Evodiamine inhibits high-fat diet-induced colitis-associated cancer in mice through regulating the gut microbiota

High-fat diet is one of the main risk factors that disrupt the balance of gut microbiota, which eventually will induce colorectal cancer (CRC). Evodiamine (EVO) is a wildly used multifunctional traditional Chinese medicine extract. In this study, we investigated the role of gut microbiota in high-fat diet-propelled CRC and the potential of EVO for CRC chemoprevention. Gut microbiota, serum d-lactic acid and endotoxin from 38 patients with colon cancer and 18 healthy subjects were detected by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA). In addition, body mass index, phospho-signal transducer and activator of transcription 3 (p-STAT3) expression in cancer tissues and paracancerous tissues were detected by immunohistochemistry. A mouse intestinal inflammatory tumor model was established by azomethane/sodium dextran sulfate, followed by treatment with EVO and 5-aminosalicylic acid (ASA). Gut microbiota and inflammatory factors were detected by quantitative polymerase chain reaction, while serum d-lactic acid and endotoxin were detected by ELISA. Furthermore, cell proliferation, cell apoptosis, and interleukin (IL)-6/STAT3/P65 pathway were evaluated by 5-ethynyl-2′-deoxyuridine, terminal-deoxynucleotidyl transferase-mediated nick-end labeling, and Western blot assays. In patients with colon cancer, the numbers of Enterococcus faecalis and Escherichia coli were increased, while those of Bifidobacterium, Campylobacter and Lactobacillus were decreased. Serum endotoxin and d-lactic acid levels and p-STAT3 levels were significantly increased. In the mouse model, both EVO and ASA inhibited tumor formation, decreased the proliferation of tumor cells, and induced apoptosis of tumor cells. Compared with the control group, the numbers of E. faecalis and E. coli were decreased, while Bifidobacterium, Campylobacter and Lactobacillus numbers were increased. In the EVO group, serum endotoxin and d-lactic acid levels and inflammatory factors were significantly decreased. Further, the IL6/STAT3/P65 signaling pathway was inhibited in the EVO group. EVO may inhibit the occurrence of colon cancer by regulating gut microbiota and inhibiting intestinal inflammation. The potential mechanism involves inhibition of the IL6/STAT3/P65 signaling pathway, revealing its potential therapeutic significance in clinical applications.