Radioactive copper (64Cu)-enabled theranostic delivery modulates cuproptosis-associated signaling for cancer treatment

Cuproptosis, a unique form of programmed cell death triggered by copper overload and subsequent proteotoxic stress, represents a promising avenue for cancer therapy. Radiotherapy may influence cuproptosis-related pathways in tumors, highlighting the possibility of combining radiotherapy to enhance cuproptosisis. However, how copper delivered in a radioactive form affects these processes remains unclear. Here, we doped radioactive 64 Cu into elesclomol (ES-Cu[II]) and encapsulated by an RGD-modified nanoparticle, named ES- 64 Cu[II] @Nanoparticle-RGD (ES- 64 Cu@NP). This agent demonstrated high tumor accumulation (7.66 ± 0.93 %ID/g in U87-MG tumors at 4 h) via PET imaging. The internal irradiation from 64 Cu upregulated key cuproptosis proteins (FDX1, DLAT), accompanied by increased DNA damage signaling (γ-H2AX) and oxidative stress. This dual-sensitization mechanism resulted in synergistic antitumor efficacy, significantly inhibiting glioblastoma growth and extending median survival to 36 days in murine models, without observable systemic toxicity. These findings indicate that radioactive copper delivery can modulate cuproptosis-associated signaling while enabling PET-guided tracking, supporting this theranostic strategy for investigating copper-dependent stress responses in cancer.