Synergistic Anticancer Effects of Akkermansia muciniphila Combined With 5‐Fluorouracil Through BAX/BCL2 Dependent Apoptosis in Colorectal Cancer Cells

Colorectal cancer (CRC) continues to be one of the deadliest cancers worldwide, mainly due to late diagnosis, chemoresistance, and the complex interactions within the tumor microenvironment. Recent studies suggest that the gut bacterium Akkermansia muciniphila plays a key role in maintaining intestinal health and may influence the effectiveness of cancer therapies. Therefore, the main aim of this study was to explore whether a lyophilized form of A. muciniphila could support CRC treatment. First, we analyzed A. muciniphila abundance in healthy, adenoma, and CRC tissues using public datasets. Next, CRC cell lines (HT29, HCT116, and SW620) and normal stromal cells (Hs738 St/Int) were treated with increasing doses of the bacterial extract, alone and with 5-fluorouracil (5-FU). Then, cell viability measured by MTT assay, apoptosis by BAX/BCL2 expression via RT-qPCR, and physicochemical properties by zeta potential analysis. The results showed a marked reduction of A. muciniphila abundance in CRC samples, with an early decline from healthy to adenoma tissues and a slight recovery in advanced tumors. In vitro, the extract demonstrated dose-dependent cytotoxicity toward cancer cells, with HT29 showing strong sensitivity at low doses, HCT116 responding at higher concentrations, and SW620 exhibiting greater resistance. Importantly, the extract was well tolerated by normal cells, unlike 5-FU. Combining the extract with 5-FU resulted in a synergistic effect, indicating the possibility of reducing 5-FU dosage to limit its toxicity. The extract significantly upregulated BAX, downregulated BCL2, and displayed strong negative zeta potential, supporting enhanced apoptotic activation and selective interaction with cancer cell membranes. These findings suggest that A. muciniphila and its derived products may serve as promising adjuncts in personalized microbiome-based CRC therapy.