Invasion by Fusobacterium nucleatum Causes Upregulation of dll4 and klf4 Expression in Caco2 Cells

Fusobacterium nucleatum is an emerging microbe of importance in the pathogenesis of colorectal cancer. Strains of this enigmatic bacterial species vary in their capacity to invade human epithelial cells, a virulence determinant which has important implications in disease. Here, we infected human colorectal epithelial (Caco-2) cells in vitro with a known, highly invasive strain of F. nucleatum isolated from a Crohn’s Disease patient, as well as a further invasive isolate of F. nucleatum derived from a colorectal cancer tumour. We used transcriptional profiling to determine the human genes upregulated during the invasion process compared to exposure to a non-invasive E.coli control strain. Infection with F. nucleatum strains resulted in the upregulation of several host genes, including two associated with tumorigenesis: dll4 and klf4 . * CRC : colorectal cancer DEG : differentially expressed genes dll4 /DLL4 : delta like canonical notch ligand 4 FC : fold change klf4 /KLF4 : Kruppel-like factor 4 qPCR : quantitative polymerase chain reaction RPKM : reads per kilobase of transcript, per million mapped reads