Differential cytostatic effects of NO donors and NO producing cells.
A 3-h exposure to NO donors (spermine-NO, DETA-NO, or SNAP), or to NOS II-expressing cells (activated macrophages or EMT6 cells) reversibly inhibited DNA synthesis in K562 tumor cells. In GSH-depleted K562 cells, cytostasis remained reversible when induced by DETA-NO or NOS II activity, but became irreversible after exposure to spermine-NO or SNAP. Only SNAP and spermine-NO efficiently inhibited GAPDH, an enzyme with a critical thiol, in GSH-depleted cells. Thus, the irreversible cytostasis induced in GSH-depleted cells by spermine-NO or SNAP can be tentatively attributed to S-nitrosating or oxidizing species derived from NO. However, these species did not contribute significantly to the early antiproliferative effects of macrophages. Ribonucleotide reductase, a key enzyme in DNA synthesis. has been shown to be inhibited by NO. Supplementation of the medium with deoxyribonucleosides to bypass RNR inhibition restored DNA synthesis in target cells exposed to DETA-NO and NO-producing cells, but was inefficient for GSH-depleted cells previously submitted to spermine-NO or SNAP. These cells also exhibited a persistent depletion of the dATP pool. In conclusion, GSH depletion reveals striking qualitative differences in the nature of the toxic effectors released by various NO sources, questioning the significance of S-nitrosating or oxidizing nitrogen oxides in NOS II-dependent cytostasis.
Lemaire
G
G
CNRS, UMR 8619, Université Paris Sud, Orsay, France. genevieve.lemaire@bbmpc.u-psud.fr
Alvarez-Pachon
F J
FJ
Beuneu
C
C
Lepoivre
M
M
Petit
J F
JF
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004273:DNA, Neoplasm / Q000096:biosynthesis; D003838:Deoxyadenine Nucleotides / Q000378:metabolism; D003854:Deoxyribonucleotides / Q000378:metabolism; D005609:Free Radicals / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000037:antagonists & inhibitors; D006801:Humans; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D009374:Neoplasms, Experimental / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D009569:Nitric Oxide / Q000096:biosynthesis*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D009589:Nitrogen Oxides; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D012264:Ribonucleotide Reductases / Q000378:metabolism; D013096:Spermine / Q000031:analogs & derivatives / Q000494:pharmacology; D014226:Triazenes / Q000494:pharmacology; D014407:Tumor Cells, Cultured
C105351:1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene; D000970:Antineoplastic Agents; D004273:DNA, Neoplasm; D003838:Deoxyadenine Nucleotides; D003854:Deoxyribonucleotides; D005609:Free Radicals; D020030:Nitric Oxide Donors; D009589:Nitrogen Oxides; C110881:S-nitro-N-acetylpenicillamine; D014226:Triazenes; C091861:spermine nitric oxide complex; D013096:Spermine; D009569:Nitric Oxide; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D012264:Ribonucleotide Reductases; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D005978:Glutathione; D010396:Penicillamine; C026600:2'-deoxyadenosine triphosphate