Role of Bifidobacterium longum in the induction of apoptotic deletion in the human enterocyte-like Caco-2 cell line

The induction of apoptosis in the human enterocyte-like Caco-2 cell line mediated by three Bifidobacterium longum strains, which displays different adhesion properties, was investigated. Methods and Results: The three strains tested were defined for their adhesion properties using adhesion and autoaggregation assays. Strain B12 shows strong autoaggregation and strong adherence to Caco-2 cells; strain B18 shows strong autoaggregation and intermediate adherence; strain B2990 shows poor autoaggregation and poor adherence. Cocultures of Caco-2 cells with B. longum resulted in the induction of apoptosis, determined by DNA fragmentation test, only when autoaggregating or strongly adherent strains were used (B12 and B18). Conclusion: These results indicate that the interaction with aggregating/adherent probiotics can induce apoptosis of human colon epithelial cells, suggesting a role for these bacteria in the regulation of the cellular homeostasis of the gastrointestinal tract. Significance and Impact of the Study: B. longum as a probiotic is known for his beneficial effects to the human gut; the knowledge of its immunomodulatory and antitumor activities can be crucial for the healthcare and the prevention of cancer