Tumor Environment Regression Therapy Implemented by Switchable Prune‐to‐Essence Nanoplatform Unleashed Systemic Immune Responses

Abstract Coevolution of tumor cells and surrounding stroma results in protective protumoral environment, in which abundant vessel, stiff structure and immunosuppression promote each other, cooperatively incurring deterioration and treatment compromise. Reversing suchenvironment may transform tumors from treatment‐resistant to treatment‐vulnerable. However, effective reversion requires synergistic comprehensive regression of such environment under precise control. Here, the first attempt to collaboratively retrograde coevolutionary tumor environment to pre‐oncogenesis status, defined as tumor environment regression therapy, is made for vigorous immune response eruption by a switchable prune‐to‐essence nanoplatform (Pres) with simplified composition and fabrication process. Through magnetic targeting and multimodal imaging of Pres, tumor environment regression therapy is guided, optimized and accomplished in a trinity way: Antiangiogenesis is executed to rarefy vessels to impede tumor progression. By seizing the time, cancer associated fibroblasts are eliminated to diminish collagen and loosen the stiff structure for deep penetration of Pres, which alternately functioned in deeper tumors, forming a positive feedback loop. Through this loop, immune cell infiltration, immunosuppression mitigation and immunogenic cells death induction are all fulfilled and further escalated in the regressed environment. These transformations consequently unleashed systemic immune responses and generated immune memory against carcinoma. This study provides new insights intotreatment of solid tumors.