Single-crystal Structure and Intracellular Localization of Zn(II)-thiosemicarbazone Complex Targeting Mitochondrial Apoptosis Pathways

Tracking of drugs in cancer cells is important for basic biology research and therapeutic applications. Therefore, we designed and synthesised a Zn(II)-thiosemicarbazone complex with photoluminescent property for organelle-specific imaging and anti-cancer proliferation. The Zn(AP44eT)(NO3)2 coordination ratio of metal to ligand was 1:1, which was remarkably superior to 2-((3-aminopyridin-2-yl) methylene)-N, N-diethylhydrazinecarbothioamide (AP44eT·HCl) in many aspects, such as fluorescence and anti-tumour activity. Confocal fluorescence imaging showed that the Zn(AP44eT)(NO3)2 was aggregated in mitochondria. Moreover, Zn(AP44eT)(NO3)2 was more effective than the metal-free AP44eT·HCl in shortening the G2 phase in the MCF-7 cell cycle and promoting apoptosis of cancer cells. Supposedly, the effects of these complexes might be located mainly in the mitochondria and activated caspase-3 and 9 proteins.