A Λ-Ir(iii)-phenylquinazolinone complex enhances ferroptosis by selectively inhibiting metallothionein-1

Abstract

Chirality plays an indispensable role in various biological processes, and interactions between chiral enantiomers and biomolecular targets provide new perspectives in precision drug development. While ferroptosis has received increasing attention as a novel pathway to reverse drug resistance, work on the design of precise ferroptosis-targeting molecules through chiral programming was limited. In this work, we designed and synthesized a pair of chirality-dependent ferroptosis-inducing Ir(III)-phenylquinazolinone complexes (Δ-IrPPQ and Λ-IrPPQ) by inhibiting ferroptosis suppressor protein-1 (FSP1), while the pair of IrPPQ complexes induced extremely different ferroptosis effects as well as distinct photodynamic therapy (PDT) responses toward pancreatic cancer cells. Interestingly, this chirality-dependent biological mechanism through proteomic analysis and molecular simulation revealed that the specific binding and inhibition of metallothionein-1 (MT1) by Λ-IrPPQ sensitized cancer cells to ferroptosis, inducing a burst of reactive oxygen species, lipid peroxidation, glutathione depletion, and inactivation of FSP1. While in comparison, Δ-IrPPQ induced mild ferroptotic cell death. Through simple chiral resolution, the obtained Λ-IrPPQ achieved precise regulation of ferroptosis in pancreatic cancer cells. This work provides new insights into the design of chiral ferroptosis-inducing metallodrugs for future pancreatic cancer therapy.