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

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 Cu²⁺ 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.