Although oncogenic activation of NFκB has been identified in various tumors, the NFκB-activating kinases (inhibitor of NFκB kinases, IKK) responsible for this are elusive. In this study, we determined the role of IKKα and IKKβ in -mutant lung adenocarcinomas induced by the carcinogen urethane and by respiratory epithelial expression of oncogenic Using NFκB reporter mice and conditional deletions of IKKα and IKKβ, we identified two distinct early and late activation phases of NFκB during chemical and genetic lung adenocarcinoma development, which were characterized by nuclear translocation of B, IκBβ, and IKKα in tumor-initiated cells. IKKα was a cardinal tumor promoter in chemical and genetic-mutant lung adenocarcinoma, and respiratory epithelial IKKα-deficient mice were markedly protected from the disease. IKKα specifically cooperated with mutant for tumor induction in a cell-autonomous fashion, providing mutant cells with a survival advantage and IKKα was highly expressed in human lung adenocarcinoma, and a heat shock protein 90 inhibitor that blocks IKK function delivered superior effects against-mutant lung adenocarcinoma compared with a specific IKKβ inhibitor. These results demonstrate an actionable requirement for IKKα in -mutant lung adenocarcinoma, marking the kinase as a therapeutic target against this disease. These findings report a novel requirement for IKKα in mutant lung tumor formation, with potential therapeutic applications..
The lungs are frequently affected by cancer metastasis. Although NRAS mutations have been associated with metastatic potential, their exact role in lung homing is incompletely understood. We cross‐examined the genotype of various tumor cells with their ability for automatic pulmonary dissemination, modulated NRAS expression using RNA interference and NRAS overexpression, identified NRAS signaling partners by microarray, and validated them using Cxcr1‐ and Cxcr2‐deficient mice. Mouse models of spontaneous lung metastasis revealed that mutant or overexpressed NRAS promotes lung colonization by regulating interleukin‐8‐related chemokine expression, thereby initiating interactions between tumor cells, the pulmonary vasculature, and myeloid cells. Our results support a model where NRAS‐mutant, chemokine‐expressing circulating tumor cells target the CXCR1‐expressing lung vasculature and recruit CXCR2‐expressing myeloid cells to initiate metastasis. We further describe a clinically relevant approach to prevent NRAS‐driven pulmonary metastasis by inhibiting chemokine signaling. In conclusion, NRAS promotes the colonization of the lungs by various tumor types in mouse models. IL‐8‐related chemokines, NRAS signaling partners in this process, may constitute an important therapeutic target against pulmonary involvement by cancers of other organs.
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