ES936 stimulates DNA synthesis in HeLa cells independently on NAD(P)H:quinone oxidoreductase 1 inhibition, through a mechanism involving p38 MAPK.
The indolequinone ES936 (5-methoxy-1,2-dimethyl-3-[(4-nitrophenol)methyl]-indole-4,7-dione) is a potent mechanism-based inhibitor of NAD(P)H:quinone oxidoreductase 1 (NQO1). Here, we report that ES936 significantly stimulated thymidine incorporation in sparse cultures of human adenocarcinoma HeLa cells, but was without effect in dense cultures. Stimulation of DNA synthesis was not related with a DNA repair response because an increase in thymidine incorporation was not observed in cells treated with 2,5 bis-[1-aziridyl]-1,4 benzoquinone, a well-established antitumor quinone that causes DNA damage. Conversely, it was related with an increase of cell growth. NQO1 inhibition was not involved in ES936 stimulation of DNA synthesis, because the same response was observed in cells where NQO1 expression had been knocked down by small interfering RNA. Stimulation of DNA synthesis was reverted by treatment with ambroxol, a SOD mimetic, and by pyruvate, an efficient peroxide scavenger, supporting the involvement of alterations in cellular redox state. Pharmacological inhibition of p38 with either SB203580 or PD169316 completely abolished ES936-stimulated DNA synthesis, indicating the requirement of p38 activity. This is the first report that demonstrates the existence of an ES936-sensitive system which is separate from NQO1, modulating the redox state and cell growth in HeLa cells through a p38-dependent mechanism. Our results show that the effect ES936 exerts on DNA synthesis may be either positive or negative depending on the cellular context and growth conditions.
González-Aragón
David
D
Departamento de Biología Celular, Fisiología e Inmunología, Facultad de Ciencias, Universidad de Córdoba, Spain.
Alcaín
Francisco J
FJ
Ariza
Julia
J
Jódar
Laura
L
Barbarroja
Nuria
N
López-Pedrera
Chary
C
Villalba
José M
JM
D016475:3T3 Cells; D000551:Ambroxol / Q000494:pharmacology; D000818:Animals; D018938:Caco-2 Cells; D002453:Cell Cycle; D004247:DNA / Q000096:biosynthesis*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000378:metabolism; D016166:Free Radical Scavengers / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D045563:Indolequinones / Q000494:pharmacology*; D007700:Kinetics; D051379:Mice; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000037:antagonists & inhibitors* / Q000235:genetics; D011725:Pyridines / Q000494:pharmacology; D019289:Pyruvic Acid / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
C444919:5-methoxy-1,2-dimethyl-3-((4-nitrophenoxy)methyl)indole-4,7-dione; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D007093:Imidazoles; D045563:Indolequinones; D011725:Pyridines; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D000551:Ambroxol; D019289:Pyruvic Acid; D004247:DNA; D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human; D066246:ErbB Receptors; D048051:p38 Mitogen-Activated Protein Kinases; C408604:2-(4-nitrophenyl)-4-(4-fluorophenyl)-5-(4-pyridinyl)-1H-imidazole; C093642:SB 203580