Invasion by Fusobacterium nucleatum Causes Upregulation of dll4 and klf4 Expression in Caco-2 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 Crohns 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.