Novel, quinone-thiosemicarbazone hybrid (QTSCHY) non-platinum antitumor agents: inhibition of DNA biosynthesis in P388 lymphocytic cells by coordinatively unsaturated copper(II) and iron(III) complexes of naphthoquinone thiosemicarbazones

A novel copper(II) complex identified as a potent drug against colorectal and breast cancer cells and as a poison inhibitor for human topoisomerase IIα

A novel complex, [Cu(acetylethTSC)Cl]Cl•0.25C2H5OH 1 (where acetylethTSC = (E)-N-ethyl-2-[1-(thiazol-2-yl)ethylidene]hydrazinecarbothioamide), was shown to have anti-proliferative activity against various colon and aggressive breast cancer cell lines. In vitro studies showed that complex 1 acted as a poison inhibitor of human topoisomerase IIα, which may account for the observed anti-cancer effects.

Synthesis, X-ray crystal structure, DNA/protein binding and DNA cleavage studies of novel copper(ii) complexes of N-substituted isatin thiosemicarbazone ligands

Copper(ii) complexes containing isatin thiosemicarbozone ligands have been synthesized and evaluated for its biological applications like DNA/protein binding and DNA cleavage studies.

Vibrational spectra, electronic absorption, nonlinear optical properties, evaluation of bonding, chemical reactivity and thermodynamic properties of ethyl 4-(1-(2-(hydrazinecarbonothioyl)hydrazono)ethyl)-3,5-dimethyl-1H-pyrrole-2-carboxylate molecule by ab initio HF and density functional methods

In this work, detailed vibrational spectral analysis of ethyl 4-(1-(2-(hydrazinecarbonothioyl)hydrazono)ethyl)-3,5-dimethyl-1H-pyrrole-2-carboxylate (EHCHEDPC) molecule has been carried out using FT-IR spectroscopy and potential energy distribution (PED). Theoretical calculations were performed by ab initio RHF and density functional theory (DFT) method, using 6-31G(d,p) and 6-311+G(d,p) basis sets. The other carried outwork cover: structural, thermodynamic properties, electronic transitions, bonding, multiple interaction, chemical reactivity and hyperpolarizability analysis. The results of the calculation were applied to the simulated spectra of (EHCHEDPC), which show excellent agreement with observed spectra. The vibrational analysis shows red shift in both group, the proton donor (pyrrole N-H) and proton acceptor (C=O of ester) indicating the presence of intermolecular hydrogen bonding. Time dependent density functional theory (TD-DFT) has been used to find electronic excitations and their nature. The results of natural bond orbital (NBOs) analysis show the charges transfer and delocalization in various intra- and intermolecular interactions. The binding energy of intermolecular multiple interactions is calculated to be 12.54 kcal mol(-1) using QTAIM calculation. The electronic descriptors analyses reveal the investigated molecule used as precursor for heterocyclic derivatives synthesis. First hyperpolarizability (β0) has been computed to evaluate non-linear optical (NLO) response.

NP. Anticancer activity and biophysical reactivity of copper complexes of 2-(benzo[d][1,3]dioxol-5-ylmethylene)-N-alkylhydrazinecarbothioamides

A series of copper complexes were synthesized from benzo[d][1,3]dioxole-5-carbaldehyde (piperonal) thio-semicarbazones (RHpTSC where R=H, CH3, C2H5 or C6H5 (Ph)). The complexes show interesting variations in geometry depending on the thiosemicarbazone; a dinuclear complex [Cu(HpTSC)Cl]2, a mononuclear complex [Cu(RHpTSC)2Cl2] (R=CH3 or C2H5) and another mononuclear complex [Cu(PhHpTSC)(PhpTSC)Cl] was generated. The complexes bind in a moderately strong fashion to DNA with binding constants on the order of 10(4)M(‒1). They are also strong binders of human serum albumin with binding constants near 10(4) M(‒1). The complexes show good in vitro cytotoxic profiles against two human colon cancer cell lines (HCT-116 and HT29) and two human breast cancer cell lines (MCF-7 and MDA-MB-231) with IC50 values in the low millimolar concentration range.

Methyl Substituent at C2 Carbon of Acetophenone Thiosemicarbazone Induces Unusual Heterobridging in the [(Ph3P)Cu(μ-I)2(μ-S-Haptsc)Cu(PPh3)] Dimer

The sulfur of acetophenone thiosemicarbazone {(Ph)(Me)C=N-NH-C(=S)NH(2); Haptsc} and two iodine atoms form an unusual heterobridge in the dinuclear complex [(Ph(3)P)Cu(mu-I)(2)(mu-S-Haptsc)Cu(PPh(3))] (1), leading to a short Cu--Cu distance of 2.504(1) Angstrom. This uncommon heterobridging is attributed to the presence of a methyl substituent at the Schiff base C2 carbon atom of the acetophenone thiosemicarbazone.

