Synergism of Fusobacterium periodonticum and N-nitrosamines promote the formation of EMT subtypes in ESCC by modulating Wnt3a palmitoylation.

N-Nitrosamine disinfection by-products (NAs-DBPs) have been well proven for its role in esophageal carcinogenesis. However, the role of intratumoral microorganisms in esophageal squamous cell carcinoma (ESCC) has not yet been well explored in the context of exposure to NAs-DBPs. Here, the multi-omics integration reveals F. periodonticum ( Fp ) as "facilitators" is highly enriched in cancer tissues and promotes the epithelial mesenchymal transition (EMT)-like subtype formation of ESCC. We demonstrate that Fp potently drives de novo synthesis of fatty acids, migration, invasion and EMT phenotype through its unique FadAL adhesin. However, N-nitrosomethylbenzylamine upregulates the transcription level of FadAL. Mechanistically, co-immunoprecipitation coupled to mass spectrometry shows that FadAL interacts with FLOT1. Furthermore, FLOT1 activates PI3K-AKT/FASN signaling pathway, leading to triglyceride and palmitic acid (PA) accumulation. Innovatively, the results from the acyl-biotin exchange demonstrate that FadAL-mediated PA accumulation enhances Wnt3A palmitoylation on a conserved cysteine residue, Cys-77, and promotes Wnt3A membrane localization and the translocation of β-catenin into the nucleus, further activating Wnt3A/β-catenin axis and inducing EMT phenotype. We therefore propose a "microbiota-cancer cell subpopulation" interaction model in the highly heterogeneous tumor microenvironment. This study unveils a mechanism by which Fp can drive ESCC and identifies FadAL as a potential diagnostic and therapeutic target for ESCC.