Microbiota-miR-101 interactions in obesity-associated colorectal cancer: from barrier dysfunction to precision therapeutic strategies.

Colorectal cancer (CRC) remains a leading cause of cancer-related morbidity and mortality worldwide, with obesity recognized as a major modifiable risk factor. Obesity-associated CRC is characterized by systemic low-grade inflammation, altered lipid metabolism, and gut microbial dysbiosis, all of which converge to create a pro-inflammatory niche. Emerging evidence implicates murine miR-101a/b, an ortholog of the human miR-101 family, as a key molecular mediator linking metabolic dysfunction, promoting inflammation, endotoxemia, and affecting epithelial homeostasis. Traditionally, the miR-101 family is considered a tumor suppressor by repressing oncogenes such as EZH2, MCL-1, and COX-2; miR-101a appears to exhibit a paradoxical microenvironment-modulating role in obese colon. Recent studies demonstrate that elevated dietary and microbiota-derived ethanolamine induces miR-101a overexpression in colonic epithelial cells. Mechanistically, miR-101a directly destabilizes the mRNA encoding the tight junction protein (ZO-1; TJP1), thereby impairing epithelial barrier integrity, increasing intestinal permeability, and promoting chronic inflammation. The chronic inflammation promotes epithelial proliferation, generates mutagenic reactive oxygen species, and activates pro-survival pathways such as STAT3 and AKT, collectively contributing to a tumor-permissive microenvironment that may support adenoma initiation and progression. The resulting chronic inflammatory milieu promotes epithelial stress, proliferative signaling, and accumulation of DNA damage, contributing to conditions that favor colorectal carcinogenesis. Importantly, this ethanolamine-miR-101a axis represents a novel mechanistic link between diet, microbiota, and cancer biology. Translationally, miR-101a holds promise as a biomarker of early barrier dysfunction and CRC risk, as detectable in tissue, serum, or fecal samples. Furthermore, microbiome-targeted interventions, dietary modifications, or direct inhibition of miR-101a may offer innovative therapeutic strategies. Collectively, these findings support the development of precision microbiome-miRNA-based approaches and highlight the importance of context-dependent miRNA regulation in obesity-associated CRC.