Dose-related intestinal injury and associated gut microbial and metabolic alterations during CPT-11 treatment in colorectal cancer mice

Irinotecan (CPT-11) is widely used in colorectal cancer (CRC) treatment, but its clinical use is limited by gastrointestinal toxicity. This study characterized dose-related intestinal injury during CPT-11 treatment in an azoxymethane/dextran sulfate sodium (AOM/DSS)-induced CRC mouse model. Mice were treated with CPT-11 at 5, 10, 20, 40, and 80 mg/kg. Intestinal injury was assessed using disease activity index, colon length, histopathology, and colonic inflammatory cytokine levels. Changes in body weight were also recorded. CPT-11, SN-38, and SN-38G concentrations in serum and tissue extracts were measured by UPLC-MS/MS. β-Glucuronidase (β-GUS) activity in colonic contents was measured. Gut microbial and serum metabolic profiles were characterized by 16S rRNA gene sequencing and untargeted metabolomics, respectively. Intestinal injury became more pronounced with increasing CPT-11 dose, particularly at 40 and 80 mg/kg. Concentrations of CPT-11, SN-38, and SN-38G showed an overall increase across CPT-11 dose groups in serum and the tissue extracts examined. β-GUS activity in colonic contents also increased at higher CPT-11 doses. Gut microbial community structure and composition differed across dose groups, with more pronounced differences observed at 80 mg/kg. Serum metabolic profiles also differed among groups. Glycerophospholipid metabolism was the only pathway that remained significant after Holm correction. Several differential features were putatively annotated as glycerophospholipid-related metabolites. Correlation analysis showed associations between bacterial taxa and serum metabolic features. CPT-11 treatment was associated with dose-related intestinal injury in AOM/DSS-induced CRC mice. These changes were accompanied by alterations in the concentrations of CPT-11 and its metabolites in intestinal tissue extracts, β-GUS activity in colonic contents, gut microbial composition, and serum metabolic profiles. These findings characterize dose-related intestinal toxicity and associated microbial and metabolic changes during CPT-11 treatment in the AOM/DSS-induced CRC model.