Identification of ebastine and ceritinib as effective inhibitors of Fusobacterium nucleatum FtsZ

ABSTRACT The role of microorganisms in cancer is not a new concept—bacteria, parasites, and viruses have all been implicated in cancer development. Fusobacterium nucleatum , a member of the oral microbiota, has emerged as an important cancer-associated bacterium. Unbiased global genomic analyses have demonstrated that F. nucleatum is enriched in human colorectal cancer (CRC) tissues compared with noncancerous colorectal tissues, underscoring the urgent need for specific antimicrobial agents targeting F. nucleatum for CRC prevention and treatment. In this study, structure-based virtual screening successfully identified ebastine and ceritinib as antimicrobial agents targeting Fusobacterium nucleatum FtsZ (FnFtsZ). Their potent anti -F . nucleatum activity was confirmed through in vitro assays, including minimum inhibitory concentration determination and microscopic observation of filamentous morphology. Both ebastine and ceritinib exhibited significant antibacterial effects. Enzyme activity and polymerization assays demonstrated that their mechanism of action involves inhibition of FnFtsZ GTPase activity and disruption of FnFtsZ polymerization. Scanning electron microscopy (SEM) and light microscopy further confirmed that these compounds effectively disrupt cell division, leading to abnormal or halted division and inhibiting F. nucleatum proliferation. Overall, our findings identified ebastine and ceritinib as potential drugs against F. nucleatum proliferation, although further structural optimization is required. Additionally, our results demonstrate the effectiveness of an integrated computational-experimental approach targeting bacterial cell division in microbiome-associated pathologies. IMPORTANCE Colorectal cancer (CRC) is strongly driven by the enrichment of the oncogenic bacterium Fusobacterium nucleatum in gut lesions. However, the lack of targeted anti- F. nucleatum drugs significantly limits microbe-related interventions for CRC. In this study, we repurposed two clinically approved drugs, ebastine and ceritinib, as highly effective inhibitors of FnFtsZ, the key protein responsible for bacterial cell division. We demonstrated that both drugs inhibit bacterial proliferation by suppressing FnFtsZ function and disrupting the cell division process. Our work offers safe, readily available candidate agents for controlling CRC-associated pathogenic bacteria and establishes a reliable computational-experimental workflow to screen division-targeted antimicrobials for microbiome-related cancers.