DNA-Binding and Thermodynamic Parameters, Structure and Cytotoxicity of Newly Designed Platinum(II) and Palladium(II) Anti-Tumor Complexes

Abstract

The complexes [Pd(bpy)(Hex-dtc)]<TEX>$NO_3$</TEX> and [Pt(bpy)(Hex-dtc)]<TEX>$NO_3$</TEX> (bpy is 2,2'-bipyridine and Hex-dtc is hexyldithiocarbamato ligands) were synthesized and characterized by elemental analysis and spectroscopic studies. The cytotoxicity assay of the complexes has been performed on chronic myelogenous leukemia cell line, K562, at micromolar concentration. Both complexes showed cytotoxic activity far better than that of cisplatin under the same experimental conditions. The binding parameters of the complexes with calf thymus DNA (CT-DNA) was investigated using UV-visible and fluorescence techniques. They show the ability of cooperatively intercalating in CT-DNA. Gel filtration studies demonstrated that platinum complex could cleave the DNA. In the interaction studies between the Pd(II) and Pt(II) complexes with CT-DNA, several binding and thermodynamic parameters have been determined, which may provide deeper insights into the mechanism of action of these types of complexes with nucleic acids.