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

Re-engineering NF-{kappa}B 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-{kappa}B translocation dynamics. We used the enteropathogenic Escherichia coli effectors Tir (NF-{kappa}B activator), NleC (NF-{kappa}B protease) and NleE (TAB2/3 methyltransferase), to manipulate NF-{kappa}B 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 TNF. Single cell analysis revealed that the sub-population of cells showing high NF-{kappa}B 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 TNF eliminated 95% cancer cells with limited NF-{kappa}B activation, potentially due to NleE-dependent blockage of the immediate pro-survival NF-{kappa}B activation without inhibiting Tirs long-term NF-{kappa}B activation that promotes cell death. This work demonstrates that effector combinations could be used to re-engineer stress responses towards favourable outcomes.