title: IFNα signaling through PKC-θ is essential for antitumor NK cell function.
abstract: We have previously shown that the development of a major histocompatibility complex class I (MHC-I)-deficient tumor was favored in protein kinase C-θ knockout (PKC-θ-/-) mice compared to that occurring in wild-type mice. This phenomenon was associated with scarce recruitment of natural killer (NK) cells to the tumor site, as well as impaired NK cell activation and reduced cytotoxicityex vivo. Poly-inosinic:cytidylic acid (poly I:C) treatment activated PKC-θ in NK cells depending on the presence of a soluble factor produced by a different splenocyte subset. In the present work, we sought to analyze whether interleukin-15 (IL-15) and/or interferon-α (IFNα) mediate PKC-θ-dependent antitumor NK cell function. We found that IL-15 improves NK cell viability, granzyme B expression, degranulation capacity and interferon-γ (IFNγ) secretion independently of PKC-θ. In contrast, we found that IFNα improves the degranulation capability of NK cells against target cancer cells in a PKC-θ-dependent fashion bothex vivoandin vivo. Furthermore, IFNα induces PKC-θ auto-phosphorylation in NK cells, in a signal transduction pathway involving both phosphatidylinositol-3-kinase (PI3K) and phospholipase-C (PLC) activation. PKC-θ dependence was further implicated in IFNα-induced transcriptional upregulation of chemokine (C-X-C motif) ligand 10 (CXCL10), a signal transducer and activator of transcription-1 (STAT-1)-dependent target of IFNα. The absence of PKC-θ did not affect IFNα-induced STAT-1 Tyr701 phosphorylation but affected the increase in STAT-1 phosphorylation on Ser727, attenuating CXCL10 secretion. This connection between IFNα and PKC-θ in NK cells may be exploited in NK cell-based tumor immunotherapy.
authors.affiliation: Apoptosis, Immunity & Cancer Group; Department of Biochemistry and Molecular and Cell Biology ; University of Zaragoza and Aragón Health Research Institute (IIS Aragón) ; Zaragoza, Spain.
authors.forename: Natalia R
authors.initials: NR
authors.lastname: Comet
authors.affiliation: Apoptosis, Immunity & Cancer Group; Department of Biochemistry and Molecular and Cell Biology ; University of Zaragoza and Aragón Health Research Institute (IIS Aragón) ; Zaragoza, Spain.
authors.forename: Juan Ignacio
authors.initials: JI
authors.lastname: Aguiló
authors.affiliation: INSERM U1040; Université de Montpellier 1; UFR Médecine ; Montpellier, France.
authors.forename: Moeez G
authors.initials: MG
authors.lastname: Rathoré
authors.affiliation: Apoptosis, Immunity & Cancer Group; Department of Biochemistry and Molecular and Cell Biology ; University of Zaragoza and Aragón Health Research Institute (IIS Aragón) ; Zaragoza, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Catalán
authors.affiliation: INSERM U1040; Université de Montpellier 1; UFR Médecine ; Montpellier, France.
authors.forename: Johan
authors.initials: J
authors.lastname: Garaude
authors.affiliation: CNRS UMR 5235; Université de Montpellier II; Place Eugene Bataillon ; Montpellier, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Uzé
authors.affiliation: Apoptosis, Immunity & Cancer Group; Department of Biochemistry and Molecular and Cell Biology ; University of Zaragoza and Aragón Health Research Institute (IIS Aragón) ; Zaragoza, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Naval
authors.affiliation: Immune Effector Cells Group; IIS Aragón; Biomedical Research Center of Aragón (CIBA); Nanoscience Institute of Aragon (INA); Zaragoza, Spain ; Aragón I+D Foundation (ARAID) ; Zaragoza, Spain.
authors.forename: Julián
authors.initials: J
authors.lastname: Pardo
authors.affiliation: INSERM U1040; Université de Montpellier 1; UFR Médecine ; Montpellier, France ; Institut de Recherche en Biothérapie (IRB); CHU Montpellier ; Montpellier, France.
authors.forename: Martín
authors.initials: M
authors.lastname: Villalba
authors.affiliation: Apoptosis, Immunity & Cancer Group; Department of Biochemistry and Molecular and Cell Biology ; University of Zaragoza and Aragón Health Research Institute (IIS Aragón) ; Zaragoza, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Anel
keywords: CDK8, cyclin-dependent kinase 8; CXCL10; CXCL10, (C-X-C motif) ligand 10/CXCL10; FCS, fetal calf serum; IFN-α, IL-15; IFNA1; IFNα, interferon-α; IFNγ, interferon-γ, IFNG; IL-15, interleukin-15/IL15; MACS, magnetic cell separation; MEF, murine embryonic fibroblast; MHC-I, major histocompability complex class I/MHC-I; NK cells; NK, natural killer; PI3K, phosphatidylinositol-3-kinase; PKC-θ; PKC-θ, protein kinase C-θ, PRKCQ; PLC, phospholipase-C; Poly I:C, poly-inosinic:cytidilic acid; RT-PCR, real-time polymerase chain reaction; STAT-1, signal transducer and activator of transcription-1/STAT1.; mAb, monoclonal antibody