Janus villus chip identifies an anaerobic probiotic that suppresses tumor growth in mice

Chronic intestinal inflammation disrupts epithelial integrity and reshapes the tumor immune microenvironment (TIME), accelerating colorectal cancer progression. We investigated how the strict anaerobic mucin-binding probiotic Bifidobacterium adolescentis OP820 modulates inflammation-driven epithelial and immune dysfunction using a Janus oxygen-gradient villus chip and in vivo models. Because Bifidobacterium requires strict anaerobic conditions for viability and physiological activity, the villus chip-engineered with an anaerobic apex and oxygenated base to reproduce the native villus oxygen gradient-was essential for accurately modeling OP820-epithelium interactions. Under these conditions, epithelial cells upregulated MUC13 and MUC17 , generating a mucin-rich glycocalyx to which OP820 adhered strongly, reflecting its natural niche preference. Transcriptomic profiling revealed that OP820 modulates inflammatory signaling by elevating CCL8, TGFA, and MMP12-genes linked to epithelial repair and immunoregulatory remodeling-while suppressing TSLP, FLT3LG, and IL18, which are typically associated with heightened inflammatory stress. These coordinated shifts indicate that OP820 promotes a resolution-oriented immune state rather than amplifying inflammation. The effects were consistent across monolayer, spheroid, and villus-chip models, underscoring the robustness of OP820's immunomodulatory activity under strict anaerobic conditions that reflect its physiological habitat. In vivo, OP820 demonstrated dual therapeutic activity. In the DSS-induced colitis model, it attenuated mucosal injury and preserved epithelial structure, supporting its inflammation-resolving function. In the colorectal cancer xenograft model, intravenous OP820 administration significantly reduced tumor burden, and OP820 cells were detected within the tumor microenvironment, suggesting that intratumoral localization may underlie its immune-modulating and tumor-suppressive activity. The presence of a strict anaerobe within tumors implies the existence of permissive micro-niches and points to direct modulation of local cytokine or stromal networks. Collectively, these findings identify OP820 as a microbiome-derived therapeutic capable of reinforcing epithelial barrier recovery and reprogramming inflammation-driven tumor microenvironments. By integrating villus-chip modeling with in vivo validation, this study highlights OP820's potential as a mechanism-based intervention for inflammation-associated colorectal cancer.