Venous neointimal hyperplasia (VNH) causes hemodialysis vascular access failure. Here we tested whether VNH formation occurs in part due to local vessel hypoxia caused by surgical trauma to the vasa vasorum of the outflow vein at the time of arteriovenous fistula placement. Selective targeting of the adventitia of the outflow vein at the time of fistula creation was performed using a lentivirus-delivered small hairpin RNA that inhibits VEGF-A expression. This resulted in significant increase in mean lumen vessel area, decreased media/adventitia area, and decreased constrictive remodeling with a significant increase in apoptosis (increase in caspase 3 activity and TUNEL staining) accompanied with decreased cellular proliferation and hypoxia inducible factor-1 alpha at the outflow vein. There was significant decrease in cells staining positive for α-smooth muscle actin (a myofibroblast marker) and VEGFR-1 expression with a decrease in MMP-2 and MMP-9. These results were confirmed in animals that were treated with humanized monoclonal antibody to VEGF-A with similar results. Since hypoxia can cause fibroblast to differentiate into myofibroblasts, we silenced VEGF-A gene expression in fibroblasts and subjected them to hypoxia. This decreased myofibroblast production, cellular proliferation, cell invasion, MMP-2 activity, and increased caspase 3. Thus, VEGF-A reduction at the time of arteriovenous fistula placement results in increased positive vascular remodeling.

A series of dinuclear copper(II) complexes has been synthesized with the aim to investigate their applicability as potential structure and function models for the active site of catechol oxidase enzyme. They have been characterized by routine physicochemical techniques as well as by X-ray single-crystal structure analysis: [Cu 2(H 2L2 (2))(OH)(H 2O)(NO 3)](NO 3) 3.2H 2O ( 1), [Cu(HL1 (4))(H 2O)(NO 3)] 2(NO 3) 2.2H 2O ( 2), [Cu(L1 (1))(H 2O)(NO 3)] 2 ( 3), [Cu 2(L2 (3))(OH)(H 2O) 2](NO 3) 2, ( 4) and [Cu 2(L2 (1))(N 3) 3] ( 5) [L1 = 2-formyl-4-methyl-6R-iminomethyl-phenolato and L2 = 2,6-bis(R-iminomethyl)-4-methyl-phenolato; for L1 (1) and L2 (1), R = N-propylmorpholine; for L2 (2), R = N-ethylpiperazine; for L2 (3), R = N-ethylpyrrolidine, and for L1 (4), R = N-ethylmorpholine]. Dinuclear 1 and 4 possess two "end-off" compartmental ligands with exogenous mu-hydroxido and endogenous mu-phenoxido groups leading to intermetallic distances of 2.9794(15) and 2.9435(9) A, respectively; 2 and 3 are formed by two tridentate compartmental ligands where the copper centers are connected by endogenous phenoxido bridges with Cu-Cu separations of 3.0213(13) and 3.0152(15) A, respectively; 5 is built by an end-off compartmental ligand having exogenous mu-azido and endogenous mu-phenoxido groups with a Cu-Cu distance of 3.133(2) A (mean of two independent molecules). The catecholase activity of all of the complexes has been investigated in acetonitrile and methanol medium by UV-vis spectrophotometric study using 3,5-di- tert-butylcatechol (3,5-DTBC) and tetrachlorocatechol (TCC) as substrates. In acetonitrile medium, the conversion of 3,5-DTBC to 3,5-di- tert-butylbenzoquinone (3,5-DTBQ) catalyzed by 1- 5 is observed to proceed via the formation of two enzyme-substrate adducts, ES1 and ES2, detected spectroscopically for the first time. In methanol medium no such enzyme-substrate adduct has been detected, and the 3,5-DTBC to 3,5-DTBQ conversion is observed to be catalyzed by 1- 5 very efficiently. The substrate TCC forms an adduct with 2- 5 without performing further oxidation to TCQ due to the high reduction potential of TCC (in comparison with 3,5-DTBC). But most interestingly, 1 is observed to be effective even in TCC oxidation, a process never reported earlier. Kinetic experiments have been performed to determine initial rate of reactions (3,5-DTBC as substrate, in methanol medium) and the activity sequence is 1 > 5 > 2 = 4 > 3. A treatment on the basis of Michaelis-Menten model has been applied for kinetic study, suggesting that all five complexes exhibit very high turnover number, especially 1, which exhibits turnover number or K cat of 3.24 x 10 (4) (h (-1)), which is approximately 3.5 times higher than the most efficient catalyst reported to date for catecholase activity in methanol medium.

