DNA Binding and cleavage activity of Ni(II) complex with all-trans retinoic acid

Absorption, fluorescence spectral, cyclic voltammetry and agarose gel electrophoresis studies have been carried out on the interaction of Ni(II) complex with all-trans retinoic acid ([Ni(RA)2(H2O)2] · H2O) with DNA. The results indicate that the [Ni(RA)2(H2O)2] · H2O can more effectively promote the cleavage of plasmid DNA than that of all-trans retinoic acid (HRA) and Ni(II) at physiological pH and temperature, which may be one of the reasons why the inhibitory effect of [Ni(RA)2(H2O)2] · H2O on the human bladder line EJ cells is much greater than that of retinoic acid. It was found that the process of plasmid DNA cleavage was sensitive to ionic strength and pH, however, these radical scavengers almost had no effect on the DNA cleavage reaction. The above results suggested that the cleavage of plasmid DNA by [Ni(RA)2(H2O)2] · H2O did not produce diffusible hydroxyl radicals via the Fenton reaction. The results of UV-absorption studies and fluorescence characterization of the interaction of [Ni(RA)2(H2O)2] · H2O with Calf thymus DNA show that the [Ni(RA)2(H2O)2] · H2O binds to DNA mainly in an intercalating mode.