infiltration of various inflammatory immune cells as well as inflammatory markers in Wilms tumor (WT), the most common renal malignancy in children. Formalin-fixed paraffin-embedded blocks from tumors and autologous normal kidneys were immunostained for inflammatory immune cells (T cells, B cells, macrophages, neutrophils, and mast cells) and inflammatory markers such as cyclooxygenase-2 (COX-2), hypoxia-inducible factor 1α, phosphorylated STAT3, phosphorylated extracellular signal–related kinases 1 and 2, inducible nitric oxide synthase, nitrotyrosine, and vascular endothelial growth factor expression. Overall, we found that there was predominant infiltration of tumor-associated macrophages in the tumor stroma where COX-2 was robustly expressed. The other tumor-associated inflammatory markers were also mostly localized to tumor stroma. Hence, we speculate that COX-2–mediated inflammatory microenvironment may be important in WT growth and potential therapies targeting this pathway may be beneficial and should be tested in clinical settings for the treatment of WTs in children.

Aim: Cigarette smoking is a recognized risk factor for cardiovascular diseases and has been implicated in the pathogenesis of atherosclerosis. Platelet adhesiveness and aggregation increases as a result of smoking. Cigarette smoking modifies haemostatic parameters via thrombosis with a consequently higher rate of cardiovascular events, but smoking-induced alterations of platelet membrane fluidity and other changes have not been studied. Methods: Thirty experimental and control subjects (mean age 35 8) were selected for the study. Experimental subjects had smoked 10 2 cigarettes per day for 7 − 10 years. The plasma lipid profile, platelet carbonyls, sulfhydryl groups, Na /K -ATPase activity, fluidity using a fluorescent probe 1,6-diphenyl-1,3,5-hexatriene (DPH), total cholesterol and phospholipids as well individual phospholipids were determined. Results: Increases in the platelet membrane cholesterol phospholipid (C/P) ratio, phosphotidylethanolamine, phosphotidylserine with decreased phosphotidylcholine, Na /K -ATPase activity, fluidity and no significant change in phosphotidylinositol and sphingomylein, as well as increases in plasma total cholesterol, LDL-cholesterol, protein carbonyls with decreased HDL-cholesterol and sulfhydryl groups were observed in cigarette smokers. Platelet membrane total phospholipids were positively correlated with plasma LDL-cholesterol (r 0.568) and VLDL-cholesterol (r 0.614) in cigarette smokers. Conclusions: Increased plasma LDL-cholesterol, VLDL-cholesterol and total cholesterol might have resulted in the increased C/P ratio and decreased platelet membrane fluidity of cigarette smokers. J Atheroscler Thromb, 2010; 17:619-627.

Seven transmembrane receptors widely known as G-proteincoupled receptors (GPCRs) 4 (1, 2) mediate an array of physiological processes in response to such diverse agonists as peptides, amino acid derivatives, and lipids. Despite the great diversity in their ligands, the conserved motifs found across this superfamily and the limited interacting partners such as G-proteins (3) and ␤-arrestins (4) at the cytoplasmic interface point toward a common activation mechanism for GPCRs. GPCRs constitute the single largest group of molecules for drug targets due to their critical importance in mediating biological responses as well as their easy accessibility on the cell surface. However, very little structural information is available for GPCRs due to difficulties in purifying and obtaining crystal structures for this class of receptors. The availability of the rhodopsin crystal structure (5) combined with the approach of computational modeling and validation by site-directed mutagenesis has led to delineation of ligand-receptor interactions in a few GPCRs (6 -9). Some elements of the activation mechanism have been identified for individual GPCRs (1,6,8,[10][11][12]. Several studies employing site-directed mutagenesis have helped uncover critical interactions between residues in transmembrane domains of the GPCRs (reviewed in Ref. 1). The approach of computational modeling with validation by site-directed mutagenesis has led to significant increases in the understanding of the processes involved in GPCR activation (6 -9).Leukotriene B 4 (LTB 4 ) is a potent leukocyte chemoattractant and mediates its biological effects through two distinct GPCRs, the high affinity receptor BLT1 and the low affinity receptor BLT2 (13,14). Several recent studies suggested a direct and critical role for BLT1 in diverse inflammatory diseases such as arthritis (15, 16), atherosclerosis (17, 18), and asthma (19). Recently, the high affinity LTB 4 receptor, BLT1, was expressed in Escherichia coli and shown to form a functional pentameric complex with heterotrimeric G-proteins (20). Computational modeling has been used to investigate the potential role of the eighth helix in signaling of BLT1 (21,22). In addition, a recent study reported an LTB 4 binding site in BLT1 deduced from computational models (23). However, the exact nature of the LTB 4 binding site and the potential changes in receptor conformation following LTB 4 binding remain unknown.In this study, computational modeling together with sitedirected mutagenesis led to precise mapping and validation of the LTB 4 binding site in BLT1. Mutation of each of the residues predicted to be in the putative binding site resulted in reduced binding affinity. Furthermore, analysis of dynamic structures of the ligand-free and ligand-bound BLT1 allowed prediction of critical movements of transmembrane helices and essential

