Reversing Temozolomide Resistance in Glioblastoma Based on Cuproptosis‐Mediated Positive Feedback Loop

ABSTRACT Glioblastoma (GBM), one of the most lethal human cancers, faces a major therapeutic challenge due to drug resistance. Temozolomide (TMZ), a standard first‐line drug for clinical GBM treatment, benefits only a subset of patients, leaving an urgent need for strategies that can restore its efficacy. Herein, we propose that cuproptosis, a recently identified regulated cell death (RCD), is capable of reversing TMZ resistance in GBM. We design copper‐TMZ (Cu‐TMZ) prodrugs, assembled via the coordination of Cu ²⁺ with TMZ and, in optimized formulations, co‐loaded with metformin (MET) as an AMPK activator, to exploit cuproptosis for overcoming TMZ resistance. Upon glutathione‐triggered disassembly, the prodrugs release Cu ⁺ and TMZ, inducing mitochondrial proteotoxic stress and initiating a self‐amplifying cuproptosis loop characterized by ATP depletion, AMPK‐p53 activation, and glycolysis inhibition. Beyond self‐reinforcement, cuproptosis directly potentiates TMZ activity by suppressing drug efflux, impairing DNA repair, and aggravating metabolic and redox stress. Both in vitro and in vivo experiments demonstrate that Cu‐TMZ/MET prodrugs markedly restore TMZ responsiveness and suppress TMZ‐resistant GBM progression. More broadly, this study illustrates how RCD pathways can be engineered into therapeutics to convert drug resistance into vulnerability, highlighting a generalizable strategy for improving the efficacy of frontline chemotherapy in otherwise intractable cancers.