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Objective To investigate the regulatory effect of Fusobacterium nucleatum (F.nucleatum) on differential expression genes (DEGs) in colorectal cancer (CRC) by bioinformatics analysis, and to identify the expression of key genes in F.nucleatum infected CRC cells. Methods The high-throughput sequencing data of DEGs in CRC regulated by F.nucleatum were downloaded and screened from Gene Expression Omnibus (GEO) database, then Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed on the datasets. Protein-protein interaction (PPI) network of DEGs were subsequently constructed with Cytoscape software. Finally, Western blotting and RT-qPCR were employed to verity the expression of hub gene MUC1 at protein and mRNA levels in the cell model, respectively. Results A total of 118 DEGs were screened out, of which 20 were up-regulated and 98 down-regulated. GO analysis showed that DEGs were noticeably enriched in cellular component (CC) such as plasma membrane and integral component of membrane, and KEGG analysis found that DEGs were significantly enriched in PI3K-Akt, MAPK, Rap1 and JAK-STAT signaling pathways (P < 0.05). In the PPI network, the hub gene MUC1 presented a high centrality score. Western blotting and RT-qPCR indicated that the infection of F.nucleatum was significantly correlated with the differential expression of MUC1. Conclusion The mechanism of CRC induced by F.nucleatum infection may be related to the overexpression of MUC1, according to the screening and verification of hub genes.

Aim Fusobacterium nucleatum (F. nucleatum) is associated with the initiation, development, and metastasis of colorectal cancer. However, it is difficult to isolate F. nucleatum from clinical specimens. In this study, we aimed to develop an effective and rapid method for isolating F. nucleatum from human feces using polyclonal antibody (PAB)-coated immunomagnetic beads (IMBs) with selective media. Methods and results IMBs conjugated with PAB were prepared and used to isolate F. nucleatum from human feces, and the bacteria were cultured with selective culture media (fastidious anaerobe agar + nalidixic acid + vancomycin). Under optimized experimental conditions, IMBs could selectively recover F. nucleatum from fecal microbiota samples spiked with Peptostreptococcus or Bacteroides fragilis. In artificial fecal samples, the detection sensitivity of IMBs for F. nucleatum was 103 CFU mL−1. In addition, IMBs combined with selective media could rapidly isolate F. nucleatum from human feces. Conclusions This study successfully established an effective method for the rapid isolation of F. nucleatum from human feces by IMBs. The whole procedure requires 2–3 days, and has a sensitivity of 103 CFU mL−1 feces. [ABSTRACT FROM AUTHOR]