title: Functional role of phosphatidylinositol 3-kinase in direct tumor lysis by human natural killer cells.
abstract: Cytotoxicity is a key function of natural killer (NK) and T cells; yet the molecular mechanism is unclear. We have biological, biochemical and molecular evidence to demonstrate that phosphatidyl-inositol (PI) 3-kinase is critical for direct NK lysis of tumor cells, via control of intracellular granule movement. Tumor cell engagement rapidly activated PI 3-kinase in NK cells within 5 min, as demonstrated by p85 subunit tyrosine phosphorylation and its ability to generate phosphatidylinositol 3-phosphate, PI(3)P, from PI. Wortmannin and LY294002 effectively inhibited NK cells to lyse 51Cr-labeled tumor cells at the same doses that blocked PI-phosphorylating function in tumor-activated NK cells. Immunostaining demonstrated that tumor engagement for only 5 min mobilized perforin and granzyme B from NK cells unidirectionally towards the target, and prior treatment of NK cells with either PI 3-kinase inhibitor effectively stopped this intracellular polarization. Lastly, ectopic expression of dominant-negative p85 or p110 mutant markedly suppressed NK lytic capacity. These results taken together demonstrate that PI 3-kinase may control NK lytic function via granule polarization towards the contacted target cell.
authors: H. Lee Moffitt Cancer Center, Department of Interdisciplinary Oncology, University of South Florida College of Medicine, Tampa 33612, USA.
authors: Bin
authors: B
authors: Zhong
authors: Jin Hong
authors: JH
authors: Liu
authors: Danielle L
authors: DL
authors: Gilvary
authors: Kun
authors: K
authors: Jiang
authors: Masato
authors: M
authors: Kasuga
authors: Connie A
authors: CA
authors: Ritchey
authors: Joseph A
authors: JA
authors: Trapani
authors: Sheng
authors: S
authors: Wei
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D002450:Cell Communication / Q000276:immunology; D002867:Chromones / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D053804:Granzymes; D018922:HL-60 Cells; D019337:Hematologic Neoplasms / Q000276:immunology / Q000473:pathology; D006801:Humans; D019169:Jurkat Cells; D007694:Killer Cells, Natural / Q000201:enzymology* / Q000276:immunology*; D007938:Leukemia; D008562:Membrane Glycoproteins / Q000096:biosynthesis; D009025:Morpholines / Q000494:pharmacology; D054353:Perforin; D019869:Phosphatidylinositol 3-Kinases / Q000276:immunology* / Q000378:metabolism; D052899:Pore Forming Cytotoxic Proteins; D012697:Serine Endopeptidases / Q000096:biosynthesis; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D014407:Tumor Cells, Cultured; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D002867:Chromones; D004791:Enzyme Inhibitors; D008562:Membrane Glycoproteins; D009025:Morpholines; D052899:Pore Forming Cytotoxic Proteins; D054353:Perforin; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D019869:Phosphatidylinositol 3-Kinases; C509213:GZMB protein, human; D053804:Granzymes; D012697:Serine Endopeptidases; D000077191:Wortmannin