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Inhibition of Autophagic Flux by Cyclometalated Iridium(iii) Complexes Through Anion Transportation

Mu-He Chen, Yue Zheng, Xiong-Jie Cai, Hang Zhang, Fang-Xin Wang, Cai-Ping Tan, Wen-Hua Chen, Liang-Nian Ji, Zong-Wan Mao

Chem Sci. 2019 Jan 31;10(11):3315-3323.

PMID: 30996918

Abstract:

Synthetic anion transporters that can interfere with the intracellular pH homeostasis are gaining increasing attention for tumor therapy, however, the biological mechanism of anion transporters remains to be explored. In this work, two phosphorescent cyclometalated Ir(iii) complexes containing 2-phenylpyridine (ppy) as the cyclometalated ligand, and 2,2'-biimidazole (H2biim, Ir1) or 2-(1H-imidazol-2-yl)pyridine (Hpyim, Ir2) as the ancillary ligands have been synthesized and characterized. Due to the protonation and deprotonation process of the N-H groups on H2biim and Hpyim, Ir1 and Ir2 display pH-dependent phosphorescence and can specifically image lysosomes. Both Ir1 and Ir2 can act as anion transporters mainly through the anion exchange mechanism with higher potency observed for Ir1. Mechanism investigation shows that Ir1 and Ir2 can induce caspase-independent cell death through reactive oxygen species (ROS) elevation. As Ir1 and Ir2 can alkalinize lysosomes through anion disturbance, they can inhibit autophagic flux. Our work provides a novel anticancer mechanism of metal complexes, which gives insights into the innovative structure-based design of new metallo-anticancer agents.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP18653753 2-(1H-Imidazol-2-yl)pyridine 2-(1H-Imidazol-2-yl)pyridine 18653-75-3 Price
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