4-hydroxy nimesulide effects on mitochondria and HepG2 cells. A comparison with nimesulide.
We previously reported that the nonsteroidal anti-inflammatory drug, nimesulide (N-[4-nitro-2-phenoxyphenyl]-methanesulfonamide), is an uncoupler and oxidizes NAD(P)H in isolated rat liver mitochondria, triggering mitochondrial Ca2+ efflux or, if this effect is inhibited, eliciting mitochondrial permeability transition (Mingatto et al., Br. J. Pharmacol. 131:1154-1160, 2000). We presently demonstrated that nimesulide's hydroxylated metabolite (4-hydroxy nimesulide) lacks the uncoupling property of the parent drug, while keeping its ability to oxidize mitochondrial NADPH. In the presence of 10 microM Ca2+, low (5-50 microM) concentrations of 4-hydroxy nimesulide elicited mitochondrial permeability transition, as assessed by cyclosporin A-sensitive mitochondrial swelling, associated with mitochondrial Ca2+ efflux/membrane potential dissipation (Deltapsi), apparently occurring on account of the oxidation of mitochondrial protein thiols; no involvement of reactive oxygen species was observed. While nimesulide (0.5 or 1 mM, 30 h incubation) did not lead to significant HepG2 cell death, 4-hydroxy nimesulide caused a low extent (approximately 15%) of cell necrosis, partly prevented by cyclosporine A, suggesting the involvement of mitochondrial permeability transition. Both nimesulide and 4-hydroxy nimesulide caused NADPH oxidation and Deltapsi dissipation in HepG2 cells. Because such Deltapsi dissipation induced by the metabolite was almost completely inhibited by cyclosporine A, it probably results from the mitochondrial permeability transition. Therefore, mitochondrial permeability transition, in apparent association with NADPH oxidation, constitutes the most probable cause of HepG2 cell death elicited by 4-hydroxy nimesulide.
Freitas
Clayton S
CS
Departamento de Física e Química, Faculdade de Ciências Farmacêuticas Rib. Preto, Universidade de São Paulo, Av. Café s/n, 14040-903 Ribeirão Preto, São Paulo, Brazil.
Dorta
Daniel J
DJ
Pardo-Andreu
Gilberto L
GL
Pestana
Cezar R
CR
Tudella
Valeria G
VG
Mingatto
Fábio E
FE
Uyemura
Sérgio A
SA
Santos
Antonio C
AC
Curti
Carlos
C
D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D019803:Glutathione Disulfide / Q000378:metabolism; D006801:Humans; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000502:physiology; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D010539:Permeability / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology*
D013438:Sulfhydryl Compounds; D013449:Sulfonamides; C055891:4-nitro-2-(4'-hydroxyphenoxy)methanesulfonanilide; D009249:NADP; D005978:Glutathione; D019803:Glutathione Disulfide; C012655:nimesulide