title: Pivotal role of phosphoinositide-3 kinase in regulation of cytotoxicity in natural killer cells.
abstract: The mitogen-activated protein kinase-extracellular signal-regulated kinase signaling element (MAPK-ERK) plays a critical role in natural killer (NK) cell lysis of tumor cells, but its upstream effectors were previously unknown. We show that inhibition of phosphoinositide-3 kinase (PI3K) in NK cells blocks p21-activated kinase 1 (PAK1), MAPK kinase (MEK) and ERK activation by target cell ligation, interferes with perforin and granzyme B movement toward target cells and suppresses NK cytotoxicity. Dominant-negative N17Rac1 and PAK1 mimic the suppressive effects of PI3K inhibitors, whereas constitutively active V12Rac1 has the opposite effect. V12Rac1 restores the activity of downstream effectors and lytic function in LY294002- or wortmannin-treated, but not PD98059-treated, NK cells. These results document a specific PI3K-->Rac1-->PAK1-->MEK-->ERK pathway in NK cells that effects lysis.
authors.affiliation: Immunology Program, H. Lee Moffitt Cancer Center, Department of Interdisciplinary Oncology, University of South Florida College of Medicine, Tampa, FL 33612, USA.
authors.forename: K
authors.initials: K
authors.lastname: Jiang
authors.forename: B
authors.initials: B
authors.lastname: Zhong
authors.forename: D L
authors.initials: DL
authors.lastname: Gilvary
authors.forename: B C
authors.initials: BC
authors.lastname: Corliss
authors.forename: E
authors.initials: E
authors.lastname: Hong-Geller
authors.forename: S
authors.initials: S
authors.lastname: Wei
authors.forename: J Y
authors.initials: JY
authors.lastname: Djeu
mesh_terms: D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007694:Killer Cells, Natural / Q000187:drug effects / Q000201:enzymology* / Q000276:immunology*; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D054462:p21-Activated Kinases; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D054462:p21-Activated Kinases; D020830:rac1 GTP-Binding Protein; C482128:MAP2K2 protein, human; C482125:MAP2K1 protein, human