Venous neointimal hyperplasia (VNH) is responsible for hemodialysis vascular access malfunction. Here we tested whether VNH formation occurs, in part, due to vascular endothelial growth factor-A (VEGF-A) and matrix metalloproteinase (MMP)-9 gene expression causing adventitial fibroblast transdifferentiation to myofibroblasts (α-SMA-positive cells). These cells have increased proliferative and migratory capacity leading to VNH formation. Simvastatin was used to decrease VEGF-A and MMP-9 gene expression in our murine arteriovenous fistula model created by connecting the right carotid artery to the ipsilateral jugular vein. Compared to fistulae of vehicle-treated mice, the fistulae of simvastatin-treated mice had the expected decrease in VEGF-A and MMP-9 but also showed a significant reduction in MMP-2 expression with a significant decrease in VNH and a significant increase in the mean lumen vessel area. There was an increase in terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining, and decreases in α-SMA density, cell proliferation, and HIF-1α and hypoxyprobe staining. This latter result prompted us to determine the effect of simvastatin on fibroblasts subjected to hypoxia in vitro. Simvastatin-treated fibroblasts had a significant decrease in myofibroblast production along with decreased cellular proliferation, migration, and MMP-9 activity but increased caspase 3 activity suggesting increased apoptosis. Thus, simvastatin results in a significant reduction in VNH, with increase in mean lumen vessel area by decreasing VEGF-A/MMP-9 pathway activity.

Background & Aims Pancreatic cancer (PC) frequently causes diabetes. We recently proposed adrenomedullin (AM) as a candidate mediator of pancreatic β-cell dysfunction in PC. How PC-derived AM reaches β-cells remote from the cancer to induce β-cell dysfunction is unknown. We tested a novel hypothesis that PC sheds AM-containing exosomes into circulation which are transported to β-cells and impair insulin secretion. Methods We characterized exosomes from conditioned media of PC-cell lines (n=5) and portal/peripheral venous blood of PC patients (n=20). Western blot analysis showed the presence of AM in PC-Exosomes. We determined the effect of AM-containing PC-Exosomes on insulin secretion from INS-1 β-cells and human islets, and showed how exosomes internalize into β-cells. We studied the interaction between β-cell AM receptors and AM present in PC-Exosomes. In addition, we studied the effect of AM on endoplasmic reticulum (ER) stress response genes and reactive oxygen/nitrogen species generation in β-cells. Results Exosomes were found to be the predominant extracellular vesicles secreted by PC into culture media and human plasma. PC-Exosomes contained AM and CA19-9, readily entered β-cells through caveolin-mediated endocytosis or macropinocytosis, and inhibited insulin secretion. AM in PC-Exosomes interacted with its receptor on β-cells. AM receptor blockade abrogated the inhibitory effect of exosomes on insulin secretion. β-cells exposed to AM or PC-Exosomes showed upregulation of ER stress genes and increased reactive oxygen/nitrogen species. Conclusions Pancreatic cancer causes paraneoplastic β-cell dysfunction by shedding AM+/CA19-9+ exosomes into circulation that inhibit insulin secretion, likely through AM-induced ER stress and failure of the UPR.

VEGF induces vascular permeability (VP) in ischemic diseases IntroductionVascular permeability (VP) plays an integral role in the pathology of cardiovascular disease, stroke, and cancer. VEGF was originally discovered as "vascular permeability factor" described as being a tumor-secreted factor that promotes microvascular permeability potently. 1 It was later discovered separately as VEGF, an endothelial mitogen 2 essential for the development of blood vessels. [3][4][5] Ischemia resulting from cardiac infarction or stroke promotes VEGF expression, which leads to hyperpermeability, edema, and tissue damage. 6,7 Angiogenesis is a key restorative mechanism in response to ischemia, 8,9 creating the therapeutical challenge of regulating the negative and beneficial actions of VEGF temporally to reduce edema and improve ischemic tissue. In cancer, VEGFmediated VP promotes tumor-cell extravasation through damaged endothelial cell junctions, often leading to widespread metastasis. 10 In addition, VEGF expression induces tumor angiogenesis through extravasation of plasma proteins into the surrounding tissue to develop a provisional matrix capable of supporting vascular sprouting and tumor growth. 1 Despite the prevalent role of VEGF-mediated VP in the pathophysiology of cardiac and cerebral diseases and cancer, the genetic regulation of VEGF-induced VP remains unclear because of the lack of an adequate, highthroughput in vivo model with which to assess quantitatively the cumulative contributions of receptors and transduction molecules to VEGF-mediated VP.New methods are necessary to elucidate genetic regulators of VP. Present in vivo VP models, such as the Miles assay, 11,12 the dual-isotopemodified Miles assay, 13 the in vivo peripheral permeability assay, 14 and intravital microscopy, 15-17 have various disadvantages, including the requirement for expensive and time-intensive murine knockout models for genetic studies. The zebrafish (Danio rerio) is a vertebrate with an optically clear embryo that allows high-resolution live imaging and is amenable to high-throughput genetic manipulation, but has yet to be used as an in vivo model to study VEGF-induced VP. In the present study, we undertook the development of a heat shock-inducible zebrafish VEGF model through which VP can be visualized and quantitated in real-time using microangiography of fluorophoreconjugated dextrans. Protein translation-blocking morpholinos (MO) microinjected into VEGF-inducible zebrafish embryos represent a relatively inexpensive and high-throughput means of identifying regulators of VEGF-mediated VP. We demonstrate the utility of this newly developed approach by identifying phospholipase C␤3 (PLC␤3) as a regulator of VEGF-mediated VP.VEGF mediates its activities through 2 receptor tyrosine kinases, VEGFR2 and VEGFR1, [18][19][20] with neuropilin acting as a coreceptor. [21][22][23] Downstream signaling events induced by VEGF include the serine phosphorylation of PLC␤3 24 and tyrosine phosphorylation of PI3K and PLC␥. 25 PLC isoforms mediate the h...

