ENHANCED APOPTOSIS VIA AKT/P53 AND CELL CYCLE ARREST VIA CYCLIN MODULATION IN HT-29 CELLS BY BACTEROIDES FRAGILIS SUPERNATANT: A COMPARATIVE STUDY WITH LYSATE

Abstract

Bacteroides fragilis, a common member of the human gut microbiome, has recently get attention for its potential anti-cancer effects and its promise as a next-generation probiotic. In this study, we evaluated the impact of B. fragilis supernatant and lysate on human colorectal cancer HT-29 cells. Cytotoxic effects were measured using the MTT assay, while changes in gene expression (including cyclins, apoptotic markers, and AKT) were analyzed using real-time PCR. Additionally, flow cytometry was used to assess apoptosis and alterations in cell cycle progression. Results showed a time-dependent reduction in cell viability, with the supernatant consistently showing a stronger effect than the lysate. Flow cytometry analysis revealed increased apoptosis and significant accumulation of cells in the sub-G1 phase, particularly after 48 hours of treatment. Gene expression analysis further confirmed upregulation of pro-apoptotic markers (Caspase-9, Caspase-2, p53, and p21) and downregulation of cyclins and the anti-apoptotic gene AKT. These findings suggest that B. fragilis extracts—especially the supernatant—can induce apoptosis and disrupt cell cycle progression in colorectal cancer cells. This highlights the potential of utilizing bacterial secretomes as the therapeutic potential in cancer treatment.