Chemotherapy-induced suppression of colorectal cancer-associated gut microbiota and modulation of host miRNA expression.

OBJECTIVES

To characterize gut microbiome alterations in colorectal cancer (CRC) patients following cancer chemotherapy (CCT) and to explore associations with bacterial translocation and host miRNA dynamics.

METHODS

Stool samples were prospectively collected from 20 CRC patients who had undergone radical surgery followed by adjuvant chemotherapy (CAPOX/mFOLFOX6). Stool samples were collected pre- and post-CCT. Microbial profiling was performed using 16S rRNA sequencing. Bacterial translocation was assessed by measuring serum anti-Lipopolysaccharides (LPS) IgA/IgG levels by ELISA. miRNA expression of miR-143 and miR-145 was quantified using qPCR.

RESULTS

Post-CCT samples showed significant increases in gut microbiome diversity (<0.05), with higher relative abundances of and , and decreased abundances of and (P<0.005). Network analysis identified and as possible CRC-associated taxa. Serum anti-LPS IgA and IgG levels significantly declined post-CCT, indicating reduced bacterial translocation. Concurrently, miR-143 and miR-145 levels increased more than twofold post-CCT (P<0.01), positively correlating with microbial shifts.

CONCLUSION

CCT induces significant remodeling of CRC-associated gut microbiota, characterized by suppression of pathogenic genera and enrichment of pro-inflammatory taxa. These changes align with reduced bacterial translocation and increased expression of tumor-suppressive miRNAs, suggesting that CCT exerts dual therapeutic effects by simultaneously modulating microbial communities and host molecular pathways.