Re-engineering of TNFα-NF-κB signalling dynamics in cancer cells using pathogenic E. coli effectors

Re-engineering NF-κB signalling towards enhancing beneficial outcomes such as tumour cell elimination, while minimising inflammatory damage, is a potential therapeutic avenue. In this study, we explored the ability of bacterial effectors injected into host cells by the type III secretion system to regulate NF-κB translocation dynamics. We used the enteropathogenic Escherichia coli effectors Tir (NF-κB activator), NleC (NF-κB protease) and NleE (TAB2/3 methyltransferase), to manipulate NF-κB translocation and cancer cell survival. We discovered that while these effectors have either limited or no cytotoxicity alone, they greatly enhanced caspase-8-dependent pancreatic cancer cell death in the presence of TNFα. Single cell analysis revealed that the sub-population of cells showing high NF-κB activation is less susceptible to cell death caused by NleC or NleE but instead is more susceptible to Tir. A combination of Tir, NleE and TNFα eliminated 95% cancer cells with limited NF-κB activation, potentially due to NleE-dependent blockage of the immediate pro-survival NF-κB activation without inhibiting Tir’s long-term NF-κB activation that promotes cell death. This work demonstrates that effector combinations could be used to re-engineer stress responses towards favourable outcomes.