Rational design of copper ionophores for efficient induction of cuproptosis via simple n-alkyl modification

Small molecules capable of disrupting cellular copper homeostasis and inducing cuproptosis represent promising candidates for cancer therapy. Cuproptosis, a unique form of regulated cell death, is characterized by intracellular copper accumulation, leading to the aggregation of mitochondrial lipidated proteins and the destabilization of iron-sulfur clusters. In this study, we designed a series of copper ionophores (C2-C10) through simple n-alkyl modification using a schiff base derivative as the copper-binding group. Our findings reveal that the length of the n-alkyl chain significantly influences their activity as copper ionophores. Among them, C6 exhibits superior ion transport efficiency, attributed to its optimal copper-binding affinity and balanced lipophilicity. Moreover, C6 effectively transports copper into intracellular compartments. Notably, C6 demonstrates potent in vitro antiproliferative activity against triple-negative breast cancer cells by inducing reactive oxygen species elevation, mitochondrial dysfunction, and cuproptosis. Importantly, C6 shows low systemic toxicity, along with significant in vivo antitumor and immunomodulatory effects. Overall, this study presents a simple yet effective strategy for designing metal ionophores, offering new insights into the development of novel immunotherapeutic agents targeting metal homeostasis.