Turning tumor cells into microvesicles as personalized cancer vaccines for cancer prevention and treatment

Autologous cancer cell-derived vaccines can arouse potent and patient-specific immunostimulation for cancer immune therapy. Here, we report a novel and simple preparation strategy of cancer cell-derived vaccines. A series of nanoinducers (NIs) are fabricated to effectively transform different kinds of cells into micrometer-sized vesicles (termed MVs) with a very high cell-to-MV conversion rate (e.g., similar to 35%, based on protein content). We surprisingly find that these cancer cells-derived MVs can be used as cancer vaccines to arouse efficient anticancer immune responses. Compared to the commonly used cell debris (e.g., the sonication- and freeze-thaw-obtained cell debris), the MVs exhibit a much stronger immunostimulation effect, which is attributed to the higher proportion of immune-related proteins in MVs. After subcutaneous administration, the MVs can massively target lymph nodes and elicit systemic immunostimulation. Preimmunization with MVs together with an adjuvant can protect the mice from both subcutaneous and intravenous 4T1 tumor challenges, and the MVs plus adjuvant also show satisfactory anticancer outcomes in tumor-bearing mice. Furthermore, the MVs can be massively induced and easily purified, which may facilitate their clinical translation. It is believed that such a cell-derived cancer vaccine may find practical applications for personalized cancer prevention and treatment.