Gut microbiome and metabolomics reveal the role of thioproline in attenuating colorectal cancer-associated inflammation

Colorectal cancer (CRC) is one of the top three cancers globally in terms of both incidence and mortality, and its development may be influenced by an inflammatory environment in the intestines, often associated with gut microbiota dysbiosis. Food bioactives could modulate gut microbiota through anti-inflammatory and epigenetic mechanisms. Given the significant role of thioproline as a food bioactive with antioxidant properties, its potential to modulate gut microbiota and mitigate CRC remains largely unexplored. This study aims to understand the effects of thioproline on gut microbiota community and investigate the mechanisms through which thioproline regulates gut microbiota and exerts its anticancer effects. Fecal and intestinal tissue samples were collected from health, CRC, and thioproline-treated CRC mice. The metagenome and metabolome data revealed that thioproline treatment significantly altered the gut microbiota community composition and metabolism in CRC mice. These CRC-associated gut microbiota and bacterial metabolites returned to normal levels. Moreover, under thioproline treatment, the microbial-metabolite interactions in CRC mice shifted toward patterns more closely resembling those observed in healthy mice. Thioproline treatment increased linoleic acid levels in mice, indicating its role in promoting linoleic acid metabolism to therapeutically restore homeostasis and alleviate inflammation in CRC. This was further supported by hematoxylin and eosin staining, which demonstrated that thioproline alleviated inflammation in CRC mice. Our study highlights thioproline's dual role in regulating the gut microbiota community and bacterial metabolism, modulating bacteria-host interactions, and ultimately reducing inflammation in CRC. These findings offer valuable insights for future research and therapeutic applications.IMPORTANCEColorectal cancer (CRC) is associated with gut microbiota dysbiosis and intestinal inflammation. While food bioactives can modulate the microbiome, whether thioproline exerts inhibitory effects against CRC through microbial regulation remains unknown. Using integrated metagenomics and metabolomics, we show that thioproline treatment restores the gut microbiota composition and bacterial metabolites disrupted by CRC to near-normal levels. Importantly, thioproline remodels microbial metabolite interaction networks, elevates linoleic acid levels, and alleviates intestinal inflammation. This study provides a systems-level perspective on how a single dietary bioactive compound reshapes the gut microbial ecosystem and its metabolic landscape to reduce inflammation in CRC. Our findings suggest a potential role for microbiome-targeted nutritional strategies in protecting against CRC progression through modulation of the gut microbiota and intestinal microenvironment.