Activation of plasminogen activator inhibitor-1 synthesis by phorbol esters in human promyelocyte HL-60--roles of PCKbeta and MAPK p42.
HL-60 cells treated by PMA develop the monocyte adherent phenotype and synthesize plasminogen activator inhibitor type-1 (PAI-1). We focused our study on the identification of the PMA-activated protein kinase C (PKC) isoform and its downstream transduction pathway activating PAI-1 synthesis. Acquisition of the monocytic phenotype was evidenced by cell adherence (90-95%) and a sharp increase of CD 36 and receptor for urokinase plasminogen activator (uPAR) surface expression. Ro 31-8220, a specific inhibitor of PKC, prevented PMA-induced PAI-1 synthesis (mRNA and protein levels) and cell adhesion. To identify the PKC isoform, we took advantage of the HL-525 cell line, an HL-60 cell variant deficient in PKCbeta gene expression. This defect prevents PMA to induce the differentiation process. HL-525 stimulated by PMA did not synthesize PAI-1 nor become adherent. However, in HL-525 cells either pretreated by retinoic acid that reinduces PKCbeta gene expression or transfected with PKCbeta cDNA, PMA significantly activated PAI-1 synthesis and adhesion of cells. Immunoblotting of active Mitogen Activated Protein Kinase (MAPK) p42/p44 in HL-60 cells showed a preferential and sustained activation of the p42 isoform by PMA over the p44 isoform. Ro 31-8220 significantly attenuated this activation. PD 098059 and U0126, both highly specific MEK inhibitors, efficiently prevented PMA-induced PAI-1 synthesis (mRNA and protein levels) and cell adhesion whereas SB203580, a specific inhibitor of stress-activated MAPK p38, did not. Results obtained from HL-60 and HL-525 cells indicate that the PMA-activated transduction pathway of uPAR expression involves a PKC isoform other than PKCbeta. In conclusion, we propose that the pathway PKCbeta-MEK-MAPK p42 is a potential linear route for PAI-1 synthesis leading to morphological changes and adherence linked to PMA-induced differentiation in HL-60 cells.
Lopez
S
S
Laboratoire d'Hématologie, Faculté de Médecine, Marseille, France.
Peiretti
F
F
Morange
P
P
Laouar
A
A
Fossat
C
C
Bonardo
B
B
Huberman
E
E
Juhan-Vague
I
I
Nalbone
G
G
D002273:Carcinogens / Q000494:pharmacology*; D018922:HL-60 Cells; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D048728:MAP Kinase Kinase Kinase 1; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis*; D011493:Protein Kinase C / Q000378:metabolism*; D064546:Protein Kinase C beta; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D002273:Carcinogens; D007527:Isoenzymes; D017395:Plasminogen Activator Inhibitor 1; D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D019950:Mitogen-Activated Protein Kinase 1; D048728:MAP Kinase Kinase Kinase 1; C482576:MAP3K1 protein, human; D013755:Tetradecanoylphorbol Acetate