Zinc complexes with cyclic derivatives of α-ketoglutaric acid thiosemicarbazone: Synthesis, X-ray structures and DNA interactions

Six new cyclic ligands derived from alpha-ketoglutaric acid thiosemicarbazone (H(3)ct) and their zinc complexes have been synthesized and characterized by analytical and spectroscopic (IR and NMR) studies. The X-ray structures of ligands Me-H(2)ct(C) (1), Allyl-H(2)ct(c) (3) and of complex [Zn(Me-Hct(C))(2)(OH(2))(2)].2H(2)O (7) have been determined. In complex (7) the zinc atom lies on a twofold axis and is surrounded in a tetrahedral coordination by two water molecules and two carboxylic oxygen donor atoms from the ligand. DNA titration in the UV-visible region and thermal denaturation have been employed to determine the details of DNA binding for the studied compounds. Studies of nuclease activity have also been performed with all our compounds through a gel electrophoresis experiment using plasmid pBR322 showing that no DNA breakings take place. Tests in vitro on human leukemia cell line U937 have been carried out on cell growth inhibition where solubility of the compounds allowed the experiments.

The cytotoxicity and mechanisms of 1,2-naphthoquinone thiosemicarbazone and its metal derivatives against MCF-7 human breast cancer cells

We have investigated the antitumor functions and mechanisms of 1,2-naphthoquinone-2-thiosemicarbazone (NQTS) and its metal complexes (Cu(2+), Pd(2+), and Ni(2+)) against MCF-7 human breast cancer cells. The cells were dosed with these complexes at varying concentrations, and cell viability was measured by a sulforhodamine B (SRB) method. To study mechanisms of action, the complexes were incubated with topoisomerase II (topo II) and supercoiled DNA, linear DNA, nicked open DNA, and relaxed DNA were detected by agarose gel electrophoresis. The results revealed that these complexes are effective antitumor chemicals in inhibiting MCF-7 cell growth, with Ni-NQTS being the most effective among the complexes studied. Our data also indicated that Ni-NQTS is more effective than the commercial antitumor drug, etoposide, based on IC(50) values. The mechanistic study of action showed that metal complexes of NQTS, NQ, and NQTS can only stabilize the single-strand nicked DNA, but not double-strand breakage intermediates. In addition, metal derivatives of these ligands, but not the parent NQ and NQTS, exerted an antagonizing effect on topoisomerase II activity. In summary, chemicals with or without metal derivatives might possess different chemical-topoisomerase II-DNA interactions.

Main targets of tetraaza macrocyclic copper complex on L1210 murine leukemia cells

Several metal complex agents have already been introduced into clinical tumor therapy and others are subject of antitumor studies. In this study we focused on the tetraaza macrocyclic copper complex (Cu(TAAB)Cl(2)). We studied the influence of the substance on cell growth, cell cycle, membrane integrity, necrosis, apotosis and glutathione level on the leukemic cell line L1210 in 1-day (22 h) and 3-day (72 h) experiments. The metal complex shows a dose-dependent antiproliferative effect, without affecting cell cycle phases. The present results confirm that copper complex can damage plasmatic membranes and trigger apoptosis, and that after treatment of leukemic cells with the copper complex, glutathione levels were increased.

Toxins from ascidians

A wide range of toxins with interesting pharmacological properties have been isolated from ascidians. These include cyclic peptides, one of which, didemnin B, is undergoing clinical trials for cancer chemotherapy and is also a powerful immunosuppressive agent. Other classes of toxins from these organisms are alkaloids, macrolides, polyethers, prenylated hydroquinones and others of diverse chemical structure. The majority of these compounds are cytotoxic and in some cases the mechanisms of action have been investigated. The toxins are most likely used for chemical defense but the question of how the ascidians themselves escape the toxic actions is also not resolved.

Involvement of metallothionein and copper in cell proliferation

Metallothionein is a low-molecular weight, cysteine-rich, metal-binding protein which has been implicated in the detoxification of toxic metals (cadmium, mercury), metabolism of zinc and copper, as well as in the scavenging of free radicals. Recent evidence suggests that the protein may also be involved in cell proliferation. Based on the experiments carried out so far, it is assumed that the fundamental role of metallothionein in cell proliferation may be to detoxify and/or transfer copper ions from the cytoplasm to the nucleus at the G1/S phase, which in turn participate in some way in nuclear DNA synthesis.