Thiosemicarbazone-derived copper(II), cobalt(II) and nickel(II) complexes as potential anticancer agents: nuclease activity, cytotoxicity and apoptosis studies

Copper(II), cobalt(II) and nickel (II) complexes (1-6) of 1-[amino(thioxo)methyl]-5-hydroxy-3-methyl-1H-pyrazole have been synthesized and characterized by IR, UV-Vis, NMR, ESI-MS and elemental analysis. Ligand and metal(II) complexes have been screened for their toxic effect on HeLa and K562 cancer cell lines, as well as on normal HUVEC cells. Cytotoxic effectiveness of copper(II) complexes (1 and 4) (IC50 2-5 mu M after 48 h) was 4-50 times higher than that of other complexes and cisplatin. These complexes were non-toxic to primary human endothelial cells. For these complexes, induction of cell apoptosis by the caspase 3/7 assay has been measured. The interactions with DNA by the enzymatic method have also been investigated.