Neutrophil-Derived IL-1β Impairs the Efficacy of NF-κB Inhibitors against Lung Cancer

Although epithelial NF-kappa B signaling is important for lung carcinogenesis, NF-kappa B inhibitors are ineffective for cancer treatment. To explain this paradox, we studied mice with genetic deletion of IK kappa beta in myeloid cells and found enhanced tumorigenesis in Kras(G12D) and urethane models of lung cancer. Myeloid-specific inhibition of NF-kappa B augmented pro-IL-1 beta processing by cathepsin G in neutrophils, leading to increased IL-1 beta and enhanced epithelial cell proliferation. Combined treatment with bortezomib, a proteasome inhibitor that blocks NF-kappa B activation, and IL-1 receptor antagonist reduced tumor formation and growth in vivo. In lung cancer patients, plasma IL-1 beta levels correlated with poor prognosis, and IL-1 beta increased following bortezomib treatment. Together, our studies elucidate an important role for neutrophils and IL-1 beta in lung carcinogenesis and resistance to NF-kappa B inhibitors.