Azo-based hypoxic-activated 6-diazo-5-oxo-L-norleucine (DON) prodrug combined with vascular disrupting agent nanoparticles for tumor-selective glutamine metabolism blockade

Glutamine antagonists, such as 6-diazo-5-oxo-L-norleucine (DON), have demonstrated remarkable anti-tumor effects by blocking tumor glutamine metabolism, but their use is frequently causing toxicity. Despite the existence of multiple glutamine antagonist prodrug designs, a tumor-selective prodrug has yet to be developed. Herein, a novel prodrug of DON, Azo-DON, has been developed, which remains stable and inactive in normal tissues with sufficient oxygen levels, while can be selectively reduced to DON by highly expressed azo-reductase in hypoxic tumor environments. This leads to blockade of glutamine metabolism in cancer cells and promotes cell death without affecting T cell proliferation. In a high-hypoxic H22 hepatoma cancer model, Azo-DON showed a 1.8-fold enhancement in glutamine blockade compared to the control group, resulting in a tumor suppression rate (TSR) of 84.2% in vivo with no significant weight loss. In a low-hypoxic CT26 colon cancer model, when combined with vascular disrupting agent nanoparticles (CBP) to induce a hypoxic environment, Azo-DON exhibited a 4.6-fold enhancement in glutamine blockade over the control group, resulted in a remarkable TSR of 96.6% in vivo . This innovative approach represents a promising strategy for the application of broad-spectrum metabolic inhibitors in the field of precision cancer treatment.