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  • Article
    Citation - WoS: 41
    Citation - Scopus: 48
    Platinated Copper(3-Clip Complexes as Effective Dna-Cleaving and Cytotoxic Agents
    (Wiley-v C H verlag Gmbh, 2008) Ozalp-Yaman, Seniz; de Hoog, Paul; Amadei, Giulio; Pitie, Marguerite; Gamez, Patrick; Dewelle, Janique; Reedijk, Jan
    The synthesis and biological activity of three heteronuclear platinum-copper complexes based on 3-Clip-Phen are reported. These rigid complexes have been designed to alter the intrinsic mechanism of action of both the platinum moiety and the Cu(3-Clip-Phen) unit. The platinum centers of two of these complexes are coordinated to a 3-Clip-Phen moiety, an ammine ligand and two chlorides, which are either cis or trans to each other. The third complex comprises two 3-Clip-Phen units and two chloride ligands bound in a trans fashion to the platinum ion. DNA-cleavage experiments show that the complexes are highly efficient nuclease agents. In addition, a markedly difference in their aptitude to perform direct double-strand cleavage is observed, which appears to be strongly related to the ability of the platinum unit to coordinate to DNA. Indeed, complex 6 is unable to coordinate to DNA, which is reflected by its incapability to carry out double-strand breaks. Nonetheless, this complex exhibits efficient DNA-cleavage activity, and its cytotoxicity is high for several cell lines. Complex 6 shows better antiproliferate activity than both cisplatin and Cu(3-Clip-Phen) toward most cancer cell lines. Furthermore, the cytotoxicity observed for 1 is for most cell lines close to that of cisplatin, or even better. Cu(3-Clip-Phen) induces very low cytotoxic effects, but a marked migratory activity. Complex 6 presents DNA-cleavage properties comparable to the one of Cu(3-Clip-Phen), but it does not show any migratory activity. Interestingly, both Cu(3-Clip-Phen) and 6 induces vacuolisation processes in the cell in contrast to complex 1 and cisplatin. Thus, the four complexes cisplatin tested, Cu(3-Clip-Phen), I and 6 stimulate different cellular responses.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 5
    Spectroelectrochemical Studies of Nuclease-Active Zinc(ii) Coordination Compounds From the Ligands Hpyramol and Hpyrimol
    (Pergamon-elsevier Science Ltd, 2010) Ozalp-Yaman, Seniz; de Hoog, Paul; Maheswari, Palanisamy Uma; Casellas, Helene; Golobic, Amalija; Kozlevcar, Bojan; Reedijk, Jan
    The electrochemical oxidation of four zinc(II) coordination compounds from the ligands 4-methyl-2-(2-pyridylmethyl)aminophenol (Hpyramol()) and 4-methyl-2-(2-pyridylmethylene)aminophenol (Hpyrimol) with chloride or acetate as counter-ions has been studied by in situ spectroelectrochemistry in dimethylformamide (DMF) Low-temperature EPR studies of electrolyte solutions of all zinc compounds indicate the presence of a phenoxyl radical with a g-value in the range 2 070-2 099 which is illustrative for an electron delocalization over the metal centre The final product of this oxidative process is shown to be a benzoquinone methide derivative (C) 2010 Elsevier Ltd All rights reserved