Home About us Contact
|
Home About us Contact | ||
|
|
||
Cytotoxicity Data (cytotoxicity + data)
Selected AbstractsCharacterization by NMR Spectroscopy, X-ray Analysis and Cytotoxic Activity of the Ruthenium(II) Compounds [RuL3](PF6)2(L = 2-Phenylazopyridine or o -Tolylazopyridine) and [RuL'2L"](PF6)2(L', L" = 2-Phenylazopyridine, 2,2'-Bipyridine)EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2005Anna C. G. Hotze Abstract Tris(ligand) complexes [RuL3](PF6)2 (L = 2-phenylazopyridine or o -tolylazopyridine) and mixed ligand [RuL'2L"](PF6)2 (L' and L" are 2-phenylazopyridine or 2,2'-bipyridine) have been synthesized, structurally characterized and investigated for cytotoxic activity. These complexes are important to study the hypothesis that the compound ,-[Ru(azpy)2Cl2] (azpy = 2-phenylazopyridine) exhibits a high cytotoxicity due to its two cis chloride ligands, which might be exchanged for biological targets as DNA. Molecular structures of mer -[Ru(azpy)3](PF6)2 (1) and mer -[Ru(tazpy)3](PF6)2 (5) (tazpy = o -tolylazopyridine) have been determined by X-ray diffraction. Series of complexes [RuL3](PF6)2 and [RuL'2L"](PF6)2 show interesting NMR spectroscopic data; e.g. the spectrum of mer -[Ru(azpy)3](PF6)2 (1) shows extremely broadened resonances at room temp. but sharpened resonances at low temperature. In the 1H NMR spectra of compounds [Ru(azpy)2(bpy)]2+ and [Ru(bpy)2(azpy)]2+ (bpy = 2,2-bipyridine), respectively, less broadened (room temp.) or completely sharp resonances (room temp.) occur in comparison to 1 (under same conditions). By selecting the right temperature and/or concentration, NMR spectra of these series of compounds have been resolved using 2D COSY and NOESY NMR spectroscopy. Remarkably, the cytotoxicity data against a series of human tumor cell lines (A498, EVSA-T, H226, IGROV, M19, MCF-7 and WIDR) show a moderate cytotoxicity for these series of tris(ligand) complexes. So, even though no chloride ligands are present in these tris(ligand) complexes, a considerable cytotoxic activity is observed. This would imply that the 2-phenylazopyridine ruthenium(II) complexes act by a completely different mechanism than the well-known cisplatin. This finding is important, because an anticancer compound acting via a different mechanism is a prerequisite in designing new anticancer drugs. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Improving methods of assessing natural killer cell cytotoxicityINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 1 2006Sandra E. Sephton Abstract Natural killer (NK) cells are a class of lymphocytes important in immune resistance to viral and other serious diseases. The cytotoxic function, or ,killing activity' of NK cells has become important in studies of the effects of stress and other psychosocial factors on physical health. Unfortunately, research on NK cell function has been plagued by discrepancies in the methods of interpreting NK cytotoxicity data. We briefly review some of the variations in measuring NK cell activity and present a new model for interpreting these results, introducing maximal target cell lysis (A) and the slope of the cytolytic curve (k) as parameters that attempt to make full use of the information and the statistical power in NK cell cytotoxicity data. Examples of these interpretation methods are presented using NK cytotoxicity data from a group of metastatic breast cancer patients. This approach will be useful in applications of NK cell measurement in psychoneuroimmunology research. Copyright © 2006 John Wiley & Sons, Ltd. [source] Classical QSAR Modeling of Anti-HIV 2,3-Diaryl-1,3-thiazolidin-4-onesMOLECULAR INFORMATICS, Issue 5 2005Kunal Roy Abstract Cytoprotection and cytotoxicity data of anti-HIV 2,3-diaryl-1,3-thiazolidin-4-ones were subjected to QSAR study using Fujita-Ban type analysis and a mixed approach based on Hansch and Fujita-Ban analyses. Apart from appropriate indicator and integer variables encoding different group contributions, different physicochemical variables like hydrophobicity (,) and steric (molar refractivity) parameters of aryl ring substituents of the compounds were used as predictor variables. Furthermore, Wang-Ford charges of the common atoms of the compounds calculated from molecular electrostatic potential surface of AM1 optimized geometries of the compounds and various topological parameters were used as additional descriptors. The variables for the multiple regression analyses were selected based on principal component factor analysis, and generated equations were statistically validated using leave-one-out technique and predicting the activity data of test set compounds. The statistical qualities of the equations for cytoprotection data (explained variance ranging 64.5,80.3%, leave-one-out predicted variance ranging 44.3,59.4%) are better than those for cytotoxicity data (explained variance ranging 59.7,60.6%, leave-one-out predicted variance ranging 52.4,54.4%). The analysis explores the structural and physicochemical requirements of the compounds for cytoprotection and cytotoxicity. [source] Cellular resistance to mitomycin C is associated with overexpression of MDR-1 in a urothelial cancer cell line (MGH-U1)BJU INTERNATIONAL, Issue 3 2001M.C. Hayes Objective To compare multidrug resistance (MDR)-1 and MDR-3 gene expression in a new urothelial cancer cell line (MGHU-1, with resistance to mitomycin C) against controls and the established (epirubicin-resistant) MDR clone, and to correlate MDR with cytotoxicity data. Materials and methods Resistance to mitomycin C was induced by the long-term exposure of wild-type MGHU-1 cells to increasing concentrations (20,400 nmol/L) of mitomycin C. The cytotoxicity of mitomycin C or epirubicin was then compared in MGHU-1, MGHU-MMC (mitomycin C-resistant) and MGHU-1R (established MDR) cells, using the tetrazolium biomass assay. The expression of MDR-1 and -3 was investigated by the reverse transcriptase-polymerase chain reaction, using cDNA-specific primers after titration, and compared with DNA and negative controls. Results MDR-1 and -3 were significantly and equally overexpressed in MGHU-1R, and associated with a dramatic increase in the 50% inhibitory drug concentration (P < 0.001) for mitomycin C and epirubicin against controls. In MGHU-MMC, the overexpression of MDR-1 was three times greater than that of MDR-3. The cytotoxicity profile for both agents was very similar to that of MGHU-1R. Trace amounts of MDR-1, but not MDR-3, were identified in the MGHU-1 wild-type. Conclusions Urothelial cancer cell resistance to mitomycin C is associated with cross-resistance to epirubicin and overexpression of MDR-1, suggesting that mitomycin C falls within the MDR category. Clinical application of this methodology may allow patients to be identified who are unlikely to benefit from intravesical chemotherapy. [source] Stereochemical Integrity of Oxazolone Ring-Containing JadomycinsCHEMBIOCHEM, Issue 10 2007Charles N. Borissow Dr. Abstract The jadomycins are a series of natural products produced by Streptomyces venzuelae ISP5230 in response to ethanol shock. A unique structural feature of these angucyclines is the oxazolone ring, the formation of which is catalyzed by condensation of a biosynthetic aldehyde intermediate and an amino acid. The feeding of enantiomeric forms of ,-amino acids indicates that the amino acid is incorporated by S. venezuelae ISP5230 without isomerization at the ,-carbon. The characterization of the first two six-membered E-ring-containing jadomycins is reported. These precursor-directed biosynthesis studies indicate flexibility in the acceptor substrate specificity of the glycosyltransferase, JadS. Analysis of cytotoxicity data against two human breast cancer cell lines indicates that the nature of the substitution at the ,-carbon, rather than the stereochemistry, influences biological activity. [source] | |||||||||||||