title: Tumor-induced apoptosis of human IL-2-activated NK cells: role of natural cytotoxicity receptors.
abstract: We provide evidence that tumor cells can induce apoptosis of NK cells by engaging the natural cytotoxicity receptors (NCR) NKp30, NKp44, and NKp46. Indeed, the binding between NCR on NK cells and their putative ligands on tumor target cells led to NK cell apoptosis, and this event was abolished by blocking NCR/NCR-ligand interaction by anti-NCR-specific mAbs. The engagement of NCR induced up-regulation of Fas ligand (FasL) mRNA, FasL protein synthesis, and release. In turn, FasL interacting with Fas at NK cell surface causes NK cell suicide, as apoptosis of NK cells was inhibited by blocking FasL/Fas interaction with specific mAbs. Interestingly, NK cell apoptosis, but not killing of tumor target cells, is inhibited by cyclosporin A, suggesting that apoptosis and cytolysis are regulated by different biochemical pathways. These findings indicate that NCR are not only triggering molecules essential for antitumor activity, but also surface receptors involved in NK cell suicide.
authors.affiliation: Laboratory of Immunology, National Institute for Cancer Research, University of Genoa, Genoa, Italy. alessandro.poggi@istge.it
authors.forename: Alessandro
authors.initials: A
authors.lastname: Poggi
authors.forename: Anna-Maria
authors.initials: AM
authors.lastname: Massaro
authors.forename: Simone
authors.initials: S
authors.lastname: Negrini
authors.forename: Paola
authors.initials: P
authors.lastname: Contini
authors.forename: Maria Raffaella
authors.initials: MR
authors.lastname: Zocchi
mesh_terms: D000911:Antibodies, Monoclonal / Q000378:metabolism; D017209:Apoptosis / Q000276:immunology*; D002118:Calcium / Q000502:physiology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002450:Cell Communication / Q000276:immunology*; D002461:Cell Line, Transformed; D002478:Cells, Cultured; D002999:Clone Cells; D003602:Cytotoxicity, Immunologic; D004789:Enzyme Activation; D053222:Fas Ligand Protein; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology*; D008545:Melanoma / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D055627:Natural Cytotoxicity Triggering Receptor 1; D055629:Natural Cytotoxicity Triggering Receptor 2; D055628:Natural Cytotoxicity Triggering Receptor 3; D012333:RNA, Messenger / Q000096:biosynthesis; D011971:Receptors, Immunologic / Q000378:metabolism / Q000502:physiology*; D015854:Up-Regulation / Q000276:immunology; D019014:fas Receptor / Q000502:physiology
chemical_list: D000911:Antibodies, Monoclonal; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D007376:Interleukin-2; D008562:Membrane Glycoproteins; C112260:NCR1 protein, human; C112837:NCR2 protein, human; C431710:NCR3 protein, human; D055627:Natural Cytotoxicity Triggering Receptor 1; D055629:Natural Cytotoxicity Triggering Receptor 2; D055628:Natural Cytotoxicity Triggering Receptor 3; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D019014:fas Receptor; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D002118:Calcium