Four neutral cyclometalated
iridium(III) (IrIII) dithioformic
acid complexes ([(ppy)2Ir(S^S)], Ir1-Ir4) were designed and synthesized. Toxicity assay revealed that these complexes showed favorable anticancer activity, especially for human
non-small cell lung cancer cells (A549). Ir1 exhibited the best anticancer activity (11.0 ± 0.4 μM) was about twice that of
cisplatin, meanwhile, which could availably restrain A549 cells migration. Complexes could target mitochondria, induce a decrease in mitochondrial membrane potential (
MMP), result in an increase of intracellular
reactive oxygen species (ROS) and disruption of the cell cycle, and ultimately generate apoptosis. Western blotting experiment indicated that complexes could inhibit the expression of B cell CLL/
lymphoma-2
protein (Bcl-2), induce the expression of
BCL2-associated X protein (Bax) and lead to a massive release of
Cytochrome C (Cyt-c), which amplified apoptosis signals by activating downstream pathway to promote apoptosis. All these confirmed the existence of mitochondrial anticancer channels for these complexes. Above all, cyclometalated
iridium(III) dithioformic
acid complexes possess the prospect of becoming a multifunctional
cancer therapeutic platform, including mitochondria-targeted imaging, anti-migration, and
anticancer agents.