Downregulation of oncogenic RAS and c-Myc expression in MOLT-4 leukaemia cells by a salicylaldehyde semicarbazone copper(II) complex.

Copper complexes with potent anti-tumor effect have been extensively developed. Most investigations of their modes of action focused on the biomolecular targets but not the signal transduction between target binding and cell death. We have previously shown that the cytotoxic complex pyridine(2,4-dihydroxybenzaldehyde dibenzyl semicarbazone)copper(II) (complex 1) shows selective binding to human telomeric G-quadruplex DNA over double-stranded DNA in vitro.

Copper(II) complexes of substituted salicylaldehyde dibenzyl semicarbazones: synthesis, cytotoxicity and interaction with quadruplex DNA.

A series of substituted salicylaldehyde dibenzyl semicarbazones [RC6H3(OH)CH=N-NHCON(CH2Ph)2] and their copper(II) complexes were synthesized and characterized. The chloridocopper(II) complexes of the 4-OH and 5-OH substituted ligands (complexes 9 and 7) show modest affinity and good selectivity (over duplex DNA) for the quadruplex formed from the human telomeric (HTelo) DNA sequence. Substitution of the chlorido ligands of these two complexes with pyridine yielded derivatives (7-py and 9-py) with increased affinity for HTelo.

Multiarray cell stretching platform for high-magnification real-time imaging.

Aim: This article reports the development of a multiarray microchip with real-time imaging capability to apply mechanical strains onto monolayered cell cultures.

Materials & Methods: Cells were cultured on an 8-µm thick membrane that was positioned in the microscope focal plane throughout the stretching process. Each stretching unit was assembled from three elastomeric layers and a glass coverslip.

Rhenium(I) tricarbonyl complexes of salicylaldehyde semicarbazones: synthesis, crystal structures and cytotoxicity.

A series of N,N-disubstituted salicylaldehyde semicarbazones (SSCs), HOC(6)H(4)CHN-NHCONR(2), and their rhenium(I) tricarbonyl complexes, [ReBr(CO)(3)(SSC)], have been synthesised and characterised by IR and (1)H NMR spectroscopy. Crystallographic analysis of the complex [ReBr(CO)(3)(H(2)Bu(2))] (H(2)Bu(2)=SSC where R=Bu(n)) showed that the SSC acts as a bidentate ligand via its imino nitrogen and carbonyl oxygen atoms. The [ReBr(CO)(3)(SSC)] complexes exhibit moderate to high cytotoxicities towards MOLT-4 cells (IC(50)=1-24μM, cf.

Rapid determination of vitamin B12 concentration with a chemiluminescence lab on a chip.

This paper reports a novel method for the rapid determination of vitamin B(12) concentration in a continuous-flow lab-on-a-chip system. This new method is based on luminol-peroxide chemiluminescence (CL) assays for the detection of cobalt(II) ions in vitamin B(12) molecules. The lab-on-a-chip device consisted of two passive micromixers acting as microreactors and a double spiral microchannel network serving as an optical detection region.

DNA binding and nucleolytic properties of Cu(ii) complexes of salicylaldehyde semicarbazones.

The copper(ii) complexes of two salicylaldehyde semicarbazones, HOC(6)H(4)CH[double bond, length as m-dash]N-NHCONR(2) [H(2)Bnz(2) (R = CH(2)Ph) and H(2)Bu(2) (R = Bu)], were evaluated for their DNA binding and cleavage properties by spectrophotometric DNA titration, ethidium bromide displacement assay and electrophoretic mobility shift assay. Results showed that the Cu(ii) complexes can bind to DNA via a partial intercalation mode with binding constants of 1.1 × 10(4) and 9.

Copper, gold and silver compounds as potential new anti-tumor metallodrugs.

Although platinum-based drugs such as cisplatin are powerful anticancer agents, they have undesirable side effects and are effective against only a few kinds of cancers. There is, therefore, a need for new drugs with an improved spectrum of efficacy and lower toxicity. Complexes of copper, gold and silver (coinage metals) are potential candidates to fulfill this need.

Cytotoxic copper(II) salicylaldehyde semicarbazone complexes: mode of action and proteomic analysis.

The in vitro cytotoxic studies of a series of salicylaldehyde semicarbazones, HOC₆H₄CH=N-NHCONR₂ (H₂R₂) and their Cu(II) complexes on a number of human tumor cell lines were conducted and it was observed that their cytotoxicities were enhanced following complexation to copper. These copper(II) complexes also demonstrated higher in vitro activities than the reference drug, cisplatin, on the tumor cell lines at micro molar range. Apoptotic assays and cell cycle analysis of the copper complexes, [Cu(HBnz₂)Cl] and [Cu(HBu₂)Cl] revealed that they mediated cytotoxicity in MOLT-4 cells via apoptosis.

Hantupeptins B and C, cytotoxic cyclodepsipeptides from the marine cyanobacterium Lyngbya majuscula.

Hantupeptins B (2) and C (3) were isolated, along with the previously reported hantupeptin A (1), from the marine cyanobacterium, Lyngbya majuscula, collected from Pulau Hantu Besar, Singapore. Their structures were elucidated by interpretation of extensive 1D and 2D NMR spectroscopic data. Compounds 2 and 3 are cyclic depsipeptides consisting of five alpha-amino/hydroxy acid residues, including phenyllactic acid, proline, N-methyl-valine, valine, N-methyl-isoleucine, and a beta-hydroxy acid unit with different degrees of unsaturation at the terminal end of each molecule.

Hantupeptin A, a cytotoxic cyclic depsipeptide from a Singapore collection of Lyngbya majuscula.

Chemical investigation of the marine cyanobacterium Lyngbya majuscula from Pulau Hantu Besar, Singapore, has led to the isolation of a cyclodepsipeptide, hantupeptin A (1). The planar structure of 1 was assigned on the basis of extensive 1D and 2D NMR spectroscopic experiments. The absolute configuration of the amino and hydroxyl acid residues in the molecule was determined by application of the advanced Marfey method, chiral HPLC analysis, and Mosher's method.