B cell lymphoma-2 transfected P815 cells resist reactive nitrogen intermediate-mediated macrophage-dependent cytotoxicity.
Activated murine peritoneal macrophage cytotoxicity against P815 tumor cells has been shown to be mediated by the reactive nitrogen intermediates (RNI) produced by macrophages from L-arginine through nitric oxide (NO) synthase. Previous results from this laboratory indicated that NO-dependent killing of P815 fulfilled the criteria for apoptotic death. Work by others, in turn, demonstrated that the product of the bcl-2 gene confers protection against various inducers of apoptosis, including reactive oxygen intermediates. Experiments were performed to determine whether Bcl-2 could equally protect sensitive cells from RNI-dependent apoptosis within the context of a relevant biologic system such as the delivery of such RNI by activated macrophages. Results demonstrated that transfection of P815 cells with the human bcl-2 gene confers immunity from RNI-dependent, macrophage-mediated cytotoxicity. In contrast with wild-type or mock-transfected P815 cells, which do not contain detectable Bcl-2, bcl-2-transfected cells showed minimal DNA fragmentation and cell membrane failure when cocultured with activated macrophages. Additional findings indicate that Bcl-2 affords the transfected cells almost complete resistance to the DNA-fragmenting effects of chemically generated NO or H202 and partial protection from their cytolytic effects. These findings are consistent with the hypothesis that tumor cells expressing bcl-2 may escape destruction by macrophage-dependent immune surveillance mechanisms.
Albina
J E
JE
Department of Surgery, Rhode Island Hospital, Providence 02903, USA.
Martin
B A
BA
Henry
W L
WL
Louis
C A
CA
Reichner
J S
JS
D000818:Animals; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D004249:DNA Damage / Q000276:immunology; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000276:immunology*; D008297:Male; D012515:Mast-Cell Sarcoma / Q000235:genetics* / Q000276:immunology*; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis / Q000633:toxicity*; D016877:Oxidants / Q000633:toxicity*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D019253:Proto-Oncogene Proteins c-bcl-2; D014162:Transfection / Q000276:immunology*; D014407:Tumor Cells, Cultured
D016877:Oxidants; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D009569:Nitric Oxide; D006861:Hydrogen Peroxide