Ferrocenyl–Triphenyltin Complexes as Lysosome-Targeted Imaging and Anticancer Agents

In this paper, two ferrocenyl–triphenyltin complexes were synthesized and characterized. Complex 2 is constructed as new multifunctional therapeutic platform for lysosome-targeted imaging and displayed much higher cytotoxicity than its analogue 1 by the introduction of a methyl group instead of a hydrogen atom in acylhydrazone. The cyclic voltammograms and reaction with GSH (glutathione) further confirmed that complex 1 has a reversible redox peak and can react with GSH, which indicate that complex 1 might lose its anticancer effect by undergoing reaction with GSH once it enters the cancer cell. Complex 2 could effectively catalyze the oxidation of NADH (the reduced form of nicotinamide adenine dinucleotide) to NAD+ and induce the production of reactive oxygen species (ROS), lead to caspase-dependent apoptosis through damaged mitochondria, simultaneously, accounting for the mitochondrial vacuolization and karyorrhexis. The caspase-3 activation and cytoplasmic vacuolation karyorrhexis induced by complex 2 revealed that the A549 cell lines might undergo cell death primarily mediated by apoptosis and oncosis; however, 1 cannot reproduce this effect. Taken together, these results indicated that complex 2 has more potential for evolution as a new bioimaging and anticancer agent.