RT Journal Article T1 Nuclear versus cytoplasmic IKKα signaling in keratinocytes leads to opposite skin phenotypes and inflammatory responses, and a different predisposition to cancer A1 García García, Verónica A. A1 Alameda, Josefa P. A1 Fernández Aceñero, M. Jesús A1 Navarro, Manuel A1 García Escudero, Ramón A1 Page, Angustias A1 Mateo Gallego, Raúl A1 Paramio, Jesús M. A1 Ramírez, Ángel A1 García Fernández, Rosa Ana A1 Bravo, Ana A1 Casanova, M. Llanos AB IKKα is known as an essential protein for skin homeostasis. However, the lack of suitable models to investigate its functions in the skin has led to IKKα being mistakenly considered as a suppressor of non-melanoma skin cancer (NMSC) development. In this study, using our previously generated transgenic mouse models expressing exogenous IKKα in the cytoplasm (C-IKKα mice) or in the nucleus (N-IKKα mice) of basal keratinocytes, we demonstrate that at each subcellular localization, IKKα differently regulates signaling pathways important for maintaining the balance between keratinocyte proliferation and differentiation, and for the cutaneous inflammatory response. In addition, each type of IKKα-transgenic mice shows different predisposition to the development of spontaneous NMSC. Specifically, N-IKKα mice display an atrophic epidermis with exacerbated terminal differentiation, signs of premature skin aging, premalignant lesions, and develop squamous cell carcinomas (SCCs). Conversely, C-IKKα mice, whose keratinocytes are nearly devoid of endogenous nuclear IKKα, do not develop skin SCCs, although they exhibit hyperplastic skin with deficiencies in terminal epidermal differentiation, chronic cutaneous inflammation, and constitutive activation of STAT-3 and NF-κB signaling pathways. Altogether, our data demonstrate that alterations in the localization of IKKα in the nucleus or cytoplasm of keratinocytes cause opposite skin changes and differentially predispose to the growth of skin SCCs. PB Springer Nature SN 0950-9232 YR 2024 FD 2024 LK https://hdl.handle.net/20.500.14352/111879 UL https://hdl.handle.net/20.500.14352/111879 LA eng NO García-García, V.A., Alameda, J.P., Fernández-Aceñero, M.J. et al. Nuclear versus cytoplasmic IKKα signaling in keratinocytes leads to opposite skin phenotypes and inflammatory responses, and a different predisposition to cancer. Oncogene (2024). https://doi.org/10.1038/s41388-024-03203-0 NO Author Contribution:VAGG and JPA conducted most of the experiments with assistance from AP, RMG, MN, AR and MLC. VAGG, AP, JMP, RAGF, MJFA, MN, AB and MLC analyzed data. MN,VAGG and MLC designed research studies. RGE, MN, JMP and MLC performed genomic analysis. Writing the manuscript: MLC. AB, RAGF and MJFA wrote histological results. Revising the manuscript: MN, RGE, JMP, AR, RAGF, AB, MLC. Theorder of the co–first authors was assigned based on their efforts and contributions to the studyRMG is a recipient of an ISCII/HFIBH12O contract NO European Commission NO Instituto de Salud Carlos III NO Ministerio de Economía, Comercio y Empresa (España) NO Centro de Investigación Biomédica en Red NO Fundación de Investigación Biomédica Hospital 12 de Octubre NO Centro Extremeño de Tecnologías Avanzadas NO Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas DS Docta Complutense RD 23 abr 2025