Guanine-rich DNA sequences have the propensity to adopt four-stranded tetrahelical G-quadruplex (G4) structures that are overrepresented in gene promoters. The structural polymorphism and physicochemical properties of these non-Watson–Crick G4 structures make them important targets for drug development. The guanine-rich nuclease hypersensitivity element III1 present in the upstream of P1 promoter of c-MYC oncogene has the ability to form an intramolecular parallel G4 structure. The G4 structure that forms transiently in the c-MYC promoter functions as a transcriptional repressor element. The c-MYC oncogene is overexpressed in a wide variety of cancers and plays a key role in cancer progression. Till now, a large number of compounds that are capable of interacting and stabilizing thec-MYC G4 have been reported. In this review, we summarize various c-MYC G4 specific molecules and discuss their effects on c-MYC gene expression in vitro and in vivo.

Four side-off compartmental ligands L1-L4 [L1 = N,N'-ethylenebis(3-formyl-5-methyl-salicylaldimine), L2 = N,N'-1-methylethylenebis(3-formyl-5-methylsalicylaldimine), L3 = N,N'-1,1-dimethylethylenebis(3-formyl-5-methylsalicylaldimine) and L4= N,N'-cyclohexenebis(3-formyl-5-methylsalicylaldimine)] having two binding sites, N2O2 and O4, have been chosen to synthesize mononuclear and dinuclear manganese(III) complexes with the aim to study their catecholase activity using 3,5-di-tert-butylcatechol (3,5-DTBC) as substrate in the presence of molecular oxygen. In all cases only mononuclear manganese complexes (1-4) were obtained, with manganese coordination taking place at the N2O2 binding site only, irrespective of the amount of manganese salt used. All these complexes have been characterized by routine physico-chemical techniques. Complex MnL2Cl.4H2O (2) has further been structurally characterized by X-ray single crystal structure analysis. Four dinuclear manganese complexes, 5-8, were obtained after condensing the two pending formyl groups on each ligand (L1-L4) with aniline followed by reaction with MnCl2 to put the second Mn atom onto another N2O2 site. The catalytic activity of all complexes 1-8 has been investigated following the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butylbenzoquinone (3,5-DTBQ) with molecular oxygen in two different solvents, methanol and acetonitrile. The study reveals that the catalytic activity is influenced by the solvent and to a significant extent by the backbone of the diamine and the behavior seems to be related mainly to steric rather than electronic factors. Experimental data suggest that a correlation, the lower the E(1/2) value the higher the catalytic activity, can be drawn between E(1/2) and Vmax of the complexes in a particular solvent. The EPR measurements suggest that the catalytic property of the complexes is related to the metal center(s) participation rather than to a radical mechanism.

Glycogen synthase kinase-3 (GSK-3), a constitutively active serine/threonine kinase, is a key regulator of numerous cellular processes ranging from glycogen metabolism to cell cycle regulation and proliferation. Consistent with its involvement in many pathways, it has also been implicated in the pathogenesis of various human diseases including Type II diabetes, Alzheimer's disease, bipolar disorder, inflammation and cancer. Consequently it is recognized as an attractive target for the development of new drugs. In the present study, we investigated the effect of both pharmacological and genetic inhibition of GSK-3 in two different renal cancer cell lines. We have shown potent anti-proliferative activity of 9-ING-41, a maleimide-based GSK-3 inhibitor. The anti-proliferative activity is most likely caused by G0–G1 and G2-M phase arrest as evident from cell cycle analysis. We have established that inhibition of GSK-3 imparted a differentiated phenotype in renal cancer cells. We have also shown that GSK-3 inhibition induced autophagy, likely as a result of imbalanced energy homeostasis caused by impaired glucose metabolism. Additionally, we have demonstrated the antitumor activity of 9-ING-41 in two different subcutaneous xenograft RCC tumor models. To our knowledge, this is the first report describing autophagy induction due to GSK-3 inhibition in renal cancer cells.