Anaerobic bacterial metabolism responsive microspheres for bacterial embolization cancer therapy

Anaerobic bacteriolytic cancer therapy, whether delivered locally or systemically, frequently encounters challenges related to limited colonization within hypoxic pockets of central tumors and activation of innate immunity. Herein we have developed trans-arterial bacteria embolization therapy using bacterial embolic microspheres. C. novyi-NT spores loaded calcium alginate embolic microspheres demonstrated C. novyi-NT metabolites-mediated microsphere degradation, releasing vegetative C. novyi-NT bacterial in hypoxic condition. Transcatheter directed bacterial microsphere embolization therapy occludes tumor feeding vessels with infused bacterial embolic microspheres and enhances tumoral hypoxia. Notably, anaerobic bacterial metabolism responsive microsphere-bacterial embolization therapy achieved a complete tumor response with enhanced tumor-specific bacterial delivery and colonization, resulting in cancer cell killing across the entire tumor. In vivo tumor response and immunological profiling revealed that bacterial embolization uniquely enhances anti-cancer response, effectively engaging direct anaerobic bacterial oncolysis and adaptive and innate immune responses in a cooperative manner.