Antitumor trans-N-Heterocyclic Carbene-Amine-Pt(II) Complexes: Synthesis of Dinuclear Species and Exploratory Investigations of DNA Binding and Cytotoxicity Mechanisms

A series of bimetallic [(NHC)PtX2](2)(diamine) complexes have been prepared as a new chemotype for potential anticancer agents. These complexes display an uncommon set of structural features as far as they combine two bifunctional, trans-configured platinum centers. They display cytotoxic activities in the micromolar range on many cancerous cell lines and do not cross-react with cisplatin in A2780/DDP cell lines. They bind slowly to double-stranded DNAs, giving monoadducts as the major products. Pathways for cellular toxicity have been investigated for both mono- and bimetallic trans-(NHC)PtX2(amine) complexes. It has been highlighted that, unlike cisplatin, these complexes do not induce cell cycle arrest. They trigger apoptosis in A2780 cells by a pathway involving translocation of apoptosis-inducing factor and caspase 12 to the nucleus. Moreover, bimetallic complexes may induce necrosis.