Isolation and characterization of a variant HL60 cell line defective in the activation of the NADPH oxidase by phorbol myristate acetate.
J Immunol
; 161(12): 6885-95, 1998 Dec 15.
Article
em En
| MEDLINE
| ID: mdl-9862721
ABSTRACT
Promyelocytic human leukemia HL60 cells can be differentiated into neutrophil-like cells that exhibit an NADPH oxidase activity through direct stimulation of protein kinase C (PKC) with PMA or through formyl peptide receptor activation. We have isolated a variant HL60 clone that exhibited a conditional PMA-induced oxidative response depending on the agent used for the differentiation. While cells differentiated with DMSO responded to either PMA or N-formyl peptide (N-formyl-Met-Leu-Phe-Lys or fMLFK), cells differentiated with dibutyryl-cAMP (Bt2cAMP) responded to fMLFK but very poorly to PMA. However, in Bt2cAMP-differentiated cells, the expression of the different PKC isoforms was similar to that observed in DMSO-differentiated cells. Moreover, PMA was able to induce a normal phosphorylation of the cytosolic factor p47phox and to fully activate extracellular signal-regulated kinases (Erk1/2). Interestingly, Bt2cAMP-differentiated cells exhibited a strong and sustained O2- production when costimulated with PMA and suboptimal concentrations of fMLFK which were, per se, ineffective. This sustained response was only slightly reduced by the conjunction of the mitogen-activated protein (MAP) kinase kinase (MEK) inhibitor PD98059 and wortmannin, a phosphatidylinositol-3 kinase (PI3K) inhibitor. Variant HL60 cells that were stably transfected with a constitutively active form of Rac1 were able, when differentiated with Bt2cAMP, to secrete oxidant following PMA stimulation. Altogether, the results suggest that, in addition to the phosphorylation of p47phox, the activation of NADPH oxidase requires the activation of a Rac protein through a pathway that diverges at a point upstream of MEK and that is independent of the activation of wortmannin sensitive PI3K.
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Base de dados:
MEDLINE
Assunto principal:
Acetato de Tetradecanoilforbol
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Transdução de Sinais
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Células HL-60
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NADPH Oxidases
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Proteínas de Ligação ao GTP
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Proteínas Quinases Ativadas por Mitógeno
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MAP Quinase Quinase Quinase 1
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Proteínas de Neoplasias
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
1998
Tipo de documento:
Article