This study investigated the effect of the probiotic *Limosilactobacillus fermentum* GR-3 on colitis-associated tumorigenesis in mice. GR-3, isolated from traditional food “Jiangshui”, demonstrated superior antioxidant capacity. In an AOM/DSS-induced CRC mouse model, GR-3 treatment alleviated colitis symptoms, reduced oxidative stress and inflammation, and reduced tumor incidence by 51.2%. The beneficial effects were linked to gut microbiome modulation, increasing SCFA producers and suppressing pro-inflammatory strains. Metagenomic and metabolic analyses revealed GR-3's impact on antioxidant genes, butyrate synthesis, and beneficial metabolites. GR-3 emerges as a promising candidate for CRC therapy.

Tuoyu Zhou, Jingyuan Wu, Aman Khan, Tianxiang Hu, Yiqing Wang, El-Sayed Salama, Shaochen Su, Huawen Han, Weilin Jin, Xiangkai Li