The C-Terminal Region Mesd Peptide Mimics Full-Length Mesd and Acts as an Inhibitor of Wnt/?-Catenin Signaling in Cancer Cells.

The C-Terminal Region Mesd Peptide Mimics Full-Length Mesd and Acts as an Inhibitor of Wnt/?-Catenin Signaling in Cancer Cells.

PLoS One. 2013; 8(2): e58102
Lin C, Lu W, Zhang W, Londoño-Joshi AI, Buchsbaum DJ, Bu G, Li Y

While Mesd was discovered as a specialized molecular endoplasmic reticulum chaperone for the Wnt co-receptors LRP5 and LRP6, recombinant Mesd protein is able to bind to mature LRP5 and LRP6 on the cell surface and acts as a universal antagonist of LRP5/6 modulators. In our previous study, we found that the C-terminal region of Mesd, which is absent in sequences from invertebrates, is necessary and sufficient for binding to mature LRP6 on the cell surface. In the present studies, we further characterized the interaction between the C-terminal region Mesd peptide and LRP5/6. We found that Mesd C-terminal region-derived peptides block Mesd binding to LRP5 at the cell surface too. We also showed that there are two LRP5/6 binding sites within Mesd C-terminal region which contain several positively charged residues. Moreover, we demonstrated that the Mesd C-terminal region peptide, like the full-length Mesd protein, blocked Wnt 3A- and Rspodin1-induced Wnt/?-catenin signaling in LRP5- and LRP6- expressing cells, suppressed Wnt/?-catenin signaling in human breast HS578T cells and prostate cancer PC-3 cells, and inhibited cancer cell proliferation, although the full-length Mesd protein is more potent than its peptide. Finally, we found that treatment of the full-length Mesd protein and its C-terminal region peptide significantly increased chemotherapy agent Adriamycin-induced cytotoxicity in HS578T and PC-3 cells. Together, our results suggest that Mesd C-terminal region constitutes the major LRP5/6-binding domain, and that Mesd protein and its C-terminal region peptide have a potential therapeutic value in cancer. HubMed – drug


Application of a Novel Microtitre Plate-Based Assay for the Discovery of New Inhibitors of DNA Gyrase and DNA Topoisomerase VI.

PLoS One. 2013; 8(2): e58010
Taylor JA, Mitchenall LA, Rejzek M, Field RA, Maxwell A

DNA topoisomerases are highly exploited targets for antimicrobial drugs. The spread of antibiotic resistance represents a significant threat to public health and necessitates the discovery of inhibitors that target topoisomerases in novel ways. However, the traditional assays for topoisomerase activity are not suitable for the high-throughput approaches necessary for drug discovery. In this study we validate a novel assay for screening topoisomerase inhibitors. A library of 960 compounds was screened against DNA gyrase and archaeal DNA topoisomerase VI. Several novel inhibitors were identified for both enzymes, and subsequently characterised and . Inhibitors from the topoisomerase VI screen were tested for their ability to inhibit Arabidopsis topoisomerase VI in planta. The data from this work present new options for antibiotic drug discovery and provide insight into the mechanism of topoisomerase VI. HubMed – drug


Systematic Functional Study of Cytochrome P450 2D6 Promoter Polymorphisms in the Chinese Han Population.

PLoS One. 2013; 8(2): e57764
Gong X, Liu Y, Zhang X, Wei Z, Huo R, Shen L, He L, Qin S

The promoter polymorphisms of drug-metabolizing genes can lead to interindividual differences in gene expression, which may result in adverse drug effects and therapeutic failure. Based on the database of gene polymorphisms in the Chinese Han population established by our group, we functionally characterized the single nucleotide polymorphisms (SNPs) of the promoter region and corresponding haplotypes in this population. Using site-directed mutagenesis, all the five SNPs identified and ten haplotypes with a frequency equal to or greater than 0.01 in the population were constructed on a luciferase reporter system. Dual luciferase reporter systems were used to analyze regulatory activity. The activity produced by Haplo3(-2183G>A, -1775A>G, -1589G>C, -1431C>T, -1000G>A, -678A>G), Haplo8(-2065G>A, -2058T>G, -1775A>G, -1589G>C, -1235G>A, -678A>G) and MU3(-498C>A) was 0.7-, 0.7-, 1.2- times respectively compared with the wild type in human hepatoma cell lines(p<0.05). These findings might be useful for optimizing pharmacotherapy and the design of personalized medicine. HubMed – drug


Rivastigmine alleviates experimentally induced colitis in mice and rats by acting at central and peripheral sites to modulate immune responses.

PLoS One. 2013; 8(2): e57668
Shifrin H, Nadler-Milbauer M, Shoham S, Weinstock M

The cholinergic anti-inflammatory system and ?7 nicotinic receptors in macrophages have been proposed to play a role in neuroimmunomodulation and in the etiology of ulcerative colitis. We investigated the ability of a cholinesterase (ChE) inhibitor rivastigmine, to improve the pathology of ulcerative colitis by increasing the concentration of extracellular acetylcholine in the brain and periphery. In combination with carbachol (10 µM), rivastigmine (1 µM) significantly decreased the release of nitric oxide, TNF-?, IL-1? and IL-6 from lipopolysaccharide-activated RAW 264.7 macrophages and this effect was abolished by ?7 nicotinic receptor blockade by bungarotoxin. Rivastigmine (1 mg/kg) but not (0.5 mg/kg), injected subcutaneously once daily in BALB/c mice with colitis induced by 4% dextran sodium sulphate (DSS), reduced the disease activity index (DAI) by 60% and damage to colon structure. Rivastigmine (1 mg/kg) also reduced myeloperoxidase activity and IL-6 by >60%, and the infiltration of CD11b expressing cells by 80%. These effects were accompanied by significantly greater ChE inhibition in cortex, brain stem, plasma and colon than that after 0.5 mg/kg. Co-administration of rivastigmine (1 mg/kg) with the muscarinic antagonist scopolamine significantly increased the number of CD11b expressing cells in the colon but did not change DAI compared to those treated with rivastigmine alone. Rivastigmine 1 and 2 mg given rectally to rats with colitis induced by rectal administration of 30 mg dintrobezene sulfonic acid (DNBS) also caused a dose related reduction in ChE activity in blood and colon, the number of ulcers and area of ulceration, levels of TNF-? and in MPO activity. The study revealed that the ChE inhibitor rivastigmine is able to reduce gastro-intestinal inflammation by actions at various sites at which it preserves ACh. These include ACh released from vagal nerve endings that activates alpha7 nicotinic receptors on circulating macrophages and in brainstem neurons. HubMed – drug