Irinotecan-gut microbiota interactions and the capability of probiotics to mitigate Irinotecan-associated toxicityOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study examined how the chemotherapy drug Irinotecan affects gut microbiota composition, given that gut microbial enzymes convert Irinotecan into the toxic metabolite SN-38 during intestinal excretion. The researchers used 16S rRNA gene sequencing to characterize microbiota composition across different patient groups. They also tested whether specific probiotic Lactobacillus species, alone or combined, could suppress bacterial beta-glucuronidase enzyme activity, the enzymatic step implicated in Irinotecan-associated toxicity. In-vitro gene expression assays and an in-vivo mouse model of Irinotecan administration were used to evaluate the protective potential of these probiotics.
Who was studied?
Stool samples were collected from three human groups: healthy individuals, colon cancer patients, and Irinotecan-treated patients, with five samples per group. In parallel, in-vitro experiments used Escherichia coli to assess beta-glucuronidase gene expression in response to three Lactobacillus species (L. plantarum, L. acidophilus, and L. rhamnosus). The in-vivo protective effects of these probiotics were assessed in mice administered Irinotecan, either with single probiotic strains or in mixed combinations.
What were the most important findings?
Irinotecan treatment was associated with changes in gut microbiota composition compared to healthy individuals and colon cancer patients, based on 16S rRNA sequencing. The three Lactobacillus species tested, in both single and mixed forms, influenced expression of the E. coli beta-glucuronidase gene, the enzyme responsible for reactivating toxic SN-38 in the gut. In mice, administration of these probiotics before Irinotecan was evaluated for effects on reactive oxidative species (ROS) levels and intestinal outcomes, indicating a potential protective role against Irinotecan-induced toxicity.
What are the greatest implications of this study?
These findings suggest that gut microbiota composition shifts during Irinotecan chemotherapy and that this altered microbial environment contributes to drug-related intestinal toxicity through beta-glucuronidase activity. Targeting this bacterial enzyme with specific Lactobacillus probiotics may offer a strategy to reduce Irinotecan-associated diarrhea and oxidative stress in the gut. This supports further investigation of probiotic co-administration as an adjunct to chemotherapy to improve tolerability in colorectal cancer treatment.