Non-steroidal anti-inflammatory drugs suppress the ERK signaling pathway via block of Ras/c-Raf interaction and activation of MAP kinase phosphatases

Cell Signal. 2008 Jun;20(6):1134-41. doi: 10.1016/j.cellsig.2008.02.004. Epub 2008 Feb 15.


Non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to inhibit cancer cell growth, induce apoptosis and decrease tumor metastasis. We have previously reported that a NSAID NS398 repressed the expression of matrix metalloproteinase-2 (MMP-2) via inhibition of the extracellular signal-regulated kinase (ERK) signaling pathway. In this study, we investigate the underlying mechanism of this inhibition. In vitro kinase assay indicated that NS398 could not directly inhibit c-Raf, MEK1 and ERK enzymatic activity. We found that NS398 increased the inhibitory phosphorylation of Ser259 in c-Raf, attenuated membrane recruitment of c-Raf and inhibited Ras/c-Raf interaction to attenuate activation of this kinase. This is a general effect for NSAIDs because sulindac sulfide, aspirin and indomethacin also inhibited the binding of c-Raf to Ras. Immunofluorescent staining verified that NS398 reduced the serum-induced membrane recruitment of c-Raf in cells. However, overexpression of constitutively active c-Raf only partly reversed NS398-induced inhibition of MMP-2 expression. Interestingly, we found that NS398 up-regulated the expression of mitogen-activated protein kinase phosphatase-1 (MKP-1) and MKP-3. Block of MKP activity by sodium orthovanadate also partly counteracted the inhibitory effect of NS398. Overexpression of constitutively active c-Raf and treatment of sodium orthovanadate together completely reversed the inhibition of MMP-2 by NS398. Taken together, we conclude that NS398 and other NSAIDs act via inhibition of Ras/c-Raf interaction and up-regulation of MKPs to suppress the ERK-mediated signaling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology*
  • Antineoplastic Agents / pharmacology*
  • Cell Line, Tumor
  • Cell Membrane / enzymology
  • Dual Specificity Phosphatase 1 / metabolism
  • Dual Specificity Phosphatase 6 / metabolism
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Humans
  • MAP Kinase Kinase 1 / metabolism
  • MAP Kinase Signaling System / drug effects*
  • Matrix Metalloproteinase 2 / genetics*
  • Mitogen-Activated Protein Kinase Phosphatases / metabolism*
  • Nitrobenzenes / pharmacology*
  • Proto-Oncogene Proteins c-raf / antagonists & inhibitors*
  • Proto-Oncogene Proteins c-raf / chemistry
  • Proto-Oncogene Proteins c-raf / metabolism
  • Proto-Oncogene Proteins p21(ras) / antagonists & inhibitors*
  • Proto-Oncogene Proteins p21(ras) / metabolism
  • Serine / metabolism
  • Sulfonamides / pharmacology*
  • Vanadates / pharmacology


  • Anti-Inflammatory Agents, Non-Steroidal
  • Antineoplastic Agents
  • Nitrobenzenes
  • Sulfonamides
  • N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide
  • Vanadates
  • Serine
  • Proto-Oncogene Proteins c-raf
  • Extracellular Signal-Regulated MAP Kinases
  • MAP Kinase Kinase 1
  • Mitogen-Activated Protein Kinase Phosphatases
  • Dual Specificity Phosphatase 1
  • Dual Specificity Phosphatase 6
  • Matrix Metalloproteinase 2
  • Proto-Oncogene Proteins p21(ras)