Molecular drug design, synthesis and structure elucidation of a new specific target peptide based metallo drug for cancer chemotherapy as topoisomerase i inhibitor

Abstract

To evaluate the biological preference of metallopeptide drugs in cancer cells, a new dinuclear copper(ii) complex [Cu 2(glygly) 2(ppz)(H 2O) 4]·2H 2O (1) (glygly = glycyl glycine anion and ppz = piperazine), was designed and synthesized as topoisomerase I inhibitor. The structural elucidation of the complex was done by elemental analysis, spectroscopic methods and single crystal X-ray diffraction. The in vitro DNA binding studies of complex 1 with CT DNA were carried out by employing different optical methods viz. UV-vis, fluorescence and circular dichroism. The molecular docking technique was also utilized to ascertain the mechanism and mode of action towards the molecular target DNA and enzymes. Complex 1 cleaves pBR322 DNA via an oxidative mechanism and strongly binds to the DNA minor groove. Furthermore, complex 1 exhibits significant inhibitory effects on the catalytic activity of topoisomerase I at a very low concentration, ∼12.5 μM, in addition to its excellent SOD mimics (IC 50 ∼ 0.086 μM). © The Royal Society of Chemistry 2012.