Study on the Mechanism of Quercetin Inducing Ferroptosis of Liver Cancer Cells Through Nrf2 Signaling Pathway

Background: Quercetin possesses anti-oxidative stress effect with potential in the treatment of tumor-related diseases. Whether it plays a role in liver cancer remains unclear. Objectives: This study aims to explore its role in the ferroptosis of liver cancer cells and the action of the nuclear factor erythroid-related factor 2 (Nrf2) signaling pathway in this process. Materials and Methods: Liver cancer cells (MHCC97-H) were cultured in vitro and assigned into two groups: the control and the experimental groups. MHCC97-H cells were given different concentrations of intervention and divided into five groups, with concentrations of 0.5, 1.0, 2.0, 4.0, and 8.0 mg/mL, and detected by the CCK8 method to observe cell viability. The culture time was set at three time points (24, 48, and 72 h). The cell proliferation activity, clone cell number, cell morphology under Hoechst staining, and cell apoptosis number of each group were compared, and the optimal dose was selected. MHCC97-H cells were further intervened with Nrf2 inhibitor ML385, Nrf2 agonist dimethyl fumarate (DMF), ferroptosis agonist Erastin, and ferroptosis inhibitor Fer-1 to observe the expression of various proteins, reactive oxygen species (ROS), and malondialdehyde (MDA). Among them, ROS was detected by flow cytometry, Nrf2, NADPH oxidase 4 (NOX4), and glutathione peroxidase 4 (GPX4) levels were detected by Western blot (WB), and MDA and glutathione (GSH) content were detected by MDA and GSH corresponding kits. Results: Compared with the control group, the cell viability of the experimental group decreased, the number of cell proliferation decreased, the number of apoptosis increased, and the cell nucleus was condensed, which showed a dose-dependent change with the change of drug concentration. The levels of GPX4 and Nrf2 in the Que+8 group decreased, and the contents of NOX4 and ROS increased significantly. Levels of Nrf2, GSH, and MDA in the ML385 group and Que+8 group decreased, and the contents of GPX4, NOX4, and ROS increased significantly. Compared with the Que+8 group, levels of Nrf2, GSH, and MDA in the Que+8+DMF group increased, and GPX4, NOX4, and ROS levels decreased significantly. Compared with the Fer-1 group, levels of MDA and ROS in the Erastin group increased, and Nrf2 levels decreased. Conclusion: Quercetin can effectively activate Nrf2 signaling to upregulate the oxidative stress response and induce ferroptosis in liver cancer cells, which is helpful for treating liver cancer.