Carbon ion combined photon radiotherapy induces ferroptosis via NCOA4-mediated ferritinophagy in glioblastoma

Glioblastoma (GBM), the most prevalent and lethal primary malignancy of the central nervous system, remains refractory to conventional photon radiotherapy due to inherent limitations in dose distribution. Although carbon ion radiotherapy offers distinct advantages, including its characteristic Bragg peak deposition and superior relative biological effectiveness, its clinical application is constrained by high costs and increased toxicity. This study explores the radiobiological interactions underlying a mixed carbon ion-photon irradiation regimen, a promising strategy in advanced particle therapy. Our findings demonstrate that combined irradiation exerts synergistic cytotoxic effects in GBM models. Mechanistic analysis reveals that this combination induces clustered DNA double-strand breaks, leading to the cytoplasmic accumulation of double-stranded DNA (dsDNA) fragments. This, in turn, activates the cGAS-STING-mediated cytosolic DNA sensing pathway, which facilitates NCOA4-FTH1 axis-driven ferritinophagy and ultimately triggering iron-dependent ferroptosis. These findings offer a new mechanistic perspective on optimizing combined particle therapy regimens for GBM treatment, with significant implications for translational applications in clinical radiation oncology.