Propionibacterium acnes Cloaked with ZnAl Layered Double Hydroxides Synergistically Inhibits Tumor Growth and Metastasis

Abstract The combination of precise tumor depletion and immunotherapy presents great potential to exterminate cancer disease. Anaerobic bacteria can trigger innate and adaptive immune responses in tumors to facilitate the antitumor effects. However, bacteria injected intravenously induce systemic inflammation and are likely to be eliminated in the blood. Herein, live bacteria, Propionibacterium acnes ( P. acnes ), are integrated with ZnAl layered double hydroxides (LDHs) to construct an effective system enabling synergistic inhibition in both tumor growth and metastasis. In this system, P. acnes carries LDHs to reach and penetrate the hypoxic tumor tissue. The metabolism of colonized P. acnes and the pH‐responsive degradation of LDHs produce reactive nitrogen species and reactive oxygen species to trigger inevitable cell death. Furthermore, the decomposition of LDHs exposes P. acnes , and thus the immune response is activated to prohibit the reoccurrence of distant tumors. The biohybrid P. acnes @LDHs, developed in this study, possesses remarkable anticancer outcomes both in vitro and in vivo.