Search results for "Cell line"
showing 10 items of 2924 documents
Identification of Three-Way DNA Junction Ligands through Screening of Chemical Libraries and Validation by Complementary in Vitro Assays
2019
International audience; The human genome is replete with repetitive DNA sequences that can fold into thermodynamically stable secondary structures such as hairpins and quadruplexes. Cellular enzymes exist to cope with these structures whose stable accumulation would result in DNA damage through interference with DNA transactions such as transcription and replication. Therefore, the chemical stabilization of secondary DNA structures offers an attractive way to foster DNA transaction-associated damages to trigger cell death in proliferating cancer cells. While much emphasis has been recently given to DNA quadruplexes, we focused here on three-way DNA junctions (TWJ) and report on a strategy t…
3′-Demethyldihydromaldoxin and dihydromaldoxin, two anti-inflammtory diaryl ethers from a Steganospora species
2012
CXCL10 (IP-10) is a highly inducible chemoattractant, which contributes to the recruitment of inflammatory cells such as macrophages and T-lymphocytes and thereby has important roles in chronic inflammatory conditions. In a search for new inhibitors of CXCL10 expression in MonoMac6 (MM6) cells, the new diaryl ether 3'-demethyldihydromaldoxin (1) along with the known compound dihydromaldoxin (2), were isolated from fermentations of a Steganospora species. The structures of the compounds were elucidated by a combination of one- and two-dimensional NMR spectroscopy and mass spectrometry. Compounds (1) and (2) inhibited lipopolysaccharide (LPS)/interferon-γ (IFN-γ)-induced CXCL10 promoter activ…
Oxacyclododecindione, a Novel Inhibitor of IL-4 Signaling from Exserohilum rostratum
2008
In a screening program for new metabolites from fungi inhibiting the IL-4 mediated signal transduction, a novel chlorinated macrocyclic lactone, designated as oxacyclododecindione, was isolated from fermentations of the imperfect fungus Exserohilum rostratum. The structure was determined by a combination of spectroscopic techniques. Oxacyclododecindione inhibits the IL-4 induced expression of the reporter gene secreted alkaline phosphatase (SEAP) in transiently transfected HepG2 cells with IC50 values of 20-25 ng/ml (54-67.5 nM). Studies on the mode of action of the compound revealed that the inhibition of the IL-4 dependent signaling pathway is caused by blocking the binding of the activat…
Guanaconetins, new antitumoral acetogenins, mitochondrial complex I and tumor cell growth inhibitors
2005
The antitumoral activity of a series of acetylated bis-tetrahydrofuranic acetogenins with a threo/trans/threo/trans/erythro relative configuration was characterized by four new natural and two semisynthetic, 15,24,30-trioxygenated acetogenins that were found to inhibit mitochondrial complex I enzyme as well as growth of several tumor cell lines. Placement of acetyl groups along the alkyl chain modulated the potency of the bis-tetrahydrofuranic acetogenins and could be important for future utilization of these compounds as chemotherapeutic agents.
Cytotoxicity of Artesunic Acid Homo- and Heterodimer Molecules toward Sensitive and Multidrug-Resistant CCRF-CEM Leukemia Cells
2010
A novel approach to circumvent multidrug resistance is hybridization of natural products in dimers. We analyzed homodimers of two artesunic acid molecules and heterohybrids of artesunic acid and betulin in human CCRF-CEM and multidrug-resistant P-glycoprotein-overexpressing CEM/ADR5000 leukemia cells. Multidrug-resistant cells were not cross-resistant to the novel compounds. Collateral sensitivity was observed for artesunic acid homodimer. Artesunic acid and artesunic acid homodimer induced G0/G1 cell cycle arrest, apoptosis, and formation of reactive oxygen species.
Cytosporones, coumarins, and an alkaloid from the endophytic fungus Pestalotiopsis sp. isolated from the Chinese mangrove plant Rhizophora mucronata
2009
Chemical examination of the endophytic fungus Pestalotiopsis sp., isolated from the leaves of the Chinese mangrove Rhizophora mucronata, yielded 11 new compounds including cytosporones J-N (1-3, 5-6), five new coumarins pestalasins A-E (8-12), and a new alkaloid named pestalotiopsoid A (14), along with the known compounds cytosporone C (4), dothiorelone B (7), and 3-hydroxymethyl-6,8-dimethoxycoumarin (13). The structures of the new compounds were unambiguously elucidated on the basis of extensive spectroscopic data analysis.
