Studies on activities, cell uptake and DNA binding of four trans-planaramineplatinum(II) complexes of the form: trans-PtL(NH 3)Cl 2, where L=2-hydroxypyridine, imidazole, 3-hydroxypyridine and imidazo(1,2-α)pyridine

Abstract

Four trans-planaramineplatinum(II) complexes code named YH9, YH10, YH11 and YH12 each of the form trans-PtL(NH 3)Cl 2, where L=2-hydroxypyridine and 3-hydroxypyridine, imidazole, and imidazo(1,2-α)pyridine for YH9, YH10, YH11 and YH12, respectively, have been synthesized and the activity of the compounds against human cancer cell lines, cell uptake, DNA-binding and nature of interaction with pBR322 plasmid DNA have been studied. The compound having imidazo(1,2-α)pyridine ligand as one the carrier ligands in the trans-configuration is found to be significantly more active than cis-platin against ovarian A2780 cisR cancer cell line corresponding with higher Pt-DNA binding. All other compounds have resistance factors less than that for cis-platin in the A2780 and A2780 cisR cell lines. A greater prevention of BamH1 digestion with increasing concentration of the compounds indicates that as the compounds bind with nucleobases in DNA, the DNA conformation is changed sufficiently so as to prevent BamH1 digestion at the specific GG site. Gel electrophoresis results also indicate that as the compounds bind to DNA, unwinding of supercoiled form I DNA takes place to change it from the negatively supercoiled form I through relaxed circular form I to the positively supercoiled form I.