Combination gut microbiota modulation and chemotherapy for orthotopic colorectal cancer therapy

Gut microbiota is closely related to the tumorigenesis and progression of colorectal cancer (CRC), especially Fusobacterium nucleatum (Fn) could promote colorectal tumor growth and cause chemoresistance. Here, we developed a tumor-triggered release drug delivery gel to inhibit CRC cell growth in situ by intestinal perfusion. Antibiotic metronidazole (MTZ) and 5-fluorouracil (5-FU), the first-line chemotherapy drug of CRC, are individually incorporated into metal polyphenol network-coated mesoporous silica nanoparticle (MSN), and then blended with carboxymethyl cellulose (CMC) to obtain an anti-CRC gel, AB-Gel. In vivo studies showed that AB-Gel could efficiently inhibit the growth and metastasis of CRC in an orthotopic mouse model attributing to the MTZ-induced modulation in the CRC-related microbiota. Chemotherapy efficacy against orthotopic CRC was significantly enhanced by the elimination of Fn. This strategy based on the combination of gut microbiota modulation and chemotherapy would be considered as an enhanced strategy for CRC treatment with potential use in the clinic.