Voluntary exercise sensitizes cancer immunotherapy via collagen degradation-orchestrated inflammatory tumor immune microenvironment

Physical activity reduces cancer-associated mortality through multiple mechanisms, including tumor immune microenvironment (TIME) reprogramming. However, whether and how physiological interventions promote anti-tumor immunity and immunotherapy remains elusive. Here we report that clinically relevant voluntary exercise promotes muscle-derived exosomal miR-29a-3p for extracellular matrix (ECM) degradation in patients and mouse models with multiple types of cancer, thereby permitting immune cell infiltration and immunotherapy. Mechanistically, an unbiased screening identified exercise-responsive exosomal miR-29a-3p that targets tumor cell and cancer associated fibroblasts to downregulate COL1A1 and reduce ECM. State-of-the-art techniques including cytometry by time-of-flight (CyTOF) demonstrated miR-29a-3p-induced TIME remodeling and immune cell infiltration. Combining immunotherapy with voluntary exercise or miR-29a-3p further increased the anti-tumor efficacy in preclinical models. Clinically, miR-29a-3p was correlated with degraded ECM and T-cell infiltration in various cancer types in patients, and correlated with immunotherapy responders. Our work reveals the novel predictive value of miR-29a-3p for immunotherapy, provides mechanistic insights into exercise-promoted anti-cancer immunity, and highlights the therapeutic potential of voluntary exercise in immunotherapy.