SYNTHESIS, CYTOTOXICITY AND SPECTROSCOPY STUDIES OF A NEW COPPER (II) COMPLEX: CALF THYMUS DNA AND T47D AS TARGETS

A water-soluble Cu (II) complex [(dien)Cu(μ-1,6-DAH)Cu(dien) (NO3)2](NO3)2 has been synthesized and its effect on the carrier model DNA structure and cancer cell line proliferation was investigated. In this regard, calf thymus DNA (CT-DNA) and human breast cancer cell line, T47D, were the targets. The effect of the complex on DNA structure was investigated by means of UV/vis, fluorescence and circular dichroism (CD) spectroscopic techniques as well as dynamic light scattering (DLS), zeta potential analysis and docking assay for more analysis. The UV–vis absorption spectra of complex with DNA showed a slight red shift and hypochromic effect, which indicated the intercalation and electrostatic effect of complex with CT-DNA. Using ethidium bromide (EB) as a probe in fluorescence studies revealed that complex can quench the EB–DNA fluorescence emission at different temperatures. Besides, the far UV–CD studies displayed that the complex induces changes in the secondary structure of CT-DNA and can increase the melting temperature of DNA up to 14 °C. The DLS and zeta potential measurements confirmed the electrostatic interaction of complex with the negatively charged DNA and subsequent DNA condensation. Besides, computational studies reflect that major and minor groove binding are two modes of interaction between complex and DNA. On the other hand, growth inhibition of the complex toward T47D cell line was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, which showed no cytotoxic properties.