Targeted Clearance of Senescent Cells Via Engineered Extracellular Vesicles Reprograms Tumor Immunosuppressive Microenvironment.

Unravelling the mechanisms for the immunosuppressive tumor microenvironment and developing corresponding therapeutic strategies are of great importance to improve the cancer immunotherapy. This study has revealed that there are abundant senescent cells accumulated in the colon cancer tissue, which contributes greatly to the immunosuppressive microenvironment. Oral delivery of Dasatinib and Quercetin (D+Q) eliminates the senescent cells with compromised efficiency due to the poor tumor penetration and short half-life. To improve the efficacy of senescent cell clearance, this work has developed an extracellular vesicle (EV) based senolytic strategy. The engineered senolytic EVs have anti-GPNMB (a senescent cell surface marker) displayed on the surface and D+Q loaded on the membrane. In a syngeneic mouse model, senolytic EVs efficiently and selectively eradicate the senescent cells and in turn unleashes the antitumor immunity. With the antitumor immunity boosted, cancer growth is inhibited and the survival is prolonged. In summary, this work has illuminated that senescent cells contribute to the immunosuppressive microenvironment in colon cancer and proposes a novel strategy to conquer the problem by EV-based senolytics.