Gut microbiota dysbiosis and the anti-inflammatory effects of probiotic-derived cell-free supernatants in HT-29 cells: insights into early stage colorectal cancer

Colorectal cancer (CRC), the third most common cancer globally, is linked to gut microbiota imbalances. This study explores the association between gut microbiota composition and CRC, focusing on the therapeutic potential of probiotic-derived cell-free supernatants (CFSs). 50 participants, including 25 CRC patients and 25 healthy controls, were recruited and assessed for the relative abundance of six targeted gut bacterial species, including three probiotic strains (Lactobacillus acidophilus, Lacticaseibacillus rhamnosus, and Bifidobacteriumbreve) and three non-probiotic bacteria (Enterococcus faecalis, Streptococcus bovis, and Porphyromonas gingivalis), using absolute quantification real-time PCR (qRT-PCR). Additionally, the in vitro studies investigated the anti-inflammatory effects of CFSs extracted from cultured L. acidophilus, L. rhamnosus, and B. breve, both individually and as a combined cocktail. The results showed that CRC patients exhibited significant increases in non-probiotic bacteria alongside reductions in the beneficial probiotics. Moreover, while the CFSs from all three probiotics exhibited anti-inflammatory properties, the combined CFS cocktail demonstrated the most pronounced effect, significantly downregulating pro-inflammatory cytokines IL-6 and TNF-α in HT-29 colon epithelial cells. These findings emphasize microbial imbalances as potential biomarkers for early CRC detection and underscore the therapeutic promise of probiotic-derived CFSs, presenting innovative, non-invasive strategies for managing CRC-associated inflammation.