Isoliquiritigenin Triggers HMOX1-Driven Ferroptosis to Suppress Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related death, and new treatment strategies are needed. Ferroptosis is an iron-dependent cell death driven by lipid peroxidation, and targeting ferroptosis has become a new strategy for anti-NSCLC. Isoliquiritigenin (ISL) is a bioactive natural flavonoid with antitumor potential, but its mechanism of ferroptosis in NSCLC remains to be elucidated. We investigated the effects of ISL on cell viability, proliferation, colony formation, cell cycle and cell death in NSCLC cells. Quantitative proteomic and bioinformatics analyses identified enriched pathways and key molecular targets. The effect of ISL on ferroptosis markers was also assessed. The regulatory effects of ISL on the main target proteins and key signaling pathways were verified by molecular docking, CETSA, co-immunoprecipitation, siRNA knockdown, overexpression and Western blotting. The antitumor effect of ISL and its synergistic effect with cisplatin in vivo were evaluated. The safety of ISL was also evaluated. ISL significantly inhibited NSCLC cell proliferation, arrested cell cycle in S phase, and induced cell death. Further investigation revealed that ferroptosis was the major cell death pathway, and this process was achieved by up-regulation of the protein HMOX1. In addition, the iron homeostasis disrupted by ISL was somewhat restored after administration of the iron chelator DFO, attenuating its mediated ferroptosis. Mechanistically, we verified that binding of ISL to Nrf2 activates Nrf2, upregulates HMOX1, inhibits CP, and disrupts iron homeostasis, thereby triggering ferroptosis. In vivo, ISL inhibited tumor growth in A549 xenograft mice without significant organ toxicity. Meanwhile, ISL can synergistically increase the antitumor efficacy of cisplatin, accompanied by more obvious ferroptosis changes in NSCLC. ISL induces ferroptosis by activating the Nrf2/HMOX1/CP pathway, leading to iron overload, thus exerting an effective antitumor effect on NSCLC. These findings indicate that ISL is a promising antitumor agent targeting ferroptosis, and also provide part of the preliminary mechanistic basis for its clinical development.