Objective:To investigate the mechanism by which Fusobacterium nucleatum ( Fn) infection promotes TNF-α-induced inflammatory changes in colorectal cancer HCT116 cells. Methods:Fn-infected cells and TNF-α inflammation induction models were established and divided into 4 groups, namely uninfected control group, Fn-infected group, TNF-α induction group, and Fn+ TNF-α group. First, Fn was used to infect normal colonic epithelial cells hcoEPIC, colorectal cancer HCT116 and LoVo cells, the cell adhesion was detected 4 h later. Subsequently, HCT116 cells were induced with TNF-α for 3 h and then infected with Fn. After 24 h, the cell survival rate and cell damage were detected by CCK8 experiment and lactate dehydrogenase (LDH) viability assay. The ELISA method was further used to detect the expression of nuclear transcription factor NF-κB and cytokines IL-6, IL-8, and IL-1β in the cell and cell culture supernatant. Results:Fn has strong adhesion to colorectal cancer cells HCT116 and LoVo ( P<0.05), but basically does not show invasion. On the contrary, it has a higher invasion rate to normal colonic epithelial cells hcoEPIC after 24 h. Compared with the uninfected Fn group, the cell survival rate of the Fn-infected group was significantly reduced and the cell damage increased ( P<0.001). Three hours after TNF-α induction, Fn infection further promoted cell death and damage ( P<0.001). The expression of NF-κB in the Fn infection and TNF-α alone treatment group was significantly higher than that of the uninfected group ( P<0.001, P<0.05), and the NF-κB expression in the Fn+ TNF-α group was significantly higher than that of the control group and the single treatment group ( P<0.001). In the Fn infection and TNF-α treatment groups, the expressions of IL-6 and IL-8 were significantly higher than those in the uninfected group ( P<0.001), and IL-1β did not change significantly ( P>0.05). The expressions of IL-6, IL-8 and IL-1β in the Fn+ TNF-α group were significantly higher than those in the normal control group and the single treatment group ( P<0.05). Conclusions:Fusobacterium nucleatum can preferentially adhere to colorectal cancer cell HCT116, further promote TNF-α-induced cell damage and death, the expression and release of NF-κB and its downstream pro-inflammatory cytokines IL-6, IL-8, IL-1β.