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The presence of mast cells in some human colorectal cancers is a positive prognostic factor, but the basis for this association is incompletely understood. Here, we found that mice with a heterozygous mutation in the displayed reduced intestinal tumor burdens and increased survival in a chemokine decoy receptor, ACKR2-null background, which led to discovery of a critical role for mast cells in tumor defense. ACKR2Apc tumors showed increased infiltration of mast cells, their survival advantage was lost in mast cell-deficient ACKR2SAApc mice as the tumors grew rapidly, and adoptive transfer of mast cells restored control of tumor growth. Mast cells from ACKR2 mice showed elevated CCR2 and CCR5 expression and were also efficient in antigen presentation and activation of CD8 T cells. Mast cell-derived leukotriene B (LTB) was found to be required for CD8 T lymphocyte recruitment, as mice lacking the LTB receptor (ACKR2BLT1Apc) were highly susceptible to intestinal tumor-induced mortality. Taken together, these data demonstrate that chemokine-mediated recruitment of mast cells is essential for initiating LTB/BLT1-regulated CD8 T-cell homing and generation of effective antitumor immunity against intestinal tumors. We speculate that the pathway reported here underlies the positive prognostic significance of mast cells in selected human tumors.

Ethanol disorders biological membranes causing perturbations in the bilayer and also by altering the physicochemical properties of membrane lipids. But, chronic alcohol consumption also increases nitric oxide (NO) production. There was no systemic study was done related to alcohol-induced production of NO and consequent formation of peroxynitrite mediated changes in biophysical and biochemical properties, structure, composition, integrity and function of erythrocyte membranes in chronic alcoholics. Hence, keeping all these conditions in mind the present study was undertaken to investigate the role of over produced nitric oxide on red cell membrane physicochemical properties in chronic alcoholics. Human male volunteers aged 44 +/- 6 years with similar dietary habits were divided into two groups, namely nonalcoholic controls and chronic alcoholics (~125 g of alcohol at least five times per week for the past 10-12 years). Elevated nitrite and nitrate levels in plasma and lysate, changes in erythrocyte membrane individual phospholipid composition, increased lipid peroxidation, protein carbonyls, cholesterol and phospholipids ratio (C/P ratio) and anisotropic value (gamma) with decreased sulfhydryl groups and Na(+)/K(+)-ATPase activity in alcoholics was evident from this study. RBC lysate NO was positively correlated with C/P ratio (r = 0.547) and anisotropic (gamma) value (r = 0.428), Na(+)/K(+)-ATPase activity was negatively correlated with RBC lysate NO (r = -0.372) and anisotropic (gamma) value (r = -0.624) in alcoholics. Alcohol-induced overproduction of nitric oxide reacts with superoxide radicals to produce peroxynitrite, which appears to be responsible for changes in erythrocyte membrane lipids and the activity of Na(+)/K(+)-ATPase.

Prolonged hyperoxia contributes to bronchopulmonary dysplasia (BPD) in preterm infants. β-Naphthoflavone (BNF) is a potent inducer of cytochrome P450 (CYP)1A enzymes, which have been implicated in hyperoxic injuries in adult mice. In this investigation, we tested the hypothesis that newborn mice lacking the Cyp1a1 gene would be more susceptible to hyperoxic lung injury than wild-type (WT) mice and that postnatal BNF treatment would rescue this phenotype by mechanisms involving CYP1A and/or NAD(P)H quinone oxidoreductase (NQO1) enzymes. Newborn WT or Cyp1a1-null mice were treated with BNF (10 mg/kg) or the vehicle corn oil (CO) i.p., from postnatal day (PND) 2 to 14 once every other day, while being maintained in room air or hyperoxia (85% O2) for 14 days. Both genotypes showed lung injury, inflammation, and alveolar simplification in hyperoxia, with Cyp1a1-null mice displaying increased susceptibility compared to WT mice. BNF treatment resulted in significant attenuation of lung injury and inflammation, with improved alveolarization in both WT and Cyp1a1-null mice. BNF exposed normoxic or hyperoxic WT mice showed increased expression of hepatic CYP1A1/1A2, pulmonary CYP1A1, and NQO1 expression at both mRNA and protein levels, compared with vehicle controls. However, BNF caused greater induction of hepatic CYP1A2 and pulmonary NQO1 enzymes in the Cyp1a1-null mice, suggesting that BNF protects against hyperoxic lung injury in WT and Cyp1a1-null mice through the induction of CYP1A and NQO1 enzymes. Further studies on the protective role of flavonoids against hyperoxic lung injury in newborns could lead to novel strategies for the prevention and/or treatment of BPD.