Modeling Fusobacterium nucleatum-Driven Colorectal Cancer in Apc-Mutant Mice.

Colorectal cancer (CRC) typically initiates with mutations in the adenomatous polyposis coli (Apc) gene, followed by the influence of environmental factors. Among these, Fusobacterium nucleatum has emerged as an important CRC-enriched microbial species with demonstrated tumor-promoting potential. To investigate the contribution of F. nucleatum in the context of oncogenic mutations, physiologically relevant mouse models are essential. While Apcmin/+ mice have been employed to study F. nucleatum-associated CRC, prior studies have not systematically evaluated the effects of different bacterial inoculation routes and dosages on tumorigenesis. Here, we utilized a reliable and reproducible inducible Apc-mutant mouse model that recapitulates F. nucleatum colonization within the gut microenvironment, closely reflecting conditions observed in CRC patients. We provide a detailed protocol describing two distinct F. nucleatum administration routes and graded dosage regimens to assess their impact on CRC progression. This platform offers a robust experimental tool for investigating the microbiota-cancer axis, with broad applicability for both preclinical and mechanistic studies aimed at advancing understanding of CRC pathogenesis.