Zinc‐Organometallic Framework Vaccine Controlled‐Release Zn(2+) Regulates Tumor Extracellular Matrix Degradation Potentiate Efficacy of Immunotherapy

Tumor extracellular matrix (ECM) not only forms a physical barrier for T cells infiltration, but also regulates multiple immunosuppressive pathways, which is an important reason for immunotherapy failure. The cyclic guanosine monophosphate‐adenosine monophosphate synthase‐stimulator of interferon genes (cGAS‐STING) pathway plays a key role in activating CD8(+) T cells, maintaining CD8(+) T cells stemness and enhancing the antitumor effect. Herein, a zinc‐organometallic framework vaccine (ZPM@OVA‐CpG) prepared by self‐assembly, which achieves site‐directed release of Zn(2+) in dendritic cell (DC) lysosomes and tumor microenvironment under acidic conditions, is reported. The vaccine actively targets DC, significantly enhances cGAS‐STING signal, promotes DC maturation and antigen cross‐presentation, and induces strong activation of CD8(+) T cells. Meanwhile, the vaccine reaches the tumor site, releasing Zn(2+), significantly up‐regulates the activity of matrix metalloproteinase‐2, degrades various collagen components of tumor ECM, effectively alleviates immune suppression, and significantly enhances the tumor infiltration and killing of CD8(+) T cells. ZPM@OVA‐CpG vaccine not only solves the problem of low antigen delivery efficiency and weak CD8(+) T cells activation ability, but also achieves the degradation of tumor ECM via the vaccine for the first time, providing a promising therapeutic platform for the development of efficient novel tumor vaccines.