Triterpene Saponins from Cyclamen trocopteranthum
2010
Two new triterpene saponins ( 1- 2) together with three known saponins, deglucocyclamin I ( 3), cyclamin ( 4), and mirabilin ( 5), were isolated from the tubers of Cyclamen trocopteranthum. They were elucidated as 3 beta- O-{4- O-[3-hydroxyl-3-methylglutaryl]- beta-D-xylopyranosyl-(1 --> 2)- beta-D-glucopyranosyl-(1 --> 4)-[ beta-D-glucopyranosyl-(1 --> 2)]- alpha-L-arabinopyranosyl}-16 alpha-hydroxy-13 beta,28-epoxy-oleanan-30-al ( 1) and 3 beta- O-{4- O-[3-hydroxyl-3-methylglutaryl]- beta-D-xylopyranosyl-(1 --> 2)-[ beta-D-glucopyranosyl-(1 --> 6)]- beta-D-glucopyranosyl-(1 --> 4)-[ beta-D-glucopyranosyl-(1 --> 2)]- alpha-L-arabinopyranosyl}-16 alpha-hydroxy-20,30-lactone-olean-12-ene ( 2…
Synthesis of platinum complexes with 2-(5-perfluoroalkyl-1,2,4-oxadiazol-3yl)-pyridine and 2-(3-perfluoroalkyl-1-methyl-1,2,4-triazole-5yl)-pyridine …
2016
Five new mononuclear Pt(II) complexes with 5-perfluoroalkyl-1,2,4-oxadiazolyl-pyridine and 3-perfluoroalkyl-1,2,4-triazolyl-pyridine ligands are reported. The ligands 2-(5-perfluoroheptyl-1,2,4-oxadiazole-3yl)-pyridine (pfhop), 2-(5-perfluoropropyl)-1,2,4-oxadiazole-3yl)-pyridine (pfpop), 2-(3-perfluoroheptyl-1-methyl-1,2,4-triazole-5yl)-pyridine (pfhtp), 2-(3-perfluoropropyl-1-methyl-1,2,4-triazole-5yl)-pyridine (pfptp) and their complexes [PtCl2(pfhop)(2)]center dot 1.5 DMSO (2a), [PtCl2(pfpop)(2)]center dot 1.5 DMSO (3a), [PtCl2(pfhtp)(2)]center dot 1.5 DMSO (4a), PtCl2(pfhtp) (4b), [PtCl2(PfPtP)(2)]center dot 1.5 DMSO (5a) have been synthesized and structurally characterized. The comple…
Stable expression in HEK-293 cells of the rat alpha3/beta4 subtype of neuronal nicotinic acetylcholine receptor.
1996
The alpha3/beta4 subtype of neuronal nicotinic acetylcholine receptor (nAChR) was stably expressed in human embryonic kidney (HEK) 293 cells that co-expressed a voltage-gated Ca2+ channel. alpha3/beta4-nAChR-expressing clones were identified using the fura-2 Ca2+ imaging technique, and were further characterised by single-cell and whole-cell patch-clamp studies. Acetylcholine (ACh) induced fast activating currents which showed desensitisation and inward rectification. The conductance of the ACh-activated channel was 29 pS. The order of potency of the nicotinic agonists tested was cytisine approximately = nicotine > acetylcholine. The EC50 value for ACh was 145 microM; the Hill coefficient w…
GFP immunogold staining, from light to electron microscopy, in mammalian cells.
2012
GFP has emerged as an important reporter for monitoring gene expression, protein localization, cell transformation and cell lineage. The development of GFP as a marker in many different biological systems has emphasized the need to image GFP at high resolution. GFP immunogold labeling with colloidal gold particles becomes essential for electron microscopy (EM) ultrastructural detection. Because of the small size, colloidal gold particles require silver enhancement, a procedure to increase the size of the particle as well as gold toning to stabilize the silver layer. GFP preembedding immunogold staining enables high quality cellular-ultrastructural EM analysis mainly for two reasons, on one …