ObjectiveThe epithelial–mesenchymal transition (EMT) pathway can mediate tumour migration, and the occurrence of EMT is closely related to the Wnt/β-catenin signalling pathway. The purpose of this paper was to study the effect of Lactobacillus fermentum ZS09 (L. fermentum ZS09) on the EMT pathway in mouse with azoxymethane/dextran sulfate sodium salt (AOM/DSS) induced colon cancer and the potential underlying mechanism.Materials and MethodsIn this study, a mouse colon cancer model was established through intraperitoneal injection of 10 mg/kg azoxymethane (AOM) and three cycles of 2.5% dextran sulfate sodium salt (DSS) in the drinking water. H&E staining, enzyme-linked immunosorbent assay (ELISA), real-time fluorescent quantitative PCR (RT-qPCR) and Western blotting (WB) were used to study the antitumour mechanisms of L. fermentum ZS09 through the EMT pathway.ResultsThe results of this study showed that compared with the model group, the high-dose L. fermentum ZS09 intervention group exhibited decreased serum levels of MMP-9, TNF-α, IL-6R, Ang-2 and VEGFR-2 and increased contents of DKK1 (P<0.05). The expression of Wnt/β-catenin signalling pathway-related genes (Dv1, GSK-3β, β-catenin, c-myc, cyclinD1, Vim, and MMP-9) was significantly reduced, and the gene expression levels of APC, CDH1, and Axin were increased. The levels of related proteins (β-catenin, N-cadherin, and VEGF) were downregulated, and the levels of p-β-catenin and E-cadherin were upregulated.ConclusionThe results indicate that L. fermentum ZS09 could inhibit EMT and angiogenesis pathways by inhibiting the Wnt/β-catenin signalling pathway, which could inhibit tumour metastasis.