New Copper (II), Palladium (II), and Platinum (II) 2-Acetylpyrazine Tert-Butylthiosemicarbazone Complexes: Inhibition of Human Topoisomerase IIα and Activity against Breast Cancer Cells

The new ligand, 2-acetylpyrazine-tertbutylthiosemicarbazone (APZ-tBTSC), and its Cu(II), Pd(II) and Pt(II) complexes have been synthesized. This ligand coordinates to the metal ions in a tridentate monoanionic fashion forming monometallic complexes with the formula [M(APZ-tBTSC)Cl]. The ligand and the three metal complexes [Cu(APZ-tBTSC)Cl], [Pd(APZ-tBTSC)Cl], and [Pt(APZ-tBTSC)Cl] were tested for anti-proliferative biological behavior with a panel of seven microbes, and the copper and palladium complexes were found to be highly active against Gram positive bacteria. The 4 compounds were also tested in human topoisomerase IIα DNA relaxation assays and all three metal complexes had topoisomerase inhibition at a concentration between 4 - 6 micro-molar. The 4 compounds were also tested for activity with the HEK293T cell line and also the breast cell cancer line, MDA-MB-231. The most effective compound for activity against the HEK293T cell line was the [Cu(APZ-tBTSC)Cl] complex, and the MDA-MB-231 breast cancer cell line was the [Pt(APZ-tBTSC)Cl] complex.