title: Synergistic enhancement of nitrite on lysophospholipid-mediated cytolysis.
abstract: Nitrogen oxide, which is produced by activated macrophages, has been demonstrated to possess anti-tumor activity. We report herein the synergistic effect of sodium nitrite (NO2-) and/or sodium nitroprusside (SNP) on lysophospholipid (LysoPL)-mediated cytolysis. The incubation of 51Cr-labeled mouse melanoma (B16) cells with NO2- alone for 3 h at 37 degrees C did not induce cytolysis. On the other hand, NO2- significantly enhanced the cytolysis of B16 cells in the presence of lysophosphatidylcholine (LysoPC; 2.0 microM). A similar effect of NO2- on B16-cytolysis was also observed in the presence of 1-O-alkyl-sn-glycero-3-phosphocholine (LysoPAF). In addition, SNP (0.05-0.5 mM) synergistically enhanced B16-cytolysis in the presence of LysoPC. However, nitrate had no effect on the cytolysis of B16 cells treated with LysoPC. Furthermore, NO2- synergistically enhanced the hemolysis of sheep erythrocytes in the presence of LysoPC, but not in the presence of an anti-sheep erythrocyte antibody and complement. These findings suggest that NO2- directly affects membrane damage in the presence of LysoPL.
authors.affiliation: Department of Environmental Biochemistry, School of Pharmaceutical Science, University of Shizuoka, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kanematsu
authors.forename: K
authors.initials: K
authors.lastname: Takagi
authors.forename: Y
authors.initials: Y
authors.lastname: Suketa
mesh_terms: D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects*; D004357:Drug Synergism; D004912:Erythrocytes / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D008244:Lysophosphatidylcholines / Q000494:pharmacology; D008246:Lysophospholipids / Q000494:pharmacology*; D008264:Macrophages / Q000378:metabolism; D008546:Melanoma, Experimental; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology*; D012756:Sheep; D012977:Sodium Nitrite / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D008244:Lysophosphatidylcholines; D008246:Lysophospholipids; D009599:Nitroprusside; D009569:Nitric Oxide; D012977:Sodium Nitrite