Integrated study of metabolomics and gut metabolic activity from ulcerative colitis to colorectal cancer: The combined action of disordered gut microbiota and linoleic acid metabolic pathway might fuel cancer

Colorectal cancer (CRC) is one of the most serious complications of ulcerative colitis (UC). Altered gut microbiota is implicated in the development of CRC and metabolic perturbations are often associated with changes in the gut microbiome composition. Given the links between gut microbiome and the metabolic profiles in the body, an approach involving ultra-high-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC-Q-TOF-MS/MS) metabolomics and 16S rDNA sequencing technology was applied to trace the development UC into CRC in rats. The study identified 11 differential metabolites related to both UC and CRC, which mainly referred to the linoleic acid metabolism. Among these, linoleic acid and 12‑hydroxy‑8,10-octadecadienoic acid could serve as key biomarkers for the development of UC into CRC. Besides, a significant change was observed in the microflora structure during the development from UC to CRC; this mainly involved a gradual increase in Escherichia-Shigella and a gradual decrease in Lactobacillus. In addition, Pearson's correlation analysis revealed strong correlations between intestinal microflora-related metabolites and specific intestinal microflora, which indicated both of them can promote the transition of UC to CRC. The results of the present study provided positive support for the involvement of intestinal microflora and host metabolism in the pathophysiological mechanism that is responsible for the development of UC into CRC. This information can help understand the risk for CRC that accompanies a diagnosis of UC and also provide different means of targeting these differential metabolites and intestinal microbiota to avoid UC-induced CRC.