Quercetin inhibits neuronal Ferroptosis and promotes immune response by targeting lipid metabolism-related gene PTGS2 to alleviate breast cancer-related depression

Background: Quercetin, the key ingredient in Xiaoyao Kangai Jieyu Formula, has been previously found to relieve breast cancer-related depression (BCRD).

Purpose: We want to explore the potential mechanisms and therapeutic targets of quercetin alleviating BCRD.

Methods: BALB/c mice were injected subcutaneously with 4T1 cells and corticosterone (CORT) to create a BCRD mice model. The primary hippocampal neurons were co-induced with 10 μg/ml lipopolysaccharide (LPS) and 200 μM CORT for 6 h to establish an in vitro model of BCRD. Quercetin was applied to explore its effect on disease symptoms, gut microbiota, and lipid metabolism of BCRD mice. Lipid metabolism-related genes were screened based on network pharmacology. Molecular docking was employed to prove whether quercetin bound to prostaglandin-endoperoxide synthase 2 (PTGS2). PTGS2 overexpression was carried out to explore the underlying mechanism of quercetin treatment on BCRD.

Results: Quercetin treatment not only altered the composition and abundance of gut microbiota but also alleviated abnormal lipid metabolism in BCRD mice. In particular, quercetin down-regulated BCRD and lipid metabolism-related genes screened by network pharmacology, especially PTGS2. Further, molecular docking verified the stable binding between quercetin and PTGS2. In hippocampal neurons, quercetin promoted proliferation but reduced ferroptosis-related markers (total Fe, Fe2+, MDA, and ROS) levels by targeting PTGS2. In BCRD mice, quercetin reduced the high immobility time and increased the sucrose preference rate and serotonin (5-HT), dopamine (DA), and noradrenaline (NE) levels. Meanwhile, quercetin increased CD4+/CD8+ T cells ratio and IL-2 and IFN-γ levels but reduced CA153 and IL-10 levels to alleviate BCRD development. However, PTGS2 overexpression reversed these effects of quercetin on BCRD.

Conclusion: Quercetin inhibited neuronal ferroptosis and promoted immune responses in BCRD mice by targeting the lipid metabolism-related gene PTGS2. This provided a reference for quercetin in the treatment of BCRD.