MicroRNA-31 induced by Fusobacterium nucleatum infection promotes colorectal cancer tumorigenesis

Persistent Fusobacterium nucleatum infection is associated with the develop-ment of human colorectal cancer (CRC) and promotes tumorigenicity, but the underlying mechanisms remain unclear. Here, we reported that F. nucleatum promoted the tumorigenicity of CRC, which was associated with F. nucleatum- induced microRNA-31 (miR-31) expression in CRC tissues and cells. F. nucleatum infection inhibited autophagic flux by miR-31 through inhibiting syntaxin-12 (STX12) and was associated with the increased intracellular survival of F. nucleatum. Overexpression of miR-31 in CRC cells promoted their tumorige-nicity by targeting eukaryotic initiation factor 4F-binding protein 1/2 (eIF4EBP1/ 2), whereas miR-31 knockout mice were resistant to the formation of colorectal tumors. In conclusion, F. nucleatum, miR-31, and STX12 form a closed loop in the autophagy pathway, and continuous F. nucleatum-induced miR-31 expression promotes the tumorigenicity of CRC cells by targeting eIF4EBP1/2. These find-ings reveal miR-31 as a potential diagnostic biomarker and therapeutic target in CRC patients with F. nucleatum infection.