A novel plasma membrane quinone reductase and NAD(P)H:quinone oxidoreductase 1 are upregulated by serum withdrawal in human promyelocytic HL-60 cells.
We have studied changes in plasma membrane NAD(P)H:quinone oxidoreductases of HL-60 cells under serum withdrawal conditions, as a model to analyze cell responses to oxidative stress. Highly enriched plasma membrane fractions were obtained from cell homogenates. A major part of NADH-quinone oxidoreductase in the plasma membrane was insensitive to micromolar concentrations of dicumarol, a specific inhibitor of the NAD(P)H:quinone oxidoreductase 1 (NQOI, DT-diaphorase), and only a minor portion was characterized as DT-diaphorase. An enzyme with properties of a cytochrome b5 reductase accounted for most dicumarol-resistant quinone reductase activity in HL-60 plasma membranes. The enzyme used mainly NADH as donor, it reduced coenzyme Q0 through a one-electron mechanism with generation of superoxide, and its inhibition profile by p-hydroxymercuribenzoate was similar to that of authentic cytochrome b5 reductase. Both NQO1 and a novel dicumarol-insensitive quinone reductase that was not accounted by a cytochrome b5 reductase were significantly increased in plasma membranes after serum deprivation, showing a peak at 32 h of treatment. The reductase was specific for NADH, did not generate superoxide during quinone reduction, and was significantly resistant to p-hydroxymercuribenzoate. The function of this novel quinone reductase remains to be elucidated whereas dicumarol inhibition of NQO1 strongly potentiated growth arrest and decreased viability of HL-60 cells in the absence of serum. Our results demonstrate that upregulation of two-electron quinone reductases at the plasma membrane is a mechanism evoked by cells for defense against oxidative stress caused by serum withdrawal.
Forthoffer
Nathalie
N
Departamento de Biología Celular, Fisiología e Immunología, Facultad de Ciencias, Universidad de Córdoba, Spain.
Gómez-Díaz
Consuelo
C
Bello
Rosario I
RI
Burón
María I
MI
Martín
Sergio F
SF
Rodríguez-Aguilera
Juan C
JC
Navas
Plácido
P
Villalba
José M
JM
D000818:Animals; D002462:Cell Membrane / Q000201:enzymology*; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D003579:Cytochrome Reductases / Q000378:metabolism; D042966:Cytochrome-B(5) Reductase; D001728:Dicumarol / Q000494:pharmacology; D004790:Enzyme Induction; D018922:HL-60 Cells; D006801:Humans; D008954:Models, Biological; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D018384:Oxidative Stress; D011808:Quinone Reductases / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D013552:Swine; D014475:Uncoupling Agents / Q000494:pharmacology; D015854:Up-Regulation
D016895:Culture Media, Serum-Free; D014475:Uncoupling Agents; D001728:Dicumarol; D003579:Cytochrome Reductases; D042966:Cytochrome-B(5) Reductase; D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human; D011808:Quinone Reductases