Brominated cyclometalated iridium(III) complexes for mitochondrial immobilization as potential anticancer agents

Area of Science:

• Medicinal Chemistry
• Inorganic Chemistry
• Cancer Biology

Background:

• Mitochondria-targeted iridium complexes are emerging as promising anticancer agents.
• Understanding their mechanism of action is crucial for developing novel cancer therapies.

Purpose of the Study:

• To synthesize and evaluate three novel cyclometalated iridium(III) complexes as mitochondria-targeted anticancer agents.
• To investigate their cellular localization, mechanism of action, and in vitro anticancer efficacy.

Main Methods:

• Synthesis of cyclometalated iridium(III) complexes (Ir1-Ir3).
• Cellular uptake and mitochondrial localization studies.
• Assessment of mitochondrial membrane potential, reactive oxygen species (ROS) levels, and thioredoxin reductase (TrxR) activity.
• Inhibition of tumor cell colony formation and angiogenesis assays.
• Apoptosis induction studies, including caspase-3 activation and protein expression analysis (Bax, KI67).

Main Results:

• The iridium complexes selectively localized in mitochondria and covalently bound to mitochondrial proteins.
• Complexes exhibited significant anticancer activity, inducing mitochondrial depolarization and elevated ROS levels.
• Inhibition of TrxR activity, tumor colony formation, and angiogenesis was observed.
• Complex Ir2 demonstrated potent apoptosis induction via caspase-3 activation and regulation of Bax/KI67 expression.

Conclusions:

• Mitochondria-targeted iridium complexes are effective anticancer agents with a multi-pronged mechanism of action.
• These complexes hold potential for developing new chemotherapeutic strategies against cancer.
• Further investigation into their therapeutic applications is warranted.