Contrasting effects of the protein kinase C inhibitor staurosporine on the interleukin-1 and phorbol ester activation pathways in the EL4-6.1 thymoma cell line.
EL 4-6.1 cells, variants of the murine EL4 thymoma cell line, can be activated by interleukin 1 (IL-1) or phorbol 12-myristate-13-acetate (PMA), or PMA+IL-1 to secrete interleukin 2 (IL-2) and interleukin 4 (IL-4) and to express the IL-2 receptor (IL-2R). To compare the different activation pathways, we examined the effects of staurosporine (STAR) and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7), two protein kinase C (PKC) inhibitors, on the induction of interleukin secretion and IL-2R expression in these cells. We report here that nanomolar concentrations of STAR strongly potentiated (20- to 30-fold) the production of IL-2 or IL-4, when EL 4-6.1 cells were induced by IL-1 alpha (or IL-1 beta) alone. By contrast, at identical concentrations, STAR dose-dependently inhibited the production of IL-2 and IL-4 resulting from PMA or PMA+IL-1 cell treatment. STAR also negatively affected the expression of IL-2R, which was dependent on PMA-sensitive PKC with either IL-1, PMA, or PMA+IL-1 stimulation. The changes in interleukin production and IL-2R expression in EL 4-6.1 activated cells were correlated with changes at the mRNA level measured by quantitative polymerase chain reaction (PCR). This finding suggests a pretranslational effect of the drug. At micromolar concentrations, H7 showed the same effects as STAR, but only increased IL-1-triggered interleukin secretions twofold. We observed that the action of PKC inhibitors did not result from modification of IL-1 receptor (IL-1R) expression in EL 4-6.1 cells. Thus, our data show that PKC inhibitors clearly distinguish between IL-1 and PMA stimulatory pathways. In addition, they suggest that the IL-1 stimulatory pathway involves PKC(s) [or other undefined kinase(s)] which regulate this pathway and differ from PKC(s) activated by PMA.
Dornand
J
J
Unité INSERM 65, U.S.T.L. CC100, Montpellier, France.
Bouaboula
M
M
d'Angeac
A D
AD
Favero
J
J
Shire
D
D
Casellas
P
P
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D007375:Interleukin-1 / Q000494:pharmacology*; D007376:Interleukin-2 / Q000235:genetics / Q000378:metabolism; D015847:Interleukin-4 / Q000235:genetics / Q000378:metabolism; D007546:Isoquinolines / Q000494:pharmacology; D051379:Mice; D008969:Molecular Sequence Data; D010879:Piperazines / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D015375:Receptors, Interleukin-2 / Q000032:analysis / Q000235:genetics / Q000502:physiology; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013945:Thymoma / Q000737:chemistry / Q000378:metabolism / Q000473:pathology*; D013953:Thymus Neoplasms / Q000737:chemistry / Q000378:metabolism / Q000473:pathology*; D014407:Tumor Cells, Cultured / Q000737:chemistry / Q000378:metabolism / Q000473:pathology
D000470:Alkaloids; D007375:Interleukin-1; D007376:Interleukin-2; D007546:Isoquinolines; D010879:Piperazines; D012333:RNA, Messenger; D015375:Receptors, Interleukin-2; D015847:Interleukin-4; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D011493:Protein Kinase C; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate