Concurrent Ferroptosis and Apoptosis in Resveratrol-Treated Glioblastoma Cells: Relevance With NRF2 Downregulation and Oxidative Stress

Abstract

Glioblastomas (GBMs) are lethal brain tumors characterized by rapid growth and resistance to standard treatment. Resveratrol (RES) increases the levels of reactive oxygen species (ROS) and induces cell death in sensitive GBM cells. However, the death patterns induced by RES and their relevance to NFE2-related factor 2 (NRF2) remain unclear. The current study aimed to address these issues using RES-sensitive U251 and less-sensitive LN428 GBM cell lines, as well as an orthotopic GBM xenograft rat model. In silico analysis revealed high NRF2 expression in GBM tissues and a strong correlation with tumor progression in the TCGA dataset. After 48 h of 100 µM RES treatment, NRF2 levels remained stable in LN428 cells but significantly decreased by 2.3-fold in U251 cells, accompanied by suppressed growth and NRF2-regulated and ferroptosis-related xCT and GPX4 downregulation. Elevated Fe^2+, ROS levels, lipid peroxidation, and ferroptotic frequency were evidenced in RES-treated U251 cells; meanwhile, apoptosis and reduced NRF2-HO-1 expression were also evident in U251 cells. Combined treatment with Ferrostatin-1 and Z-VAD FMK rescued 60% of U251 cells compared to RES-treated counterparts. In vivo, lumbar puncture (LP) administration of RES induced both ferroptosis and apoptosis in rat orthotopic GBM xenografts. These findings highlight the dual cell death induced by RES in sensitive GBM cells and identify NRF2 signaling status as a novel determinant of cellular response to RES treatment.