Mitochondrial dysfunction and impaired growth of glioblastoma cell lines caused by antimicrobial agents inducing ferroptosis under glucose starvation

Glioblastoma is a difficult-to-cure disease owing to its malignancy. Under normal circumstances, cancer is dependent on the glycolytic system for growth, and mitochondrial oxidative phosphorylation (OXPHOS) is not well utilized. Here, we investigated the efficacy of mitochondria-targeted glioblastoma therapy in cell lines including U87MG, LN229, U373, T98G, and two patient-derived stem-like cells. When glioblastoma cells were exposed to a glucose-starved condition (100 mg/l), they rely on mitochondrial OXPHOS for growth, and mitochondrial translation product production is enhanced. Under these circumstances, drugs that inhibit mitochondrial translation, called antimicrobial agents, can cause mitochondrial dysfunction and thus can serve as a therapeutic option for glioblastoma. Antimicrobial agents activated the nuclear factor erythroid 2-related factor 2–Kelch-like ECH-associated protein 1 pathway, resulting in increased expression of heme oxygenase-1. Accumulation of lipid peroxides resulted from the accumulation of divalent iron, and cell death occurred via ferroptosis. In conclusion, mitochondrial OXPHOS is upregulated in glioblastoma upon glucose starvation. Under this condition, antimicrobial agents cause cell death via ferroptosis. The findings hold promise for the treatment of glioblastoma.