A role for keratin 17 during DNA damage response and tumor initiation
Menée à l'aide de lignées cellulaires et de modèles murins de cancer de la peau, cette étude met en évidence le rôle de la kératine 17 dans la réponse aux dommages causés à l'ADN et dans l'initiation tumorale
Expression of keratin 17 (K17), an intermediate filament-forming cytoskeletal protein, is induced in a broad range of human carcinomas and has prognostic value for a growing number of tumor types. We report here that K17 is induced in response to DNA damage and that a nuclear pool of K17 regulates the immediate response to such damage, with an associated impact on cell survival. Impairing the nuclear pool of K17 markedly attenuates tumor initiation in mouse skin. Our finding adds a role for nuclear K17 in the DNA damage response (DDR) and further substantiates the significance of K17 expression and function during tumorigenesis.High levels of the intermediate filament protein keratin 17 (K17) are associated with poor prognoses for several human carcinomas. Studies in mouse models have shown that K17 expression is positively associated with growth, survival, and inflammation in skin and that lack of K17 delays onset of tumorigenesis. K17 occurs in the nucleus of human and mouse tumor keratinocytes where it impacts chromatin architecture, gene expression, and cell proliferation. We report here that K17 is induced following DNA damage and promotes keratinocyte survival. The presence of nuclear K17 is required at an early stage of the double-stranded break (DSB) arm of the DNA damage and repair (DDR) cascade, consistent with its ability to associate with key DDR effectors, including γ-H2A.X, 53BP1, and DNA-PKcs. Mice lacking K17 or with attenuated K17 nuclear import showed curtailed initiation in a two-step skin carcinogenesis paradigm. The impact of nuclear-localized K17 on DDR and cell survival provides a basis for the link between K17 induction and poor clinical outcomes for several human carcinomas.All study data are included in the article and/or SI Appendix.