Targeting the gut–tumor axis: probiotic therapy as an adjunct strategy in colorectal cancer treatment

Abstract

Colorectal cancer (CRC) is a multifactorial disease driven by interactions among host genetics, immune dysregulation, environmental factors, and gut microbiota. The gut–tumor axis regulates CRC progression through inflammatory signaling, oxidative stress, epithelial barrier disruption, and immune imbalance. Probiotic-derived metabolites act as bioactive molecules capable of restoring host–microbiome homeostasis and modulating tumor-associated pathways. To evaluate probiotic metabolites as adjunct therapeutic agents in CRC using integrative multi-omics analysis and in vitro validation. A systems biology approach integrating network pharmacology, transcriptomics, proteomics, metabolomics, and microbiome profiling was applied. Twelve probiotic metabolites yielded 428 predicted targets, with 162 overlapping CRC-associated genes. CRC cell lines (HCT116, HT-29, Caco-2, SW480) were treated and analyzed for viability, apoptosis, gene/protein expression, cytokines, metabolites, and microbial composition. Sodium butyrate (5 mM) reduced cell viability by 35.5–42.3% (p < 0.001) and increased apoptosis from 8.6% to 32.4%, reaching 41.2% when combined with indole-3-acetic acid (IAA, 100 μM), suggesting a synergistic pro-apoptotic effect. RNA-seq identified 1,248 DEGs, with upregulation of BAX and CASP3 (log 2 FC +1.8 to +2.3) and downregulation of IL6, TNF, and NFKB1 (−1.5 to −2.1). Proteomics revealed 412 differentially expressed proteins, including downregulation of AKT1 (−1.6-fold), MAPK1 (−1.4-fold), and EGFR (−1.3-fold), and upregulation of CASP3 (+1.7-fold) and BAX (+1.5-fold). Cytokines IL-6, TNF-α, and IL-1β decreased by 48.2%, 44.7%, and 39.5%, respectively, while IL-10 increased by 26.3%. Metabolomics showed a 2.8-fold increase in butyrate and ~35% reduction in oxidative stress. Microbiome diversity improved (Shannon index 2.8–3.6). Probiotic-derived metabolites modulate NF-κB, PI3K–Akt, MAPK, and apoptosis pathways, supporting their potential role as adjunct therapeutic agents in CRC management.