Ruthenium(ii)–Arene Complex Triggers Immunogenic Ferroptosis for Reversing Drug Resistance

Chemoresistance remains an arduous challenge in oncology, but ferroptosis shows potential for overcoming it by stimulating the immune system. Herein, a novel high-performance ruthenium­(II)-based arene complex [Ru­(η6-p-cym)­(BTBpy)­Cl] (RuBTB) is developed for ferroptosis-enhanced antitumor immunity and drug resistance reversal via glutathione (GSH) metabolism imbalance. RuBTB shows significantly enhanced antiproliferation activity against cisplatin (CDDP)-resistant lung cancer cells (A549R), with 26.35-fold better anticancer effects than CDDP. Immunogenic ferroptosis is induced by GSH depletion/glutathione peroxidase 4 (GPX4) inactivation, mitochondrial dysfunction, and endoplasmic reticulum (ER) stress in RuBTB-treated cells. Mechanism studies indicate that RuBTB regulates ferroptosis and immune-related pathways, coordinating with GSH metabolism-mediated glutathione S-transferase (GST) inhibition to reverse drug resistance in platinum-combined therapy. Tumor vaccination experiments demonstrate the intensified antitumor effects endowed by highly immunogenic ferroptosis in vivo. This study provides the first example of a metal–arene complex for achieving satisfactory ferroptosis therapeutic effects with efficient immunogenicity to overcome drug resistance in metal-based immunochemotherapy.