Quercetin induces ferroptosis in ovarian cancer through regulating HSPB1/Notch1 pathway

Ferroptosis, characterized by iron dependency and lipid peroxidation, is essential in tumor development and chemotherapy resistance. Quercetin, a natural flavonoid, exhibits anticancer activity in various tumors. The study aimed to explore whether quercetin suppresses ovarian cancer by inducing ferroptosis, as well as to uncover the associated regulatory mechanisms. The impact of quercetin on promoting ferroptosis, affecting cell apoptosis, growth, and lipid peroxidation, was assessed in the human ovarian cancer cell lines A2780 and SKOV3. Cell proliferation was evaluated by CCK-8 and colony formation experiments, whereas apoptosis and lipid peroxidation were measured through flow cytometry and malondialdehyde assays, respectively. Bioinformatics analysis identified potential targets of quercetin-induced ferroptosis, and molecular docking predicted the binding interaction between quercetin and HSPB1. The expression levels of ferroptosis-related genes at the mRNA level were quantified by qRT-PCR, while the protein levels of heat shock protein beta-1 (HSPB1), glutathione peroxidase 4 (GPX4), Notch1, Notch intracellular domain (NICD) and its downstream effectors HEY1 and HES1 were assessed by western blotting. Ferrostatin-1 was co-treated with quercetin to determine the role of ferroptosis in quercetin-mediated anti-proliferative effects. The Notch1 inhibitor tangeretin was used to explore mechanistic pathways. An in vivo study was conducted using a xenograft mouse model. Quercetin inhibited cell proliferation and colony formation, triggered apoptosis, and promoted ferroptosis in A2780 and SKOV3 cells, marked by GPX4 downregulation and malondialdehyde levels increase. Quercetin decreased HSPB1 expression and was predicted to bind HSPB1. Silencing HSPB1 enhanced quercetin-induced cell death and malondialdehyde accumulation, while its overexpression reversed these effects. HSPB1 regulated Notch1/NICD expression, and Notch1 inhibition amplified ferroptosis. In vivo, quercetin suppressed tumor growth and reduced HSPB1, NICD, and GPX4 levels, and increased 4-hydroxynonenal (4-HNE). This study demonstrates that quercetin promotes ferroptosis and suppresses ovarian cancer progression through the HSPB1/Notch1 axis, highlighting its potential as an adjuvant in ovarian cancer therapy.