Inhibition of Tumor Necrosis Factor-induced p42/p44 Mitogen-Activated Protein Kinase Activation by Sodium Salicylate

doi:10.1074/jbc.271.14.8089

Inhibition of Tumor Necrosis Factor-induced p42/p44 Mitogen-Activated Protein Kinase Activation by Sodium Salicylate (*)

From the (1)Departments of Microbiology and Pharmacology,
(2)Skirball Institute for Biomolecular Medicine, and Kaplan Cancer Center, New York University Medical Center, New York, New York 10016

** To whom correspondence should be addressed:
Dept. of Microbiology, New York University Medical Center, 550 First Ave., New York, NY 10016.
Tel.: 212-263-6756; Fax: 212-263-7933; vilcej01{at}mcrcr.med.nyu.edu.

Abstract

Tumor necrosis factor (TNF) activates both p42 and p44 mitogen-activated protein kinases (MAPK) in human FS-4 fibroblasts, cells for which TNF is mitogenic. We now show that TNF activates p42 MAPK in two cell lines whose growth is inhibited by TNF. A mutant TNF that binds only to the p55 TNF receptor (TNFR) produced a similar degree of activation as wild-type TNF in FS-4 fibroblasts, indicating that the p55 TNFR is sufficient to mediate p42/p44 MAPK activation. The upstream intracellular signals that couple the TNFR to MAPK activation are still poorly defined. We now show that neither phorbol ester-sensitive protein kinase C nor G link TNF to p42/p44 MAPK activation, because pretreatment of FS-4 cells with phorbol ester to down-regulate protein kinase C or pretreatment with pertussis toxin to block G does not inhibit p42/p44 MAPK activation by TNF. To further analyze MAPK activation in FS-4 cells, we compared p42/p44 MAPK activation by TNF and epidermal growth factor (EGF). While tyrosine phosphorylation of p42/p44 MAPK was detected almost immediately (30 s) after stimulating cells with EGF, TNF-induced tyrosine phosphorylation was detected only after a more prolonged time interval (initially detected at 5 min and peaking at 15-30 min). In addition, the anti-inflammatory drug sodium salicylate, previously demonstrated to inhibit NF-κB activation by TNF, blocked the activation of p42/p44 MAPK in response to TNF but not in response to EGF. These findings demonstrate that the TNF and EGF receptors utilize distinct signaling molecules to couple to MAPK activation. Elucidation of the mechanism whereby sodium salicylate blocks TNF-induced p42/p44 MAPK activation may help to clarify TNF-activated signaling pathways.

Footnotes

↵^§ Supported by a predoctoral fellowship from National Institutes of Health Training Grant 5-T32-CA09161.
↵^¶ Supported by NIDDK, National Institutes of Health, Grant 49207 and an American Diabetes Association research award.
↵* This work was supported by NCI, National Institutes of Health, Grant R35CA49731. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

TNF

tumor necrosis factor

EGF

epidermal growth factor

IL-1

interleukin 1

MAPK

mitogen-activated protein kinase

SAPK

stress-activated protein kinase

JNK

c-Jun N-terminal kinase

MBP

myelin basic protein

PT

pertussis toxin

LPA

lysophosphatidic acid

anti-Tyr(P)

anti-phosphotyrosine

ERK

extracellular signal-regulated kinase

MEK

MAPK-ERK kinase

MEKK

MEK kinase

FBS

fetal bovine serum

TPA

12-O-tetradecanoylphorbol-13-acetate

TNFR

TNF receptor

NF-κB

nuclear factor kappa B

PKC

protein kinase C

Tricine

N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine.
- Received November 27, 1995.