Dual-sensitization nanoformulation combining glutamine metabolism inhibition and Fas/FasL activation for enhanced colorectal cancer immunotherapy.

Altered glutamine metabolism in colorectal cancer (CRC) promotes immune evasion by inducing an immunosuppressive tumor microenvironment. Herein, we developed a nanocomplex by linking the anti-programmed death ligand 1 (PD-L1) antibody (αPDL1) with alanine-serine-cysteine transporter 2 antagonist V-9302 covalently via a glutathione-responsive linker (PVN). The PVN disintegrated and released V-9302, which suppresses glutamine uptake and upregulates the expression of PD-L1 and the Fas cell surface death receptor (Fas/CD95/Apo-1) in tumor cells via the Ca2+/NF-κB signaling axis. This converted the PD-L1 elevation into therapeutic vulnerability, sensitizing tumor cells to immune checkpoint blockade. The upregulated tumor-associated Fas expression was utilized by Fas ligand (FasL)-overexpressing dendritic cell (FasL-DC) to activate death receptor pathways and induce Fas/FasL-mediated tumor apoptosis. The combination strategy termed PVN/FasL-DC, promoted dendritic cell maturation, epitope spreading, and increased the infiltration of CD8+ T cells, thereby enhancing antitumor efficacy. This study emphasizes the synergistic modulation of glutamine metabolism and death receptor pathways as a dual-sensitization strategy with promise for CRC immunotherapy.