Soft cell-derived hybrid microparticles with platelet decoys for enhanced cancer chemotherapy.

Platelets play a critical role in tumor development, metastasis and chemoresistance, making the effective killing of tumor cells and simultaneously targeted disruption of platelet functions essential for improving cancer treatment outcomes, especially in post-surgical malignant tumor patients. Here, we develop soft hybrid microparticles (3D-PMPs) by fusing tumor-repopulating cell-derived microparticles with inactivated platelet membranes to deliver the anticancer agent doxorubicin (DOX@3D-PMPs). Leveraging their unique softness, DOX@3D-PMPs demonstrate superior tumor accumulation, deep tumor penetration, and enhanced internalization into tumor cells, leading to efficient tumor cell killing. Additionally, 3D-PMPs function as highly targeted platelet decoys to disrupt platelet-tumor cell interaction and reduce platelet-driven tumor proliferation and metastasis. Mechanistically, Toll-like receptor 4 (TLR-4) presented on 3D-PMPs is responsible for their platelet decoy function. DOX@3D-PMPs demonstrate significantly enhanced therapeutic efficacy in both orthotopic 4T1 breast tumors and post-surgical orthotopic 4T1 breast tumors. This work offers a novel and effective approach to enhance the therapeutic outcomes in cancer treatment, particularly in post-surgical settings.